Je Souhaite Remercier

Je Remercie

Mme Virgine Mouillet

Mme Ann Vanelstraete

M François Olard

Stéphane

Nadège Olivier

Sebastien Gilles

Jean- Phillippe Julien

Cedric Je N'

Keywords: Durability, Recycling, RAP, Mechanical performance, Foaming process, warm mix asphalt, ageing

avoir accepté le rôle d'examinateurs. Je vous remercie beaucoup pour le temps consacré et votre disponibilité.

Je suis également très reconnaissant envers les différentes personnes qui ont acceptées de prendre du temps pour participer à mes comités de suivi et dont j'ai apprécié les remarques sur mon

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PEREZ-MARTINEZ, Miguel DURABILITE DES ENROBES TIEDES INTEGRANT DES RECYCLES

Résumé

Les routes constituent le moyen de transport le plus utilisé dans le monde et le développement d'un pays est souvent mesuré en terme de kilométrage total des routes revêtues. Les chaussées sont essentielles à notre réseau social et l'enrobé bitumineux est le matériau le plus utilisé pour leur fabrication. À l'heure actuelle, le réseau routier européen n'est plus en forte croissance et nécessite surtout un entretien. Dans un contexte de développement durable de plus en plus exigeant, la route pourrait donc représenter sa propre source d'approvisionnement en tirant parti du recyclage. Elle doit aussi limiter les quantités d'énergies et de ressources naturelles nécessaires à sa propre maintenance.

La combinaison des techniques d'enrobés tièdes (WMA) et de taux de recyclage élevés d'agrégats d'enrobés (RAP) apparaît comme une solution permettant d'économiser à la fois l'énergie et les ressources naturelles. Mais sa durabilité doit être vérifiée. Un programme expérimental a donc été mis en place pour montrer l'évolution des performances de ces enrobés bitumineux avec le temps, mettant en évidence le vieillissement essentiellement lié à la fraction bitumineuse. A l'échelle du bitume, l'évaluation à long terme est effectuée notamment en appliquant la δ-méthode et en comparant avec les mesures de masses moléculaires par GPC à la fois sur des échantillons modèles à teneur en asphaltènes contrôlée et sur des échantillons de laboratoire. A l'échelle de l'enrobé bitumineux, une étude comparative a été réalisée entre un enrobé à chaud traditionnel et des WMAs incluant 0% ou 50% de RAP soumis à une procédure de vieillissement en laboratoire. Les performances à long terme des mélanges sont comparées au moyen d'essais de module complexe et de fatigue.

Les résultats montrent une relation entre l'évolution de la structure des bitumes par vieillissement et les performances mécaniques. Le vieillissement à court terme au moment de la fabrication est beaucoup moins marqué pour les procédés tièdes. Après vieillissement à long terme, les tendances générales sont similaires pour tous les procédés.

Mots-clés : Durabilité, Enrobé tièdes, Agrégats d'enrobé, Recyclage, Performance mécanique, Moussage de bitume, Vieillisement Visa du Directeur de Recherche ~ iv ~ I would like to express my gratitude to Davide Lo Presti and Gordon Airey for letting me to be part of this project, and to all supervisors, associate partners and fellows for their support and encouragement during these three years. Thanks to Ana and Luca, this project without you would not have been the same.

También quiero dar las gracias al profesor Pedro Partal, por abrirme las puertas del Laboratorio de Fluidos Complejos de la Universidad de Huelva. Por su paciencia, disponibilidad y por permitirme aprender de un campo totalmente desconocido para mí.

Igualmente quiero agradecer a la profesora Mayca Rubio el haberme mostrado y despertado la curiosidad investigadora cuando terminé la carrera, así como la confianza que me has dado durante todos estos años.

A Fernando Moreno, no solo por el tiempo pasado en el LabIC sino por todos los años que ya llevamos juntos. A todo el LabIC, siempre formará parte de mi presente y pasado, con especial cariño a Gema, Miguel y Jesús, esta tesis también es tuya.

Gracias a toda mi familia, abuelos, tíos y primos, que aunque dudo mucho que ninguno sea capaz de decir a lo que me dedico, siempre habéis estado ahí apoyándome y animándome. Gracias por vuestras visitas a Nantes en estos tres años, ha sido maravilloso teneros en casa.

A mi familia Hurtado Fernández, Nanni, Pepe, Pablo, Ana y Alex, gracias por hacerme uno más de la familia, y por el apoyo tan grande que me habéis proporcionado y más con la distancia que nos ha separado. Y a los tres sobrinos tan fantásticos que siempre han tenido una sonrisa para su tito el exiliado.

A mis hermanos, Belén y Javi, por la paciencia y cariño que me habéis transmitido durante toda vuestra vida, es lo que tiene que seáis más pequeños. He aprendido mucho de vosotros y me habéis hecho mejor persona. Gracias también a Manu por toda la ayuda que siempre nos das. Y a ti también Bea, gracias especiales por traernos a la pequeña Lucía, que tanta alegría ha traído a la familia.

Gracias a mis padres, Jose Antonio y Nieves. Esto es parte vuestra también, por todo lo que me habéis dado y nunca os podré agradecer lo suficiente. Por vuestro tiempo, por vuestros consejos, paciencia, ánimos y cariños. Por la educación que nos habéis dado, por haberme permitido viajar, conocer mundo y hacerme creer que todo lo que quisiera lo podría conseguir trabajando duro y siendo perseverante, como habéis hecho vosotros siempre.

Elena, llevo un tercio de mi vida contigo, no tengo palabras para agradecerte todo lo que has hecho por mí y todo lo que me hemos pasado. Gracias por darme la oportunidad de disfrutar de la vida a tu lado. Gracias por la paciencia que has tenido durante esta tesis, todo el tiempo que le he dedicado te lo he tenido que quitar a ti. Gracias por darme a Gonzalo, porque es la muestra más grande de lo que somos.

Gracias a todos, thanks to everyone, merci à tous.

Ethics Code

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Ethics Code

Along with the right to use sources of information to create or to produce anything, comes the obligation to comply with legal and ethical rules. Copyright compliance and honesty prohibit the passing off of another's work as one's own, whether intentionally or by omission.

The abundance of documents available online, for which content can be appropriated via a simple "copy and paste", gives renewed impetus to the issue of the correct use of bibliographic sources and references.

Thus, all of the following examples, drawn from the library of the Université de Québec à Montréal (UQAM), constitute plagiarism:

-Copying word for word a passage of a book, magazine or Web page without placing it within quotation marks and/or without stating the source; -Including within a piece of work images, graphs, data etc. from external sources without indicating their source; -Summarising an author's original idea in one's own words, but omitting the source; -Translating in part or in whole a text without indicating its source; -Re-using work produced in another class without prior authorisation from the teacher; -Using another's work and presenting it as one's own (even with the person's permission).

Not only is plagiarism a lie to oneself, it also constitutes gross misconduct towards others. For this reason and according to a policy to prevent plagiarism, based on information and training, the École Centrale Nantes requires all producers of documentation (students and personnel) to undertake to carefully distinguish at all times between their own work and ideas and those borrowed from others. Sources and authors must be systematically cited.

École Centrale Nantes reserves the right to search for instances of plagiarism, including with the help of electronic tools. The perpetrators may face disciplinary or even criminal sanctions.

I undertake to distinguish explicitly in my academic and/or professional work, that which I borrowed from that which I produced, throughout my activities within and in the name of École Centrale Nantes.  Providing advanced characterisation of recycled and reused materials generated from road and railway infrastructure and/or other production processes for use in road and railway infrastructure.

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List of Figures

List of Tables

 Developing detailed material modelling and design approaches for immediate uptake by industrial stakeholders working in the area of transport infrastructure.

 Developing and refining estimation tools so that industry can assess where it currently stands in key sustainability indicators and determine how much it can improve using lowenergy and more recycled materials. Such estimation tools will allow industry, road and railway agencies to recognize the sustainability of different construction techniques, materials and methods, as well as the potential cost and resource savings enabling the deployment of more sustainable technologies.

Work packages

The project is divided in three work packages according to the main objectives of the project:

The study of sustainable pavement solutions, the study of sustainable railway technologies, and the integration of both in a tool for decision making. This software will allow users to decide the most sustainable solution on their projects.

Work package 1 is focuses on investigating several sustainable technologies for road pavements.

The six different projects are listed below. In black the name of the project that has inspired this thesis work.

 Project 1.1 (ESR1) :

Pavement design for cold in-situ recycled materials



Justification of the thesis

In this new era made of invisible communication networks where we are all connected worldwide, roads still remain as the most widely used mode of transportation in the world. Even more when countries development is often measured in terms of its total paved roads mileage.

Road construction is a major industry in developing countries. Besides, as the infrastructure matures, it will be a major industry in developed countries as well [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF]. Pavements are an essential part of our social network and asphalt concrete is the main material used for manufacturing them. Transport in Europe moved a total of 1.3 billion euros, which 46.6% Durabilité des enrobés tièdes intégrant des recyclés -4 -comprised any kind of pavement uses, giving a total impact of roads of 0.6 billion euros on the overall transport system (Data from European Road Federation, 2011 [START_REF]European Road Federation[END_REF]).

Currently, the European road network is not much growing anymore (5,525 million km of paved roads [START_REF]European Road Federation[END_REF]) and mostly needs maintenance. The budget for road maintenance by the EU is been decreasing since 2008. This trend resumed in Figure 1-2 could endanger the future of the infrastructure system.

In a context of increasing demand of performance and durability of asphalt mixtures, a sustainable, durable and economical conception is required. Indeed, it could be oriented towards a self-sufficient road providing its own raw materials through recycling while limiting the use of energy and other natural resources for its maintenance.

Figure 1-2 Evolution of road infrastructure and road maintenance i nvestment in selected countries [START_REF]European Road Federation[END_REF] Towards a saving in energy consumption and an emission limitation: warm processes Conventionally, asphalt mixtures production (HMA) for road construction involves high manufacturing temperatures (~ 160°C) which require a high consumption of energy. These high temperatures also lead to emissions of volatile organic compounds (VOCs) likely to harm the health of workers in a context of greatly reduced social acceptability of occupational risks [START_REF] Pérez-Martínez | Analysis of cleaner technologies based on waxes and surfactant additives in road construction[END_REF].

Solutions at lower temperatures have been developed by the road industry but, unlike in the United States, these so-called "warm" (WMA) procedures are struggling to establish themselves in Europe. In general, these types of mixtures present several benefits such as reductions on fuel consumption and emissions, as well as an increase of the hauling distances and extended paving period. On the other hand, they present potential problems linked to plastic deformations, water sensitivity and durability [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF][START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF].

Towards the preservation of resources: recycling

European road network could be described as mature in the sense that, after a continuous increase throughout the last century, it no longer requires significant extension. This stabilization is translated into an increasing proportion of road maintenance works to ensure the sustainability of the existing system.

Additionally, by evolving from a production policy to a maintenance approach, road construction has opened up widely for recycling. Indeed, the degradation of a pavement structure does not mean irreversible degradation of the properties of the materials which constitute it. With adapted techniques, these materials after the end of the pavements service life can be recycled in new structures.

Durabilité des enrobés tièdes intégrant des recyclés -6 -

In consequence, the ideal situation would include a self-sufficient system. So then, it would produce necessary materials for its maintenance without subtraction from natural resources. In Then, RAP addition is usually limited in the interest of not modifying the properties of the new mixture. Consequently, the remarkable specific properties of the reclaimed aggregates are not fully engaged and then the rates of addition restricted.

Chapter 1 -Introduction -7 -

A new track of progress: Recycling and Warm mix asphalts techniques combination

The environmental impact of road construction could still be significantly improved by parallel improvements in recycling techniques and warm mix asphalts procedures. But then again the margin for progress seems much more important if the two developments are combined. It is therefore necessary to redefine and make more reliable the recycling techniques in the specific context of the WMA processes.

Separately, WMA procedures and RAP addition to the mixtures have been widely used. However, innovation related to their combined application is still ambiguous, mainly because of their long term performance. Both techniques present their own benefits. They are considered more environmentally friendly in terms of reduced greenhouse gases emissions, extraction of natural aggregates or disposal in landfill of old pavements [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF][START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF]. On the other hand, concerning durability, rutting or low temperature resistance, their service life could compromise [START_REF] Copeland | Reclaimed Asphalt Pavement in Asphalt Mixtures: State of the Practice[END_REF][START_REF] Hamzah | Evaluation of the potential of Sasobit® to reduce required heat energy and CO2 emission in the asphalt industry[END_REF][START_REF] Rubio | Comparative analysis of emissions from the manufacture and use of hot and half-warm mix asphalt[END_REF][START_REF] Rubio-Gámez | Mechanical properties of hot bituminous mixes manufactured with recycled aggregate of Silestone(R) waste[END_REF].

Objectives

The main objective of this research is to determine the possible application of high rates of reclaimed asphalt pavement under warm mix asphalt technique for providing a sustainable solution to road construction. With the aim of developing this objective in more detail, this thesis has the following secondary operational goals:

i.

The characterization of ageing evolution through the increment of asphaltenes phase concentration on bitumen,

ii.

The study and analysis of mechanical performances in laboratory of a conventional hot mix asphalt in order to serve as reference mixture,

iii.

The addition of 50% of reclaimed asphalt mixture when manufacturing mixtures under foaming warm mix asphalt technique, iv.

Assessment of ageing or rejuvenation rheological behaviour of bitumen through the δ-method analysis, v.

Influence of bitumen evolution on Huet-Such model parameters, vi. And finally, establishing a possible relationship between bitumen properties and asphalt mixture performances.

Durabilité des enrobés tièdes intégrant des recyclés -8 -

Scope of research

The scope of the thesis consists of a literature review followed by three chapters, each of them focusing on one of the three objectives of the thesis, bitumen, asphalt mixtures and their possible relationship. A final chapter presents the conclusions and perspectives for future research works.

The literature review describes in general terms the asphalt mixtures, their composition and the different existing levels of testing. Warm mix asphalt techniques and reclaimed asphalt pavements are described and presented. Moreover, deeper study is carried out with regard to physico-chemical structure, properties and characteristics of bitumen and its ageing procedures.

The main objectives of the thesis have been divided in three chapters. The first one (Chapter 3),

focuses on the study of bitumen. The physico-chemical response of the material is characterized with regards to the evolution of the asphaltene content during ageing. So, in order to understand these effects, laboratory ageing procedures are performed.

Additionally, bitumen mechanical behaviour is usually evaluated by standard empirical tests (penetrability and softening point temperature). These tests are used to classify bitumen according to their consistency. However, they do not provide the intrinsic properties of bitumen.

For these reasons, chemical and physical characterisation is carried out. For the chemical evaluation, the Fourier transform infrared analysis, thermogravimetric analysis and thin layer chromatography for SARA fractions determination are performed. Whereas bitumen solubility in n-heptane, gel permeation chromatography, atomic force microscopy and rheological testing are used to evaluate the physical evolution and performance of the materials.

In the second chapter (Chapter 4), mechanical performance evolution of asphalt mixtures is developed. Ageing current knowledge is essentially gained from practical experience on traditional asphalt mixes and typically on HMA. However, as the WMA are relatively new techniques, so little is known about their ageing evolution and end of life state, especially when they are combined with RAP.

Within this framework, the objective of this chapter is to study and compare two WMA techniques when 50% of RAP is added to the mixture. For that reason, an ageing protocol is followed within the lines proposed by the RILEM TC-ATB TG5, consisting of two separate ageing phases. Mixtures long term related performances are compared by means of complex modulus and fatigue testing. Penetration and ring and ball tests are undertaken on the recovered bitumen. Ageing evolution is also characterised by the Fourier Transform Infrared analysis and evaluated through the δ-method analysis.

Chapter 1 -Introduction -9 -Finally, the last chapter is focused on comparing the mechanical related performance of the mixtures and its bitumen evolution. The evaluation is developed in terms of SHRP parameters, δ-method parallel analysis of curves and relation between critical design factors.

Introduction (Français)

Terminology

In British English bitumen, in American English asphalt, in French bitume and in Spanish betún, but all of them from the Latin word bitümen. The etymology of the word asphalt comes from the early 14 th century. It defined asphalt as a hard, resinous mineral pitch found originally in Biblical lands. From the Late Latin asphaltum, and from the Greek word asphaltos "asphalt, bitumen".

Another theory holds it to be from Greek a-"not" + -sphaltos "able to be thrown down". Thus taken as verbal adjective of sphallein "to throw down", in reference to a use of the material in construction. Later on, in the mid of the 15 th century the word bitumen appeared, from Latin bitumen "asphalt", probably from Celtic *betu-"birch, birch resin" (compare Gaulish betulla "birch," used by Pliny for the tree supposedly the source of bitumen).

The Collins Dictionary defines bitumen as any of various viscous or solid impure mixtures of hydrocarbons that occur naturally in asphalt, tar, mineral waxes, etc, used as a road surfacing and roofing material. Also, the American Society of Testing Materials (ASTM) defines asphalt as "a dark brown to black cementitious material in which the predominant constituents are bitumens which occur in nature or are obtained in the petroleum processing".

In American English, the refined residue of the distillation process of a selected crude oil is called asphalt or asphalt cement. In Europe in contrast, asphalt has a different meaning, and it usually refers to the asphalt mixture, which combines bitumen with stone aggregates and is used as a paving material. So, outside of the United States, that black product is often called bitumen.

In this thesis, European terms will be followed, bitumen for binder and asphalt mixture to the combination of bitumen and aggregates.

Asphalt mixtures

Road pavements are structures formed by a set of several centimetres thickness of horizontally superposed compacted layers, and composed of different materials [START_REF] Corté | Matériaux routiers bitumineux 1: Description et propriétés des constituants[END_REF]. Asphalt pavements are expected to perform adequately and be durable during their service life, without suffering any deterioration that could compromise safety, users comfort or the proper integrity of the road. In order to ensure this, pavements must be designed, constructed, maintained, and managed

properly [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF].

Durabilité des enrobés tièdes intégrant des recyclés -14 -Commonly, the structure is divided in three layers of asphalt mixtures. From the bottom to the top are base, binder and surface layer. The base layer needs to be strong enough in flexion resistance and bearing capacity, but standard requirements are not the same as for the binder and surface mixtures. The binder layer is very similar to the surface layer, and it usually consists on the same type of mixture but with larger aggregates size. Finally, the layer on the surface of the pavement has to resist the maximum solicitations and the changing atmospheric conditions (low temperatures, rain, heat, solar radiation…) [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF]. Asphalt mixtures are composite materials. They are a combination of aggregates of different sizes (gravel, sand and filler) and binder from hydro-carbonate nature (i.e. bitumen). So that, all the aggregates particles get coated by a continuous and homogeneous thin film, providing the blend an adhesive effect that will keep it together [START_REF] Kraemer | Ingenieria de Carreteras[END_REF].

Materials

Aggregates and filler

Aggregates provide the resistance to the system. They are particles from different nature and with different sizes that usually come from quarries operations. Their performance depends on both their physio-chemical composition and their granulometry distribution. Among the aggregate properties it could be highlighted their porosity, specific gravity, surface texture, shape, hardness and their alkalinity or acidity [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF].

On the other hand, filler is in charge of cohesion, and it is defined as the smallest fraction. This means that is the material that passes the 0.063 mm width sieve (EN 13043). Filler can come from a natural source, from the crushing of aggregates or be an added material, which is the usually employed. In general, aggregates and filler represent between 94%-96% of the mixture by weight and 83%-87% by volume [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF].

Hydrocarbon binder

Hydrocarbon binders are agglomerates of complex hydrocarbon chains with thermoplastic properties [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF]. There are different types of hydrocarbon binders, such as asphaltic bitumens, fluxed bitumens or bituminous emulsions. Bitumen usually represents between 4%-6% by weight and 8%-12% by volume in the total mixture. This part will be further described in detail on Section 2.5.

Air voids content

Although it is not a direct design input parameter most of the asphalt mixtures are designed to have certain air voids content after layout and compaction. They represent in regular mixtures between 3%-8% of the system by volume, but they can rise up to 20% in porous asphalt mixtures [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF].

Durabilité des enrobés tièdes intégrant des recyclés -16 -

Properties of asphalt mixtures

Every asphalt mixture has their own intrinsic properties, so it is difficult to design an asphalt mixture that will fulfil all the properties due to the antagonism between some of them. However, the principal properties of an asphalt mixture and pavement could be the followings [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF]:

 Stability. Capacity of the mixture to resist loads and strains on the tolerable limits. This mechanical resistance is the sum of the one produced by internal aggregates friction and the cohesion provided by the bitumen.

 Resistance to plastic deformations. The accumulation of small plastic deformations due to the repetitive loading at low speed and high temperature might happen when the characteristics of the mixture have not been well defined. This may lead to the damage of the pavement. For this purpose special attention should be taken on the filler/bitumen relation as well as on the chosen bitumen and the angularity of the aggregate.

 Ravelling. It is the loss of particles due to traffic loading when the resistance of the asphalt mixture is only provided by their internal friction. In order to avoid this anomaly the design of the mixture needs to provide enough cohesion and resistant to the action of water.

 Skid resistance. It is determined by the polishing resistance of the aggregates. It is necessary to choose aggregates with high polishing resistance and design a granulometry curve that may provide the adequate surface roughness texture.

 Impermeability. In order to avoid the presence of water on the granular layers underneath at least one of the pavement layers must be impermeable.

 Durability. Asphalt mixture layers, especially surface layers, need to be resistant to the action of traffic, solar radiation, bitumen ageing, and freeze and thaw cycles or vehicles loss of fuel…  Fatigue resistance. Repetitive loading produce the progressive loss of performance of the material.

The exposure of asphalt mixtures during service to heavy traffic loads and climate effects would cause a deterioration of their properties that may result in the pavements loss of functionality.

The different pathologies that road pavements could suffer can be classified in four principal groups as follows [START_REF] Chailleux | A mathematical-based master-curve construction method applied to complex modulus of bituminous materials[END_REF]:

 Material displacements:
 Bleeding, it is the appearance of bitumen on the pavement surface.

 Delamination, separation of layers, mainly top wearing course and the layer underneath.

Chapter 2 -Literature Review -17 - Material loss:

 Potholes, bow-shaped holes.

 Ravelling, loss of bitumen and displacement of aggregates.

 Aggregates polishing, due to wearing away of the surface of the asphalt mixture.

 Deformations:

 Corrugations, as a result of lack of stability on the mixture.

 Rutting, plastic deformations.

 Cracking:

 Fatigue cracks, due to repeated cycles loading.

 Block cracking, mainly due to shrinkage of the asphalt mixture.

 Edge cracks.

 Longitudinal joint cracks.

 Reflective cracking.

 Slippage cracks.

 Thermal cracks.

Viscoelasticity of asphalt mixtures

Due to the nature of bitumen, the mechanical performance of the asphalt mixture depends not only on the magnitude of the stress applied, but also how this stress is applied (particularly the speed and the temperature of loading). When the asphalt mixture is stressed on compression the friction between particles is opposite to their relative displacement. On the other hand, when the asphalt mixture is submitted to traction stress it is the bitumen which resists [START_REF] Moreno-Navarro | Design of a laboratory test method for the analysis of asphalt mix response to fatigue cracking[END_REF].

So then, asphalt mixtures could respond from a totally elastic behaviour (at cold temperatures and high loading speed rates, or high frequency) to a more viscous behaviour (at higher temperature and lower loading speed rates). In general, it could be assumed that asphalt mixtures behaviour is a sum of both responses, elastoplastic response for the aggregates and viscous response for the bitumen, evolving to a visco-elasto-plastic behaviour for the system, the asphalt mixture [START_REF] Kraemer | Ingenieria de Carreteras[END_REF][START_REF] Moreno-Navarro | Design of a laboratory test method for the analysis of asphalt mix response to fatigue cracking[END_REF].

To have elastic response means that when a material with linear elastic characteristics is loaded it responds with in an immediate deformation. Thus, if the load increases linearly, deformation does as well. But once the load is removed, deformation is recovered and the material recovers its original position. Hooke postulated it in 1678 'ut tension sic vis', that means, such us the extension so is the force.

Durabilité des enrobés tièdes intégrant des recyclés -18 -

The proportionality factor that relates stress (loads) and strain (deformations) depends on the origins of the material, temperature, pressure and the type of stress applied. As so, different elastic modulus can be defined and considered constants for some solid materials [START_REF] Woldekidan | Response modelling of bitumen, bituminous mastic and mortar[END_REF]:

- In the case of only bitumen it is assumed a value of ν = 0.5 as it is considered non-compressible at low temperatures [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF].

In contrast, when the deformation increases linearly for a constant load the material is classified as viscous. Thus, the strain on the material remains after load removal. The fundamental equation for this type of materials is the Newton's viscosity law τ = η • 𝛾. In both cases, elastic and viscous, if the material follows Hooke's or Newton's law it can be considered as linear elastic or linear viscous. Otherwise it is called nonlinear [START_REF] Woldekidan | Response modelling of bitumen, bituminous mastic and mortar[END_REF]. Then, viscoelastic materials as asphalt mixtures present characteristics from both behaviours.

Firstly an immediate deformation against constants loads, followed by a continuously increasing strain with time. When the load is removed the elastic deformation is recovered while there is a rate of deformation that remains, it is called viscous deformation [START_REF] Woldekidan | Response modelling of bitumen, bituminous mastic and mortar[END_REF]. by their corresponding phase angle (). In this last case, this type of representation shows the different performances at high temperatures or low frequencies.

Time Temperature Superposition Principle

Another way of presenting complex modulus results is by their master curves. These type of curves let determining the complex modulus of the mixture or bitumen at frequencies or temperatures non reachable by experimental testing. In this case it is necessary to use the Time Temperature Superposition Principle (TTSP) [START_REF] Williams | The temperature dependence of relaxation mechanisms in amorphous polymers and other glass form liquids[END_REF]. This principle considers that longer periods of loading (or reduced testing frequencies) results in the same effects on the mechanical properties than an increase on the testing temperature.

This principle is based on the idea that the material structure do not evolve within a change of temperature or with the loading time [START_REF] Williams | The temperature dependence of relaxation mechanisms in amorphous polymers and other glass form liquids[END_REF]. Thus, considering bitumens as thermorheologically simple materials [START_REF] Corté | Matériaux routiers bitumineux 1: Description et propriétés des constituants[END_REF], this principle is applicable to the most of them. Considering the Black space as a singular curve that implies the absence of structural changes during a temperature variation. Then, the same pair of complex modulus and phase angle values could be obtained from different frequency-temperature sets, so that: with aTref = 1. Several formulas have been proposed for obtaining these logs (aT). However, two equations are the most commonly used, the Arrhenius law [START_REF] Arrhenius | On the reaction velocity of the inversion of cane sugar by acids[END_REF] and the William-Landel-Ferry [START_REF] Williams | The temperature dependence of relaxation mechanisms in amorphous polymers and other glass form liquids[END_REF]. In this document the WLF equation is chosen for the construction of the master curves. C1 and C2 are constants that depend on the material and the reference temperature, Tref.

) , ( * ) , ( * ) , ( * 2 2 1 1 i i f T E f T E f T E   )) , (( , ( * ) , ( * i i ref i i f T T E f T E  
) (

) ( log C T T T T C a ref ref T     
Based on a series of hypotheses on the mechanical response of the material, in particular Boltzmann's superposition principle and the principle of causality, Chailleux et al. in 2006 [14] have shown that the expressions of modulus and compliance (1/J'') are analytic in the lower part of the complex frequency domain.

It has been demonstrated that the real and imaginary parts of a function respecting these conditions, and also without singularities in the real axis, are connected by Kramers-Kronig relationship. Booij and Thoone in 1982 [START_REF] Booji | Generalization of Kramers-Kronig transforms and some approximations of relations between viscoelastic quantities[END_REF]showed that:

           ln ) ( ' 2 ) ( ' ' d dE E               ln ] ) ( ' ' [ 2 ) 0 ( ' ) ( ' d E d E E          ) (log )) ( (log 2 ) (      d E d d
Considering now the TTSP, the translation coefficients aT(Ti,Tref) between two isotherms can therefore be calculated as follows:

2 ) ( ) , ( * log ) , ( * log )) , ( log( ) , ( 1
1             ref j j j i j T T moy j j ref i T T E T E T T a
Then, it is possible to construct the master curve. Furthermore, it is possible to evaluate the validity of this method by comparing the values obtained for different reference temperatures.

Linear viscoelastic modelling

The purpose of modelling is to provide a mathematical approximation of real material behaviour with the aim of saving the time and cost of performing the test. These types of analytical models are defined by combining springs and dashpots. Springs represent the elastic part of the material, while dashpots represent its Newtonian viscous behaviour. Represented by an infinite number of Maxwell elements in parallel or Kelvin-Voigt elements in series. It is an viscous element with a parabolic creep function.

Huet model [START_REF] Huet | Etude par une methods d'impédance du comportement viscoélastique des matériaux hydrocarbons[END_REF] Initially proposed for bitumens and mixtures. It is an analogical model composed by a combination of a spring and two parabolic elements in series.

Huet-Sayegh model [START_REF] Sayegh | Variation des modules des quelques bitumes purs et enrobés bitumineux[END_REF] It is an evolution of the previous model proposed for mixtures modelling. Very complete model that can successfully fit mechanical response of most bituminous materials.

Huet-Such model [START_REF] Such | Etude de la structure du bitume -analyse du comportement visqueux[END_REF][START_REF] Such | Analyse du comportement visqueux des bitumes[END_REF] Improved the Huet model in order to adequately describe bitumens behaviour at high temperatures and low frequencies.

Denomination Description Schema/Formula

2S2P1D model [START_REF] Olard | Comportement thermomécanique des enrobés bitumineux à basses temperatures: Relations entre les propriétés du liant et de l'enrobé[END_REF][START_REF] Olard | General "2S2P1D" Model and Relation Between the Linear Viscoelastic Behaviours of Bituminous Binders and Mixes[END_REF] Very complete model that can successfully fit mechanical response of most bituminous materials.

Analytical LVE approach

CA model [START_REF] Christensen | Interpretation of Dynamic Mechanical Test Data for Paving Grade Asphalt[END_REF] me=1

CAM model [START_REF] Marasteanu | Inter-conversions of the linear viscoelastic functions used for the rheological characterization of asphalt binders[END_REF] Generalized CAM model [START_REF] Zeng | Rheological modeling of modified asphalt binders and mixtures[END_REF]

Mixture design

Asphalt mixture design depends on the desired performance. Depending on the application layer of the mixture the desired properties may vary. Base courses are designed in order to distribute loads over the soil foundation and must be resistant to fatigue. Intermediate layers must be compacted, stiff and resistant plastic deformations. And finally, wearing courses which are in direct contact with traffic and environmental agents provides the durability to the system. They need to be resistant to the action of water, to permanent deformations and to have acceptable surface characteristics. But sometimes, the characteristics desired can be contradictory [START_REF] Delorme | Manuel LPC d'aide à la formulation des enrobés[END_REF].

From the RILEM Report 17 [START_REF]Bituminous Binders and Mixes: State of the art and interlaboratory tests on mechanical behaviour and mix design[END_REF], six design methods for road asphalt mixtures can be distinguished:

i. Formula

ii. Empirical testing iii. Analytical computations iv. Volumetric method v.

Performance related testing vi.

Fundamental testing

In this thesis, the French design method and the associated testing procedures have been applied. This method is based on the asphalt mixture performance to the greatest extent [START_REF] Delorme | Manuel LPC d'aide à la formulation des enrobés[END_REF].

The method may be classified as fundamental or empirical depending if the material has a structural function or not. However, the gyratory compactor test is the base test for all asphalt concrete studies, as this test takes into account the volume of the system. In this case specimens have to be manufacture in function of the device employed, small, large or extra-large. As French procedure is followed the rutting resistance is supplied by the large device. Specimens are of parallelepiped shape (500x180) mm with 100 mm thickness. This slab is submitted to a one-wheel traffic load at 60°C, 1Hz, 5kN and 0.6 The resistance to fatigue can be determined by 5 different procedures. French design follows Annex A of the standard, the two point bending on trapezoidal specimens at 25

Hz and 10°C in strain controlled mode. By convention, fatigue life of a specimen is equal to the number of loading cycles needed to decrease the specimen's apparent stiffness modulus by 50%. Three different strain amplitude levels are selected and generally 6

specimens tested for each level. Then fatigue law curves are fitted on the experimental points by linear regression in a log-log diagram of number of cycles by strain level. The parameters that characterize the fatigue performance of a mixture are the strain level ε6 corresponding to 1,000,000 cycles and the slope of the fatigue law (-1/b).

Chapter 2 -Literature Review -25 - All these tests define the 4 levels of testing. Depending on the desired type of mixture, according to the French procedure for pavements design, a certain level of testing may be completed. For example, for base and intermediate courses Level 4 is needed. In contrast, for surface course to Level 2 is required.

Manufacturing procedures

Over the last century, production and spreading of the asphalt mixtures has evolved from manual works to computerized power plants with equipments highly automated. Along this period, it has been widely accepted that the temperature control is essential. It have to be high enough to ensure aggregates coating, the stability of the matrix during production and transportation, and for the workability on site and performance of the asphalt mixture. And at the same time, it must be below the limit that could cause excessive ageing of the binder [START_REF] Newcomb | An introduction to warm-mix asphalt[END_REF]. For usual paving grade bitumens the mixing temperature ranges between 200°C to 150°C [START_REF] Delorme | Manuel LPC d'aide à la formulation des enrobés[END_REF].

In consequence, pavement industry is directly linked to high energy consumption and greenhouse gases emissions [START_REF] Rubio | Comparative analysis of emissions from the manufacture and use of hot and half-warm mix asphalt[END_REF]. That is why temperature reduction in the production process has been implemented through Warm Mix Asphalt.

Based on the different ranges of manufacturing temperature, asphalt mixtures can be classified as follows [START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF][START_REF] Vaitkus | Analysis and evaluation of possibilities for the References -173 -use of warm mix asphalt in Lithuania[END_REF]:

 Hot Mix Asphalts (HMA) is the original and still the most widespread procedure. Their production temperature exceeds 160˚C. As discussed above, these high temperatures are necessary to achieve the adequate workability of the mixtures, and the best coating of the aggregates.

Durabilité des enrobés tièdes intégrant des recyclés -26 - Warm Mix Asphalts (WMA) are in the temperature range of production from 110˚C to 140˚C. Three different processes can be distinguished, bitumen foaming and the use of chemical or organic additives.

 Half Warm Mix Asphalts (HWMA) are characterized by a production temperature that never exceeds the boiling point of water (100˚C). In most of the cases moisturized aggregates are used.

 Cold Mixtures (CM) are the asphalt mixtures produced at ambient temperature (up to 40˚C). In order to achieve adequate workability either emulsions or foamed bitumen is employed.

Asphalt mixtures could also be classified by different criterion, such as the air voids content of the mixtures (open graded, dense graded or porous asphalts), the maximum aggregates size (fine or coarse), the aggregate fraction employed (mastic, macadam or concrete) or by the granulometry (continuous, discontinuous or uniform). Also, among all classifications discontinuous micro-surface mixtures, hot rolled asphalts, mastic asphalt or gussasphalt mixtures, stone mastic asphalts or soft asphalts [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF] can be find on roads.

Warm mix asphalt procedures

From the study of all the technologies that are currently in use, various classifications can be performed to try to group the various products commercialized. Thus, although the goal of all these technologies is the same (reduce production and extended temperature), initially each product has its particular characteristics.

Several common features can be identified between some of them, and this allow the establishment of a more detailed classification based on their operating principle [START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF][START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF][START_REF] Vaitkus | Analysis and evaluation of possibilities for the References -173 -use of warm mix asphalt in Lithuania[END_REF][START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF]:

 Foaming processes: The foaming effect is created by the vaporisation of the water due to its contact with the hot bitumen, increasing the volume and decreasing the apparent viscosity [START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF]. The process can be:

 Direct: Injection of water directly to the supply line of bitumen.

 Indirect: Through materials that absorb and lose water without damaging its crystalline structure, such as synthetic zeolites, or by aggregate moisture.

 Organic additives: Is based on the addition of different types of waxes which cause a decrease in viscosity.

 Chemical additives: These products generally include a combination of emulsifying agents, surfactants and other products to improve workability and compaction of the mixture.

Chapter 2 -Literature Review -27 -

Foaming procedure

It is the first process developed for reducing asphalt mixtures manufacturing temperature. The working principle of such WMA technology is based on the use of small amounts of water. When water gets in contact with the hot bitumen, the high temperatures cause its evaporation and the steam is trapped within the matrix of the bitumen. Thus, a significant amount of steam is generated, which is responsible for temporarily increasing the volume of the bitumen and decreasing its viscosity [START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF].

This effect gives a remarkable coverage and mix workability improvement. A common feature of the different processes is the limited duration of the foaming effect. The spread and compaction in such mixtures should be carried out soon after their production [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF]. Special precautions must be taken in regards to the amount of water added. It means that it must be enough to ensure the foaming effect but not as much as to induce cohesion problems that may occur because of the incorrect evaporation of all the water added [START_REF] Jenkins | Mix design considerations for cold and half-warm bituminous mixes with emphasis on foamed bitumen[END_REF].

Although the main process is the same for a large number of products, the way in which water is added to the mixture may vary. Thus, it is possible to distinguish between two different types:

water-based or direct method and water-continents or indirect method [START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF][START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF].

Indirect method

This method is based on the use of the zeolites principle to achieve the foaming process. Due to the honeycomb microstructure of the zeolites, water can be preserved within their micro-pores and released above the boiling point of water when heated [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF]. Thus, it is also possible to manufacture synthetic zeolites (Aspha-min® and Advera ®).

These synthetic materials are composed of alkali metal aluminium-silicates, which have been hydrothermally crystallized. The ability to absorb and lose water without damaging its crystal structure is one of the main characteristics of these silicates [START_REF] Chowdhury | A review of warm mix asphalt[END_REF]. The structure is formed by relatively large openings compared to its size, where cations and even molecules or groups of molecules (in this case water) can be stored. The content of water of crystallization is approximately 20%, which is liberated when the temperature increases by the addition of bitumen, causing a micro-foaming effect in the asphalt mixture [START_REF] Hurley | NCAT Report 05-06 -Evaluation of Sasobit for Use in Warm Mix Asphalt[END_REF].

Direct method

This group is based on systems that use water in a direct way. Mainly in all the processes the water is injected directly into the flow of hot bitumen, in the most cases through nozzles to create the effect of foaming. This effect is produced when the water evaporates producing a large Durabilité des enrobés tièdes intégrant des recyclés -28 -volume of steam that slowly disappears [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF]. Within this group, a greater distinction can be made based on commercial products.

There is another way to introduce water in the mixture, and it is through the use of aggregates in the wet state. The idea is to make a partial drying so a foaming effect will be produced with the contact of the aggregates with the hot binder. This procedure is known as sequential mixing, where the final water content is about 0.5% at 95˚C, thus ensuring sufficient workability and compaction [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF][START_REF] Bueche | Warm asphalt bituminous mixtures with regards to energy , emissions and performance[END_REF].

Advera®

Advera is an aluminosilicate or hydrated zeolite powder with about 20% of water. It produces a sustained, time-release foaming of the asphalt binder, to achieve a temperature reduction between 15 and 20°C (www.adverawma.com).

Foaming Process Direct Method

Double Barrel Green

Water is delivered to the system using a positive displacement piston pump capable of accurately metering water into the system. Using feedback controls, pump speed is modulated to maintain the appropriate flow of (www.astecinc.com).

Ultrafoam GX2™

Gencor has devised a simple, robust and reliable method to inject steam into the foaming process, using only the energy of the pump. As a result, the bitumen and water can be introduced at widely different flow rates and temperatures (gencorgreenmachine.com).

LT Asphalt

It consists of foamed bitumen hydrophilically additived. The addition of water ranges 0.5%-1 % by bitumen's weight (www.nynas.com).

WMA Foam

Known as the two-phase method. It is based on a two component binder system, where initially a softer binder is introduced and subsequently one harder foamed within the production cycle. The hard bitumen is foamed by introducing cold water in small amounts so the process can be induced and so, an increase on the ability coverage is generated. This combination of soft bitumen and a stiffer foamed one lowers the viscosity of the global mixture permitting its proper workability (www.shell.com).

Procedure Product Description

Foaming Process Direct Method

Low Energy Asphalt (LEA)

Developed by Eiffage TP, the low energy asphalt is a sequential process. First the coarse aggregate and bitumen are heated, then mixed. After the fine aggregates partially dried to create the foam are added, so the expansion of the bitumen is created (www.lea-co.com)

Low Emission Asphalt

It is an update of LEA. In this case, the process also uses sequential mixing, but now a chemical additive is added to the binder before mixing it with the coarse aggregate, and then the moistured fines, so the foaming effect is induced (www.suit-kote.com).

EcoFoam II It is a WMA system for continuous flow and batch plants using the Static Inline Vortex Asphalt Blender (www.asphaltequipment.com).

Aquablack

The center convergence nozzle design provides more efficient foaming. It reduces the number of nozzles and the maintenance related to each. The high-pressure system enables low water-toliquid-asphalt ratio during foaming. There are no moving parts in the foaming gun (www.marini-ermont.fayat.com).

Organic additives

This procedure is based on the addition of different types of wax to the mixture. The waxes used in these products are molecules composed of chains of hydrocarbon that melt at temperatures between 80 and 120˚C, thus changing the original properties of the binder. The melting point depends largely on the length of the carbon chain (C45 or more) [START_REF] Bueche | Warm asphalt bituminous mixtures with regards to energy , emissions and performance[END_REF]. Between 2% and 4% wax the total mass of the binder is the usual dosage.

Organic additives usually achieve a temperature reduction of between 20 to 30˚C, while also improve the deformation resistance [START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF]. Such processes have been developed since the end of the 1980s, currently distinguishing between three different types. The waxes are Fischer-Tropsch, Fatty acid amides and Montana waxes. Their only difference is the type of wax used to achieve the viscosity reduction. Above the melting point of the waxes a decrease in the viscosity is generally produced [START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF]. Thus carefully attention is needed on the selection of the type of wax, so that potential problems with the temperatures are avoided. During the cooling period after lay out, the wax additives solidify on microscopic particles uniformly distributed increasing the hardness/stiffness of the binder. That is if the melting point of the wax is lower than the temperatures expected in service asphalt. If not, complications can occur, turning the asphalt in a brittle material at low temperatures [START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF].

Durabilité des enrobés tièdes intégrant des recyclés -30 -

Asphaltan B

It is a product of Romonta GmbH. Asphaltan B is created especially for rolled asphalt and it consists of a mixture based on montan waxes and high molecular weight hydrocarbon substances. Romonta recommends adding between 2%-4% by weight of bitumen. It can be added in the mixing plant or directly to the bitumen, and also can also contain modified polymers. The melting point is about 100°C. Similar to Sasobit, this wax acts as a flow improver mix, with the associated reduction in production temperatures (www.wachs-und-mehr.de).

Greenseal BT

It is a product of Green World. Green Seal BT additive is a surfactant for the handling of bitumen, is an energetic reducing agent, which improves the workability of the mix, allowing manufacture hardened asphalt at lower temperatures while maintaining the mechanical properties of these hot. Greenseal BT is made from vegetable resins and esters, solvent less source of petroleum or carbo-chemical vegetable oils. Contains no volatile organic matter and is free of polycyclic aromatic hydrocarbons (ceocor.lu/gw)

3E LT

It is a product of Colas. 3E mixes achieves a reduction temperature of manufactured and application between 40°C to 45°C. These manufacturing temperatures allows a 15-25% reduction in greenhouse gas emissions, savings in energy consumption, and less fumes during application (www.colas.com)

Chemical additives

The last type of WMA technologies to be considered is the chemical additives. These products do not depend on any foaming process or reduction of viscosity to reduce the mixing and compaction temperatures [START_REF] Eapa | The use of warm mix asphalt. Eur Asph Paving Assoc[END_REF][START_REF] Chowdhury | A review of warm mix asphalt[END_REF]. Instead, they typically include a combination of emulsifying agents, surfactants, polymers and other products to improve the coating, the workability and the compaction of the mixture. They are as well adhesion promoters. The amount of added additive and the temperature reduction achieved by these technologies depend on the specific product used. The additives are usually mixed with the binder before it is introduced into the mixing drum. Its use has spread mainly in the USA, but also in European countries like France and Norway [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF].

Chapter 2 -Literature Review -31 -

Cecabase RT

It is a product of Arkema group. CECABASE is a surfactant based on compounds of at least 50% of renewable raw material, that when mixed with the bitumen, the temperature spread can be reduced by up to 50°C, without any adverse effect on the performance of pavement. It is therefore a process that uses less energy (reducing consumption between 20% and 50%) and that ultimately is therefore less harmful to the environment. The incorporation of the additive is between 2 and 4 kg per ton of asphalt mix, reducing the temperature to 120°C, while that retains the same properties as conventional mixtures (www. arkema.fr).

Rediset WMA

It is a product of Azkonobel. The system was designed in order to solve the problems with the water in WMA, the reduced stiffness and the existing uncertainty in the properties at low temperatures.

Rediset WMA consists of a chemical additive in solid tablet form is added to the binder before or during the mixing process. The amine product technology provides it with adhesion promoting properties and antioxidant effects, whereas the physical form of the product causes some reduction in viscosity at temperatures of the mixture, increasing the rigidity at service temperatures (www.akzonobel.com).

Iterlow T

It is a liquid product, added in quantities of 0.3%-1% that allows a reduction between 90°C-120°C. Iterlow T, acts on the bitumen's surface tension. It limits the gas emissions that cause the greenhouse effect and reduces fuel consumption. The mechanical characteristics of the obtained mixes are identical to the ones produced at normal temperatures (www.coldlay.co.uk).

Durabilité des enrobés tièdes intégrant des recyclés -32 -

Reclaimed materials

The concept of recycling goes far back in time, both ways the use and reuse of materials has been around since the early days of human history. To recycle consists on subjecting a used material to a process, so that it can be used again (Oxford English dictionary). The purpose of this process is turning waste into new available products, reducing raw materials consumption, energy usage and greenhouse gasses emissions.

All the economic and environmental considerations have encourage the recycling of paper, paperboard, glass, steel, plastic and many other materials, where asphalts materials are included. The term RAP (Reclaimed Asphalt Pavement) appeared in 1915 [START_REF] Taylor | Life expectancy of recycled asphalt paving[END_REF], but it was not until the oil embargo in the mid-1970's when the first sustained efforts were developed. The main cause was the increase of asphalt price as well as the lack of quality aggregates near some utilization points [START_REF] Sondag | Investigation Of Recycled Asphalt Pavement ( RAP ) Mixtures[END_REF]. Nowadays, the restricted environmental laws in conjunction with the economic incentives applied make the manufacture of asphalt mixtures integrating RAP a prominent technique. Moreover, by recycling, the bitumen contained is reutilized reducing virgin asphalt contribution and helps to decrease the quantity of waste produced resolving the disposal problems of road construction engineering [START_REF] Elseifi | Reclaimed asphalt pavement -A literature review[END_REF].

RAP procedures

There are several problems on the road that can be solved through milling and recycling. When the road achieves the time of resurfacing or when it has ended its service life, recycling appears as a suitable solution [START_REF] Gapa | Recycling of asphalt. New set of rules and standards shows the way forward[END_REF]. The effects of adding RAP to asphalt mixtures have been studied by several authors during the years, concluding that any road is a candidate for recycling. Also, any asphalt layer is susceptible of RAP incorporation [START_REF] Karlsson | Material-Related Aspects of Asphalt Recycling-State-of-the-Art[END_REF] if the best practices are followed. According to different researchers the percentage of addition can vary from 0% to 100% or full recycling, depending on the type of road, the quality of the RAP material and the manufacture process [START_REF] Gapa | Recycling of asphalt. New set of rules and standards shows the way forward[END_REF][START_REF] Makowska | Development of specifications and guidelines for hot in-place recycling in Finland[END_REF]. Special attention is Chapter 2 -Literature Review -33 -needed for the performance of mixtures containing RAP against rutting, water and fatigue resistance. While permanent deformations and stiffness modulus are typically improved, issues are raised as regards to the fatigue life and low temperature properties [START_REF] Tam | Five-year experience of low-temperature performance of recycled hot mix[END_REF][START_REF] Oliver | The Influence of the Binder in RAP on Recycled Asphalt Properties[END_REF][START_REF] Judycki | Fatigue of asphalt mixes[END_REF].

Reclaimed asphalt pavement is generally obtained through two processes, milling and ripping [START_REF] Gapa | Recycling of asphalt. New set of rules and standards shows the way forward[END_REF]. When milling in layers, the reclaimed material can be stored and processed separately.

When ripping, the slabs obtained needs to be crushed until the size desired. In this case, special attention may be needed to characterize the different fractions. The recycling techniques can be classified into different categories, according to the working temperature and the location where it is performed [START_REF] Karlsson | Material-Related Aspects of Asphalt Recycling-State-of-the-Art[END_REF][START_REF] Decker | (RAP) in hot-mix asphalt[END_REF]. Thus the following types of recycled processes can be distinguished:



 Cold recycling with emulsion

Reclaimed asphalt pavement is a material where certain characteristics have to be noted as EN 13108-8 standard requires. Before milling it is important to verify that the layers do not contain hazardous materials like PAHs (Polycyclic Aromatic Hydrocarbons) or asbestos can be avoided. This determines the suitability for being recycled.

The challenge of recycling is to create a homogeneous material from different sources. For this purpose the material can be classified to be treated and stocked separately. To facilitate the mix design for high RAP content it can also be separated in different fractions [START_REF] West | Reclaimed Asphalt Pavement Management : Best Practices[END_REF].

As a rule of thumb, for a given property the asphalt mixture, the additional scatter due to the added RAP depends on the scatter of this property in the RAP multiplied by the RAP content in the mix [START_REF] Ipavec | Synthesis of the european national requirements and practices for recycling in HMA and WMA (DIRECT_MAT PROJECT). 5th Eurasphalt Eurobitume Congr[END_REF]. As the obtained mix must generally comply given homogeneity requirements, RAP with highly scattered properties implies low RAP content. For this reason, limit values for recycling or maximum content of RAP is allowed [START_REF] Ipavec | Synthesis of the european national requirements and practices for recycling in HMA and WMA (DIRECT_MAT PROJECT). 5th Eurasphalt Eurobitume Congr[END_REF]. To avoid moisture accumulation, the recommendation is to cover the stockpile so the rain might not penetrate, as well as leave a sloped surface underneath so water can drain naturally [START_REF] West | Reclaimed Asphalt Pavement Management : Best Practices[END_REF].

Durabilité des enrobés tièdes intégrant des recyclés -34 -If best practices are taken, RAP stockpiles should have lower variability on gradation. The tests that may be done to get data from the RAP are according to West (2010) [START_REF] West | Reclaimed Asphalt Pavement Management : Best Practices[END_REF] and the European Standard EN 13108-8, the asphalt binder content (and properties, softening point, if using high percentages of incorporation), the granulometry (<0.063 mm; between 0.063 and 2 mm; > 2mm), bulk density and consensus properties of the aggregate of the processes material. In the case of layer specifications, as happens with surface layers, polishing or mineralogical composition of the RAP aggregate may be needed. Following the German Asphalt Pavement Association [START_REF] Gapa | Recycling of asphalt. New set of rules and standards shows the way forward[END_REF] indications on the report Recycling of Asphalt, the addition of RAP can be determined depending on the range of the corresponding characterization results. The amount of added material depends on the type of layer. In the nomogram presented in Figure 2-10, the maximum possible material addition can be calculated with reference to its characteristics. The ranges of each parameter are entered in the nomogram at each corresponding ordinate, where the most restricting determines the maximum percentage of RAP to be added.

RAP characteristics

The fact of incorporating RAP material into asphalt mixtures should be considered as addition of a constituent element. That is why, their service characteristics, physical and rheological changes should be taken into account for a correct design of the resulting mix. In any case, the performance requirements for the mixture with RAP are the same as for conventional hot mix asphalts [START_REF] Elseifi | Reclaimed asphalt pavement -A literature review[END_REF]. In order to estimate the properties of the mixed bitumens the formulas from the EN 13108-1 standard are widely used:

a log PEN1 + b log PEN2 = (a+b) log PENmix SPmix = a SP1 + b SP2 a + b = 1
It should be noted that in these equations, a complete blending of the binders is assumed.

RAP bitumen

Several authors have investigated the different stages of ageing that suffer the bitumen when being manufactured and during service life [START_REF] Elseifi | Reclaimed asphalt pavement -A literature review[END_REF][START_REF] Karlsson | Material-Related Aspects of Asphalt Recycling-State-of-the-Art[END_REF][START_REF] Roberts | Hot Mix Asphalt Materials, Mixture Design and Construction. Second Edi[END_REF][START_REF] Thyrion | Asphalt Oxidation, Asphaltenes and Asphalts[END_REF]. There are two phases of ageing inducing an increase of the asphalt viscosity. Knowing the level of damage and ageing of the binder, soft binders, softening agents and rejuvenators can be chosen to reactivate the old binder.

Use of rejuvenators

The rheological properties of the bitumen contained in RAP could be restored, and for this purpose rejuvenating agents or softer asphalts are used. There is a need of lowering binder viscosity by softening agents, as well as restoring physical and chemical properties of the aged binder [START_REF] Sondag | Investigation Of Recycled Asphalt Pavement ( RAP ) Mixtures[END_REF][START_REF] Roberts | Hot Mix Asphalt Materials, Mixture Design and Construction. Second Edi[END_REF][START_REF] Blomberg | Laboratory Simulation of Bitumen Aging and Rejuvenation to Mimic Multiple Cycles of Reuse[END_REF][START_REF] Makowska | The "false positive" on antiaging properties of asphalt fines investigqted by RTFO laboratory aging of mastics[END_REF].

The importance of the physical and chemical bonding arrives when talking about mixture performance. An asphalt section constructed by the New York DoT suffered ravelling due to the fact that the virgin bitumen only covered the aged one, but did not interact chemically with it [START_REF] Sondag | Investigation Of Recycled Asphalt Pavement ( RAP ) Mixtures[END_REF] (double coating effect).

Durabilité des enrobés tièdes intégrant des recyclés -36 -

Bitumen

Among all the exposed pathologies that could cause the failure of the pavement, a common element is the performance of bitumen. So as the mechanical performance of the mixture is highly dependent upon the properties of the bitumen, it has to fulfil certain mechanical and rheological requirements to ensure the integrity of the pavement [START_REF] Airey | Bitumen properties and test methods[END_REF].

Bitumen is a crucial component of the asphalt mixtures, it is used to build roads that connect our cities, our countries and hold our city streets together. Bitumen is a very valuable material with countless applications, it is not only flexible as well as durable, it is also 100% recyclable [START_REF]Eurobitume[END_REF]. It is a popular belief, even among engineers that asphalt can be made from the heavy end of any crude oil. But unfortunately this belief is far from being correct because the asphalt product must have a series of properties in order to meet the specifications for the different grades [START_REF] Jones | Handbook of petroleum processing[END_REF].

Origin and manufacture

In general, bitumen is viscous material at relatively high temperatures and solid or semisolid at room temperature. It can occur in nature as such or obtained as residue by refining petroleum [START_REF] Barth | Asphalt: Science and Technology[END_REF], though they vary enormously in their composition and their properties [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF].

Natural bitumen

Naturally occurring asphalts could be divided in three groups, lake asphalts, rock asphalts and gilsonite [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF]. Lake asphalts contain actual bitumen but also a proportion of mineral matter i.e.

southern part of Trinidad, Kentucky, Alberta, Albania or the Dutch East Indies. The rock asphalts provided the foundations of the modern asphalt industry; it consists of natural rocks impregnated with bitumen, i.e. Pirymont-Volant or Avejan (France), Val de Travers (Switzerland), Syracuse (Sicily) or Hanover (Germany). Finally, the gilsonite, also known as "asphaltites" is a bitumen characterized by a high softening point, i.e. Utah (USA) or Albania [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF][START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF].

Refined bitumen

On the other hand, crude oil refining is the principal source of bitumen for road engineering. It is primarily obtained by vacuum distillation of carefully selected crude oils or blends of crude oils.

Among the crude oils or blends that are available not all of them are suitable for producing bitumen as the quality standards require. In general heavy crude oils (specific gravity > 0.9) are used, but these types of crude oils tend to present higher sulphur contents (>1 %m) [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF]. The manufacture procedure followed to produce bitumen is called fractional distillation. During this process, the different hydrocarbon chains are separated according to their different boiling Chapter 2 -Literature Review -37 -points. Distillation is carried out in tall steel towers (fractionating or distillation columns), divided inside at intervals by horizontal steel trays punctured to allow the steam to rise up.

The crude oil is initially distilled under atmospheric pressure and normally involves heating between 345°C-450°C to separate the lighter fractions as overhead products and the bitumen left as a residuum. In order to obtain the desired bitumen consistency as well as to recover all the high boiling fractions for other purposes it is necessary to complete the process. So a second fractionating tower is added, operating under low pressure (10-100 mmHg) and high temperature (350-425°C) [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF][START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF]. Depending upon the specification grade requirements, the vacuum residuum can be used either directly, further processed, or used as a component of blended bitumen. The non-distillable materials as residuum on the vacuum distillation are described by bitumen and residues (petroleum) vacuum [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF][START_REF]Bitumen Production[END_REF]. These materials can be rectified by a mild degree of air-blowing to make minor adjustments to the physical properties. Also, the vacuum residue can be modified by solvents deasphalting. It uses different solvents in order to separate asphaltenes-type fractions, and the hard bitumen remaining can be blended to produce specification grade bitumens [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF].

Structure and composition

Generally, asphaltic bitumens elementary composition reveals that the chemical elements present in the highest amounts are hydrocarbons (C 82% -88% and H 8% -11%). Then, most of the bitumens also contain small amounts of sulphur (S 0% -6%), oxygen (O 0% -1.5%), nitrogen (N 0% -1%) and traces of different metals as calcium, iron, magnesium, nickel or vanadium [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF][START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF].

Durabilité des enrobés tièdes intégrant des recyclés -38 -

In terms of elementary analysis, the carbon to hydrogen ratio is an important parameter of hydrocarbons. It indicates to what degree the hydrocarbons deviate from paraffinic structures of the general formula CnH2n+2. The two elements next in importance are nitrogen and sulphur [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF],

influencing the chemical make-up and the behaviour of the asphaltic bitumen. The degree of chemical stability or inertness is determined by the chemical arrangements of the elements in the various molecules and on the ratio of reactive to non-reactive components. Therefore, it is generally accepted to subdivide asphaltic bitumens into asphaltenes and malthenes, and a relatively loose subdivision of the malthenes into resins and oils [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF].

Physical characterization

Regarding chemical structures, bitumens differ from one another not only physically, but also as to molecular weight, boiling points, and other characteristics [START_REF] Barth | Asphalt: Science and Technology[END_REF]. Physically it depends on the concentration, particle size and nature of the dispersed phase, and the nature of the dispersion medium [START_REF] Airey | Bitumen properties and test methods[END_REF]. They are colloidal dispersions of asphaltenes (high molecular weight hydrocarbons) in malthenes (dispersion medium, including resins, aromatics and saturates).

Each of these groups may be separated from the other.

Two types of colloid structures are distinguished, the sol and gel bitumens. The division line between them is diffused, calling the materials falling there sol-gel bitumens [START_REF] Barth | Asphalt: Science and Technology[END_REF]. Figure 2345678910111213141516illustrates the typical sol and gel structures.

 Gel bitumens display a large micelle together with high content of asphaltenes and moderate to low peptization of the latter due to low and often insufficient resin content.

Gel bitumens maintained in fluid condition show no instability or sedimentation, as do some highly cracked bitumen, which are seriously deficient in resins. At ambient temperature their structure is only slowly destroyed by solvents or by an increase in temperature [START_REF] Barth | Asphalt: Science and Technology[END_REF]. Nearly all bitumens contain asphaltenes, besides the resins and oils, at different quantities. But what physically distinguishes bitumens is the presence or absence of micelles [START_REF] Barth | Asphalt: Science and Technology[END_REF]. Then, bitumen physical properties not only determine the suitability for a given application, but also define the conditions under which the product must be handled and placed in the structure [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF].

The behaviour and properties of bitumens are dependent on their constitution [START_REF] Barth | Asphalt: Science and Technology[END_REF]. From the manufacturing process petroleum light components are removed leaving behind relatively high molecular weight and low volatility compounds [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF]. Then, bitumens are engineering designed products and therefore the product specifications focus on defining physical properties, rather than being based upon chemical composition.

Chemical characterization

Bitumen is the resulting product from engineering distillation. Generally it is a solid or semisolid material at ambience temperature. It softens as the temperature increases behaving as

Newtonian fluids when it is elevated, and hardens as the temperature decreases behaving as brittle material when it is too low [START_REF] Barth | Asphalt: Science and Technology[END_REF][START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF].

Durabilité des enrobés tièdes intégrant des recyclés -40 -Citing Hoiberg's book [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF], it can be considered that bitumens are viscous materials with relatively high-boiling points. This could be justified by the chemical reactions involved in the natural formation of bitumens. Polymerization, condensation, and oxidation reactions combined with evaporation, filtration, and blending operations form bitumens. Then, geologically, it could be said that older deposits usually contain higher molecular weight products, indicating further polymerization and condensation of the material. In both natural and manufactured bitumens it can observed that the older is the material the harder it becomes, obtaining higher melting points and less solubility in low-boiling hydrocarbons [START_REF] Barth | Asphalt: Science and Technology[END_REF][START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF].

However, chemically speaking, bitumens are a mix of heterogeneous chemical compounds. But yet all bitumens have certain common characteristics and properties which indicate that the components of all bitumens, independently of their origin, must be similar in many significant properties [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF]. In order to establish the nomenclature used in this document, the following definitions are suggested:

 Asphaltenes. Their structure varies considerably with the origin of the asphalt. This is the heaviest fraction and can be obtained by precipitation methods. Usually n-pentane, n-hexane or n-heptane are commonly used as solvents, resulting on the c5, c6 or c7 asphaltenes. They are dark brown to jet black friable solids that show no definite melting point [START_REF] Barth | Asphalt: Science and Technology[END_REF][START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF][START_REF] Redelius | Asphaltenes in Bitumen, What They Are and What They Are Not[END_REF].

They are normally characterized as highly polar due to the presence of nitrogen, oxygen and sulphur. Asphaltenes have different molecular weight ranging from 500 to 10,000 g/mol [START_REF] Mullins | Advances in asphaltenes science and the Yen-Mullins model[END_REF]. The values of molecular weight may vary in relation to the polar strength of the solvents used and the temperature of determination [START_REF] Yen | Asphaltenes and asphalts[END_REF]. So it is no surprise to find in the literature a very wide range of molecular weight values for asphaltenes. They usually represent 5% to 20% of the total bitumen [START_REF] Corbett | Composition of Asphalt Based on Generic Fractionation Using Solvent Deasphalteneing, Elution-Adsorption Chromatography and Densiometric Characterization[END_REF][START_REF] Lesueur | The colloidal structure of bitumen: consequences on the rheology and on the mechanisms of bitumen modification[END_REF].

 Malthenes. Resins, aromatics and saturates compose the malthenes. Opposite to the asphaltene fraction, the malthenes are soluble in the solvents that make asphaltenes precipitate, i.e. n-heptane.

 Resins. The term resin refers to the material eluted from various solid adsorbents, but it does not include the oils (aromatics and saturates). They are a transition from oils to asphaltenes [START_REF] Paliukaitė | Evaluation of bitumen fractional composition depending on the crude oil type and production technology[END_REF]. Resins are dark coloured material, heavy, semisolid or solid, and very adhesive [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF][START_REF] Barth | Asphalt: Science and Technology[END_REF]. This group shows molecular weights ranging from 300 to 2,000 g/mol [START_REF] Paliukaitė | Evaluation of bitumen fractional composition depending on the crude oil type and production technology[END_REF]. And as happens with the asphaltenes on the literature it can be find a very wide range of molecular weight values.

Chapter 2 -Literature Review -41 -Resin fractions contain considerable unsaturated hydrocarbon constituents, but still their molecular weight fractions are lower than those of asphaltenes. They are present by 13% to 25% in the total bitumen [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF]. Their composition depends on the kind of precipitating solvent employed.

 Aromatics are non-polar hydrocarbon chains in which the unsaturated ring systems dominate. They have a high dissolving ability for other high molecular weight hydrocarbons, and represent the major proportion of the dispersion medium for the peptised asphaltenes. Aromatics are dark brown colour and represent from 40% to 65% of the total bitumen. They have an average molecular weight of 800 g/mol but it can appear on a range between 300 and 2,000 g/mol [START_REF] Paliukaitė | Evaluation of bitumen fractional composition depending on the crude oil type and production technology[END_REF].

 Saturates. They are non-polar viscous oils which are straw or white in colour. Their average molecular weight is the smallest (600 g/mol) [START_REF] Paliukaitė | Evaluation of bitumen fractional composition depending on the crude oil type and production technology[END_REF], but similar to that of aromatics (300 to 2,000 g/mol). The components are essentially linear aliphatic hydrocarbons, ramified and naphthenic elements [START_REF] Hammoum | La structure chimique des bitumes pétroliers[END_REF]. They constitute between 5% and 20% on the SARA fractions in general [START_REF] Such | Les matériaux de chaussées traités aux liants hydrocarbonés. Les References -175 -liants Hydrocarb[END_REF]. Moreover, since the real molecular weight cannot be determined, the concept of average molecular weight, introduced by polymer chemistry, is used. On Greenfeld's research [START_REF] Greenfeld | Chemical changes occurring during the weathering of two coating-grade asphalts[END_REF], it is remarked that although the average molecular weight of asphaltenes decreases during ageing, the total amount of asphaltenes molecules in the bitumen increases. Thus, the asphaltenes created by ageing has substantially lower molecular weight than those originally present.

Bitumen evolution

Bitumen characterization is very important in order to determine the effect of temperature and stress on the engineering properties. There are mainly two principal applications or steps where the choice of the right bitumen is essential, the mix design and the construction process [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF].

Through the asphalt mixture design, the bitumen must be of such a grade that it can produce a mix able to resist the traffic and environment effects during its service life. But previously, it has

Durabilité des enrobés tièdes intégrant des recyclés -42 -to resist the construction process, including transport from refinery, storage in plant, pumping and mixing during manufacture. Then it needs to be hauled to the construction site, laid down and compacted at the specific temperatures. Therefore, the influence of the different techniques could condition the selection of the bitumen.

According to the colloidal model, the asphalt oxidizing mechanisms could be explained as a change of the asphaltenes to resins and resins to oils by hydrogenation [START_REF] Jones | Handbook of petroleum processing[END_REF]. But resins can also be oxidized to asphaltenes and oil to resins. For example, during the refining process, the air blown generates a polymerization that leads to a decrease of penetration, an increase of softening point. This induces a reduction of ductility as the bitumen hardens due to the increase of asphaltene content [START_REF] Jones | Handbook of petroleum processing[END_REF]. The steps that conduct this polymerization could be resumed as the addition of oxygen to form unstable compounds from which water is eliminated, leaving unsaturated compounds that polymerize. Then the further addition of oxygen leads the formation of carboxyl derivatives from which carbon dioxide is eliminated and followed again by polymerization. Finally, the formation and elimination of volatile oxidation products other than water and carbon dioxide are again followed by polymerization [START_REF] Jones | Handbook of petroleum processing[END_REF]. Those structural changes are dependent of the oxygen exposure. Thus, ageing is faster when the bitumen is in thin films rather than in bulk quantities as happens in service materials [START_REF] Barth | Asphalt: Science and Technology[END_REF].

During mixture manufacture where high temperatures are employed, a loss of volatile oils compounds may occur to some level. However, this loss is considered minor during service because the material is working at ambient temperatures [START_REF] Jones | Handbook of petroleum processing[END_REF].

The phenomenon of ageing implies deep chemical changes within the bitumen. Thus, bitumen durability covers both rheological and physicochemical, or colloidal changes that lead to the failure of the pavement [START_REF] Barth | Asphalt: Science and Technology[END_REF]. Additionally, temperature susceptibility is key for the performance of the bitumen, whose oxidation changes the relationship penetration -softening point [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF].

Chapter 2 -Literature Review -43 - Bitumen hardening could be reversible or irreversible, depending if the changes are physical or chemical. Reversible hardening does not alter the composition of bitumen, and the adhesive properties of the material remain practically unaltered. In this case the original penetration of the bitumen could be restored by heating, stirring or other forms of physical actions, as long as the loss of penetration is not so accused that it could lead to the pavements break up [START_REF] Barth | Asphalt: Science and Technology[END_REF].

On the other hand, irreversible hardening implies rheological changes due to oxidation. As a result, the loss of bitumen-aggregate adhesion induces stripping of the mixture in presence of water and heterogeneity [START_REF] Barth | Asphalt: Science and Technology[END_REF]. As the resin content decreases, the asphaltenes in the dispersion medium are less stable.

Ageing detection

Bitumen ageing can be divided in two principal phases, a short term ageing and a long term ageing. The first one is basically associated with oxidation and the loss of volatile compounds during the asphalt mixture manufacture. Then, the long term is due to the progressive oxidation in the field as part of the exposure of the mixture to environmental agents. During all this period, there are also other factors that may contribute to ageing, such as steric hardening (molecular structuring over time) and actinic light (mainly ultraviolet radiation) [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF].

However, the list of factors is not the same for all researchers. Vallerga and co-workers [START_REF] Vallerga | A study of some factors influencing the weathering of paving asphalts[END_REF] listed six factors in 1957, then Traxler in 1963 [START_REF] Traxler | Durability of asphalt cements[END_REF] added three more up to nine, while Petersen in 1984 [START_REF] Petersen | Chemical Composition of Asphalt As Related To Asphalt Durability: State of the Art[END_REF] reduced them to three and Mallick and El-Korchi in 2013 [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF] gave a list of fifteen Durabilité des enrobés tièdes intégrant des recyclés -44 -factors. Although the identified list of factors can vary, oxidation in the darkness, volatilization, steric or physical factor and the exudation of oils are considered to be the most important ones [START_REF] Mallick | Pavement Engineering: Principles and Practice[END_REF]. All these factors produce commons effects. The stiffness increase leads to higher bearing capacity and permanent deformation resistance. However, the loss of flexibility could result in cracking and total failure of the system [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF][START_REF] Vallerga | Pavement deficiencies related to asphalt durability[END_REF].

Ageing indicators and analysis techniques

In Europe, ageing characterization is made traditionally by monitoring the response of the bitumen to specific testing configurations and conditions. But it is necessary to distinguish between tests related to ageing on bitumens or ageing on asphalt mixtures. Penetration test and softening point test are the classical semi-empirical tests (they do not measure mechanical properties) performed with the aim of measuring the hardening experienced by bitumen.

Penetration test

The penetration tests follows the European Standard EN 1426 and it consist in evaluating the consistency of the bitumens expressed in terms of depth 1/10 mm. It is performed by a standard needle that penetrates vertically on the asphalt sample at specified conditions of temperature (25°C), load (100 g) and time (5 seconds).

Hardening

Penetration index (PI) defines the susceptibility of the bitumen to temperature changes, hardening [START_REF]Eurobitume. The Bitumen Industry -A Global Perspective: Production, chemistry, use, specification and occupational exposure (IS-230)[END_REF]. It generally ranges from -1 to +1 and as higher is the value of PI, the lower is the susceptibility.

𝑃𝐼 = 20 -500 𝐴 1 + 50 𝐴 𝐴 = log 𝑃 𝑎𝑡 𝑇 1 -log 𝑃 𝑎𝑡 𝑇 2 𝑇 1 -𝑇 2
Where A represents the temperature susceptibility of the material, and can be measured with the penetration at two different temperatures.

Fourier Transform Infrared Analysis

The Fourier Transform Infrared (FTIR) analysis consists of exciting the material with infrared light. A quantification of the different types of molecular bonds through characteristic absorption bands in the transmitted infrared light spectrum is carried out. Carbonyl groups (esters, ketones etc.) and sulfoxides are among the major functional groups formed during oxidative ageing [START_REF] Petersen | A Review of the Fundamentals of Asphalt Oxidation: Chemical, Physicochemical, Physical Property, and Durability Relationships[END_REF] and it was demonstrated that their formation changes the physical properties of the binder in a predictable way [START_REF] Liu | The kinetics of carbonyl formation in asphalt[END_REF]. They are characterised by C=O and S=O double bonds. The test can be performed both on transmission or reflection (ATR) mode. Once the signal is obtained, Ico and ISo values can be calculated following different procedures [START_REF] Marsac | Potential and limits of FTIR methods for reclaimed asphalt characterisation[END_REF].

Ageing simulation in laboratory

In order to evaluate the effect of ageing on short and long term conditions, the ageing of the bituminous materials, bitumen itself and asphalt mixture, can be simulated in laboratory.

Ageing tests for bitumens

The correlation between laboratory ageing and field performance has been a battle for more than eighty years already [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF]. The most common laboratory procedures are the standardised Durabilité des enrobés tièdes intégrant des recyclés -46 -test RTFOT (EN 12607-1) and PAV (EN 14769) for simulating the short term and long term ageing respectively. Airey, 2003 [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF] summarizes all the available tests for ageing simulation on bitumen.

Ageing tests for asphalt mixtures

In the case of asphalt mixtures, the idea of these ageing procedures is to assess the effect on key material properties as stiffness, viscosity or strength. Ageing methods for asphalt mixtures can be divided in extended heating procedures (EH), oxidation tests (O), ultraviolet treatment (UV) and steric hardening (SH). Table 2-6 summarizes all the available tests for ageing simulation on asphalt mixtures [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF].

Introduction

As it has been described in the literature, the elementary composition of bitumen is carbon and hydrogen, then sulphur, oxygen, nitrogen and traces of different metals as calcium, iron, magnesium, nickel or vanadium [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF][START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF]. Bitumen degree of chemical stability is determined by the chemical arrangements of the elements in the various molecules and on the ratio of reactive to non-reactive components. Therefore, it is generally accepted to subdivide asphaltic bitumens into asphaltenes and malthenes, and then malthenes into resins, aromatics and saturates in polar affinity [START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF]. These fractions fit in the colloidal model (dispersions of asphaltenes in malthenes), that is still the model that best explains the physical and mechanical properties of bitumen. It is therefore the model considered in this work.

In this chapter, the objective is to determine the influence of asphaltenes fraction onto the physico-chemical response of the material. The bitumens used for the study are presented at the beginning. The protocol for separating asphaltenes and malthenes phases for later recomposition is also shown. Then, bitumens containing different asphaltenes ratios are recomposed and studied. Moreover, in order to understand the effects of ageing on the chemical species and on the physico-chemical organization of the bitumen, laboratory ageing procedures are performed on some samples for comparison.

Bitumens mechanical behaviour is usually evaluated by standard empirical tests of consistency (penetrability and softening point temperature). However, such tests do not provide intrinsic properties of bitumens. For these reasons, chemical and physical characterisation is carried out.

For the chemical evaluation, the Fourier transform infrared analysis, thermogravimetric analysis and thin layer chromatography for SARA fractions determination are performed. Whereas bitumen solubility in n-heptane, gel permeation chromatography, atomic force microscopy and rheological testing are used to evaluate the physical evolution and performance of the materials.

Additionally, from rheological testing and through the application of the -method, bitumen ageing and asphaltenes ratio are tried to be correlated. In fact, the ability of the -method to track bitumen ageing is assessed.

Materials, methods and experimental program

Materials

Neat bitumens

The physico-chemical study is conducted on two neat bitumens, conventional 35/50 and 50/70.

The proximity in the gradation will also allow discussing the differences that exist between two grades of bitumens. Bitumen main characteristics defined by EN 1426 and EN 1427 standards

Model bitumens

Protocol for bitumen separation and reconstitution

With the aim of manufacturing model bitumens with defined asphaltenes content, a protocol for fractions separation and further recomposition is followed. The protocol can be divided in its two principal phases, asphaltenes-malthenes separation and asphaltenes-malthenes reconstitution. The first step consists of separating bitumen in its two principal fractions, asphaltenes (n-heptane insoluble phase) and malthenes (n-heptane soluble phase). The second phase of the process is the reconstitution of constituents, both soluble on dichloromethane.

Asphaltenes-malthenes separation

This first step consists of solubilizing the malthenes phase of the bitumen on n-heptane for precipitating the asphaltenes (c7) fraction. A dispersion around 15 g of bitumen is separated in ~450 ml of solvent (ratio is 30 ml per gram of bitumen) and assembled in a 500 ml Erlenmeyer flask. Through stirring, the solution is heated up to 110°C in a heater plate until boiling and left then at 90°C during 60 min, so that a good dispersion of phases is assured. After cooling during 15 min still stirring, the flask is kept in the darkness for 120 min in order to favour a proper sedimentation of asphaltenes particles.

Subsequently, the dispersion is placed in sample holders of 20 ml and centrifuged at 3,000 rpm during 5 min for asphaltenes separation. This process is repeated several times until cleaning the asphaltenes and recovering the n-heptane transparent from centrifugation. The separated asphaltenes are left at mild temperature for drying. Meanwhile, the malthenes liquid phase is ready for solvent removal. The extraction is done with a rotatory evaporator in two steps. Firstly the flask is kept at 75°C, 4-7 mbar during approximately 90 min, and again for 30 min at 7 mbar and 98°C to assure the n-heptane evaporation.

Asphaltenes-malthenes recomposition

The second phase of the process is the reconstitution of constituents, but at certain rates of combination. The first step of this phase is to weight the malthenes obtained after two processes of separation (around 26-27 g) in order to choose a concentration of asphaltenes. So the malthenes-asphaltenes (m/a) ratio is well defined. Afterwards, the flask is placed in the rotatory evaporator for solvent removal. The conditions followed are the same as for the separation step (75°C, 4-7 mbar, 90 min, and then for 30 min at 7 mbar and 98°C). Denomination code will follow the sequence "Bitumen" + "Percentage" + "Fraction". So 35/50

85M+15A bitumen is the model bitumen from 35/50 with 85% malthenes and 15% asphaltenes.

Chemical characterization

ATR FTIR analysis

The Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy analysis is performed with the purpose of verifying the evaporation of the solvent when manufacturing the model bitumens. Additionally, it is also use to monitor ageing on the laboratory aged bitumens (RTFOT and PAV).

Carbonyl groups (Ico) and sulphoxide groups (Iso) are characterized from the raw ATR-FTIR spectra according to the RILEM method [START_REF] Marsac | Potential and limits of FTIR methods for reclaimed asphalt characterisation[END_REF]. The spectrum (5 spectra per sample) is collected in the wavenumber range of 4,000-400 cm -1 . Limits are fixed for the carbonyl area (peak centred on 1,700 cm-1), sulphoxide area (~1,030 cm-1) and the reference area for the methyl and ethylene groups (CH2 ~1,380 cm -1 and CH3 ~1,430 cm -1 ). Only those areas above the baseline between limits are taken into account. The limits on the spectra for carbonyl compounds are fixed in this study between 1,642 and 1,723 cm -1 , the sulphoxide area fixed between 980 and 1,082 cm -1 , while the reference area is fixed between 1,350 and 1,525 cm -1 .

Thermogravimetric analysis

Thermogravimetric analysis (TGA) is a method of thermal analysis. With the TGA Q50 device, physical and chemical changes on material are measured as a function of increasing temperature Chapter 3 -Physico-chemical study of bitumens -55 -or time, with constant heating rate or with constant temperature and/or constant mass loss respectively. TGA measurements are made in temperature ramp (10°C/min in nitrogen atmosphere, between 30°C and 600°C), in samples of 5-10 mg, measuring a constant mass loss rate to show specific reaction kinetics in the asphaltenes fraction.

Thin layer chromatography with flame ionization detector

Thin Layer Chromatography coupled with a Flame Ionization Detector (TLC-FID) performed with an Iatroscan MK-6s device is used to determine SARA fractions (Saturates, Aromatics, Resins and Asphaltenes). From this type of analysis the asphaltenes will not be c7-asphaltenes as the solvent used for separation is not n-heptane. Following Le Guern [START_REF] Guern | Physico-chemical analysis of five hard bitumens: Identification of chemical species and molecular organization before and after artificial aging[END_REF] notation, this type of asphaltenes will be called i-asphaltenes.

For the samples preparation, 0.05 g of bitumen is diluted in 5 ml of toluene solution of HPLC [START_REF] Nellensteyn | The constitution of asphalt[END_REF][START_REF] Pfeiffer | Aspahltic Bitumen as Colloid System[END_REF] to explain the difference between sol and gel bitumens. Ic typically ranges from 0.5 to 2.7 for road bitumens and is presented as follows [START_REF] Gaestel | Contribution à la connaissance des propriétés des bitumes routiers[END_REF]:

𝐼𝑐 = 𝑖 -𝐴𝑠𝑝ℎ𝑎𝑙𝑡𝑒𝑛𝑒𝑠 + 𝑆𝑎𝑡𝑢𝑟𝑎𝑡𝑒𝑠 𝐴𝑟𝑜𝑚𝑎𝑡𝑖𝑐𝑠 + 𝑅𝑒𝑠𝑖𝑛𝑠
Durabilité des enrobés tièdes intégrant des recyclés -56 -

Physical characterization

Atomic force microscopy (AFM)

Atomic force microscope Multimode TM connected to a Nanoscope IV scanning probe microscope controller (Digital Instruments, VeecoMetrology Group Inc., Santa Barbara, USA) placed over a vibration isolator is used for images acquisition. This technique is used to measure phase and topography in order to characterize the microstructural features of the surface of the bitumen samples. It reflects possible colloidal and intermolecular interactions in the binder as well as its chemical composition.

Bitumen films are prepared by applying gout of sample onto a 12 mm steel disk. The samples are prepared by heat-casting, a method that causes a negligible effect on the material morphology if compared to solvent-casting [START_REF] Partal | Effect of processing temperature on the bitumen/MDI-PEG reactivity[END_REF]. The disk is then heated on a heater plate at 110°C for a short period of time while turning it for assuring its spread on a thin film, this process is repeated several times. The film is afterwards cooled at room temperature and covered to prevent dust pollution, and annealed for 96 hours before testing. This annealing is performed to allow the ordering of the asphaltenes responsible for steric hardening [START_REF] Masson | Bitumen morphologies by phase-detection atomic force microscopy[END_REF]. For each bitumen disk, topographic and phase-lag AFM images of 50 x 50 µm 2 and 20 x 20 µm 2 are acquired in piezoelectric tapping mode at 40°C. In all cases, two tests of each sample are carried out at stress control mode, but to be sure that the samples remain in the linear domain, a stress sweep is performed at each testing temperature for each sample.

In addition, with the aim of controlling the contraction effects that the samples may suffer at low temperatures, special attention is taken for the PP08 test. Bitumen as many other materials is contracted when the temperature decrease. In order to control that there is no loss of contact between the device and the sample, a cooling rate of 1°C/min is established, imposing at the same time a normal force of zero on the sample. This last condition maintains the contact as the sample is contracting. However, during the test it is removed so there is no normal force applied on the sample. shows the standards used to calibrate the apparatus curves. The molecular weights are then calculated by integration of the peaks from 500 to 30,000 g/mol.

GPC measurements are carried out on 0.1 wt.% solutions in THF. Each bitumen sample is dissolved in THF and filtered through a 0.45 µm syringe filter prior to the injection. Each test lasts for 18 minutes, and is repeated three times. The average value is taken as material molecular weight distribution.

δ-method calculus

It has been generally assumed that Molecular Weight Distribution (MWD) of bitumen and its rheological properties can be related [START_REF] Lesueur | The colloidal structure of bitumen: consequences on the rheology and on the mechanisms of bitumen modification[END_REF][START_REF] Tuminello | Determining molecular weight distributions from viscosity versus shear rate flow curves[END_REF][START_REF] Wu | Characterization of polymer molecular weight distribution by transient viscoelasticity: Polytetrafluoroethylenes[END_REF][START_REF] Tuminello | Molecular weight and molecular weight distribution from dynamic measurements of polymer melts[END_REF][START_REF] Zanzotto | Molecular weight distribution of regular asphalts from dynamic material functions[END_REF]]. Themeli's work in 2015 [START_REF] Themeli | Etude du potentiel d'emploi des bitumes naturels dans la production des liants bitumineux durs et des enrobés à module élevé[END_REF], suggests that the phase angle (δ) of the complex modulus for a given frequency is proportional to the fraction of relaxed molecules at this frequency. It considers the material as a combination of monodispersed molecular weight (MW) species, so therefore, a relationship between the oscillation frequency and the MW of the material can be established [START_REF] Themeli | Molecular weight distribution of asphaltic paving binders from phase-angle measurements[END_REF].

From vapour pressure osmometry measurements, Zanzotto established a relationship between the crossover frequencies (ω(co), i.e. storage modulus equal to loss modulus) at a temperature T=0°C and the MW [START_REF] Zanzotto | Molecular weight distribution of regular asphalts from dynamic material functions[END_REF], defined by the formula:

log (MW) = 2.880 -0.06768•log(ω) (1)
When this equation is applied to the frequency axis of the phase angle master curve, it can be plotted as a function of the MW. Considering the hypothesis that the cumulative molecular weight distribution, cumf, is proportional to the phase angle master curve, the formula that relates both can be obtained. Where f is a differential distribution, A and B are the proportionality constants which are calculated from the boundary conditions:

for MW → 0 δ(MW)=0° cumf(MW)=0 for MW → ∞ δ(MW)=90° cumf(MW)=1
As a result of the calculus, A = 0 and B = 1/(90°).

It should be noted that, according to these assumptions, the cross-over frequency, δ(MW)=45° corresponds to the median of the AMWD probability distribution, cumf(MW)=0.5.

If this last formula (2) is differentiated, the differential molecular weight distribution (DMWD) can be calculated [START_REF] Themeli | Molecular weight distribution of asphaltic paving binders from phase-angle measurements[END_REF]. The differentiation can be obtained numerically according to the equation:

𝑓(𝑀𝑊) = 𝑑𝑐𝑢𝑚𝑓(𝑀𝑊) 𝑑𝑙𝑜𝑔𝑀𝑊 ≅ ∆𝑐𝑢𝑚𝑓(𝑀𝑊) ∆𝑙𝑜𝑔𝑀𝑊 (3)
This differentiation requires a continuous curve, so the data from DSR measurements must be fitted with a continuous model. The Huet-Such model parameters fitted as describe in §2.4 are used for this purpose.

The numerical differentiation was carried out applying a numerical differential step of 1/3,000 to the log (MW) in order to achieve the convergence. The MWD is termed "apparent" because the proportionality to the phase angle, proved for polymers, is assumed for bitumen in this study.

This assumption is still to be confirmed. The word "apparent" is also used because the δ-method appears to capture the effect of groups of molecules (like clusters of asphaltenes) and not only individual molecules.

Chapter 3 -Physico-chemical study of bitumens -61 -

Testing results

In this section all results are presented, analysed and discussed. The structure is divided in five points as Figure 3-12 summarizes. In the first place both malthenes and asphaltenes phases from both neat bitumens are characterized. Secondly, the protocol of bitumen fractions separation and reconstitution is validated. This decision is taken in order to avoid solvents waste in the case that recomposition of bitumens is inaccurate. Then all results for the model bitumens are exposed, followed by the results concerning the bitumens aged in laboratory conditions. Finally, a relationship between laboratory ageing bitumens and model bitumens is assessed.

Asphaltenes and malthenes characterization

As it is described in Materials and Methods Model bitumens section, both neat bitumens are separated in their two principal phases, asphaltenes and malthenes. With this purpose, this first section analyses the characteristics of both malthenes and asphaltenes from both neat bitumens.

ATR-FTIR results

ATR-FTIR is used to differentiate the quality of the bitumen fractions separation protocol. With this type of analysis the presence of solvent (n-Heptane) is traced.

TGA results

Thermogravimetric analysis is only performed on the c7-asphaltenes phases. Results presented in Figure 3-14 show the loss of sample weight in % (straight line) and its derivative as respect to temperature (dashed line) for the two tests (A-1 and A-2) per sample.

It can be observed that there is no specific kinetics reaction of asphaltenes below 300°C, which is far from conventional mixtures manufacturing temperature (160°C). However, weight loss of

SARA fractions

Bitumen chemical composition can be commonly described by its content of saturates, aromatics, resins and asphaltenes, or SARA fractions [START_REF] Corbett | Composition of Asphalt Based on Generic Fractionation Using Solvent Deasphalteneing, Elution-Adsorption Chromatography and Densiometric Characterization[END_REF][START_REF] Petersen | Chemical Composition of Asphalt As Related To Asphalt Durability: State of the Art[END_REF]. As it is described in the methodology §3.2.2, this analysis is done with a thin layer chromatograph, Iatroscan MK-6s.

Results from fractions separation, 100M (100% malthenes) and 100A (100% asphaltenes), are summarized in Table 3-4. In general, they show very similar SARA content for each fraction. On the one hand, both malthenes fractions present a high content of aromatics, going up to 86% in the case of 50/70 100M. Moreover, due to solvent employed, malthenes phase presents certain presence of asphaltenes (i-asphaltenes). In terms of Ic, values are very low which recalls the softness of the material (Ic<0.22 leads to a softer material [START_REF] Paliukaitė | Evaluation of bitumen fractional composition depending on the crude oil type and production technology[END_REF]). On the other hand, asphaltenes phases present traces of saturates and aromatics. But again, the presence of resins in this case, it is due to the solvent (toluene) employed for fractions separation. The value of Ic is not really important here because such as values are not found on road bitumens, as they are more like a solid rather than a viscoelastic material.

DSR results: Overlapping temperature results

Regarding rheological testing, as it is mentioned on the methodology, the results of both DSR geometries PP25 and PP08 at the overlapping temperatures are compared. This is needed to prove that the material has the same rheological response with both geometries, and in order to achieve a smooth and complete Black diagram [START_REF] Airey | Use of Black Diagrams to Identify Inconsistencies in Rheological Data[END_REF]. In the following figures, Figure 3 On the other hand, in Figure 3-17 the differences between PP25 and PP08 geometries are at high frequencies. In order to avoid compliance of the apparatus with PP25 geometry, results from PP08 are taken into account for the calculus of the master curve. After testing the asphaltenes on the TGA and remark their superposed response, the idea is to test the malthenes phase. Rheological behaviours for malthenes fractions are identical. In the case of the -method, where the model curve is derived from the black diagram, it is then normal to find equivalent distributions.

Conclusion

Bitumen main phases, asphaltenes and malthenes, are very similar for the two different neat bitumens. However, even if they are composed of the same components, they don't show the same consistency, neither the sale rheological behaviour. This could indicate that the asphaltenes/malthenes ratios would play an important role.

Validation of the recomposition protocol

After characterizing both malthenes and asphaltenes phases from the neat bitumen, in this section neat and model bitumen are compared in order to validate the process of recomposition.

ATR-FTIR results

ATR-FTIR is used to differentiate the quality of the bitumen model manufacturing protocol .

Additionally, it is employed as ageing detector through Ico and Iso characterization,. With this type of analysis the presence of solvents (Dichloromethane) is traced. Ico and Iso values are calculated to check the influence of the process on these indicators. First results show no difference in terms of neat spectra. This is not surprising due to the fact that this type of analysis is not adapted to distinguish bitumens grades [START_REF] Pieri | Etude du vieillissement simulé et in situ des bitumes routiers par IRTF et fluorescence UV en excitation-émission synchrones : détermination des relations structures chimiques -propriétés rhéologiques par analyse en composantes principales[END_REF]. The chemical composition of both bitumens is the same at the FTIR scale. sulphoxide (1,030 cm -1 ) peaks. Table 3-6 summarizes Ico and Iso values for all bitumens. Both neat bitumens do not exhibit carbonyl groups but they do show sulphoxide groups already. In addition, it seems that sulphoxide groups are more sensitive to the process of reconstitution, due to the higher values exhibited by the recomposed bitumens. This could be due to the polarity of asphaltenes. When added to malthenes phase, they have a tendency to connect better with sulphoxide groups [START_REF] Guern | Physico-chemical analysis of five hard bitumens: Identification of chemical species and molecular organization before and after artificial aging[END_REF].

SARA fractions

In this section, SARA fractions are measured in order to see the presence of each fraction in the total system. Results from fractions separation are summarized in Table 3-7 differentiating between i-asphaltenes and c7-asphaltenes. They show very similar content for each fraction. It should be remarked the high content of aromatics in all bitumens. i-Asphaltenes and c7-asphaltenes do not have the same presence on the bitumens. This is due to the solvent employed for their separation. Some researchers [START_REF] Planche | Identification of chemical species and molecular organization of bitumens[END_REF] have defined this difference as "polar resins" that are trapped in the i-asphaltenes. In terms of SARA fractions, bitumen recomposition respects the balances between fractions.

Moreover, in the last column of Table 3-7, the colloidal indexes are calculated. The colloidal index typically ranges from 0.5 to 2.7 for current road bitumens. A marked gel (non-Newtonian behaviour) character is observed for Ic>1.2 and a typical sol (Newtonian) behaviour is found for Chapter 3 -Physico-chemical study of bitumens -71 -Ic<0.7 [START_REF] Lesueur | The colloidal structure of bitumen: consequences on the rheology and on the mechanisms of bitumen modification[END_REF][START_REF] Gaestel | Contribution à la connaissance des propriétés des bitumes routiers[END_REF]. Overall, all bitumens seem to present sol behaviour. Model bitumens present a slightly inferior value of Ic, but still it is very similar to the corresponding neat bitumen.

In Figure 3 On the other hand, 35/50 85M+15A bitumen images (b) and (d) reveal the development of small structures at the bitumen/air interfaces exhibiting rippled surface (some bees) as it is found by other researchers when recomposing the asphaltene-malthenes phases [START_REF] Hofko | Impact of maltene and asphaltene fraction on mechanical behavior and microstructure of bitumen[END_REF]. They may not be as clear as 35/50 Neat bitumen images, but their distribution within the image does.

According to these observations, after bitumen separation and recomposition, bitumen microstructure is very similar.

Rheological performance

All tests are performed under the same conditions, as it is described in Materials and methods section § Complex shear modulus test. Overlapping temperatures are 30°C, 25°C and 15°C for PP25 and PP08. Then, the most suitable temperature is chosen for assuring a smooth Black diagram [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF].

All coupling results are presented in Annex 1. As a summary, it can be said that in general, at 30°C there is a difference at low frequencies in the phase angle  and tan () response for the PP08 geometry. It is considered that PP08 is a too small geometry to study the material response at this temperature. In contrast, the response of the material for the PP25 geometry at 15°C is not accurate. The measuring system gets to compliance of the device due to the needed torque in order to stress the material at the required level at high frequencies, as δ(°) and tan(δ) show.

Huet-Such modelling

Once the master curves of all bitumens are constructed, following the same procedure described in the previous section, the modelling can be applied.

δ-method analysis results

The δ-method analysis is focused on the changes on the apparent molecular weight distribution.

The AMWD is illustrated in Figure 3-27 in the range between 100 and 10,000 g/mol in logarithmic scale with the ordinate axis corresponding to the probability density f(AMW), including cross-over frequency points ω(co). difference in asphaltene content show a similar curve. In Figure 3-27 (d), it can be observed the similarity on the curve distribution for both neat bitumens. All characteristics (penetration, softening point, asphaltene content and rheological behaviour) showed that 35/50 bitumen is harder than 50/70. The δ-method does as well but the difference is not very important. In the same way, the value of the cross over frequency is slightly different with a trend to move to higher AMW.

GPC results

The GPC results from 35/50 bitumens are used to have an indication of the variation in molecular size from a more conventional test. When a bitumen sample is dissolved in a solvent (THF), the different molecules separate. Then if the solution is applied to the top of the porous column, the smaller molecules are distributed through a larger volume of gel than is available to From both figures it can be noted again the similarity between curves. Higher molecules seem to appear at highest concentrations at 7 min of retention time, corresponding to 10,000 g/mol of average molecular weight. Besides, at 8.8 min the peak of the smaller molecules is obtained, corresponding to 1,000 g/mol of molecular weight. The red bands in the borders correspond to extrapolation calculus, as the column only covers between 500 and 30,000 g/mol.

Moreover, Table 3- As to the MW obtained from the GPC spectra, model bitumen seems to have higher MW than the Neat bitumen. Durabilité des enrobés tièdes intégrant des recyclés -76 -

Conclusions

Bitumen recomposition is possible in laboratory using dissolution and recomposition processes described in this thesis. The responses obtained by recomposed model bitumens are quasi equivalent in general to the neat bitumens. There is a big difference between manufacturing procedures, refining versus laboratory recomposition. However, bitumen response is not so different. This step validates the process of separation and recomposition for further analysis.

Model bitumens at different m/a ratios

Once the separation-recomposition protocol is validated for the reference bitumens the rest of the model bitumens could be manufactured. In the following subsections the line of analysis is going to be the same as before. In general, it can be highlighted that the dichloromethane solvent extraction protocol is not 100% assured in all cases. It seems that there are still traces in the model bitumens for both types and at different ratios. Moreover, the variation of asphaltenes content has led to variations in the ATR-FTIR spectra. For example 50/70 91M+9A model bitumen presents higher absorbance between 1,100 and 1,000 cm -1 , which is not usually common in bitumens spectra.

ATR-FTIR results

The changes of other molecular structures (e.g. benzene, methylene and methyl) can also reflect the chemical modification of bitumen [START_REF] Feng | FTIR and rheology analysis of aging on different ultraviolet absorber modified bitumens[END_REF], as the increment on the C=C bonds for the asphaltene phase in both bitumens. Regarding Ico and Iso values, the influence of manufacturing process in possible ageing of the samples is summarized in Table 3-9. There is no real correlation between the m/a ratio and the evolution of aging indexes. Carbonyls groups are commonly employed for tracing ageing evolution. However, in this case the material is not naturally aged, so the measure of Ico can be influenced by the increase of C=C bonds at 1600 cm -1 . On the other hand, sulphoxide groups are one of the most polar parts of the bitumen, so then the asphaltenes play an important role on the increase of this value [START_REF] Guern | Physico-chemical analysis of five hard bitumens: Identification of chemical species and molecular organization before and after artificial aging[END_REF].

SARA fractions

The different family fractions are measured in order to see how they vary according the different c7-asphaltene content. Iatroscan separation results are organized by c7-asphaltenes content. Generally, the i-asphaltenes (i-Asph) content follow the same track. It can be observed that the increment of asphaltenes on the blend is inversely proportional to the aromatics. The equilibrium between fractions will play a role on the colloidal index stability.

Asphaltenes and saturates are the highest and lowest fractions in polarity, and the solubility of the first ones in the colloidal system is enriched by the presence of aromatics and resins, intermediate polarity fractions [START_REF] Oliver | Changes in the Chemical Composition of Australian Bitumens[END_REF]. Then, as happens with the 100% asphaltene fraction, the highest the Ic the more unstable is the system. For an almost constant rate of saturates in all model bitumens, the increase on the asphaltenes content has a direct impact on the Ic, increasing its value, so hardening the resulting bitumen.

AFM results

Atomic force microscopy on model bitumens is presented in Figure 3 asphaltenes, (e-f) 10% asphaltenes and (g-h) 100% malthenes. All images are topographic providing microstructural overview by 50x50 µm 2 on top and 20x20 µm 2 on the bottom images.

In general, in all model bitumens independently of their asphaltenes content the catana or beelike structure can be distinguished, even if the size is not always constant. Qualitative the cooling rate of the sample. In this case, cooling ratio was not controlled. After samples preparation at 110°C they were left freely to cool to room temperature (~25°C), leading the asphaltenes to participate as "cold spots" [START_REF] Merce | Importance of thermal gradient in the bitumen bees genesis[END_REF].

All these measurements show only bitumen surface characteristics. They seem very powerful but they require very strict protocol for sample preparation and thermal conditioning.. Any change on the methodology may change the surface visualization and conclusions about bitumen characteristics.

Rheological performance and Huet-Such modelling

DSR testing is performed for the model bitumen under the same conditions, as it is described in Materials and methods section §3.2.3 Complex shear modulus test. After doing the coupling between geometries and dealing with the same problems of compliance as in the previous subsection, rheological master curves are built at T = 0°C.

Then, once the master curves are constructed, Huet-Such modelling is applied. All results from bitumen modelling, including parameters values for the fitting are included and resumed in Annex 3. Rheological behaviour shows in both types of bitumens a clear difference by their asphaltene content. In this sense it could be assured that the increase of asphaltene content induces an evolution similar to the hardening experienced by the bitumens with ageing.

δ-method analysis results

After applying the δ-method calculations, Figure 3-33 presents the AMWD in the range between 100 and 10,000 g/mol with the ordinate axis corresponding to the probability density f(AMW), including cross-over frequency points ω(co).

As the asphaltene content increases, a shift of the curve to the right (towards higher AMW) is observed. Also, the shape of the curves evolves from mono-modal, to bimodal or tri-modal distribution. As well, the cross-over frequency points moves towards higher AMWs and lower f(MW). highest peak corresponds to the malthenes fraction of the bitumen. This is a fraction without c7-asphaltenes so it can serve as reference of how everything changes when the c7-asphaltenes fraction is added. The increment of 10% of c7-asphaltenes has a drastic effect on the rheological behaviour: the bitumen becomes "harder". The change from an almost mono-modal distribution to bi-modal distribution is clear as the increase of the cross-over frequency.

Then, another 5% of asphaltenes is added to have the 35/50 85M+15A model bitumen. This bitumen is the one that represents the neat bitumen curve, the middle point of the study. Again the shift is towards higher AMW, cross-over frequency keeps increasing and the bi-modal distribution is more accused, bitumen is becoming harder. Finally, the highest asphaltenes content of 20% that turns the curve to tri-modal distribution. Differences between all model bitumens are led by the addition of asphaltenes to the malthenes phase.

GPC results

The GPC results from 35/50 model bitumens are used to have an indication of the variation in molecular size. Regarding the trends obtained from δ-method analysis, the decision of applying GPC on one type of model bitumen is done. What is expected from this test is to see the increase of concentration of high molecular weight due to the increase of asphaltene content on the system. The second big family of molecules is centred at 8.9 min and in could simply be called malthenes family. The peak of the 35/50 100M (only malthenes) is the one supporting this denomination.

Again, the decrease in malthenes content follows the inverse trend of the asphaltenes.

When talking about molecular weights instead of retention times, as Figure 3-34 (b) illustrates.

The two "big families" are centred at 1,000 g/mol (malthenes) and 10,000g/mol (asphaltenes). Weight of average molecular weight (Mw) is around 1,100 g/mol. Mn and Mw increase with the addition of asphaltenes. The general trend for all parameters is the increase of value as the rate of asphaltene content increases. On the other hand, it does not mean that polydispersity follows the same tendency. Actually, PDI remains around 1.42 for the three model bitumen showing an intermediate distribution of molecules.

Conclusion

Model bitumens have represented the changes that produce the asphaltenes on the bitumen.

They provide the stiffness to the material by interconnecting fractions within its colloidal distribution. Based on other studies, on AFM it is seen that the sign of bee-like structures is not obvious and directly linked to the asphaltene content. However, rheologically speaking, the increment of asphaltenes gives a straight forward increase of bitumen stiffness. This influence is also observed on the δ-method curves and on the GPC molecular weight measurements.

Durabilité des enrobés tièdes intégrant des recyclés -84 -

Laboratory aged bitumens

With the aim of relating ageing with the ratio of m/a on the bitumen, in this section Neat bitumens are submitted to laboratory ageing procedures, RTFOT and PAV. Table 3456789101112summarizes the ratio of malthenes and asphaltenes of each aged bitumen.

ATR-FTIR analysis

In this case bitumens are not submitted to any separation in n-heptane or recomposition in dichloromethane, so ATR-FTIR analysis will just look for the Ico and Iso variations with ageing. Sulphoxide index, Iso, increases rapidly their values. Growth ratio is much higher than Ico that varies from 0% for Neat bitumen, to 3.94% in the case of 50/70 PAV. These parameters by themselves do not indicate the level of ageing of the material. They always need to be presented as an evolution.

SARA fractions

In order to add more information and to know more about the internal changes on the bitumens with ageing, the different family fractions are measured. Table 3-14 summarizes the SARA fraction results, differentiating between i-asphaltenes and c7-asphaltenes for all aged bitumens. The evolution of fraction families is very similar for both 35/50 and 50/70 bitumens. Aromatics decrease with ageing. In contrast i-asphaltenes increase. There is no obvious general trend for Durabilité des enrobés tièdes intégrant des recyclés -86 -saturates and resins. Moreover, colloidal indexes also increase with ageing, representing a hardening of the material (still all show typical sol behaviour, Ic<0.7 [START_REF] Lesueur | The colloidal structure of bitumen: consequences on the rheology and on the mechanisms of bitumen modification[END_REF][START_REF] Gaestel | Contribution à la connaissance des propriétés des bitumes routiers[END_REF]). This Ic increase is mainly led by the asphaltenes and the reduction on the aromatic fraction.

δ-method analysis results

Subsequently the δ-method calculations are applied, Figure 3-38 shows the AMWD in the range between 100 and 10,000 g/mol with the ordinate axis corresponding to the probability density f(AMW), including cross-over frequency points ω(co) of the aged bitumens.

As it has been presented, ageing (or asphaltenes content increase) induces growth of the higher molecular weights. On the δ-method curves, it is illustrated as a displacement of the curve to the right, with a possible evolution of the shape of the curve from mono-modal, to bimodal or trimodal distribution. However, Figure 3-38 (b) shows that the fitting process for the angle is not as accurate as for the |G*|. This leads to overestimate peaks in the distribution. As well, the cross-over frequency points moves towards higher AMWs and lower f(MW).

The differences between curves reflects evolutions of particles inside bitumen, aromatics evolve to resins and then to polar resins and asphaltenes. These results are in accordance with the literature. It is described that with ageing, part of the oily fraction (mainly resins) seems to be absorbed by the asphaltenes and dispersed in the light matrix [START_REF] Lesueur | The colloidal structure of bitumen: consequences on the rheology and on the mechanisms of bitumen modification[END_REF][START_REF] Guern | Physico-chemical analysis of five hard bitumens: Identification of chemical species and molecular organization before and after artificial aging[END_REF]. Molecules are reorganized into new colloidal system and could produce some clustering as well. Looking at the values of number average molecular weight (Mn), weight average molecular weight (Mw), they increase with ageing. Table 3-15 resumes the results of GPC average molecular weights. On the other hand, if polydispersity (PDI) is represented versus the asphaltene content of each bitumen (Figure 3-40), the trend followed is equivalent to the one obtained for the cross-over frequencies of the δ-method.

Conclusions

After chemical and physical characterization of 35/50 Neat, RTFOT and PAV bitumens, the central point of the study is the asphaltenes fraction. Bitumen principal families, saturates, aromatic, resins and asphaltenes modify their presence on the material with ageing, raising up or decreasing their content. But among them, the asphaltenes phase plays the most important role by increasing the stiffness of the material.

Relationship between laboratory ageing and model bitumens

In this section, model bitumen with high c7-asphaltenes content (35/50 80M+20A) and ageing bitumen (35/50 PAV) are compared.

ATR-FTIR spectra shows in Figure 3-41 the difference between bitumens on the pointed peaks, Ico (1,700 cm -1 ) and Iso (1,030 cm -1 ) respectively. Compared with the Neat bitumen (Ico 0.00% and Iso 5.71%) the 20A model bitumen does not show much variation in terms of Ico (0.09%).

However, in relation to Iso (12.60%) separation and recomposition procedure have make it grows. On the other hand, after PAV bitumen experiences an increase of both indicators due to the chemical evolutions (Ico 3.22% and Iso 20.10%). Regarding to rheological, the response master curves at T=0°C of both bitumens are shown in The differences seen between the two methods could be related to the type of sample preparation. δ-method curves come from rheological measurements and modelling derivation.

In contrast, GPC curves depend on the measuring method and testing conditions [START_REF] Lesueur | La rhéologie des bitumes: Principes et modificiation[END_REF] that come from the dilution and molecular separation of the bitumen. GPC do not take into account the interaction between molecular species. What can be highlighted from this comparison is that aged bitumen and bitumen with high asphaltenes content can have the same mechanical response with a different origin of the asphaltenes part.

Conclusions

In this chapter, a study of the influence of the asphaltene content is carried out both in neat, model and laboratory aged bitumens. The objective is to evaluate the influence of this fraction on the physical and chemical characteristics of bitumen and to understand the effects of aging on chemical species and their organization. From the results obtained during the investigation the following conclusions can be drawn:

i.

In terms of ATR-FTIR analysis, sulphoxide groups seem to be more affected by the addition of asphaltenes fractions than carbonyl groups, indicating the affinity of polar fractions towards these components.

ii. By Iatroscan chromatography for SARA fractions determining, it can be observed that asphaltenes increase with ageing. It has also been exposed that during aging the increase in asphaltenes content is due to the association of aromatics to resins (and polar resins)

and then to asphaltenes. In addition, the oxidation of aromatics or resins to polar resins or asphaltenes is also possible during aging.

iii. By AFM observation, asphaltenes micelles appeared in all bitumens tested. Then in the malthenes fraction bee-like structure is present, so the presence of asphaltenes is not mandatory for their apparition as other researchers have stated already.

iv. Rheological behaviour is linked to the asphaltenes content of the bitumen. Finalement, l'effet de vieillissement est évalué par l'analyse de la -méthode décrite dans le chapitre précédent. Le potentiel de la δ-méthode comme outil d'étude du recyclage est évalué.

Introduction

The reduction of the manufacturing temperature of asphalt mixtures and the re-use of materials from old pavements, usually classified as solid waste disposals, present numerous advantages compared with traditional HMA. The use of WMA and RAP separately are not new concepts, however innovation related to their combined application and performance is still ambiguous in terms of durability. Both techniques present their own benefits and drawbacks [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF][START_REF] Zaumanis | Warm Mix Asphalt Investigation[END_REF], as to durability issues, rutting or low temperature resistance that could be compromised during their service life. There are many environmental advantages associated with using these techniques, including reduction in fuel consumption and greenhouse gas emissions, reduced extraction of natural aggregates and disposal of old asphalt [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF][START_REF] Hamzah | Evaluation of the potential of Sasobit® to reduce required heat energy and CO2 emission in the asphalt industry[END_REF][START_REF] Rubio | Comparative analysis of emissions from the manufacture and use of hot and half-warm mix asphalt[END_REF][START_REF] Rubio-Gámez | Mechanical properties of hot bituminous mixes manufactured with recycled aggregate of Silestone(R) waste[END_REF].

As it has been described in Chapter 2, warm mix asphalts are produced in the range of temperature of 140°C and 110°C. And three different processes that enable this temperature reduction can be distinguished. They are the foaming of bitumen, the use of chemical additive and the use of organic additives.

Those same processes that reduce energy consumption and improve workability in WMA technologies also allow them to act as compaction agents [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF][START_REF] Kristjansdottir | Warm Mix Asphalt for Cold Weather Paving[END_REF]. These improvements on compaction and densities achieved in situ tend to reduce permeability and bitumen ageing, which generally results in better performance of the blends in terms of crack resistance and moisture sensitivity [START_REF] Angelo | Warm-Mix asphalt : European Practice[END_REF].

Regarding RAP, this material can fulfil the requirements for a sustainable pavement solution. It can present material cost savings while reducing the environmental impact of the asphalt manufacturing stage by 23% [START_REF] Chiu | Life cycle assessment on using recycled materials for rehabilitating asphalt pavements[END_REF]. RAP is usually considered a stiffer material due to the aged bitumen, which can promote unexpected failures [START_REF] Xiao | Rutting Resistance of Rubberized Asphalt Concrete Pavements Containing Reclaimed Asphalt Pavement Mixtures[END_REF] depending on the percentage content in the new mixture.

Several authors have investigated the different stages of ageing of the asphalt binder during the mix manufacture and the pavement service life [START_REF] Elseifi | Reclaimed asphalt pavement -A literature review[END_REF][START_REF] Karlsson | Material-Related Aspects of Asphalt Recycling-State-of-the-Art[END_REF][START_REF] Roberts | Hot Mix Asphalt Materials, Mixture Design and Construction. Second Edi[END_REF][START_REF] Thyrion | Asphalt Oxidation, Asphaltenes and Asphalts[END_REF]. Two phases can be distinguished:

short term ageing and long term ageing. Short term ageing takes places during manufacturing and construction of the road, and leads to an increase in bitumen viscosity. Meanwhile, long term ageing depends on the time of service and is related to progressive ageing by various mechanisms. Both types of ageing are associated with numerous phenomena, such us oxidation, evaporation of lighter components, thixotropy and syneresis, polymerization through chemical reaction of molecular components or components separation through the absorption of oily constituents by some type of aggregates [START_REF] Elseifi | Reclaimed asphalt pavement -A literature review[END_REF][START_REF] Thyrion | Asphalt Oxidation, Asphaltenes and Asphalts[END_REF].

Durabilité des enrobes tièdes intégrant des recyclés -96 -

The current knowledge on ageing is essentially gained from practical experience on traditional asphalt mixes and typically on HMA. However, the road industry has embraced recycling and developed new techniques, particularly with WMA in order to limit its environmental impacts.

Within this framework, the objective of this chapter is to study and compare the foamed asphalt technique for WMA production when 50% of RAP is added to the mixture. For that reason, an ageing protocol is followed within the lines proposed by the RILEM TC-ATB TG5, consisting of two separate ageing phases. Mixtures long term related performances are compared by means of complex modulus and fatigue testing. Penetration and softening point tests are undertaken on the recovered bitumens. Ageing evolution is also characterised by the Fourier Transform Infrared analysis.

Finally, the ageing effect is evaluated through the δ-method analysis described in the previous chapter. The potential of the δ-method as a tool for recycling studies is assessed.

Materials and methods

Mixtures

With the aim of comparing different manufacturing techniques, three types of mixtures are chosen for the study. One hot mix asphalt of reference and two warm mix asphalts, one with a surfactant product and the other under the foaming process. The reference hot mix asphalt and the warm mix asphalt with surfactant were initially designed by Manuela de Mesquita Lopes in her thesis [START_REF] De Mesquita | Avaliação da durabilidade de misturas asfálticas a quente e mornas contendo material asfáltico fresado[END_REF] and are now used in this work as comparison.

The reference mixture is an AC1O, typically used as both a thick surface/structural layer.

Figure 4-1 illustrates the grading curves and design of the mixtures. In all cases, a constant bitumen content of 5.4% [START_REF] Lopes | Durability of hot and warm asphalt mixtures containing high rates of reclaimed asphalt at laboratory scale[END_REF] is selected. A MLPC BBMAX 80 is used as mixer. The working sequence lasts for 75 seconds, with 15 seconds for the aggregates and fines mixing (and RAP when used) plus 60 seconds after the addition of the bitumen. RAP is preheated for 2h at 110°C before manufacture, whereas virgin aggregates are heated at different temperatures depending on the type of mixture as shown in Table 4-1.

Chapter 4 -Ageing evolution of WMA combined with RAP -97 -

Materials

Bitumen

The neat bitumen chosen for the manufacture of all mixtures is conventional 35/50 bitumen with a penetration index of 37 [1/10 mm] (EN 1426) and a softening point temperature of 53.8°C (EN 1427). This bitumen is the same type of bitumen from RAP.

For the first WMA, the WMA with surfactant, the base bitumen was chemically modified by adding a surfactant product (CECABASE RT®) in laboratory [START_REF] De Mesquita | Avaliação da durabilidade de misturas asfálticas a quente e mornas contendo material asfáltico fresado[END_REF]. For the second WMA, using the foam technique, the foaming effect was produced by injecting 1.5% of water under pressure into the hot bitumen pipe during its introduction into the mixer. This type of mixture was manufacture at EIFFAGE Travaux Public facilities in Corbas, Lyon, as part of the Marie Curie project partnership [START_REF] Perez-Martinez | Ageing evolution of foamed warm mix asphalt combined with reclaimed asphalt pavement[END_REF][START_REF] Martinez | Durability analysis of different warm mix asphalt containing reclaimed asphalt pavement[END_REF][START_REF] Perez-Martinez | Effects of Ageing on Warm Mix Asphalts with High Rates of Reclaimed Asphalt Pavement[END_REF].

Durabilité des enrobes tièdes intégrant des recyclés -98 -

Virgin aggregates

Gneiss rock, the original aggregate from RAP, is the virgin aggregate used for both coarse and fine fractions (0/2, 2/6 and 6/10 mm) in order to retain continuity between grading curves.

Ageing procedure

The purpose of this ageing step is to characterise in laboratory the ageing experienced by the mixtures during road construction and its service life. This procedure is applied to 6 of the 12 mixtures manufactured. The ageing protocol carried out is based on the one proposed by the RILEM Technical Committee ATB TG5 [START_REF] De | Hot Recycling of Bituminous Mixtures[END_REF]. It consists of two phases of oxidative thermal ageing on asphalt mixtures, a short term ageing simulating the manufacturing and construction phase of the road and a long term ageing that reproduces the end of life of the pavement. The short term ageing is performed after manufacturing on the loose mix, and involves its heating at 135°C during 4h before compaction. Then, the long term ageing holds the mixtures for 9 days at 85°C in a ventilated oven. This step was performed on compacted samples.

Laboratory testing

Tests on mixtures

Complex modulus

To study the rheological and stiffness evolution of the mixtures, the complex modulus is measured according to EN 12697-26, Annex A (two point bending on trapezoidal specimens) between 1 Hz and 40 Hz, and from -10°C to 40°C. In all cases, four samples are tested for each mixture.

Fatigue resistance

The resistance to fatigue is determined according to EN 12697-24, Annex A (2PB on trapezoidal specimens) at 25 Hz and 10°C in strain controlled mode. The fatigue law curves are fitted on the experimental points by linear regression in a log-log diagram of number of cycles by strain level.

In order to compare the value of ε6 under the same air voids content (C), the formula ∆ε6 (µdef) = 3.3•∆C(%) [START_REF] Moutier | Etude statistique de l'effet de la composition des enrobés bitumineux sur leur comportement en fatigue et leur module complexe[END_REF] is used to correct the results. This formula allows the value of ε6 at 4.5% of voids to be evaluated and compared.

Tests on bitumen

After the 12 mixtures are manufactured and the ageing protocols applied, bitumen are extracted and recovered using the rotary evaporator for bitumen recovery following the EN 12697-3 standard. The aged bitumen from the RAP (35/50 RAP) is also recovered under the same procedure. Additionally, with the original (35/50 Neat) and the foamed bitumen (35/50 Foam), a total of 15 bitumen samples are tested.

Standard consistency tests

The standard consistency of the bitumen is characterized by the penetration depth (1/10 mm) (EN 1426) and the temperature of the softening point (°C) (EN 1427).

ATR -FTIR analysis

ATR-FTIR analysis is performed with the purpose of monitoring the ageing of the binders.

Carbonyl index, Ico, is calculated from the raw FTIR spectra according to the RILEM method [START_REF] Marsac | Potential and limits of FTIR methods for reclaimed asphalt characterisation[END_REF]. The limits on the spectra for carbonyl compounds are between 1.660 and 1.753 cm -1 while the reference area is between 1.350 and 1.525 cm -1 .

Complex shear modulus test

The determination of the complex shear modulus and phase angle is performed using the dynamic shear rheometer Kinexus® device to assess the rheological properties of the bitumen.

Modelling and δ-method representation

In this chapter, bitumen rheology is modelled following the procedure described in Chapter 3.

The modelling has followed the same principles, but with different device sources. Chapter 3 bitumen results are from Anton Paar MCR 501 DSR and in this chapter results are form Kinexus® device.

Moreover, from the different modelled master curves, the changes in rheology are also discussed via the determination of the rheological value (Rvalue) [START_REF] Christensen | Interpretation of Dynamic Mechanical Test Data for Paving Grade Asphalt[END_REF][START_REF] Rowe | Evaluation of a 100 % rap recycling project in Fort Wayne, Indiana[END_REF]. The Rvalue is the logarithmic distance between the value of the complex modulus |G*∞| from the model and at the crossover frequency (G'=G'', phase angle 45°). This index will allow assessing the ageing evolution of the materials. In general, cross-over frequencies decrease with ageing while R-values tend to increase.

𝑅𝑣𝑎𝑙𝑢𝑒 = log |𝐺 * ∞ | |𝐺 * 45°|
According to several authors [START_REF] Rowe | Evaluation of a 100 % rap recycling project in Fort Wayne, Indiana[END_REF][START_REF] Del | Design and characterisation of reclaimed asphalt mixtures with biobinder[END_REF], crossover frequency versus R-value could be used to visually evaluate binders' ageing as well as rejuvenation when RAP is used.

Analysis of results

In this section all results are presented as Figure 4-6 illustrates. The results analysis is divided in five points. In the first place, an analysis of the manufacturing technique is carried out. Secondly, the way these mixtures age is discussed. It is important to see how the different techniques evolve with time.

In addition, the influence of RAP addition and how it changes the response of the system is part of the third point, continuing with the evaluation of aged RAP mixtures. Finally, the last subsection tries to give a global perspective of the state of the materials for a first recycling step in the case of aged mixtures and second recycling phase for the mixtures with RAP. This last part should be taken into account for assessing the sustainability of each process.

Influence of manufacturing technique

This first analysis compares conventional HMA, WMA and FWMA processes in terms of stiffness and fatigue resistance. In addition, extracted bitumen responses to the manufacturing process are studied. The tests carried out are the standard indicators, penetration and softening point, and the characterization through rheology and the δ-method representation. This type of analysis is going to be repeated in all subsections. The results obtained for the dynamic complex modulus and the fatigue resistance, including the values of ε6 (strain level leading to 1,000,000 cycles) obtained and corrected to the target air voids of 4.5%, are presented in Table 4-6. Additionally, the values of penetration, softening point, carbonyl index and rheological index from the original, Foam and recovered bitumen are indicated.

Complex modulus

The values obtained for the dynamic complex modulus at 15°C and 10 Hz are all above the standard required for this type of mixtures (|E*|>7,000 MPa; EN13108-1). The stiffness modulus is similar for HMA0 and WMA0 and slightly lower for the FWMA process.

Fatigue

Fatigue laws of each procedure and the 95% confidence interval hyperboles are illustrated in Figure 4567. FWMA and WMA are similar (ε6c respectively 98 and 100 µdef) . In all cases, they could be considered on the limit of the standard (ε6 > 100 µdef).

Regarding to the slopes of fatigue law for the three mixtures, they can be considered equivalent.

Thus, the 15% more performance in terms of ε6 compared to warm procedures for the HMA0 can be assimilated to a translation of the fatigue law. This effect may be due to the ageing experienced by the bitumen during HMA manufacturing.

Durabilité des enrobes tièdes intégrant des recyclés -106 - Foaming process may preserve the bitumen but it somehow still needs to achieve certain levels of transformation in order to perform under the specifications. So then, harder bitumen (type 10/20 or 15/25) might be recommended for mixtures manufacture through the foaming process.

Dynamic shear rheometer

δ-method analysis

Furthermore, when regarding to δ-method representation, the so named AMWD is again illustrated and presented in Figure 4-11 with the ordinate axis corresponding to the probability density f(AMW). The cross-over frequency point ω(co) (i.e. storage modulus equal to loss modulus, G'=G'') is also plotted in the graphs for each bitumen.

Looking at Figure 4-11 (a) the four bitumens can be observed. Ageing is presented as a displacement of the curves to the right. Also as a decrease of the cross-over frequency value (w(co)).

The curve for the base bitumen 35/50 Neat shows an almost mono-modal distribution. Then, the distribution for FMWA0 bitumen, that has a very similar shape, shows the trend towards lower probability. In the case of WMA0 and HMA0 bitumens, the curves turn to bimodal look with HMA curve displaced to the right. All curves show a principal peak around 900 g/mol.

Chapter 4 -Ageing evolution of WMA combined with RAP -109 -At that point, hardening of bitumens could be ordered as Neat, FWMA, WMA and HMA.

Regarding w(co), the classification would be the same. Cross over frequencies tend to decrease with ageing or hardening (i.e. to appear at higher AMW). where it is described that, with ageing, part of the oily fraction (mainly resins) seems to be absorbed by the asphaltenes and dispersed in the light matrix [START_REF] Lesueur | The colloidal structure of bitumen: consequences on the rheology and on the mechanisms of bitumen modification[END_REF][START_REF] Guern | Physico-chemical analysis of five hard bitumens: Identification of chemical species and molecular organization before and after artificial aging[END_REF].

Rvalue -Ico -crossover frequency correlations

In addition, recovered bitumens are evaluated as well by comparing cross-over frequencies and carbonyl results with the R-value [START_REF] Rowe | Evaluation of a 100 % rap recycling project in Fort Wayne, Indiana[END_REF]. Figure 4-12 shows both associations. Firstly, ageing is traced by an increment of Ico.. Finally, the Rvalue , which is the logarithmic difference between |G*45°| and |G*∞|, provides a measure of stiffness in an equi-elastic state and at a given temperature (T = 0°C). So for the same elasticity level, it can be said that the greater the Rvalue the stiffer is the bitumen.

In Figure 4-12 (a) and (b), 35/50 Neat bitumen with Rvalue = 1.46 is the reference value. It corresponds to zero Ico and to the highest w(co). Consequently, the ageing effect by the manufacture process is expressed as a shift to higher Rvalues, higher Ico and lower w(co).

In this sense, it can be said that high temperature manufacture procedures results in more elastic and stiffer bitumens than warm procedures.

Influence of ageing

Table 4-7 summarizes the results obtained for the dynamic complex modulus and the fatigue resistances, for all procedures after ageing. As well, the values of penetration, softening point, carbonyl index and rheological value from the original, RAP, Foam and recovered bitumen are indicated. RAP bitumen is being added to the analysis with the aim of comparing the ageing experience in laboratory with bitumen aged on service. The foaming procedure does not age bitumen at the same ratio as WMA or as HMA does.

Besides, it seems that the lesser the ageing experienced by the bitumen during manufacture, the higher will be the ratio of ageing (Ico) during service life.

In Figure 4-14 penetration and softening point are shown before and after ageing. Comparing laboratory ageing procedure and natural ageing from RAP, it seems that the first one is more aggressive.

DSR results

Considering now the rheological performance of the extracted bitumen, they tend to have the same response. This observation is illustrated in Figure 4-15, where the master curves of the different aged bitumen are plotted with the 35/50 Neat bitumen. Although the response at medium/low frequencies is different depending on the procedure, the difference at high frequencies is not so clear at this scale. In this sense, the δ-method analysis may help to evaluate these differences.

From the measurements shown in Figure 4-15, it can be noted that the adjustment for the phase angle master curve may seem weak. However, the process of modelling calculus takes into account the cole-cole and the black plan, and both master curves. Indeed, these measurements highlight the quality needed for the test in order to be well modelled.

Durabilité des enrobes tièdes intégrant des recyclés -114 - the brittleness and scattering of performances. The greater stiffness of WMA0a may be explained as well by the presence of higher concentration of asphaltenes in the bitumen.

It is clear that this analysis would not be possible only considering the values of Ico or the standard indicators of penetration and softening point.

Rvalue -Ico -crossover frequency correlations

In Figure 4-17, Ico by Rvalue (a) and cross-over frequencies by Rvalue (b) are illustrated. In the first place, Ico normally increases after ageing more than after manufacture. For the analysis, Ico and Rvalue should increase always with ageing.

However, the evolution of cross-over frequencies and Rvalue seems to follow a more consistent relationship. The path towards higher Rvalues and lower cross-over frequencies of each pair of data is clearer than for the Ico evolution.

Once more, the Rvalue for WMA0a is the highest of all aged mixtures with a very low cross-over frequency. This difference in elasticity with the other aged materials would explain the fragility of the mixtures when tested to fatigue.

Influence of RAP addition

The specificity of mixtures with RAP is the presence of already aged bitumen in the mixture.

Complex modulus

The effect of RAP addition to the mixture is developed in the literature [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF][START_REF] Copeland | Reclaimed Asphalt Pavement in Asphalt Mixtures: State of the Practice[END_REF][START_REF] West | Reclaimed Asphalt Pavement Management : Best Practices[END_REF][START_REF] Kodippily | Performance of Recycled Asphalt Pavement Mixes -Comparing New Zealand Experience to American Experience[END_REF]. Our results mostly follow in general the same path. Regarding in detail, dynamic complex modulus has increased in 2,000 MPa for HMA50 and FWMA50, but for the WMA procedure, the difference with the original mixture without RAP is not clear within this test.

Fatigue

The fatigue performance of all materials in terms of ε6 increases with RAP, performing in all cases above the 100 µdef specified on the standards for these types of mixtures (EN 13108-1).

This could be a result of the increment of stiffness experienced by the addition of 50% of RAP [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF][START_REF] Copeland | Reclaimed Asphalt Pavement in Asphalt Mixtures: State of the Practice[END_REF][START_REF] West | Reclaimed Asphalt Pavement Management : Best Practices[END_REF][START_REF] Kodippily | Performance of Recycled Asphalt Pavement Mixes -Comparing New Zealand Experience to American Experience[END_REF].

Besides, slopes of fatigue laws do not vary much with RAP addition. In fact they experience a translation to higher resistances whatever the strain solicitation level is. In Figure 4-18 the fatigue laws for all procedures with 50% of RAP are illustrated (a-b-c) and the comparison with HMA0 (d) mixture as well.

In the case of WMA50 (b), the dispersion found on the results let some doubt on the performances of the material tested. Once again, it is not clear whether these high dispersions should be attributed to flaws in the test procedure, test execution or if it reflects the intrinsic properties of the mixtures.

Chapter 4 -Ageing evolution of WMA combined with RAP -117 -

Technical and environmental performances analysis

If the three techniques are compared, the conventional procedure for mixtures manufacture HMA shows higher results than warm techniques, despite all perform above minimum required on the standards. However, warm materials with 50% of RAP, are produced 30°C lower. This could be considered as more efficient materials from an environmental point of view.

Ageing, Ico, penetration and softening point discussion

Additionally, in Figure 4-19 penetration and softening point results are shown. As expected, the addition of RAP makes the bitumen stiffer, due to the presence of the already aged bitumen.

DSR results

Figure 4-20 illustrates the master curves obtained from rheological testing of all bitumens. The rheological evolution of bitumen blending during manufacture follows the trend observed for the standard indicators. The "softer" bitumen would be the one from the foaming process even having a greater Ico index, while the "harder" would be the conventional HMA procedure.

Master curves are very close, but still HMA50 is harder than WMA bitumen. The softest of the three bitumens is the FWMA50.

-method analysis

For an accurate development of the analysis, the data obtained at low temperatures with the dynamic shear rheometer is very important. From derivation of the model curves, the δ-method analysis is presented. In Figure 4 On the part (a) of the figure, the trend followed by the -curves is the same as for the master curves (FWMA50<WMA50<HMA50). At high frequencies the response of the material is better distinguished through the δ-method. In general, if ageing analysis were done just in terms of Ico results, it might seem confusing. Ico value for FWMA50 is the highest (5.47%), however considering penetration or stiffness, this bitumen could be considered the softest. This proves that soft is not equivalent to "young". This is the true potential of the -method, the evaluation of bitumens from rheological measurements.

Complex modulus

From Table 4-9 it can be observed that warm mix asphalts, WMA and FWMA with 50% of RAP have suffered the highest increment of complex modulus (~2,300 MPa).

Fatigue

Rvalue Rvalue

Ageing evolution

In Figure 4-28 the evolution of penetration and softening point of all mixtures is illustrated, comparing results before and after ageing. It can be seen that foaming procedures ages less the bitumen at the beginning of its service life, but at the end of life it is at the same level than HMA mixtures. Then, the effect of ageing is bigger for these warm techniques. of easily characterize materials, but not the evolution and history followed, which also seems important. Information about the last state of a material is not enough. Not considering the evolution of the material, and the path followed to that last state may lead to overrate the quality or underestimate its possibilities.

-method analysis

The δ-method diagrams increase the information of the material. Figure 4-30 illustrates the δ-method curves of the previous recovered aged bitumen. From δ-method diagrams it could be extracted that RAP is not the same in both cases. Depending if it has RAP already added or not, then it should be a characteristic to consider. Thus, the manufacture procedure makes the bitumen evolve in a different way. Recall: -curves evolution from mono-modal distribution to bi-modal or tri-modal as in Chapter 3 PAV bitumen is important (see also Annex 3 results).

Rvalue, Ico and w(co) analysis

In terms of Rvalue, Figure 4-31 shows the evolution of this parameter versus Ico (a) and crossover frequencies (b) for all recyclable materials. The analysis should be global because WMA0a and WMA50a could be considered as equal, but regarding Rvalue, Ico or w(co) they are not. One is more aged than the other. The idea of these two graphics is that for further recycling it is important to perform a global analysis of the material and to have all available information to choose the best way of using it.

In part (a) the difference on Ico results are important between mixtures without RAP and with 50% of RAP. Then, in part (b) these RAP mixtures may seem closer as the scale is in log.

Conclusions

In this chapter, a comparison between three techniques, conventional HMA, surfactant WMA and foaming WMA is carried out. These procedures can also include the addition of 50% of RAP, in order to evaluate the influence of the use of reclaimed materials at high rates. Additionally, ageing of the mixtures is simulated using a laboratory procedure adapted from the RILEM TG5 protocol. The results obtained during the investigation led to the following conclusions:

In terms of stiffness:

i. Temperature reduction for the manufacture of foamed warm mix asphalts may lead to a lack of stiffness after the process. This decrease, compared to the other mixtures, may be related to the reduced ageing experienced by the bitumen during the production process.

In terms of fatigue:

ii. Concerning the fatigue related performance all procedures reach the standards limits. It is very interesting that reducing by 30°C the production of the mixture, with all the advantages associated, the performance of the mixture is over the minimum standards.

iii. The addition of RAP increases in general the immediate performance of the mixtures, both for conventional and warm mixtures.

Rvalue Rvalue

Chapter 4 -Ageing evolution of WMA combined with RAP -129 -iv. However, when RAP is added or after long term ageing, the fatigue slope increases and consequently, the fatigue resistance of the material tends to be more sensitive to the strain level.

In terms of bitumen performances:

v. Regarding bitumen performance, the foaming process ages the bitumen to a lower degree during manufacture compare to the conventional procedure. When long term ageing is applied, the levels become comparable in both cases. Similarly, the hardening experienced when RAP is added is less pronounced due to the already aged bitumen present in the RAP.

vi. The application of the δ-method reveals contrasting ageing effects for the different processes, as well as the influence of RAP addition. The general pattern observed on the curves is a decrease of the lower molecular weight fractions and an increase of the high molecular weight fractions due to ageing for the samples with or without RAP.

vii. Compared to the FWMA technique, the HMA production process induces a significant displacement of the distribution towards higher AMW. After ageing or RAP addition the distributions tend to be similarly shifted for the all processes.

viii. Combined with standard bitumen testing, the δ-method appears to be a powerful tool for the quantification of structural evolutions of bitumen, providing a clear visualization of the structural modifications induced. These results are likely to confirm that a structural interpretation of RAP addition and ageing evolution is possible with the δ-method.

ix. The -method can also show some rejuvenation aspects, like the presence of low AMW in bitumen aged, not seen with other tests. These results can be helpful when a decision must be taken for recycling again the material.

Introduction

This chapter presents findings relative to the influence of ageing, RAP content and manufacturing technique on the relationship between asphalt mixtures and bitumen. With the aim of further contributing to the study of this relationship, correlations have been established

for SARA fractions, c7-asphaltenes content, SHRP parameters, Rvalue and fatigue and complex modulus results.

Materials and Methods

The materials considered for analysis in this section are already described in Chapter 3.

Table 5-1 summarizes bitumens and test results chosen for comparisons from Chapter 3.

Chapter 5 -Correlation between structure and mechanical performance -133 -

Model parameters vs Bitumen chemistry

Table 5-2 summarizes the principal characteristics of Chapter 3 bitumens. On the different columns it can be found the content in % of asphaltenes c7, saturates, aromatics, resins and i-asphaltenes. Additionally, the colloidal index, polydispersity, rheological value and crossover frequency are presented. Table 5-3 summarizes all parameters obtained from the modelling of bitumen rheological results from Chapter 3 testing. In the denomination of the samples, as a recall M means malthenes and A asphaltenes, and the number attached to them the percentage of the fraction. Although all Huet-Such model parameters have been studied and compared with the different characteristics of the material, in this section only the viscosity β and the frequency multiplier τ(s) at 0°C are shown. In fact, these two parameters show better correlation in terms of the SARA fractions, c7-asphaltene content, the colloidal index and the bitumen polydispersity.

In Annex 7 all model parameters correlations are reported.

Saturates vs. model parameters

In Chapter 5 -Correlation between structure and mechanical performance -137 -colloidal index is a manner of showing the ageing of the system. This is traduced with as increase of the viscosity of the samples at high temperatures or low frequencies, graph (a).

In contrast, in graph (b), weaker relationship is found between τ(s) and the colloidal index.

Laboratory aged bitumens seems to show better the increase of this parameter as the material ages.

Rvalue and w(co) influence

Moreover, on model bitumens, the changes in rheology are also discussed via the cross over frequency and the determination of the rheological value (Rvalue) [START_REF] Christensen | Interpretation of Dynamic Mechanical Test Data for Paving Grade Asphalt[END_REF][START_REF] Rowe | Evaluation of a 100 % rap recycling project in Fort Wayne, Indiana[END_REF] from the different previous modelled master curves. This adimensional index allows assessing the ageing evolution of the materials. The Rvalue is the distance, in the log space, between the glassy modulus |G*∞| and the crossover frequency modulus (G'=G'', phase angle 45°). Ageing leads to widen the curve, so the distance between G*45° and G*∞ increases, and so the Rvalue. It is calculated with the following formula:

𝑅 𝑣𝑎𝑙𝑢𝑒 = log |𝐺 * ∞ | |𝐺 * 45°|
In Figure 5 Chapter 5 -Correlation between structure and mechanical performance -139 -

SHRP parameters

SHRP specifications for bitumens

Through the project A-002A [START_REF] Anderson | Development of SHRP binder specification[END_REF], the Asphalt Research Program of the Strategic Highway

Research Program (SHRP) has developed several bitumen tests that measure its physical properties. Rutting and fatigue parameters from complex modulus tests are the ones with the most interest for our analysis.

Rutting parameter (G*/sin)

Even though global properties of asphalt mixtures govern rutting, bitumen properties cannot be neglected on this phenomenon. This is more relevant in the case of RAP addition and ageing as they increase stiffness and promote rutting resistance. In general, rutting takes place at high temperatures, so the properties related to it should be measured for the same conditions. So then, RTFOT aged bitumen are used for testing [START_REF] Petersen | Binder Characterization and Evaluation[END_REF].

With this purpose, SHRP established a non-recoverable deformation at high temperatures as bitumen rutting parameter. Dynamic sinusoidal testing at 10 rad/s (1.59 Hz) simulates truck speeds of 80 km/h. Rutting criterion is taken as the loss compliance (1/J"), which is numerically equivalent to the complex modulus divided by the sinus of the phase angle (G*/sin) [START_REF] Anderson | Development of SHRP binder specification[END_REF].

Consequently, the SHRP specification stated that at the maximum pavement design temperature, this rutting parameter should fulfil the following requirements [START_REF] Anderson | Development of SHRP binder specification[END_REF][START_REF] Petersen | Binder Characterization and Evaluation[END_REF]:

(G*/sinδ)unaged bitumen > 1.0 kPa (G*/sinδ)RTFOT aged bitumen > 2.2 kPa However, this relationship has not always been verified in France with the LPC rutting tester. In contrast, it was found that (G*sin) > 3.8 kPa leads to lower rutting rates [START_REF] Delorme | Manuel LPC d'aide à la formulation des enrobés[END_REF].

Fatigue parameter (G*sin)

Fatigue is related to the end of life of the pavement when the bitumen has experienced long term ageing (PAV bitumen). This parameter is related to the dissipated energy per load cycle at the same frequency than rutting, 10 rad/s. Fatigue parameter is calculated for the intermediate pavement design temperature by multiplying the complex modulus by the sin of the phase angle G*sin [START_REF] Ferry | Viscoelastic properties of polymers[END_REF], and the requirements are as follows: Bitumens with asphaltene content at least equal to 9%would have less chances to experience rutting. However, if test temperature is higher than the critical (Tt > Tc), rutting would be a problem to consider. In the case of fatigue requirements, the limit would be established by long term ageing testing (35/50 PAV) with a result of 27°C as minimum service temperature of the pavement to suffer fatigue cracking.

Correlation between bitumen and asphalt mixture

Materials and Methods

The materials considered for analysis in this section are already described in Chapter 4.

Table 5-4 summarizes the materials selected and the tests taken into account. It is observed in Chapter 4 analysis that the foaming process shows reduced initial ageing but greater gradient after mixing . Then, the observed trend is an increase of the fatigue life, in terms of ε6 (micro deformation for 10 6 cycles), with the hardening of the bitumen. In Figure 5-16 the relationship between parameters is developed. In the ordinate axis it is shown the parameter from Huet Such modelling. Then, in the abscise axis the parameter from 2S2P1D modelling results on the asphalt mixtures.

G∞ parameter

The glassy modulus G∞ represents the value of G* at infinite frequency. This parameter remains seems to be higher for the Metravib® modelling. It seems as traction-compression testing obtains higher values of complex modulus than shear testing. There is a difference between means around 100 MPa.

δ parameter

The δ parameter represents the balance between the two parabolic elements k and h at medium temperatures or frequencies. In both models this parameter tends to be similar.

k parameter

The k parameter, first parabolic element, is proportional to the slope of the model in the Cole-Cole plan at low temperature and/or high frequency (proportional to the ratio ΔE''/ΔE'). This parameter is higher in the case of Metravib® modelling. However, the means are not very different (0.26 for Kinexus® and 0.28 for Metravib®).

h parameter

The h parameter of the second parabolic element is proportional to the slope of the model in the Cole-Cole plan at high temperature and/or low frequency (proportional to the ratio ΔE''/ΔE').

This parameter seems to be linked to β, as they tend to find the equilibrium between them. In the Figure-16 the samples that are farther from the unity are highlighted.

β parameter

The dashpot parameter β represents the viscosity of the model at very high temperatures or very low frequencies. β is found smaller for Kinexus. As it is said for h parameter, samples farther from the unity are highlighted. All come from aged bitumens. And they have an inverse tendency, when h increases, β decreases to give equilibrium to the model.

τ parameter

Finally, the frequency multiplier τ at 0°C seems to increase between devices. In general, the disposition of this parameter is to change with ageing phases, being the main parameter on affecting the value of |G*|.

Chapter 5 -Correlation between structure and mechanical performance -149 - No obvious correlation is found between the parameters determined from the two sets of data.

The parameters determination seems very sensitive to the test device and test conditions.

Additionally, differences can also be attributed to modelling and fitting process as compensation are noted between h and b parameters.

Durabilité des enrobes tièdes intégrant des recyclés -150 -

Parameters from Huet-Such versus 2S2P1D

2S2P1D model

According to literature review, 2S2P1D model is the best suited rheological model for asphalt mixture This model is a combination of two springs, two parabolic creep elements and one dashpot with a coefficient that regulates the balance between the two parabolic elements. In Chapter 4, complex modulus testing on asphalt mixtures samples with two points bending configuration allowed obtaining their rheological performance. Then, through 2S2P1D modelling, the information of the frequency and temperature sweeps is concentrated in the 7 model parameters (E0, E∞, , k, h, β and τ), describing the properties of the mixture in the whole time-temperature domain. The parameters are determined for a reference temperature Tref = 0°C.

As an example of the obtained data, isothermal curves of the norm of complex modulus and phase angle of HMA0 mixture, with their respective master curve are shown in Figure 5-18.

Experimental data from all mixtures, WLF fitting, shift factors aT, Black and Cole-Cole curves, and 2S2P1D model curves are reported in Annex 6.

Chapter 5 -Correlation between structure and mechanical performance -151 -

SHStS transformation

Based on mechanical testing different approaches can be followed in order to establish a relationship between bitumen and mixture properties [START_REF] Olard | General "2S2P1D" Model and Relation Between the Linear Viscoelastic Behaviours of Bituminous Binders and Mixes[END_REF][START_REF] Zeng | Rheological modeling of modified asphalt binders and mixtures[END_REF][START_REF] Heukelom | Road design and dynamic loading[END_REF][START_REF] Ugé | Nouvelle méthode de calcul du module complexe des mélanges bitumineux[END_REF][START_REF] Franken | Relation between mix stiffness and binder complex modulus[END_REF][START_REF] Francken | Complex moduli of bituminous binders and mixes: interpretation and evaluation[END_REF][START_REF] Witczak | Revised predictive model for dynamic (complex) modulus of asphalt mixtures[END_REF][START_REF] Christensen | Hirsch Model for Estimating the Modulus of Asphalt Concrete[END_REF][START_REF] Bari | Development of a new revised version of the Witczak E Predictive Model for hot mix asphalt mixtures[END_REF][START_REF] Benedetto | Linear viscoelastic behaviour of bituminous materials: From binders to mixes[END_REF]. In this chapter, bitumen and mixture performances correlation is developed through the Shift-Homothety-Shift in time-Shift transformation (SHStS) [START_REF] Olard | General "2S2P1D" Model and Relation Between the Linear Viscoelastic Behaviours of Bituminous Binders and Mixes[END_REF][START_REF] Benedetto | Linear viscoelastic behaviour of bituminous materials: From binders to mixes[END_REF]. This transformation is illustrated in Figure 5 This transformation is based on a rheological approach, allowing the prediction of mixtures complex modulus from linear viscoelastic behaviour of the bitumen. Thus, it takes into account the aggregate gradation of the mixture. In order to compare bitumen and mixture complex modulus, it is convenient to normalize them. bitumens and mixtures. Thus, this difference reflects the asphalt mixture results of complex modulus as more viscous than the bitumen. At medium-high temperatures, the increase of E'' is greater for all mixtures than for the bitumen results.

𝐸 𝑛𝑜𝑟𝑚 * = 𝐸 * -𝐸 0 𝐸 ∞ -𝐸 0 (a) (b) (c) (d
As a result, experimental calculations of mixtures complex modulus from bitumens measurements would not be very accurate. These differences may not be extensible to all type of mixtures. However, caution should be taken due to the presence of RAP, the warm mix procedures or the different ageing states considered

Relationship between Huet-Such and 2S2P1D parameters

Table 5-8 summarizes all parameters obtained from the 2S2P1D modelling of asphalt mixtures dynamic complex modulus results from Chapter 4 and the coefficients C1 and C2 when constructing the master curves. while on the mixture it seems to remain constant around 2.00 for the mixture.

k parameter

As it can be observed, an almost constant average value of ≈0.18 is obtained for all mixtures, but for the bitumens it changes from 0.20 to 0.30.

h parameter

The tendency for h is to increase, but not in the same ratio for mixtures and bitumens.

β parameter

The standardized tendency observed is to substantially increase in the case of bitumens compared to the low values experienced by the mixtures results.

τ parameter

From a mechanical point of view, the relation between bitumen and mixture should be equivalent to multiplying the angular frequency by a factor of 10. However, the factor found is closer to 100.

α parameter

This parameter relates bitumen and mix design though the formula α = log (τmixture/ τbitumen) at any temperature. It has been calculated for the ordinate axis on Kinexus results, and on the abscise axis on Metravib results. In our study, α is the only parameter that stays close to the identity curve. Then, on the abscise axis the respective C1 and C2 from 2S2P1D modelling on mixture is shown.

Also when both components are close to each other, they are not the same. It can be observed how C1 and C2 parameters fluctuate more for the bitumens than for the mixtures. On Table 5-9 each bitumen extracted from mixture manufacture that has been tested is summarized with its corresponding ageing state, Neat, RTFOT or PAV.

Chapter 5 -Correlation between structure and mechanical performance -157 - Bitumen stiffness and resistance to rutting is presented as a penetration reduction (increase of softening point) and an increase of Tc. It can be observed that both penetration and softening point seems to saturate for Tc between 82 and 85°C. Global correlation is not obvious for all procedures. FWMA technique seems to be still evolving.

With the red arrow bitumen stiffness increase with penetration and softening point is pointed out for the FWMA process. In the case of rutting critical temperature the increase of material stiffness is shown normally by an increase of temperature. Even if there is no direct correlation, there is a trend in both graphics that relates all results.

Influence of fatigue criterion on penetration and softening point results

Fatigue parameter, G*sinδ indicates material stiffness at intermediate temperatures as a result of long-term aging [START_REF]Performance graded asphalt binder specification and testing[END_REF]. On Figure 5-25, critical temperatures for G*sinδ = 5 MPa is shown for all mixtures. In this case, the critical temperature of each material is presented in the last column of each set of samples (aged material after PAV). All the materials have equivalent behaviour with a critical temperature at around 25°C for all of the , it can probably be expected that FWMA asphalt mixes would resist a little bit better due to slightly lower Tc, with or without RAP. In contrast, for the FWMA procedure that saturation is not clearly achieved. The less ageing experienced by this process at the beginning seems to widen the ageing window for Ico. In general, RAP addition to the mixture could be seen as an increase of rutting critical temperature and a decrease of fatigue critical temperature. In the case of HMA mixtures, the addition of 50% of RAP widens the "window" of pavement service temperatures. In contrast, this increment is not so clear for WMA procedure, even if the tendency follows the same path; both curves are very close, with a difference in Tc lower than 1°C.

For the foaming FWMA procedure, the addition of RAP increases substantially (~6°C) the rutting critical temperature allowing higher service pavement temperature. Then, a reduction of 2°C is experienced for the fatigue by adding 50% of RAP. Again, asphalt mixtures performances must be studied in detail with more pertinent testing; however, these simple parameters show the line to follow to take into account the service temperatures.

Conclusions

In this chapter, a study of the influence of bitumen characteristics on asphalt mixture performance is developed. In addition, the effect of the asphaltene content on neat, model and laboratory aged bitumen modelling parameters is investigated. From the results obtained in previous chapters some correlations of results are obtained in certain cases.

The following conclusions can be drawn: ii.

Model and laboratory aged bitumens

In contrast, no obvious correlation is observed between the glassy modulus G∞ or the parabolic element h and the asphaltene content.

iii.

For the rutting and fatigue SHRP parameters, asphaltenes content plays an important role on bitumen stiffness. So then, critical service temperatures would increase (rutting)

or decrease (fatigue) as the asphaltene content increases.

Mixtures and bitumens relationship

iv.

The parameters obtained after Huet-Such and 2S2P1D modelling on bitumens and mixtures respectively do not show clear correlation, for both Metravib® and Kinexus results. This effect may be due to the presence of RAP, the effect of the manufacture procedure or the ageing experienced by the mixtures.

v.

In terms of complex modulus, good correlation is found for bitumens between penetration, softening point and stiffness. The increase of stiffness in the asphalt mixture is presented as a reduction of penetration and an increase of softening point.

vi.

On the other hand, fatigue parameter ε6 does not follow any correlation. However, for the foaming procedure FWMA, an increase of softening point (and decrease of penetration) is directly linked to better fatigue resistance. These findings should be taken with caution, due to the fact that fatigue slopes are not considered.

Durabilité des enrobes tièdes intégrant des recyclés -162 -vii. SHRP rutting and fatigue critical service temperatures do not show clear correlation with penetration and softening point results. Nevertheless, in terms of recycling, RAP addition widens the temperature range for the resulting mixtures independently of the manufacture procedure.

These conclusions highlight the difficulty to establish correlations between all the tests performed on bitumen and mixtures, empirical or rheological. It shows the complexity of bituminous mixtures, their evolution in time and the difficulty to model such material for further predictions.

Chapter 6 -Conclusions and perspectives -163 -Chapter 6. Conclusions and perspectives

Final conclusions

The general objective of this thesis is to study the durability of low temperature asphalt mixture containing reclaimed asphalt pavement. For this purpose, bitumen structure is studied in order to set the basis of the changes produced by asphalt mixtures ageing. In particular, the influence of the asphaltenes content on bitumens properties is studied. Model bitumens with different asphaltenes content are built by separation and recomposition of asphaltenes and maltenes fractions. These model bitumens are characterized both physically and chemically.

With the aim of studying the mechanical performance of warm mix asphalt mixtures and their evolution during ageing, an experimental plan is set. Twelve asphalt mixtures are characterized through different tests performed both on asphalt mixtures and recovered bitumens. The chosen manufacture techniques are conventional hot mix asphalt, warm mix asphalt with surfactant addition and foamed bitumen. Then, 50% of reclaimed asphalt is added to the mixtures. Finally, laboratory ageing procedure in loose and compacted samples is applied in order to assess the response of the materials after simulated long term ageing.

Consequently, the main conclusions drawn from all studied can be summarized as follows:

Influence of asphaltene content during ageing I.

In terms of ATR-FTIR analysis, sulphoxide groups seem to be more affected by the addition of asphaltenes fractions than carbonyl groups, indicating the affinity of polar fractions towards these components.

II.

By Iatroscan chromatography for SARA fractions determining, it is observed an increase of asphaltenes with ageing. It is also exposed that during ageing the increase of asphaltenes content is due to the evolution of aromatics to resins (and polar resins) and then to asphaltenes. In addition, the oxidation of aromatics or resins to polar resins or asphaltenes is also possible during ageing.

III.

By AFM observation, asphaltenes micelles appeared in all bitumens tested. Then in the malthenes fraction bee-like structure is observed, so the presence of asphaltenes does not seem necessary for their apparition as other researchers have stated.

IV.

Rheological behaviour of bitumen is mainly characterized by its stiffness. Then, it is strongly controlled by the asphaltenes content of the bitumen. Small changes in the ratio asphaltenes/malthenes have a direct impact on the material.

Durabilité des enrobes tièdes intégrant des recyclés -164 -V. δ-method analysis is proven as a powerful tool for ageing determination. Curve shifting is clearly observed when asphaltenes content increase. Cross-over frequencies, corresponding to the median of the AMWD probability distribution, could be taken as an indicator of ageing.

VI.

By GPC testing, aged and model bitumen follow the same line of asphaltenes content consideration. Colloidal indexes increase with asphaltenes ratio, as the number and weight average molecular weight.

VII.

Asphaltenes content plays an important role on bitumen structure. The variation of the asphaltene fraction, induced by model bitumen or by ageing procedures, leads to a fairly good correlation with β and τ parameters of the Huet-Such modelling.

VIII.

For the rutting and fatigue SHRP parameters, asphaltenes content plays an important role on bitumen stiffness. So then, critical service temperatures would increase (rutting)

or decrease (fatigue) as the asphaltene content increases, widening the range of use.

IX.

Influence of manufacturing procedure X.

Temperature reduction for the manufacture of foamed warm mix asphalts may lead to a lack of stiffness after the process. This decrease, compared to the other mixtures, is related to the reduced ageing experienced by the bitumen during the production process.

XI.

Concerning fatigue related performance; all procedures reach the standards limits. It is very interesting that reducing by 30°C the production of the mixture, with all the advantages associated, the performance of the mixture is on the standards.

XII.

In terms of complex modulus, good correlation has been found for penetration and softening point for all tested mixtures. The reduction of penetration and an increase of softening point of the bitumen are indicators of an increase of stiffness of the mix.

XIII.

On the other hand, fatigue parameter ε6 does not follow any clear evolution with manufacturing temperature. However, for the foaming procedure FWMA, an increase of softening point (and decrease of penetration) is directly linked to better fatigue resistance. These findings should be taken with caution, due to the fact that fatigue slopes are not considered.

Chapter 6 -Conclusions and perspectives -165 -

Influence of reclaimed asphalt pavement addition

XIV.

In general, the addition of RAP increases the performance of the mixtures, both for conventional and warm mixtures. However, when RAP is added or ageing occurs, the fatigue slope increases and consequently, the fatigue resistance of the material tends to be more sensitive to the strain level.

XV.

Regarding bitumen performance, the foaming process ages the bitumen to a lower degree during manufacture compare to the conventional procedure. When long term ageing is applied, the levels become comparable in both cases. Similarly, the hardening experienced when RAP is added is less pronounced due to the already aged bitumen present in the RAP.

XVI.

For the SHRP criteria, rutting and fatigue critical service temperatures for pavements do not show clear relation with empirical penetration and softening point results.

Nevertheless, in terms of recycling, RAP addition widens the temperature range of application independently of the manufacture procedure.

-method for ageing detection XVII.

The application of the δ-method reveals contrasting ageing effects for the different processes, as well as the influence of RAP addition. The general pattern observed on the curves is a decrease of the lower molecular weight fractions and an increase of the high molecular weight fractions due to ageing for the samples with or without RAP. Compared to the FWMA technique, the HMA production process induces a significant displacement of the distribution towards higher AMW. After ageing or RAP addition the distributions tend to be similarly shifted for the all processes.

XVIII.

Combined with standard bitumen testing, the δ-method appears to be a suitable tool for the quantification of structural evolutions of bitumen, providing good visualization of the modifications induced. These results could be considered as a first step towards possible prediction of materials response. Structural interpretation of RAP addition and ageing evolution would be possible with the δ-method.

Durabilité des enrobes tièdes intégrant des recyclés -166 -

Recommendations for future research

The potential of applying reclaimed asphalt pavements on warm mix asphalt manufacturing procedures has been widely discussed throughout this thesis. During the different stages of this thesis new research lines have come up with the aim of improving all procedures employed. The work presented here opens up new perspectives and practical possibilities which are listed below:

I.

The proposed method for rheological testing at low temperatures on PP08 geometry is promising. However, the comparison of these measurements with a smaller geometry as it is PP04 could allow improving rheological results at very low temperatures.

II.

This study would go in line with the effect of reliability of measurements for the -method calculus. Data source for modelling should cover all temperature spectrums from elastic response of the material to Newtonian behaviour.

III.

The facts of having studied the influence of the asphaltene content on two close grade bitumen opens the possibility of widen the range of grades. It would be very interesting to see these effects on soft bitumen.

IV.

Deeper study of fatigue response of warm mix asphalts is recommended. Fatigue life comparison through different types of testing, as four point bending or indirect traction, could be interesting in order to choose the most accurate system to measure fatigue life.

V. Further investigation should be carried out on the relationship between bitumen and asphalt mixture. It has been generally focused on complex modulus prediction, but somehow it should also be orientated to the study of fatigue life.

HUET-SUCH MODELLING PARAMETERS

Reference temperature for master curve T=0°C

HUET-SUCH MODELLING PARAMETERS

Reference temperature for master curve T=0°C

2S2P1D MODELLING PARAMETERS

Reference temperature for master curve T=0°C

Abstract

Roads are the most widely used mode of transportation in the world, and a country's development is often measured in terms of its total paved roads mileage. Pavements are an essential part of our social network and asphalt concrete is the main material used for manufacturing them. Currently, the European road network is not much growing anymore and mostly needs only maintenance. In a context of increasing demand of performance and durability of asphalt mixtures, a sustainable, durable and economical conception is required. Indeed it could be oriented towards a selfsufficient road providing its own raw materials through recycling while limiting the use of energy and other natural resources for its maintenance. The combination of warm mix asphalts (WMA) technologies and high rates of reclaimed asphalt pavements (RAP) appears as a solution to achieve both energy and natural resources savings. But it is still ambiguous in terms of durability. Therefore, an experimental program is set up to show the evolution of the performances of such asphalt concretes with time, highlighting the notion of ageing mostly related to the bituminous fraction. At the bitumen scale, the long term assessment is carried out in particular by applying the δ-method compare with GPC measurements both on model samples with controlled asphaltene content and laboratory aged ones. At the asphalt mixture scale, a comparison study is carried out between a reference HMA and WMAs with 0% -50% of RAP submitted to a laboratory ageing procedure. The long term performances of the mixtures are compared by means of complex modulus and fatigue testing. Results show a relation between the evolution of the structure of the bitumen with ageing and the mechanical performances. Short term ageing is less important for warm processes. After ageing, the overall tendencies are similar for all processes.

Figure 1 - 1 Figure 1 - 2

 1112 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 2 - 1

 21 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 2 - 2

 22 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 2 - 7

 27 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 2 - 8

 28 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 2 -

 2 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 1

 31 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 2

 32 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 3

 33 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 5

 35 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 6

 36 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 8

 38 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 - 9

 39 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 -Figure 3 -

 33 Figure 1-1 Principal partners of the SUP&R ITN project ................................................................. Figure 1-2 Evolution of road infrastructure and road maintenance investment in selected countries [2] ................................................................................................................................... Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] ............................................................................................................. Figure 1-4 Total reclaimed asphalt pavement available in Europe and U SA [4] ............ Figure 2-1 Conventional asphalt mixture [4] ........................................................................................ Figure 2-2 Aggregates for asphalt mixture manufacture .............................................................. Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images) ................................................................................................... Figure 2-4 Material response to a step lo ad (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure taken from Woldekidan Thesis [16] ................................................. Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen ................................................................................................................... Figure 2-6 Summary of the different testing levels .......................................................................................... Figure 2-7 Level 2 testing devices and mixture slab .......................................................................Figure 2-8 Level 3 and 4 testing devices and fatigue principles [34] ................................. Figure 2-9 Managing pavement maintenance and rehabilitation by monitoring riding quality [46] ........................................................................................................................................ Figure 2-10 Example of nomogram for determining the maximum possible RAP addition [45] ..................................................................................................................................................... Figure 2-11 RAP stockpile ready to be use on mixture manufacture ................................... Figure 2-12 Distillation process diagram [62] ..................................................................................... Figure 2-13 General diagram of fractioning [60] ............................................................................... Figure 2-14 Sol and Gel types of bitumens [63] .................................................................................. Figure 2-15 SARA fractions, Saturates, Arom atics, Resins and Asphaltenes .................. Figure 2-16 Asphaltenes-Resins transfer [58] ..................................................................................... Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, from Petersen (1984) [72] ..................................................................................................................... Figure 2-18 Penetration test on bitumen ................................................................................................. Figure 2-19 Softening point test on bitumen ........................................................................................Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery ................Figure 3-2 Asphaltenes and malthenes for bitumen recomposition .....................................Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content .................................................................................................................................................................................... Figure 3-4 Flowchart followed on model bitumens ..........................................................................Figure 3-5 Iatroscan MK-6s device used for SARA fractions determination ..................Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position Figure 3-7 PP25 and PP08 geometries used for the testing .......................................................Figure 3-8 GPC standards for curve calibration ..................................................................................Figure 3-9 Bitumen testing protocols ......................................................................................................... Figure 3-10 Huet-Such model, equation and Cole-Cole representation .............................Figure 3-11 Example of curve cumf(MW) and (AMW) [91] ......................................................Figure 3-12 Analysis of results and discussion schem a followed ..........................................Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases ..........................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 4 - 2 Figure 4 - 8

 4248 Figure 3-14 TGA diagram from 35/50 and 50/70 a sphaltenes fraction ............................ Figure 3-15 35/50 Malthenes phase PP25 and PP08 results at 15°C .................................. Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C .................................. Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C ..................................... Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C .... Figure 3-19 35/50 malthenes fitting model curves .......................................................................... Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase ............ Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions .................... Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens ..........................Figure 3-23 ATR-FTIR bitumens and solvent spectrum.................................................................Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens ....................................................................................................... Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning .... Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A ....................................................................................................... Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens ....... Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A ................................................. Figure 3-29 ATR-FTIR model bitumens and solvent spectrum ................................................. Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens ..................................Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°C ........................Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens ................................................................................................................................................................. Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens .............................................................................................................................................. Figure 3-34 GPC plots from 35/50 model bitumens ......................................................................... Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens .................................. Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens ..................................... Figure 3-37 Master curves at T=0°C of 35/50 bitumens ...............................................................Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross -over frequencies by asphaltene content ................................................................................................... Figure 3-39 GPC plots from 35/50 aged bitumens ............................................................................ Figure 3-40 Polydispersity of 35/50 aged bitumens ....................................................................... Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens ........................Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens ........... Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens .............................................................................................................................................................. Figure 4-1 Mixtures gradations with and without RAP ..................................................................Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing ................................................................................................................................................................. Figure 4-3 Mixtures testing protocols ..................................................................................................... Figure 4-4 Bitumen testing protocols ...................................................................................................... Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagram .............................................................................................................................................................. Figure 4-6 Analysis of results flowchart................................................................................................ Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures ............................................................................................................................................................

Figure 5 - 2

 52 Figure 4-8 Penetration and Softening point trend by manufacturing process .......... Figure 4-9 Master curve construction at 0°C for 35/50 Neat bitumen ............................ Figure 4-10 Recovered bitumen after manufacture master curves at 0°C .................... Figure 4-11 δ-method diagram of recovered bitumens after manufacture .................. Figure 4-12 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) ................................................................................................................................................................................. Figure 4-13 Fatigue laws and 95% interval confidence of aged H MA, WMA and FWMA mixtures ........................................................................................................................................... Figure 4-14 Penetration and Softening point trend after ageing ........................................ Figure 4-15 Recovered bitumen after ageing master curves at 0°C .................................. Figure 4-16 δ-method diagram of recovered bitumens after ageing ................................. Figure 4-17 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) before and after ageing .......................................................................................................................... Figure 4-18 Fatigue laws and 95% interval confidence of mixtures with RAP: HMA50, WMA50 and FWMA50 .......................................................................................................... Figure 4-19 Penetration and Softening point trend after RAP addition ......................... Figure 4-20 Recovered bitumen after 50%RAP mixtures manufacture master curves at 0°C ................................................................................................................................................................... Figure 4-21 δ-method diagram of recovered bitumens of RAP mixtures after manufacture ...................................................................................................................................................Figure 4-22 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after RAP addition ........................................................................................................................... Figure 4-23 Fatigue laws and 95% interval confidence of aged HMA50, WMA50 and FWMA50 mixtures after ageing ........................................................................................................ Figure 4-24 Penetration and Softening point trend after ageing on RAP mixtures Figure 4-25 Recovered bitumen after ageing on 50%RAP mixtures master curves at 0°C ......................................................................................................................................................................... Figure 4-26 Fatigue laws and AMWD of HMA, WMA and FWMA technique with 50% of RAP at the end of life situation .................................................................................................. Figure 4-27 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after ageing on mixtures with RAP ...................................................................................... Figure 4-28 Penetration and softening point evolution of all mixtures ......................... Figure 4-29 Penetration and softening point from available RAP materials .............. Figure 4-30 δ-method diagrams for aged mixtures with 0% and 50% of RAP ........... Figure 4-31 Rvalue analysis of all available aged materials ....................................................... Figure 5-1 Schema of the chapter ...............................................................................................................Figure 5-2 Parameters β and τ(s) represented in function of saturates ........................Figure 5-3 Parameters β and τ(s) represented in function of aromatics .......................Figure 5-4 Parameters β and τ(s) represented in function of c7 -asphaltene content ................................................................................................................................................................................. Figure 5-5 Parameters β and τ(s) represented in function of i -asphaltenes ..............Figure 5-6 Parameters β and τ(s) represented in function of the colloidal index ..Figure 5-7 Parameters β and τ(s) represented in function of the polydispersity ... Figure 5-8 Parameters β and τ(s) represented in function of the rheol ogical value ................................................................................................................................................................................. Figure 5-9 Parameters β and τ(s) represented in function of the crossover frequency .........................................................................................................................................................

Figure 5 - 3

 53 Figure 4-8 Penetration and Softening point trend by manufacturing process .......... Figure 4-9 Master curve construction at 0°C for 35/50 Neat bitumen ............................ Figure 4-10 Recovered bitumen after manufacture master curves at 0°C .................... Figure 4-11 δ-method diagram of recovered bitumens after manufacture .................. Figure 4-12 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) ................................................................................................................................................................................. Figure 4-13 Fatigue laws and 95% interval confidence of aged H MA, WMA and FWMA mixtures ........................................................................................................................................... Figure 4-14 Penetration and Softening point trend after ageing ........................................ Figure 4-15 Recovered bitumen after ageing master curves at 0°C .................................. Figure 4-16 δ-method diagram of recovered bitumens after ageing ................................. Figure 4-17 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) before and after ageing .......................................................................................................................... Figure 4-18 Fatigue laws and 95% interval confidence of mixtures with RAP: HMA50, WMA50 and FWMA50 .......................................................................................................... Figure 4-19 Penetration and Softening point trend after RAP addition ......................... Figure 4-20 Recovered bitumen after 50%RAP mixtures manufacture master curves at 0°C ................................................................................................................................................................... Figure 4-21 δ-method diagram of recovered bitumens of RAP mixtures after manufacture ...................................................................................................................................................Figure 4-22 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after RAP addition ........................................................................................................................... Figure 4-23 Fatigue laws and 95% interval confidence of aged HMA50, WMA50 and FWMA50 mixtures after ageing ........................................................................................................ Figure 4-24 Penetration and Softening point trend after ageing on RAP mixtures Figure 4-25 Recovered bitumen after ageing on 50%RAP mixtures master curves at 0°C ......................................................................................................................................................................... Figure 4-26 Fatigue laws and AMWD of HMA, WMA and FWMA technique with 50% of RAP at the end of life situation .................................................................................................. Figure 4-27 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after ageing on mixtures with RAP ...................................................................................... Figure 4-28 Penetration and softening point evolution of all mixtures ......................... Figure 4-29 Penetration and softening point from available RAP materials .............. Figure 4-30 δ-method diagrams for aged mixtures with 0% and 50% of RAP ........... Figure 4-31 Rvalue analysis of all available aged materials ....................................................... Figure 5-1 Schema of the chapter ...............................................................................................................Figure 5-2 Parameters β and τ(s) represented in function of saturates ........................Figure 5-3 Parameters β and τ(s) represented in function of aromatics .......................Figure 5-4 Parameters β and τ(s) represented in function of c7 -asphaltene content ................................................................................................................................................................................. Figure 5-5 Parameters β and τ(s) represented in function of i -asphaltenes ..............Figure 5-6 Parameters β and τ(s) represented in function of the colloidal index ..Figure 5-7 Parameters β and τ(s) represented in function of the polydispersity ... Figure 5-8 Parameters β and τ(s) represented in function of the rheol ogical value ................................................................................................................................................................................. Figure 5-9 Parameters β and τ(s) represented in function of the crossover frequency .........................................................................................................................................................

Figure 5 - 4

 54 Figure 4-8 Penetration and Softening point trend by manufacturing process .......... Figure 4-9 Master curve construction at 0°C for 35/50 Neat bitumen ............................ Figure 4-10 Recovered bitumen after manufacture master curves at 0°C .................... Figure 4-11 δ-method diagram of recovered bitumens after manufacture .................. Figure 4-12 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) ................................................................................................................................................................................. Figure 4-13 Fatigue laws and 95% interval confidence of aged H MA, WMA and FWMA mixtures ........................................................................................................................................... Figure 4-14 Penetration and Softening point trend after ageing ........................................ Figure 4-15 Recovered bitumen after ageing master curves at 0°C .................................. Figure 4-16 δ-method diagram of recovered bitumens after ageing ................................. Figure 4-17 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) before and after ageing .......................................................................................................................... Figure 4-18 Fatigue laws and 95% interval confidence of mixtures with RAP: HMA50, WMA50 and FWMA50 .......................................................................................................... Figure 4-19 Penetration and Softening point trend after RAP addition ......................... Figure 4-20 Recovered bitumen after 50%RAP mixtures manufacture master curves at 0°C ................................................................................................................................................................... Figure 4-21 δ-method diagram of recovered bitumens of RAP mixtures after manufacture ...................................................................................................................................................Figure 4-22 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after RAP addition ........................................................................................................................... Figure 4-23 Fatigue laws and 95% interval confidence of aged HMA50, WMA50 and FWMA50 mixtures after ageing ........................................................................................................ Figure 4-24 Penetration and Softening point trend after ageing on RAP mixtures Figure 4-25 Recovered bitumen after ageing on 50%RAP mixtures master curves at 0°C ......................................................................................................................................................................... Figure 4-26 Fatigue laws and AMWD of HMA, WMA and FWMA technique with 50% of RAP at the end of life situation .................................................................................................. Figure 4-27 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after ageing on mixtures with RAP ...................................................................................... Figure 4-28 Penetration and softening point evolution of all mixtures ......................... Figure 4-29 Penetration and softening point from available RAP materials .............. Figure 4-30 δ-method diagrams for aged mixtures with 0% and 50% of RAP ........... Figure 4-31 Rvalue analysis of all available aged materials ....................................................... Figure 5-1 Schema of the chapter ...............................................................................................................Figure 5-2 Parameters β and τ(s) represented in function of saturates ........................Figure 5-3 Parameters β and τ(s) represented in function of aromatics .......................Figure 5-4 Parameters β and τ(s) represented in function of c7 -asphaltene content ................................................................................................................................................................................. Figure 5-5 Parameters β and τ(s) represented in function of i -asphaltenes ..............Figure 5-6 Parameters β and τ(s) represented in function of the colloidal index ..Figure 5-7 Parameters β and τ(s) represented in function of the polydispersity ... Figure 5-8 Parameters β and τ(s) represented in function of the rheol ogical value ................................................................................................................................................................................. Figure 5-9 Parameters β and τ(s) represented in function of the crossover frequency .........................................................................................................................................................

Figure 5 - 6

 56 Figure 4-8 Penetration and Softening point trend by manufacturing process .......... Figure 4-9 Master curve construction at 0°C for 35/50 Neat bitumen ............................ Figure 4-10 Recovered bitumen after manufacture master curves at 0°C .................... Figure 4-11 δ-method diagram of recovered bitumens after manufacture .................. Figure 4-12 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) ................................................................................................................................................................................. Figure 4-13 Fatigue laws and 95% interval confidence of aged H MA, WMA and FWMA mixtures ........................................................................................................................................... Figure 4-14 Penetration and Softening point trend after ageing ........................................ Figure 4-15 Recovered bitumen after ageing master curves at 0°C .................................. Figure 4-16 δ-method diagram of recovered bitumens after ageing ................................. Figure 4-17 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) before and after ageing .......................................................................................................................... Figure 4-18 Fatigue laws and 95% interval confidence of mixtures with RAP: HMA50, WMA50 and FWMA50 .......................................................................................................... Figure 4-19 Penetration and Softening point trend after RAP addition ......................... Figure 4-20 Recovered bitumen after 50%RAP mixtures manufacture master curves at 0°C ................................................................................................................................................................... Figure 4-21 δ-method diagram of recovered bitumens of RAP mixtures after manufacture ...................................................................................................................................................Figure 4-22 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after RAP addition ........................................................................................................................... Figure 4-23 Fatigue laws and 95% interval confidence of aged HMA50, WMA50 and FWMA50 mixtures after ageing ........................................................................................................ Figure 4-24 Penetration and Softening point trend after ageing on RAP mixtures Figure 4-25 Recovered bitumen after ageing on 50%RAP mixtures master curves at 0°C ......................................................................................................................................................................... Figure 4-26 Fatigue laws and AMWD of HMA, WMA and FWMA technique with 50% of RAP at the end of life situation .................................................................................................. Figure 4-27 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after ageing on mixtures with RAP ...................................................................................... Figure 4-28 Penetration and softening point evolution of all mixtures ......................... Figure 4-29 Penetration and softening point from available RAP materials .............. Figure 4-30 δ-method diagrams for aged mixtures with 0% and 50% of RAP ........... Figure 4-31 Rvalue analysis of all available aged materials ....................................................... Figure 5-1 Schema of the chapter ...............................................................................................................Figure 5-2 Parameters β and τ(s) represented in function of saturates ........................Figure 5-3 Parameters β and τ(s) represented in function of aromatics .......................Figure 5-4 Parameters β and τ(s) represented in function of c7 -asphaltene content ................................................................................................................................................................................. Figure 5-5 Parameters β and τ(s) represented in function of i -asphaltenes ..............Figure 5-6 Parameters β and τ(s) represented in function of the colloidal index ..Figure 5-7 Parameters β and τ(s) represented in function of the polydispersity ... Figure 5-8 Parameters β and τ(s) represented in function of the rheol ogical value ................................................................................................................................................................................. Figure 5-9 Parameters β and τ(s) represented in function of the crossover frequency .........................................................................................................................................................

Figure 5 - 7 Figure 5 -

 575 Figure 4-8 Penetration and Softening point trend by manufacturing process .......... Figure 4-9 Master curve construction at 0°C for 35/50 Neat bitumen ............................ Figure 4-10 Recovered bitumen after manufacture master curves at 0°C .................... Figure 4-11 δ-method diagram of recovered bitumens after manufacture .................. Figure 4-12 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) ................................................................................................................................................................................. Figure 4-13 Fatigue laws and 95% interval confidence of aged H MA, WMA and FWMA mixtures ........................................................................................................................................... Figure 4-14 Penetration and Softening point trend after ageing ........................................ Figure 4-15 Recovered bitumen after ageing master curves at 0°C .................................. Figure 4-16 δ-method diagram of recovered bitumens after ageing ................................. Figure 4-17 Rvalue compared in terms of Ico(%) (a) and cross -over frequencies (b) before and after ageing .......................................................................................................................... Figure 4-18 Fatigue laws and 95% interval confidence of mixtures with RAP: HMA50, WMA50 and FWMA50 .......................................................................................................... Figure 4-19 Penetration and Softening point trend after RAP addition ......................... Figure 4-20 Recovered bitumen after 50%RAP mixtures manufacture master curves at 0°C ................................................................................................................................................................... Figure 4-21 δ-method diagram of recovered bitumens of RAP mixtures after manufacture ...................................................................................................................................................Figure 4-22 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after RAP addition ........................................................................................................................... Figure 4-23 Fatigue laws and 95% interval confidence of aged HMA50, WMA50 and FWMA50 mixtures after ageing ........................................................................................................ Figure 4-24 Penetration and Softening point trend after ageing on RAP mixtures Figure 4-25 Recovered bitumen after ageing on 50%RAP mixtures master curves at 0°C ......................................................................................................................................................................... Figure 4-26 Fatigue laws and AMWD of HMA, WMA and FWMA technique with 50% of RAP at the end of life situation .................................................................................................. Figure 4-27 Rvalue compared in terms of Ico(%) and cross-over frequencies before and after ageing on mixtures with RAP ...................................................................................... Figure 4-28 Penetration and softening point evolution of all mixtures ......................... Figure 4-29 Penetration and softening point from available RAP materials .............. Figure 4-30 δ-method diagrams for aged mixtures with 0% and 50% of RAP ........... Figure 4-31 Rvalue analysis of all available aged materials ....................................................... Figure 5-1 Schema of the chapter ...............................................................................................................Figure 5-2 Parameters β and τ(s) represented in function of saturates ........................Figure 5-3 Parameters β and τ(s) represented in function of aromatics .......................Figure 5-4 Parameters β and τ(s) represented in function of c7 -asphaltene content ................................................................................................................................................................................. Figure 5-5 Parameters β and τ(s) represented in function of i -asphaltenes ..............Figure 5-6 Parameters β and τ(s) represented in function of the colloidal index ..Figure 5-7 Parameters β and τ(s) represented in function of the polydispersity ... Figure 5-8 Parameters β and τ(s) represented in function of the rheol ogical value ................................................................................................................................................................................. Figure 5-9 Parameters β and τ(s) represented in function of the crossover frequency .........................................................................................................................................................

Figure 5 -

 5 Figure 5-10 Rutting and fatigue parameters evolution with temperature ................... Figure 5-11 Critical temperatures for rutting and fatigue parameters ........................... Figure 5-12 Influence of bitumen penetration and softening point on |E*| at 15°C 10 Hz ................................................................................................................................................................... Figure 5-13 Influence of bitumen penetration and softening point on ε 6 ..................... Figure 5-14 Influence of bitumen index carbonyl on (a) ε 6 and (b) |E*| at 15°C Hz ........................................................................................................................................................................... Figure 5-15 Metravib® device and complex modulus testing description ................... Figure 5-16 Relationship between Kinexus® and Metravib® Huet -Such parameters ................................................................................................................................................................................. Figure 5-17 2P2S1D model, equation and Cole-Cole representation, from Olard 2003 [22,24] ..................................................................................................................................................Figure 5-18 2PB complex modulus test resul ts on HMA0 mixture (a) |E*| (MPa), (b)  (°), (c) WLF shift factors, and (d) Cole -Cole 2S2P1D model fitting .................. Figure 5-19 Shift-Homothety-Shift in time-Shift transformation (SHStS) [134] ...... Figure 5-20 SHStS transformation on HMA asphalt mixtures and recovered bitumens ........................................................................................................................................................... Figure 5-21 Relationship between model mixtur es and bitumens parameters .........Figure 5-22 Relationship between C1 and C2 from mixtures and bitumens modelling ................................................................................................................................................................................. Figure 5-23 Rutting critical temperatures on mixtures without RAP (a) and with 50% RAP (b) ................................................................................................................................................... Figure 5-24 Influence of rutting critical temperature on penetration (a) and softening point (b) results .................................................................................................................. Figure 5-25 Fatigue critical temperatures on mixtures without RAP (a) and with 50% RAP (b) ................................................................................................................................................... Figure 5-26 Influence of carbonyl index on rutting (a) and fatigue (b) critical temperatures ................................................................................................................................................. Figure 5-27 Influence of RAP addition of the fatigue/rutting parameters relationship ....................................................................................................................................................

Figure 5 -

 5 22 Relationship between C1 and C2 from mixtures and bitumens modelling .................................................................................................................................................................................Figure 5-23 Rutting critical temperatures on mixtures without RAP (a) and with 50% RAP (b) ................................................................................................................................................... Figure 5-24 Influence of rutting critical temperature on penetration (a) and softening point (b) results .................................................................................................................. Figure 5-25 Fatigue critical temperatures on mixtures without RAP (a) and with 50% RAP (b) ................................................................................................................................................... Figure 5-26 Influence of carbonyl index on rutting (a) and fatigue (b) critical temperatures ................................................................................................................................................. Figure 5-27 Influence of RAP addition of the fatigue/rutting parameters relationship .................................................................................................................................................... Durabilité des enrobés tièdes intégrant des recyclés ~ xiv ~

  Base bitumen of the study ........................................................................................................... Table 4-3 Virgin aggregates properties ..................................................................................................... Table 4-4 RAP characteristics .......................................................................................................................... Table 4-5 RAP bitumen properties [115] ..............................................................................................

  ............................................................................ The research presented in this document has been carried out as part of the European project Sustainable Pavement and Railway Initial Training Network Project (SUP&R ITN) 1.1 SUP&R ITN project SUP&R ITN project is an EU-funded Marie Curie project that offered a training-throughresearch programme to 15 selected young researchers across Europe. The SUP&R ITN network comprises industry and research partners who complement each other to bring together the necessary scientific and professional power needed to provide high quality training and cutting edge research in designing sustainable transport infrastructure technologies.

Figure 1 - 1 2 -

 112 Figure 1-1 Principal partners of the SUP&R ITN project The university partners are present in four different European countries. The University of Nottingham in England, the University College of Dublin in Ireland, the University of Palermo in Italy and the University of Huelva and University of Granada in Spain.



  Project 1.4 (ESR4) : Rubberised binder and asphalt mixes for wearing course  Project 1.5 (ESR5) : Binder design for low-temperature asphalt mixes  Project 1.6 (ESR6) : Half Warm Mixes Asphalt Recycling Asphalt in urban roads Chapter 1 -Introduction -3 -Then, work package 2, which is focused on studying several sustainable technologies for railway infrastructure, included the following projects:  Project 2.1 (ESR7) : Optimization of track bed design and maintenance  Project 2.2 (ESR8) : Characterisation of rubberised asphalt for railways sub-ballasts  Project 2.3 (ESR9) : Modelling and Design of rubberised asphalt for railways sub-ballast  Project 2.4 (ESR10) : Settlement monitoring and prediction in railway tracks Project Project 2.6 (ESR12) : The use of waste materials in railways Finally, work package 3 which is focused on the definition of a methodology and the creation of a tool to perform a broad sustainability assessment of the technologies investigated in WP1 and WP2. This tool will be based on environmental Lifecycle Assessment (LCA) that will incorporate cost analysis and social sustainability metrics together with a comprehensive set of economic, social, and environmental indicators. This part of the project also included three tasks, covered by postdoctoral students.  Project 3.1 (ER1) : Definition of sustainability assessment factors and current state-of-the-art in sustainable practices  Project 3.2 (ER2) : Sustainability assessment of Railways and SUP&R ITN technologies  Project 3.3 (ER3) : Life cycle impact assessment of Road and Railway Practicesmethodology and tools Within the basis of the SUP&R ITN project, ESR3 research project has become also a thesis.

Figure 1 -

 1 3 illustrates the trend of asphalt mixtures manufacturing (HMA and WMA) from 2007 to 2015 and the production of WMA mixtures in Europe and USA. In 2015 warm mix processes only represent 2% of the European production of asphalt, while in the USA it has been increasing up to 33% of the total production [4]. This technique must assure Chapter 1 -Introduction -5 -aggregates coating, the stability during production and transportation, and workability during on site lay out, not forgetting enough mechanical performance during service life [5].

Figure 1 - 3

 13 Figure 1-3 Total production of asphalt mixtures and warm mix asphalts in Europe and USA from 2007 to 2015 [4] As a result, recent pavement industrial developments have been directly linked with temperature reduction in the production process. Warm mix asphalts are manufactured in the temperature range of production of 110˚C to 140˚C by mainly three different procedures. They are bitumen foaming and the use of chemical or organic additives.

Figure 1 -

 1 Figure 1-4, the available reclaimed material from 2007 to 2015 in Europe and USA is illustrated.

Figure 1 - 4

 14 Figure 1-4 Total reclaimed asphalt pavement av ailable in Europe and USA [4]In the particular case of maintenance works on the French road network, RAP generation is only about 7 Mt annually, whereas the corresponding production of asphalt mixtures is about 31.5 Mt (data from 2015 [4]). Besides, several issues could be remarked. Firstly, French natural aggregates are of extreme quality and at low production costs. In this context, economic incentives to invest in recycling are less powerful than in countries that have a lack of raw materials, such as Iceland or the Netherlands. Secondly, current recycling techniques are generally based on formulation studies designed for new materials. This means that the reclaimed asphalt is roughly characterized and it is considered as disruptive additive material.

Figure 2 - 1

 21 Figure 2-1 Conventional asphalt mixture [4]

Figure 2 - 2

 22 Figure 2-2 Aggregates for asphalt mixture manufacture

Figure 2 - 3

 23 Figure 2-3 Example of natural and refined bitumen for asphalt mixture manufacture (from google images)

  Young Modulus (E). It establishes the proportional relation between normal stress and longitudinal strain, in simple compression or traction tests. dσ = E • dε -Shear Modulus (G). It establishes the proportional relation between shear stress and shear strain. dτ = G • dγ -Poisson Coefficient (ν). It establishes the inverse proportional relation between longitudinal strains and transversal strains in simple traction tests. εt = -ν • εl And the three are related with the formula 𝐺 = 𝐸 2 (1+ ν)

Figure 2 - 4

 24 Figure 2-4 Material response to a step load (a) Load, (b) Elastic, (c) Viscous, (d) Viscoelastic. Figure take n from Woldekidan Thesis [16]

  Durabilité des enrobés tièdes intégrant des recyclés -20 -where T is the testing temperature and Tref is the arbitrary reference temperature. Thus, the function α (Ti, fi) = fi •aT(Ti) represents the translation of the isothermal curve by multiplying the frequencies of each curve by the shift factor (aT) of each tested temperature.

Figure 2 - 5

 25 Figure 2-5 Example of master curves of complex modulus (left) and phase angle (right) for a single bitumen The translational coefficients for each isotherm T to the reference temperature Tref is a function of the logarithm of the shift factor, log (aT), so: E * (ω, T) = E * (ω•aT (T), Tref)

  MPa of wheel pressure. Results are shown by depth of deformation against number of cycles. Each type of mixture should fulfil the specifications to a certain rut percentage at a given number of cycles.

Figure 2 - 7

 27 Figure 2-7 Level 2 testing devices and mixture slab D. Stiffness modulus test (EN 12697-26)In order to get input values for the pavement structure design, the complex modulus needs to be measured. The French procedure is included on the European standards on Annex A (two point bending on trapezoidal specimens). The testing conditions are frequency sweep between 1 Hz and 40 Hz, and temperature sweep from -10°C to 40°C.

Figure 2 - 8

 28 Figure 2-8 Level 3 and 4 testing devices and fatigue principles[START_REF] Soenen | Fatigue Behaviour of Bituminous Materials: From Binders to Mixes[END_REF]

Figure 2 - 9

 29 Figure 2-9 Managing pavement maintenance and rehabilitationby monitoring riding quality[START_REF]Cold recycling[END_REF]



  In plant recycling:  Hot recycling -RAP heated by the aggregates -RAP heated with the aggregates -RAP heated in a separate device  Cold recycling -With emulsion  In situ recycling: Hot recycling (Reshape, remix and remix compact)

Figure 2 -

 2 Figure 2-10 Example of nomogram for determining the maximum possible RAP addition[START_REF] Gapa | Recycling of asphalt. New set of rules and standards shows the way forward[END_REF]

Chapter 2 -Literature Review - 35 -

 35 In general, the following characteristics are asked in the European countries(EN 13108-8): Type of bitumen  Bitumen content and properties (Penetration and softening point) Content of foreign materials  Type of aggregates, granularity and maximum diameter D  Maximum size of reclaimed particles (U)  Homogeneity

Figure 2 -

 2 Figure 2-11 RAP stockpile ready to be use on mixture manufacture

Figure 2 -

 2 Figure 2-12 Distillation process diagram[START_REF]Bitumen Production[END_REF]

Figure 2 -

 2 Figure 2-13 General diagram of fractioning[START_REF] Hoiberg | Bituminous Materials: Asphalts, Tars and Pitches. First[END_REF]

Figure 2 -

 2 Figure 2-14 Sol and Gel types of bitumens[START_REF] Hammoum | La structure chimique des bitumes pétroliers[END_REF]

Figure 2 -

 2 Figure 2-15 SARA fractions, Saturates, Aromatics, Resins and Asphaltenes

Figure 2 -

 2 Figure 2-16 Asphaltenes-Resins transfer[START_REF] Jones | Handbook of petroleum processing[END_REF]

Figure 2 -

 2 Figure 2-17 Asphalt molecules normally present or formed on oxidative ageing, fromPetersen (1984)[START_REF] Petersen | Chemical Composition of Asphalt As Related To Asphalt Durability: State of the Art[END_REF]

Figure 2 -

 2 [START_REF] Williams | The temperature dependence of relaxation mechanisms in amorphous polymers and other glass form liquids[END_REF] illustrates the procedure and device of testing. The purpose of this test is to classify the bitumens in different grades depending on the penetration value range.

Figure 2 -

 2 Figure 2-18 Penetration test on bitumen

Figure 2 -

 2 Figure 2-19 Softening point test on bitumen

Chapter 3 -

 3 Physico-chemical study of bitumens -51 -are summarized in

Figure 3 -

 3 1 shows different parts and results of the process. Durabilité des enrobés tièdes intégrant des recyclés -52 -

Figure 3 - 1

 31 Figure 3-1 Asphaltenes centrifugation and drying, and malthenes recovery

Figure 3 -

 3 Figure 3-2 illustrates the still separated phases, in an Erlenmeyer flask, before dichloromethane is poured inside the flask (25 ml per gram of bitumen). Then, the solution is stirred on a heating plate during 30 min at 70°C to assure the mixing and dissolution of both components.

Figure 3 - 2

 32 Figure 3-2 Asphaltenes and malthenes for bitumen recompositionFinally, model bitumens with defined m/a ratio are ready to pass control tests in order to check solvent presence. Then, once the validation is done, bitumens are ready to be stored and tested.

Figure 3 -

 3 Figure 3-3 shows the 10 bitumens of this study by their malthenes and asphaltenes content.

Figure 3 - 3 Figure 3 - 4

 3334 Figure 3-3 Model bitumens studied by malthenes (M) and asphaltenes (A) content

  purity. A microliter syringe is used for loading 1 µl of sample, resulting on one spot of 1 -1.5 mm size on the 10 different silica bars (Chromarod-SIII) employed on each test. Rods are then sequentially developed using hexane (∼ 100% of the bar length), toluene (∼ 50%), and solution of dichloromethane:methanol (95:5 v:v, ∼ 25%) before the analysis.

Figure 3 - 5

 35 Figure 3-5 Iatroscan MK -6s device used for SARA fractions determination Results from the TLC-FID Iatroscan test are used to determine the different SARA fractions content of each sample. Moreover, it serves to determine the colloidal index (Ic) [84] of the samples when doing the relation between them. The colloidal instability index is based on the colloidal model[START_REF] Nellensteyn | The constitution of asphalt[END_REF][START_REF] Pfeiffer | Aspahltic Bitumen as Colloid System[END_REF] to explain the difference between sol and gel bitumens. Ic typically

Figure 3 - 6

 36 Figure 3-6 Atomic force microscope Multimode T M with a detail of sample position

Figure 3 - 7

 37 Figure 3-7 PP25 and PP08 geometries used for the t estingGel permeation chromatography testNeat, model and aged bitumens are analysed using gel permeation chromatography test. GPC separates and measures their molecular size distribution and the changes produced by the different asphaltenes content. Waters 2414 Refractive Index Detector equipment is used for chromatographic analysis with a Styragel® HR3 column (500 to 30,000 g/mol range) for separating the constituents dissolved in tetrahydrofuran (THF).

Figure 3 - 8 GPC standards for curve calibration 3 . 2 . 4

 38324 Figure 3-8 GPC standards for curve calibration 3.2.4 Synthesis of the chemical and physical tests A total of 14 bitumen samples are tested according to the 6 different tests chosen. All the tests are summarized in Figure 3-9.

Figure 3

 3 Figure 3-9 Bitumen testing protocols

Figure 3 -

 3 Figure 3-10 Huet-Such model, equation and Cole -Cole representation

Figure 3 - 2 )Figure 3 -

 323 Figure 3-11 Example of curve cumf(MW) and (AMW) [94]

Figure 3 -

 3 Figure 3-12 Analysis of results and discussion schema followed

Figure 3 -

 3 [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF] shows ATR-FTIR spectra from 35/50 and 50/70 Neat malthenes and asphaltenes phases. Additionally, the spectrum from n-heptane solvent is added for reference in the case of it is present in the system.

Figure 3 -

 3 Figure 3-13 ATR-FTIR spectra from malthenes and asphaltenes phases Both parts, (a) and (b), from Figure 3-13 show the spectra of malthenes and asphaltenes respectively. Malthenes and asphaltenes spectra are equal for both bitumens. Solvent seems to have disappeared from the samples.

  at 98°C (boiling point of n-Heptane) would suggest that the solvent is not 100% removed after separation. Actually, TGA tests have been used to detect that asphaltenes from both bitumens have the same response to thermal analysis. Asphaltenes residue in both tests is 60% on average of carbon black or dust.

Figure 3 -

 3 Figure 3-14 TGA diagram from 35/50 and 50/ 70 asphaltenes fraction

  -15, 16 and 17 rheological results for G' (Pa), G'' (Pa), δ (°) and tan(δ) are compared at the overlapping temperatures 15°C, 10°C and 0°C for the 35/50 malthenes phase. This analysis is carried out for all bitumens (results can be found in Annex 1).

Figure 3 -Figure 3 -

 33 Figure 3-15 35/50 Malthenes phase PP25 and PP08 resu lts at 15°C

Figure 3 -

 3 Figure 3-16 35/50 Malthenes phase PP25 and PP08 results at 10°C

Figure 3 -Figure 3 -

 33 Figure 3-17 35/50 Malthenes phase PP25 and PP08 results at 0°C

Figure 3 -

 3 Figure 3-18 35/50 100M master curve fitting from DSR measurements at T=0°C

Figure 3 -

 3 Figure 3-19 shows as an example the fitting of the model to the 35/50 malthenes Cole-Cole diagram (a), Black diagram (b) and master curve (c-d).

Figure 3 -

 3 Figure 3-19 35/50 malthenes fitting model curves

Figure 3 -

 3 Figure 3-20 Master curves at T=0°C of (a) 35/50 and50/70 Malthenes phase

Figure 3 -

 3 Figure 3-21 δ-method diagrams of 35/50 and 50/70 malthenes fractions

Figure 3 -

 3 Figure 3-22 shows ATR-FTIR spectra from 35/50 and 50/70 Neat bitumens, plotting the absorbance versus the wavelength number on cm -1 .

Figure 3 -

 3 Figure 3-22 ATR-FTIR spectrum from 35/50 and 50/70 Neat bitumens Secondly, in Figure 3-23 (a), 35/50 Neat bitumen and two reconstituted bitumen are shown. Oneof the reconstituted bitumens is considered as wrong after its comparison with the neat bitumen. This is in terms of FTIR spectrum, especially at 1600, 1500 and around 800 cm -1 . It is believed that in the first separation/recomposition procedure an error happened during the process that is reflected with a very different spectrum.

Figure 3 -

 3 Figure 3-23 ATR-FTIR bitumens and solvent spectrum

  -24 (a) SARA fractions are illustrated by percentage with their respective error bars, while in Figure 3-24 (b) the colloidal indexes calculated for all systems are shown.

Figure 3 -Figure 3 - 25 .

 3325 Figure 3-24 (a) SARA fractions from neat and recomposed model bitumens, (b) Colloidal indexes of all bitumens

Figure 3 -

 3 Figure 3-25 Microstructure of 35/50 Neat and 35/50 85M+15A samples: AFM topography images of 50x50 µm 2 and 20x20 µm 2 after 4 days conditioning

Figure 3 -

 3 26 (a) illustrates the master curves at 0°C for both 35/50 Neat and its recomposed bitumen, and then Figure 3-26 (b) the results for the 50/70 Neat and model bitumen.

Figure 3 -

 3 Figure 3-26 Master curves at T=0°C of (a) 35/50 Neat and35/50 85M+15A and (b) 50/70 Neat and 50/70 86M+14A In Figure 3-26 (a) a slight difference between 35/50 and 35/50 85M+15A can be found at high frequencies. Even having higher c7-asphaltene content, the model bitumen seems to have softer rheological response. In the case of 50/70 bitumens presented in Figure 3-26 (b) the softer response of the model bitumen can be directly justified by the difference in the asphaltene content. These results are in accordance with the higher Ic values found for both neat bitumen (See Table 3-7 above).

Figure 3 -

 3 Figure 3-27 δ-method diagrams of 35/50 and 50/70 Neat and model bitumens δ-method analysis applied on the four bitumens show the similarities on the curves. Both 35/50 bitumens in Figure 3-27 (a) have the same shape. Even cross-over frequencies are close to each other. In the case of 50/70 bitumens in Figure 3-27 (b) the curves are not as similar as the others, but still the model bitumen represent the shape of the neat one.

  . Consequently, the large molecules move faster through the column and in this way out, the detector can measure the intensity of the signal for the different components.

Figure 3 -

 3 Figure 3-28 (a) represents molecules retention time versus the normalized signal from the device. The first molecules that appear at shorter retention times are the large molecules and then the smaller ones. In the case of Figure 3-28 (b) the ordinate axis corresponds to the translated molecular weight after the application of the calibration curve.

Figure 3 -

 3 Figure 3-28 GPC plots from 35/50 Neat and 35/50 85M+15A

  8 summarizes the results of the molecular weights of 35/50 Neat and model bitumen, where Mn is the number-average molecular weight (g/mol), Mw is the weight-average molecular weight (g/mol), Mp is the peak molecular weight (g/mol), Mz is th z-average molecular weight (g/mol) and PDI = Mw/Mn is the polydispersity index, relative to the spread in MW. PDI is usually used as a measure of the broadness of the distribution. PDI=1 indicates a monodisperse distribution, PDI = 1.1 to 2.0 shows an intermediate polydisperse distribution type. PDI>2 indicates a broad distribution, while narrow distribution shows a PDI between 1.02-1.10.

Figure 3 -Figure 3 -

 33 Figure 3-29 represents in (a) the spectra of the 35/50 model bitumens, in (b) the spectra of the 50/70 model bitumens and in (c) the spectra from the solvents employed during the separation and recomposition. With the arrows pointing at the carbonyl and sulphoxide peaks

Figure 3

 3 Figure 3-30 SARA fractions from 35/50 and 50/70 model bitumens

  -31. Microstructure morphology of 35/50 model bitumens corresponds to (a-b) 20% asphaltenes, (c-d) 15%

  observation of 20% asphaltenes (Figure3-31 (a-b)) bitumen shows more crowded population of catana phase and bigger dimensions. Then when decreasing to 15% asphaltenes content (Figure3-31 (c-d)) the perception of the ripple structure is not obvious but it is present.

Figure 3 -

 3 Figure 3-31 AFM results on 35/50 model bitumens after 4 days at 40°CWhen the asphaltene content is only 10% (Figure3-31 (e-f)), the differentiation of all three phases becomes challenging.

Figure 3 -

 3 32 (a) illustrates the master curves at 0°C for all 35/50 model bitumen and

Figure 3 -

 3 Figure 3-32 (b) the results for the 50/70 model bitumen.

Figure 3 -

 3 Figure 3-32 Master curves at T=0°C of (a) 35/50 model bitumens, and (b) 50/70 model bitumens

Figure 3 -

 3 Figure 3-33 δ-method diagrams of (a) 35/50 model bitumens, and (b) 50/70 model bitumens In Figure 3-33 (a), the δ-method curves obtained for the 35/50 model bitumens are shown. The

70

 70 The analysis is equivalent for the 50/70 model bitumens illustrated in Figure3-33 (b). Furthermore, in Annex 3 all model bitumens represented by the δ-method are shown in the same graphic. And the trend is followed in line by asphaltene content. The curves from 35/50 and 50/70 model bitumens get one after the other as asphaltenes content increase.

Figure 3 -

 3 Figure 3-34 (a) represents molecules retention time versus the normalized signal obtained. However, in Figure 3-34 (b) the ordinate axis corresponds to the translated molecular weight after the application of the calibration curve from 500 to 30,000 g/mol as it is the range of the column.

Figure 3 -

 3 Figure 3-34 GPC plots from 35/50 model bitumens As it is observed in previous analysis, in Figure 3-34 (a) the presence of the asphaltene phase is notice at 6.8 min. At this retention time 35/50 100A shows the highest peak, and then it decreases as the asphaltene content decrease. Still, in the case of malthenes phase, there are molecules at those retention times.

  partitioned in slices and divided in parts (large, medium or small molecules)[START_REF] Lee | Short-term aging characterization of asphalt binders using gel permeation chromatography and selected Superpave binder tests[END_REF][START_REF] Jennings | High pressure liquid chromatography as a method of measuring asphalt composition[END_REF]. From these divisions, in Table3-11 are summarized the results of the molecular weights of 35/50 model bitumens. Where Mn is the number-average molecular weight (g/mol), Mw is the weight-average molecular weight (g/mol), Mp is the peak molecular weight (g/mol), Mz is th z-average molecular weight (g/mol) and PDI = Mw/Mn is the polydispersity index, relative spread in MW. PDI is usually used as a measure of the broadness of the distribution. PDI=1 indicates a monodisperse distribution, PDI = 1.1 to 2.0 shows an intermediate polydisperse distribution type, PDI>2 broad distribution, while narrow shows a PDI between 1.02-1.10.

Figure 3 -

 3 Figure 3-35 (a) and (b) represents the spectra from 35/50 and 50/70 bitumens respectively.

Figure 3 - 50 (b) 50/ 70 Chapter 3 -

 350703 Figure 3-35 ATR-FTIR spectra from RTFOT and PAV aged bitumens

Figure 3 -

 3 36 represents graphically the variation of fractions with ageing.

Figure 3 -

 3 Figure 3-36 SARA fractions from 35/50 and 50/70 aged bitumens

Figure 3 -

 3 37 (a) shows the master curves at 0°C for all 35/50 Neat, RTFOT and PAV bitumens. Ageing plays an important role on bitumen hardening as rheological master curves show. There is strong difference after RTFOT and PAV. This could be linked to the variation of aromatic and asphaltene content.

Figure 3 -

 3 Figure 3-37 Master curves at T=0°C of 35/50 bitumens

Figure 3 -

 3 Figure 3-38 (a) δ-method diagrams of 35/50 aged bitumens and (b) Cross-over frequencies by asphaltene content

Figure 3 -Figure 3 -

 33 Figure 3-38 (a) shows how the 35/50 Neat curve develops a deeper valley and increase of the second peak to get to 35/50 RTFOT bitumen. Then, it moves to the right and increase even more the second peak, concentrating the biggest part of the material over 1,000 g/mol of AMW.Regarding to cross-over frequencies in, they tend to decrease when the asphaltene content increase.

Figure 3 -

 3 Figure 3-40 Polydispersity of 35/50 aged bitumens

Figure 3 -

 3 Figure 3-41 ATR-FTIR spectra from 35/50 80M+20A and PAV bitumens

Figure 3 - 42 .

 342 Figure 3-42. It should be remarked that the curves are very similar for the 2 bitumen. Nevertheless, a stiffer response can be differentiated from PAV bitumen at low frequencies in part (a) of the figure.

Figure 3 -Figure 3 -

 33 Figure 3-42 Master curves at T=0°C from 35/50 80M+20A and PAV bitumens

Figure 3 -

 3 Figure 3-43 δ-method (a) and GPC (b) curves from 35/50 80M+20A and PAV bitumens

93 -

 93 analysis has proven as a powerful tool for ageing determination. Curves shifting when asphaltenes content increase is clear. This shift is directly represented by the decrease of the Cross-over frequency. This value could be taken as an indicator of ageing.vi.By GPC testing, ageing and model bitumens have followed the same trends. Colloidal indexes have increased with asphaltenes ratio, as the number and weight average molecular weight. Chapter 4 -Ageing evolution of WMA combined with RAP -Chapter 4. Ageing evolution of warm mix asphalts combined with reclaimed asphalt pavement Résumé du chapitre La réduction de la température de fabrication des enrobé bitumineux et la réutilisation des agrégats d'enrobé, habituellement classés comme déchets solides, présentent de nombreux avantages par rapport à l'enrobé à chaud traditionnel. Ce couplage durable d'un point de vue environnemental doit montrer qu'il est durable d'un point de vue de ses performances techniques. Chaque technique possède ses avantages et inconvénients. D'un point de vue technique, des problèmes potentiels de tenue à l'eau, d'orniérage ou de résistance à basse température pourraient apparaitre prématurément. D'un autre côté, il existe de nombreux avantages environnementaux associés à l'utilisation de ces techniques, comme la réduction de la consommation de carburant et des émissions de gaz à effet de serre, l'extraction réduite de granulats naturels et l'élimination des stocks d'agrégats d'enrobés. Les enrobés tièdes sont fabriqués dans la gamme de température 110°C-140°C. Trois processus différents permettent cette réduction de la température: la mousse de bitume, les additifs chimiques et les additifs organiques. Ces technologies réduisent la consommation d'énergie, améliorent la maniabilité, et opèrent comme agents de compactage. Ces améliorations sur le compactage et les densités réalisées in situ tendent à réduire la perméabilité et le vieillissement du bitume, ce qui se traduit généralement par une meilleure performance des mélanges en termes de résistance aux fissures et de sensibilité à l'eau. En ce qui concerne l'agrégat d'enrobé, ce matériaux peut répondre aux exigences d'une solution de chaussée durable. Il peut présenter des économies de coûts, en réduisant de 23% l'impact environnemental lors de sa fabrication. Les agrégats d'enrobé sont généralement plus rigides en raison du bitume vieilli. Ceci peut induire une fragilité de l'enrobé à basse température en fonction de la proportion contenue dans le nouveau mélange. Plusieurs auteurs ont étudié les différentes étapes du vieillissement des liant bitumineux pendant la fabrication de l'enrobé et au long de sa vie. Deux phases peuvent ainsi être distinguées: le vieillissement à court terme et le vieillissement à long terme. Le vieillissement à court terme se produit plus exactement pendant la fabrication et la construction de la chaussée, et entraîne une augmentation importante de la viscosité du bitume ; le vieillissement à long terme est progressif et est induit par différents mécanismes. Les origines de ces vieillissements sont multiples : l'oxydation, l'évaporation de composants plus légers, la thixotropie et la synérèse, la polymérisation par réaction chimique de composants moléculaires ou encore la Durabilité des enrobes tièdes intégrant des recyclés -94 -séparation des composants par l'absorption de constituants huileux par certains types d'agrégats… Les connaissances actuelles sur le vieillissement sont essentiellement tirées de l'expérience pratique sur les enrobés traditionnels. L'objectif de ce chapitre est d'étudier et de comparer la technique tiède mousse aux autres techniques tièdes, en utilisant jusqu'à 50% d'agrégats d'enrobé dans le mélange. Pour ce qui traite du comportement à long termes des enrobés, un protocole de vieillissement est appliqué aux échantillons avant caractérisation mécanique. Ce vieillissement s'inspire de la méthode proposée par la RILEM TC-ATB TG5. Il comporte deux phases de vieillissement séparées. Les performances mécaniques à long terme sont comparées au moyen des essais de module complexe et de fatigue. Des essais de pénétration et de point de ramollissement sont effectués sur les bitumes récupérés. L'évolution du vieillissement est également caractérisée par une analyse infrarouge.

Figure 4 - 1

 41 Figure 4-1 Mixtures gradations with and without RAP

Figure 4 -

 4 Figure4-2 illustrates the manufacturing procedure followed.

Figure 4 - 2

 42 Figure 4-2 Mixtures manufacture procedure for bitumen extraction and mixture testing

Figure 4 - 3

 43 Figure 4-3 Mixtures testing protocols

  The complex shear modulus (G*) is obtained by combining the measurements performed on geometries of parallel plates of 25 mm and 8 mm from 20°C to 60°C and -20°C to 20°C respectively, and at a frequency range from 1 to 25 Hz.Chapter 4 -Ageing evolution of WMA combined with RAP -103 -

Figure 4 - 4

 44 Figure 4-4 Bitumen testing protocols

Figure 4 - 5

 45 Figure 4-5 Rvalue and w(co) determination from Black diagram and phase angle diagramCross-over frequencies ω(co) at 0°C and R-values of bitumen are determined in order to assess the ageing effect of the different analyses. Bitumen crossover frequencies are measured as in the literature[START_REF] Christensen | Interpretation of Dynamic Mechanical Test Data for Paving Grade Asphalt[END_REF][START_REF] Rowe | Evaluation of a 100 % rap recycling project in Fort Wayne, Indiana[END_REF]. On the other hand, the glassy modulus value, usually taken as 1,000 MPa in shear loading, is taken from the parameters of the model |G*inf|.

Figure 4 - 6

 46 Figure 4-6 Analysis of results flowchart

Figure 4 - 7

 47 Figure 4-7 Fatigue laws and 95% interval confidence of HMA, WMA and FWMA mixtures

Figure 4 - 8

 48 Figure 4-8 Penetration and Softening point trend by manufacturing proc ess

Figure 4 - 9

 49 Figure 4-9 Master curve construction at 0°C for 35/50 Neat bitumen As it has been developed in Chapter 3, the raw data obtained from DSR testing on the Kinexus® device is presented in terms of master curves and model fitting curves at T=0°C. As an example, 35/50 Neat bitumen is shown in Figure 4-9.

Figure 4 - 10

 410 Figure 4-10 Recovered bitumen after manufacture ma ster curves at 0°C Bitumen master curves show the hardening experienced by the bitumen after manufacture. The trend is the same as for the penetration values. The procedure that apparently modifies less the 35/50 Neat bitumen, i.e. induces less ageing, is the foaming process. Reducing 30°C the manufacturing temperature shows a clear difference in both diagrams.

Figure 4 -

 4 Figure 4-11 δ-method diagram of recovered bitumens after manufacture In the right part, Figure 4-11 (b) it can be observed shadowed the increment of ageing between the foaming and the conventional procedure. These results are in accordance with the literature,

Figure 4 - 12

 412 Figure 4-12 Rvalue compared in terms of Ico(%) (a) and cross-over frequencies (b)

Figure 4 - 13

 413 Figure 4-13 Fatigue laws and 95% interval confidence of aged HMA, WMA and FWMA mixt ures Ageing, Ico, penetration and softening point discussion From Table 4-7, penetration, softening point and Ico values seem to achieve respectively an imaginary minimum (~15 1/10 mm) and maximum (~66°C and ~5.50%). These values show how important is to include in the analysis the evolution of results with ageing as the starting point was different.

  results are compared by Ico evolution (Table 4-7), it can be appreciated that without being at the same ageing stage the same values of penetration and softening point can be obtained. As an example, FWMA0a and RAP bitumen have the same values of penetration and softening point, but they are in a different ageing stage in term of Ico (5.40 % and 8.60 % respectively).

Figure 4 - 14

 414 Figure 4-14 Penetration and Softening point trend after ageing

Figure 4 -

 4 Figure 4-15 Recovered bitumen after ageing master curves at 0°C -method analysis Figure 4-16 represents the δ-method curves for the neat bitumen and the bitumen extracted after ageing. In part (a) of the figure the aged bitumens are compared with the 35/50 Neat bitumen. They show all an evolution with ageing. After ageing they are all centred around 1,100 g/mol and present a clearer bimodal distribution, showing in the case of HMA0a bitumen the beginning of a third peak at the beginning of the curve.

Figure 4 -

 4 Figure 4-16 δ-method diagram of re covered bitumens after ageingThen in part (b), it is highlighted the difference of ageing between the WMA process and the other procedures. This higher concentration (maybe due to asphaltenes increase) could explain

Figure 4 - 17

 417 Figure 4-17 Rvalue compared in terms of Ico(%) (a) and cross-over frequencies (b) before and after ageing

Figure 4 -

 4 Figure 4-18 Fatigue laws and 95% interval confidence of mixtures with RAP: HMA50, WMA50 and FWMA50

Figure 4 -

 4 Figure 4-19 Penetration and Softening point trend after RAP addition

Figure 4 -

 4 Figure 4-20 Recovered bitumen after 50%RAP mixtures manufacture master curves at 0°C

  -21 each bitumen curve is shown with respect to 35/50 Neat bitumen (a). Also, in part (b) of the figure, the comparison is done with respect to 35/50 RAP bitumen.

Figure 4 -

 4 Figure 4-21 δ-method diagram of recovered bitumens of RAP mixtures after manufacture On the right part (b) of the figure 4-21, the 35/50 RAP bitumen is shown, in clear grey full line. It presents a bimodal distribution, but when mixed with virgin bitumens for all procedures and techniques the second peak becomes smaller.

120 -

 120 (a) With Neat bitumen (b) Without RAP bitumen Durabilité des enrobes tièdes intégrant des recyclés -Rvalue -Ico -crossover frequency correlations Regarding to the viscoelastic response of the material expressed in terms of Rvalue and compared by Ico and cross-over frequencies, in Figure 4-22 (a) an increase of Ico can be observed when RAP is used, without any clear change in the Rvalue. Then, in Figure 4-22 (b), the addition of RAP leads the Rvalue to increase or decrease, as well as the cross over frequencies. Then, no clear correlation can be established between Rvalue and Ico or Rvalue and w(co).

Figure 4 - 22

 422 Figure 4-22 Rvalue compared in terms of Ico(%) and cross -over frequencies before and after RAP addition 4.3.4 Ageing on mixtures with RAP

Figure 4 -

 4 Figure 4-23 Fatigue laws and 95% interval confidence of aged HMA50, WMA50 and FWMA50 mixtures after ageing

Figure 4 - 24

 424 Figure 4-24 Penetration and Softening point trend after ageing on RAP mixtures

Figure 4 -

 4 Figure 4-27 Rvalue compared in terms of Ico(%) and cross -over frequencies before and after ageing on mixtures with RAP

Figure 4 -

 4 Figure 4-28 Penetration and soften ing point evolution of all mixtures

Figure 4 -

 4 Figure 4-29 Penetration and softening point from available RAP materials

Figure 4 -

 4 Figure 4-30 (a) shows -curves from materials equivalent to a first ageing level, before a first recycling situation.Figure 4-30 (b) shows -curves from bitumen containing RAP, representing a

  Figure 4-30 (b) shows -curves from bitumen containing RAP, representing a second level of recycling situation. The comparison shows a displacement of the curves to the right (materials more aged).

Figure 4 -

 4 Figure 4-30 δ-method diagrams for aged mixtures with 0% and 50% of RAP

Figure 4 -

 4 Figure 4-31 Rvalue analysis of all av ailable aged materials

Chapter 5 - 131 - 5 .

 51315 Correlation between structure and mechanical performance -Chapter Correlation between structure and mechanical performance Résumé du chapitre Ce chapitre présente les résultats relatifs à l'influence du vieillissement, du taux d'agrégats d'enrobé et de la technique de fabrication sur la relation entre les enrobés et le bitume. Dans le but de contribuer à l'étude de cette relation, des corrélations ont été établies pour les fractions SARA, la teneur en asphaltènes c7, les paramètres SHRP, le Rvalue pour les bitumes, et la fatigue et les résultats des modules complexes dans les enrobés. Les matériaux considérés sont déjà décrits aux chapitres 3 et 4. Bien que tous les paramètres du modèle Huet-Such aient été étudiés et comparés avec les différentes caractéristiques du matériau, seule la viscosité β et le multiplicateur de fréquence τ (s) à 0°C sont représentés dans le chapitre. En fait, ces deux paramètres montrent la meilleure corrélation en termes de fractions SARA, de teneur en asphaltènes c7, d'indice colloïdal et de polydispersité des bitumes. La relation entre les paramètres du modèle de Huet-Such calculés à partir des mesures réalisées avec le rhéomètre Metravib® et à partir des mesures réalisées avec le rhéomètre Kinexus® est étudiée. Ensuite, une comparaison est faite entre les paramètres du modèle de Huet-Such des bitumes et les paramètres de la modélisation 2S2P1D des enrobés. Les critères SHRP d'orniérage et de fatigue sont comparés avec les paramètres standards Européens. Le paramètre SHRP d'orniérage (G*/sinδ)RTFOT> 2200 Pa est calculé sur les bitumes vieillis après RTFOT. Le paramètre de fatigue (G* sin)PAV < 5MPa est mesuré sur les échantillons vieillis après PAV.

Figure 5

 5 Figure 5-1 Schema of the chapter

Figure 5 -

 5 2 (a) viscosity β and (b) τ(s) at 0°C are plotted in function of saturates content from Iatroscan. In general, saturates content evolve less than the asphaltenes, however good correlations are found. There is good correlation for all systems, aged and model samples. On part (a) of the figure it can be observed that β increases as saturates content decreases. On part (b), τ shows good Chapter 5 -Correlation between structure and mechanical performance -135 -correlation for all 35/50 bitumens (aged and model). As β, τ(s) is inversely proportional to saturates content.

Figure 5 - 2

 52 Figure 5-2 Parameters β and τ(s) represen ted in function of saturates

Figure 5 - 3

 53 Figure 5-3 Parameters β and τ(s) represented in function of aromatics

  a) β and (b) the frequency multiplier τ(s) at 0°C are plotted in function of c7-asphaltene content. In part (a) of the figure, the best correlation is found for an exponential fitting, with R 2 = 96% for the viscosity parameter.

Figure 5 - 4

 54 Figure 5-4 Parameters β and τ(s) represented in function of c7 -asphaltene content Moreover, 35/50 aged and model samples experience an increase of τ(s) with ageing (higher asphaltenes content R 2 ~94%).

Figure 5 - 5

 55 Figure 5-5 Parameters β and τ(s) represented in function of i -asphaltenesAgeing leads to an increase in the asphaltenes content (c7 and i). As the bitumen samples age, they viscosity increases.

Figure 5 - 6

 56 Figure 5-6 Parameters β and τ(s) represented in function of the colloidal index

Figure 5 - 7

 57 Figure 5-7 Parameters β and τ(s) represented in function of the polydispersity

  -8 (a) viscosity β and (b) τ(s) are plotted in function of the rheological values (Rvalue) of the systems. Both parameters increase their value, β exponentially and τ(s) potentially with the increase of Rvalue.

Figure 5 - 8

 58 Figure 5-8 Parameters β and τ(s) represented in function of the rheological value

Figure 5 - 9

 59 Figure 5-9 Parameters β and τ(s) represented in function of the crossover frequency

(

  critical temperature (Tc) is obtained by interpolation for the rutting and fatigue parameter when: G*/sin = 2.2 kPa and G*sin = 5 MPa Durabilité des enrobes tièdes intégrant des recyclés -140 -On Figure 5-10 the evolution of the parameters by temperature increment is illustrated on 35/50 laboratory aged bitumen. The area where fatigue or rutting parameter does not fulfil the requirements is defined in red. It can be observed how rutting resistance decreases with temperature. The concept of critical temperature can be observed in both figures.

Figure 5 -

 5 Figure 5-10 Rutting and fatigue parameters evolution with temperature For the neat bitumen, G*/sinδ)unaged bitumen > 1,000 Pa (blue pointed line) and (G*/sinδ)RTFOT aged bitumen > 2,200 Pa (red dashed line) limits are figured. On the other hand, fatigue critical temperature would be determined by PAV results. SHRP criterion is that G*sin < 5 MPa at the average pavement temperature.

Figure 5 -

 5 Figure 5-11 Critical temperatures for rutting and fatigue parameters As an example, if 45°C is considered as test temperature (Tt), it can be observed that all materials would fulfil the rutting requirements but 35/50 100 M and 50/70 100M (malthenes

  This part of the Chapter is conducted with all data available from mixtures and their extracted bitumens. The comparisons is done considering, when possible, the three techniques together HMA, WMA and WMA.

Chapter 5 -Figure 5 -

 55 Figure5-12 presents the evolution of complex modulus on the mixtures by penetration and softening point of bitumens. As expected, in both cases the increase of hardening is represented by an increase of the complex modulus at 15°C 10 Hz. Thus, a good correlation is found in (a) with a potential law, and in (b) with a linear law.

Figure 5 -Figure 5 -

 55 Figure 5-12 Influence of bitumen penetration and softening point on |E*| at 15°C 10 Hz

Figure 5 - 13

 513 Figure 5-13 Influence of bitumen penetration and softening point on ε 6

Figure 5 -

 5 Figure 5-16 Relationship between Kinexus® and Metravib® Huet -Such parameters

Figure 5 -

 5 Figure 5-17 illustrates the model Cole-Cole representation and its formula.

Figure 5 -

 5 Figure 5-17 2P2S1D model, equation and Cole -Cole representation, from Olard 2003[START_REF] Olard | Comportement thermomécanique des enrobés bitumineux à basses temperatures: Relations entre les propriétés du liant et de l'enrobé[END_REF][START_REF] Olard | General "2S2P1D" Model and Relation Between the Linear Viscoelastic Behaviours of Bituminous Binders and Mixes[END_REF]

Figure 5 -

 5 Figure 5-18 2PB complex modulus test results on HMA0 mixture (a) |E*| (MPa), (b)  (°), (c) WLF shift factors, and (d) Cole -Cole 2S2P1D model fitting

  -18 as a Cole-Cole diagram.

Figure 5 -

 5 Figure 5-19 Shift-Homothety-Shift in time-Shift transformation (SHStS)[START_REF] Benedetto | Linear viscoelastic behaviour of bituminous materials: From binders to mixes[END_REF]

)

  Durabilité des enrobes tièdes intégrant des recyclés -152 -E∞ and E0 are the maximum (glassy modulus) and the minimum values of the complex modulus are obtained from the Huet-Such (for the bitumens) and 2S2P1D (for the mixtures) shown on previous Tables. Mixtures and recovered bitumens rheological performance, through the Cole-Cole plan (E', E''), can be compared.

Figure 5 -

 5 Figure 5-20 represent the normalized Cole-Cole curves obtained for the (a) HMA0, (b) HMA0a, (c) HMA50 and (d) HMA50a mixtures and their respective bitumens. It serves as an example of the trend followed by the other procedures. Complex modulus measurements on bitumens were performed both on Metravib® and Kinexus® devices. As it is hard to define which apparatus is the most appropriate to characterize the rheological behaviour of bitumen, it was decided to present both results. 2PB complex modulus values are obtained for the respective asphalt mixtures. All individual results and transformations are reported in Annex 9.

Figure 5 -

 5 Figure 5-20 SHStS transformation on HMA asphalt mixtures and recovered bitumens

Durabilité des enrobes tièdes intégrant des recyclés - 154 -In Figure 5 -Figure 5 -

 15455 Figure5-21 shows that in the case of the bitumen, this parameter has a wide range of variation,

Figure 5 -

 5 Figure 5-21 Relationship between model mixtures and bitumens parameters

Figure 5 -

 5 Figure 5-22 Relationship between C 1 and C2 from mixtures and bitumens modelling

Figure 5 -

 5 23 maximum temperatures before rutting for all type of mixtures manufactured are shown. In part (a) of the figure are represented the three mixtures without RAP, and in part (b) the mixtures with 50% RAP.An increase in the parameter G*/sinδ would indicate an improvement in rutting resistance of the asphalt mixtures under operational conditions of heavy traffic loadings and at high service temperatures. So then, a higher factor of G*/sinδ is required from rutting resistance point of view. In line with SHRP report A-409[START_REF] Leahy | Validation of relationships between specification properties and performance[END_REF], the implication is that for temperatures above these threshold values, bitumen may contribute to rutting.

Figure 5 -

 5 Figure 5-23 Rutting critical temperatures on mixtures without RAP (a) and with 50% RAP (b) Mixtures without RAP, Figure 5-23 (a), show that HMA0 and WMA0 mixtures have similar threshold temperature (Tc) around 78°C. On the other hand, this edge temperature is 10°C lower for the foaming procedure. FWMA0 needs to suffer long term ageing to get to the same level of the other procedures.

  criterion on penetration and softening point resultsIn general, permanent deformations resistance mainly depends on aggregate properties and mix design. But still, bitumen characteristics cannot be neglected as it has an influence around 30%[START_REF] Leahy | Validation of relationships between specification properties and performance[END_REF]. In Figure5-24, penetration (a) and softening point (b) results from each manufacture technique are represented in function of the critical temperature.

Figure 5 -

 5 Figure 5-24 Influence of rutting critical temperature on penetration (a) and softening point (b) results

Figure 5 -

 5 Figure 5-25 Fatigue critical temperatures on mixtures without RAP (a) and with 50% RAP (b)

Figure 5 -

 5 Figure 5-26 Influence of carbonyl index on rutting (a) and fatigue (b) critical temperatures

Figure 5 -

 5 Figure 5-27 Influence of RAP addition of the fatigue/rutting parameters relationship

  an important role on bitumens structure. The variation of the asphaltene fraction, induced by model bitumen or by ageing procedures, shows fairly good correlation with β and τ parameters of the Huet-Such modelling.

Chapter 6 -- 6 . 3

 663 Conclusions and perspectives-167 Conclusions finales L'objectif général de cette thèse est d'étudier la durabilité des enrobés tièdes intégrant des recyclés. À cette fin, la structure du bitume est étudiée afin de définir l'origine des changements produits par le vieillissement des enrobés bitumineux. En particulier, l'influence de la teneur en asphaltènes sur les propriétés des bitumes est étudiée. Des bitumes modèles à teneurs en asphaltènes différentes sont fabriqués à partir de la séparation et la recomposition de fractions d'asphaltènes et de malthènes.Ces bitumes modèles sont caractérisés physiquement et chimiquement. Dans le but d'étudier la performance mécanique des enrobés tièdes et leur évolution au cours du vieillissement, un plan expérimental est défini. Douze enrobés sont caractérisés par différents essais, effectués à la fois sur des enrobés et leurs bitumes récupérés. Les techniques de fabrication choisies sont à chaud, tiède avec surfactant et tiède à la mousse du bitume. Ensuite, 50% d'agrégats d'enrobés sont ajoutés aux mélanges. Finalement, la procédure de vieillissement en laboratoire sur des échantillons foisonnés et compactés est appliquée afin d'évaluer la réponse des matériaux après un vieillissement simulé à long terme. Les principales conclusions des études conduites peuvent être résumées comme suit: Influence de la teneur en asphaltènes sur le vieillissement: I. En ce qui concerne l'analyse ATR-FTIR, les groupes sulfoxyde semblent être plus affectés par l'addition de fractions d'asphaltènes que les groupes carbonyle, ce qui indique l'affinité des fractions polaires vis-à-vis de ces composants. II. La détermination des fractions SARAP par chromatographie Iatroscan nous permet d'observer une augmentation des asphaltènes avec le vieillissement. Il est également montré qu'au cours du vieillissement, l'augmentation de la teneur en asphaltènes est due à l'évolution des composés aromatiques en résines (et aux résines polaires) puis en asphaltènes. De plus, l'oxydation des composés aromatiques ou des résines en résines polaires ou en asphaltènes est également possible pendant le vieillissement. III. Par l'observation de l'AFM, des micelles d'asphaltènes apparaissent dans tous les bitumes testés. Dans la structure malthènique, on observe une structure en abeille. Ainsi, la présence d'asphaltènes ne semble pas une condition nécessaire pour leur apparition contrairement à ce qui a été proposé par d'autres chercheurs. IV. Le comportement rhéologique du bitume se caractérise principalement par sa rigidité. En conséquence, il est fortement contrôlé par la teneur en asphaltènes du bitume. De Durabilité des enrobes tièdes intégrant des recyclés -168 -petits changements dans le rapport asphaltènes / malthènes ont un impact direct sur le matériel. V. L'analyse par la δ-méthode s'avère être un outil puissant pour la détermination du vieillissement. Une translation des courbes de distribution est clairement observée lorsque la teneur en asphaltènes augmente. Les fréquences de cross-over, correspondant à la médiane de la distribution de probabilité de l'AMWD, pourraient être considérées comme un indicateur du vieillissement. VI. Selon les tests de GPC, les types de bitumes vieillis et modèles suivent la même tendance en matière de teneur en asphaltènes. Les indices colloïdaux augmentent avec le taux d'asphaltènes, comme les masses moléculaires moyennes en poids et en nombre. VII. La teneur en asphaltènes joue un rôle important dans la structure des bitumes. La variation de cette fraction, contrôlée dans un bitume modèle ou induite par le vieillissement, présente une corrélation assez bonne avec celles des paramètres β et τ du model de Huet-Such. VIII. Pour les critères SHRP d'orniérage et fatigue, la teneur en asphaltènes joue un rôle important sur la rigidité du bitume. Ainsi, les températures critiques de service augmentent (orniérage) ou diminuent (fatigue) lorsque la teneur en asphaltène augmente, ce qui élargit la plage d'utilisation. Influence de la procédure de fabrication IX. La réduction de la température de fabrication des enrobés à la mousse de bitume peut entraîner une plus faible de rigidité après la fabrication. Cette diminution, par rapport aux autres types d'enrobés, est liée au vieillissement réduit par le bitume pendant la fabrication. X. Concernant la réponse à la fatigue, toutes les procédures donnent des résultats conformes aux exigences normatives. Il est très intéressant de constater qu'avec une diminution de 30°C de la température de fabrication d'enrobés, et tous les avantages associés, les performances mécaniques restent conformes aux normes. XI. En termes de module complexe, une bonne corrélation a été trouvée avec la pénétration et le point de ramollissement bille anneau de tous les bitumes testés. Une réduction de la pénétration et une augmentation du point de ramollissement du bitume sont des indicateurs d'une augmentation de la rigidité du mélange. XII. D'autre part, le paramètre de fatigue ε6 ne suit aucune évolution claire avec la température de fabrication. Cependant, pour la procédure de moussage FWMA, une Chapter 6 -Conclusions and perspectives -169 -augmentation du point de ramollissement (et une diminution de la pénétration) est directement liée à une meilleure résistance à la fatigue. Ces résultats doivent être pris avec précaution, car les pentes des droites de fatigue ne sont pas prises en considération. Influence de l'ajout de chaussée d'asphalte récupérée XIII. En général, l'addition d'agrégats d'enrobés (AE) augmente la performance des enrobés bitumineux, à la fois pour les enrobés à chaud et les tièdes. Néanmoins, lorsque les AE sont ajoutés ou après vieillissement, la pente de la fatigue augmente. Par conséquent la résistance à la fatigue du matériau tend à être plus sensible au niveau de déformation. XIV. En ce qui concerne la performance du bitume, le processus de moussage vieillit moins le bitume pendant la fabrication en comparaison avec la procédure à chaud. Lorsque le vieillissement à long terme est appliqué, les niveaux deviennent comparables dans les deux cas. De même, le durcissement expérimenté lorsque les AE sont ajoutés est moins prononcé car du bitume déjà vieilli est présent dans les AE.XV. Pour les critères SHRP, les températures critiques du service d'orniérage et de fatigue pour les chaussées ne montrent pas de relation claire avec les résultats empiriques de pénétration et point de ramollissement. Néanmoins, en termes de recyclage, l'addition d'AE élargit la gamme de température d'application indépendamment de la procédure de fabrication. δ-méthode de détection du vieillissement XVI. L'application de la δ-méthode révèle des effets de vieillissement contrastés pour les différents processus, ainsi que l'influence de l'addition d'AE. Le schéma général observé sur les courbes est une diminution des fractions de faible masse moléculaire apparente et une augmentation des fractions de masse moléculaire apparente élevée en raison du vieillissement des échantillons avec ou sans AE. Par rapport à la technique tiède mousse, le processus de production à chaud induit un déplacement important de la distribution vers une masse moléculaire apparente plus élevée. Après le vieillissement ou l'addition d'AE, les distributions ont la tendance à être déplacées de manière similaire pour tous les processus. XVII. Combinée aux essais standards sur bitume, la δ méthode semble être un outil approprié pour la quantification des évolutions structurelles du bitume permettant une bonne visualisation des modifications induites. Ces résultats pourraient être considérés comme une première étape vers une prédiction possible de la réponse des matériaux. L'interprétation structurelle de l'addition d'AE et de l'évolution du vieillissement serait ainsi possible avec la δ méthode. ANNEXES Annex 1 -OVERLAPPING TEMPERATURES FOR MODEL AND AGED BITUMENS Annex 2 -MASTER CURVES, WLF ADJUSTMENT, BLACK DIAGRAMS AND COLE-COLE PLAN OF MODEL AND AGED BITUMENS Annex 3 -HUET-SUCH MODELLING PARAMETERS AND -METHOD CURVES OF MODEL AND AGED BITUMENS Annex 4 -MASTER CURVES, WLF ADJUSTMENT, BLACK DIAGRAMS AND COLE-COLE PLAN OF RECOVERED BITUMENS FORM ASPHALT MIXTURES MANUFACTURE Annex 5 -HUET-SUCH MODELLING PARAMETERS AND -METHOD CURVES FROM KINEXUS® DEVICE -RECOVERED BITUMENS FROM ASPHALT MIXTURES Annex 6-2S2P1D MODELLING PARAMETERS AND MASTER CURVES OF ASPHALT MIXTURES Annex 7 -HUET-SUCH MODELLING PARAMETERS BY C7-ASPHALTENES, SARA FRACTIONS, COLLOIDAL INDEX, POLYDISPERSITY RVALUE AND W(co) Annex 8 -SHRP RUTTING AND FATIGUE PARAMETERS CURVES WITH TEMPERATURE Annex 9 -SHSTH TRANSFORMATION BETWEEN ASPHALT MIXTURES RESULTS AND RECOVERED BITUMEN RESULTS Annex 1 OVERLAPPING TEMPERATURES FOR MODEL AND AGED BITUMENS Annex 3 HUET-SUCH MODELLING PARAMETERS AND -METHOD CURVES OF MODEL AND AGED BITUMENS Annex 3 -Huet-Such modelling parameters and -method curves of model and aged bitumens -Annex 3 -i -

Annex 3 -

 3 Huet-Such modelling parameters and -method curves of model and aged bitumens -Annex 3 -iii -50/70 MODEL BITUMENS -method representation curve -method representation 35/50 model bitumens Durabilité des enrobés tièdes intégrant des recyclés -Annex 3 -iv --method representation 50/70 model bitumens -method representation ALL model bitumens of recovered bitumens form asphalt mixtures manufacture -Annex 4 -i -HMA0 Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Durabilité des enrobés tièdes intégrant des recyclés -Annex 4 -ii -HMA0a Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves of recovered bitumens form asphalt mixtures manufacture -Annex 4 -iii -HMA50 Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Durabilité des enrobés tièdes intégrant des recyclés -Annex 4 -iv -HMA50a Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves of recovered bitumens form asphalt mixtures manufacture -Annex 4 -v -WMA0 Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Durabilité des enrobés tièdes intégrant des recyclés -Annex 4 -vi -WMA0a Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves of recovered bitumens form asphalt mixtures manufacture -Annex 4 -vii -WMA50 Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Durabilité des enrobés tièdes intégrant des recyclés -Annex 4 -viii -WMA50a Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves of recovered bitumens form asphalt mixtures manufacture -Annex 4 -ix -FWMA0 Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Durabilité des enrobés tièdes intégrant des recyclés -Annex 4 -x -FWMA0a Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves of recovered bitumens form asphalt mixtures manufacture -Annex 4 -xi -FWMA50 Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Durabilité des enrobés tièdes intégrant des recyclés -Annex 4 -xii -FWMA50a Rheological data measurements from Metravib® (left) and Kinexus® (right) Cole-Cole plan, Black diagram and |G*| and  master curves Annex 5 HUET-SUCH MODELLING PARAMETERS AND -METHOD CURVES FROM KINEXUS® DEVICE -RECOVERED BITUMENS FROM ASPHALT MIXTURES-Annex 5 -Huet-Such modelling parameters and -method curves from Kinexus® device -Annex 5 -i -

6 2S2P1D

 6 Durabilité des enrobés tièdes intégrant des recyclés -Annex 5 -ii -NEAT BITUMENS -method curves for 35/50 Neat, RAP and Foam bitumens HMA0 -HMA0a-HMA50 -HMA50a -method curves of 35/50 Neat and RAP bitumen compared with recovered asphalt mixture bitumen Annex 5 -Huet-Such modelling parameters and -method curves from Kinexus® device -Annex 5 -iii -WMA0 -WMA0a-WMA50 -WMA50a -method curves of 35/50 Neat and RAP bitumen compared with recovered asphalt mixture bitumen FWMA0 -FWMA0a-FWMA50 -FWMA50a -method curves of 35/50 Neat and RAP bitumen compared with recovered asphalt mixture bitumen Annex MODELLING PARAMETERS AND MASTER CURVES OF ASPHALT MIXTURES Annex 6 -2S2P1D Modelling parameters and Master curves of asphalt mixtures -Annex 6 -i -

Table 2 -

 2 1 LVE models for bituminous materials[START_REF] Olard | Comportement thermomécanique des enrobés bitumineux à basses temperatures: Relations entre les propriétés du liant et de l'enrobé[END_REF][START_REF] Mangiafico | Linear viscoelastic properties and fatigue of bituminous mixtures produced with Reclaimed Asphalt Pavement and corresponding binder blends[END_REF] ............................................................................... Table 2-2 Resume of Foaming WMA commercial processes obtained from producers websites ................................................................................................................................................... Table 2-3 Resume of Organic additives WMA commercial processes obtained from producers websites ......................................................................................................................... Table 2-4 Resume of Chemical additives WMA commercial processes obtained from producers websites ......................................................................................................................... Table 2-5 From Airey 2003, chronological bitumen ageing methods [76] ....................... Table 2-6 From Airey 2003, chronological as phalt mixture ageing methods [76] ..... Table 3-1 Base bitumens of the study ........................................................................................................ Table 3-2 Aged bitumens studied by malthenes and asphaltenes content ...................... Table 3-3 Neat bitumens a/m ratio .............................................................................................................. Table 3-4 SARA fractions of malthenes and asphaltenes of 35/50 and 50/70

bitumens ..................................................................................................................................................

Table 3 -

 3 5 Neat and model bitumens a/m ratio ....................................................................................

Table 3 -

 3 6 ATR-FTIR analysis of Ico and Iso values ...........................................................................

Table 3 -

 3 7 SARA fractions of neat and recomposed bitumens .................................................... Table 3-8 Molecular weights of 35/50 bitumens ................................................................................ Table 3-9 ATR-FTIR analysis of Ico and Iso values of 35/50 model bitumens .............

Table 3 -

 3 10 SARA fractions and colloidal indexes of 35/50 and 50/70 model

bitumens ..................................................................................................................................................

Table 3 -

 3 11 Polydispersity of 35/50 model bitumens ......................................................................

Table 3 -

 3 12 Aged bitumens m/a ratio on n-heptane determination ......................................

Table 3 -

 3 13 ATR-FTIR analysis of Ico and Iso values of aged bitumens ..............................

Table 3 -

 3 14 SARA fractions and colloidal indexes of 35/50 and 50/70 aged bitumens .

.......................................................................................................................................................................

Table 3 -

 3 15 Polydispersity on 35/50 aged bitumens ........................................................................

Table 3 -

 3 [START_REF] Woldekidan | Response modelling of bitumen, bituminous mastic and mortar[END_REF] ATR-FTIR analysis of Ico and Iso values from 35/50 80M+20A and PAV bitumens ...

Table 3 -

 3

17 SARA fractions from model and aged bitumens at the highest asphaltene content ......................................................................................................................................................

Table 4 -

 4 1 Mixtures studied and manufacturing temperatur e ...................................................

Table 4 - 2

 42

Table 4 -

 4 [START_REF] Hill | Performance evaluation of warm mix asphalt mixtures incorporating reclaimed asphalt pavement[END_REF] Influence of manufacturing technique on the mechanical performance . Table 4-7 Influence of ageing on the mechanical performance of the different techniques ........................................................................................................................................... Table 4-8 Influence of RAP addition on the mechanical performance of the different techniques .................................................................................................................... Table 4-9 Influence of ageing on the characteristics of the mixtures with RAP .......

Table 4 -

 4

10 Characteristics from 0%RAP aged an d 50%RAP aged mixtures following EN 13108-8 ......................................................................................................................................... Table 5-1 Materials and results selected from Chapter 3 .........................................................

Table 5 -

 5

	Durabilité des enrobés tièdes intégrant des recyclés

2 Resume of results for Chapter 3 bitumens ...................................................................

Table 5 -

 5 3 Chapter 3 bitumen parameters .............................................................................................Table 5-4 Materials selected from Chapter 3 for further analysis ...................................... Table 5-5 Principal results from asphalt mixtures and extracted bitumens testing ..................................................................................................................................................................... Table 5-6 Extracted bitumens parameters from Kinexus® testing .................................... Table 5-7 Extracted bitumens parameters from Metravib® testing ................................. Table 5-8 Asphalt mixtures parameters from complex modu lus 2S2P1D modelling ..................................................................................................................................................................... Table 5-9 SHRP bitumens tested and compared ..

Chapter 2. Literature Review

  Le comportement mécanique du bitume est généralement évalué par des essais empiriques (pénétrabilité et température du point de ramollissement bille anneau). Ces tests sont utilisés pour classer le bitume selon leur consistance. Cependant, ils ne fournissent pas les propriétés intrinsèques du bitume. Pour ces raisons, une caractérisation chimique et physique est effectuée.

	Chapter 1 -Introduction Chapter 2 -Literature Review
	Objectifs
	L'objectif principal de cette recherche est d'évaluer les possibilités offertes par la combinaison
	du recyclage d'agrégats d'enrobé à taux élevés et les techniques tièdes de fabrication des Pour l'évaluation chimique, l'analyse par infrarouge, l'analyse thermogravimétrique et la
	enrobés pour fournir une solution durable à la construction routière. De façon plus détaillée, chromatographie en couche mince pour la détermination des fractions SARA sont utilisées. Pour
	cette thèse a les objectifs opérationnels secondaires suivants: évaluer l'évolution physique et la performance des matériaux, on utilise la solubilité du bitume
	i. dans le n-heptane, la chromatographie par permeation de gel, la microscopie à force atomique et La caractérisation de l'évolution du vieillissement par le suivi de l'augmentation de la
	teneur en asphaltènes du bitume, les tests rhéologiques.
	ii. Dans le deuxième chapitre (chapitre 4), l'évolution des performances mécaniques des enrobés L'étude et l'analyse des performances mécaniques en laboratoire d'un enrobé classique à
	chaud, choisi comme enrobé de référence, est étudiée. Les connaissances actuelles sur le vieillissement des enrobés sont essentiellement
	iii.
	Pour cette raison, un protocole de
	vieillissement constitué de deux phases de vieillissement séparées est suivi conformément à la
	procédure proposée par le RILEM TC-ATB TG5. Les performances à long terme des enrobés sont
	comparées au moyen des essais de module complexe et de fatigue. Des essais de pénétration et
	de bille-anneau sont aussi effectués sur le bitume récupéré. L'évolution du vieillissement est
	également caractérisée par l'analyse infrarouge et évaluée par l'analyse de la δ méthode.
	Finalement, le dernier chapitre se concentre sur la comparaison des performances mécaniques
	des enrobés et de l'évolution de leur bitume. L'évaluation est développée en utilisant les critères
	SHRP et l'analyse comparée des courbes obtenues par la δ méthode. Les relations entre les
	différents paramètres sont étudiées.
	-11 --13 -

L'addition de 50% d'agrégats d'enrobé lors de la fabrication d'enrobé pour la technique tiède à la mousse de bitume, iv. L'évaluation de l'effet du vieillissement ou de la régénération sur le comportement rhéologique du bitume à travers la δ-méthode, v. L'influence de l'évolution du bitume sur les paramètres du modèle Huet -Such, vi. Et enfin, établir une éventuelle relation entre les propriétés du bitume et les performances des enrobés bitumineux. Portée de la recherche La structure de la thèse comporte une étude bibliographique suivie de trois chapitres, chacun d'eux se concentrant sur l'un des trois objectifs de la thèse, le bitume, les enrobé bitumineux et leur éventuelle relation. Un dernier chapitre présente les conclusions et les perspectives pour les travaux de recherche futurs. L'état de l'art décrit en termes généraux les enrobés bitumineux, leur composition et les différents niveaux d'essais existants. Les techniques d'enrobage tièdes et l'utilisation des agrégats d'enrobés sont décrits et présentés. En outre, une étude plus détaillée est réalisée en ce qui concerne la structure physico-chimique, les propriétés et les caractéristiques du bitume et ses procédures de vieillissement. Les principaux objectifs de la thèse ont été divisés en trois chapitres. Le premier (chapitre 3) se concentre sur l'étude du bitume. La réponse physico-chimique du matériau est caractérisée par l'évolution de la teneur en asphaltène pendant le vieillissement. Ainsi, pour comprendre ces effets, des procédures de vieillissement en laboratoire sont appliquées. tirées de l'expérience acquise sur les enrobés traditionnels et généralement sur les enrobés à chaud. Cependant, comme la procédure tiède est une technique relativement nouvelle, leur évolution avec le vieillissement et leur état de fin de vie est mal connue, surtout lorsqu'ils sont combinés avec les agrégats d'enrobé. Dans ce cadre, l'objectif de ce chapitre est d'étudier et de comparer deux techniques tièdes lorsque 50% d'agrégats d'enrobé sont ajoutés au mélange.

Table 2 -1 LVE models for bituminous materials [22,23] Denomination Description Schema/Formula

 2

			One spring and one dashpot in
		Maxwell model	series. Represent the viscoelastic
	spectrum		liquid behaviour of the material. One spring and one dashpot in
	relaxation	Kelvin-Voigt model	parallel. Represent the viscoelastic solid behaviour of the material.
	Discrete	Generalized Maxwell model (Prony series)	Formed by a spring, a group of n Maxwell elements and a dashpot in parallel
		Generalized Kelvin-Voigt model	Formed by a spring, a group of n Kelvin-Voigt elements and a dashpot in series
		Parabolic element [24]
	spectrum
	relaxation
	Continuous

Figure 2-6 Summary of the different testing levels

	Durabilité des enrobés tièdes intégrant des recyclés	Chapter 2 -Literature Review
	French pavement design is developed in laboratory. It uses materials that should represent the C. Rutting resistance test (EN 12697-22)
	materials of the future construction works. It is based on mechanical performance related limits.
	The method has four levels of study:
	Level 4: Fatigue resistance
	Level 3: Stiffness modulus
	Level 2: Rutting resistance
	Level 1: Gyratory compaction and
	water resistance
	Test protocols and European standards
	A. Gyratory compactor (EN 12697-31)
	Asphalt mixture is introduced, bulked, in the mould and heated to the test temperature,
	between 130°C and 160°C. A vertical pressure of 0.6 MPa with a deviation angle of ~1° is
	applied on the top of the specimen. At the same time a circular rotation takes place. The
	increase of compactness, through the decrease of air voids content, is observed against
	the number of revolutions.
	B. Water sensitivity test (EN 12697-12)
	Water resistance is at the base of the bituminous mixtures durability. In general, the
	followed procedure is the indirect tensile strength resistance (ITSR). But within the
	French scope the regular test carried out is the Duriez direct compression test, described
	on the Annex B of the standard.
	Duriez test consists on the compaction of the asphalt mixture in cylindrical moulds
	under static pressure. The set of samples is divided in two groups, one conserved in dry
	conditions and the other immersed under water at 18°C, both during 72h. Then, each
	specimens group is loaded under simple compression.
	In both methods, water resistance ratio is the coefficient of the immersion resistance to
	dry results.
	-23 --24 -

Table 2 -2 Resume of Foaming WMA commercial processes obtained from producers websites Procedure Product Description

 2

	Aspha-min®
	Foaming
	Process
	Indirect
	Method

Supplied by Eurovia Services GmbH. It is a finely powdered synthetic zeolite hydro-thermally crystallized. Added at 0.3% percent by total weight of HMA mix. It can give up 20% of water by mass, which microscopically foams the asphalt to aid coating of the aggregate. (www.eurovia.fr).

Table 2 -3 Resume of Organic additives WM A commercial processes obtained from producers websites Procedure Product

 2

	Description

Table 2 -4 Resume of Chemical additives WMA commercial processes obtained from producers websites Procedure Product Description

 2 Evotherm is product of Eurovia. It consists on a chemical package designed to promote adhesion, coverage, compaction and workability of asphalt mixtures at lower temperatures. Base components of the chemical compounds are the surfactants, which act as emulsifiers. Approximately 50% of the chemical package is derived from renewable resources. Evotherm allows a reduction of between 50°C to 75°C, both in the production and spread, compared with the HMA (www.eurovia.fr).

	Evotherm
	Chemical
	Additives

Table 2 -5 From Airey 2003, chronological bitumen ageing methods

 2 [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF]

	Test method	Temperature (°C)	Duration	Sample size (g)	Film thickness	Extra features
	Thin film oven test (TFOT) ASTM D1754, EN 12607-2	163	5 h	50	3.2 mm	-
	Shell microfilm test	107	2 h	-	5 µm	-
	Rolling thin film oven test (RTFOT)
	AASHTO T240, ASTM D2872,	163	75 min	35	1.25 mm	Air flow-4000ml/min
	EN12607-1
	Modified Shell microfilm test (Traxler, 1961; Halstead and Zenewitz, 1961)	107	2 h	-	15 µm	-
	Modified Shell microfilm test (Hveem et al., 1963)	99	24 h	-	20 µm	-
	Rolling microfilm oven test (RMFOT)	99	24 h	0.5	20 µm	Benzene solvent
	Modified RMFOT	99	48 h	0.5	20 µm	1.04 mm ∅ opening
	Iowa durability test (IDT)	65	1,000 h	TFOT residue -50	3.2 mm	2.07 MPa -pure oxygen
	Tilt-oven durability test (TODT)	113	168 h	35	1.25 mm	-
	Alternative TODT	115	100 h	35	1.25 mm	-
	Modified thin film oven test (MTFOT)	163	24 h	-	100 µm	-
	Pressure oxidation bomb (POB)	65	96 h	ERTFOT residue	30 µm	2.07 MPa -pure oxygen
	Extended rolling thin film oven test (ERTFOT)	163	8 h	35	1.25 mm	Air flow-4000ml/min
	Thin film accelerated ageing test (TFAAT)	130/113	24/72 h	4	160 µm	3 mm ∅ opening
	Accelerated ageing test device/
	Rotating cylinder ageing test	70-110	144 h	500	2 mm	4 -5 l/h -pure oxygen
	(RCAT)
				RTFOT or
	Pressure ageing vessel (PAV)	90-110	20 h	TFOT residue -	3.2 mm	2.07 MPa -air
				50
	Modified rolling thin film oven test (RTFOTM)	163	75 min	35	1.25 mm	Steel rods
	High pressure ageing test (HiPAT)	85	65 h	RTFOT residue -50	3.2 mm	2.07 MPa -air
	Nitrogen rolling thin film oven test (NRTFOT)	163	75 min	35	1.25 mm	N2 flow-4000ml/min
	Rotating Flask Test (RFT)-DIN 52016, EN12607-3	165	150 min	100	-	Flask rotation -20 rpm

Table 2 -6 From Airey 2003, chronological asphalt mixture ageing methods

 2 [START_REF] Airey | State of the Art Report on Ageing Test Methods for Bituminous Pavement Materials[END_REF]

	Test method	Temperature (°C)	Duration	Sample	Extra features
	Ottawa sand mixtures (Pauls and Welborn, 1952)	163	Various periods 50 x 50 mm 2 cylinders EH
	Huveem et al. (1963)	60	1,000 h	50 x 50 mm 2 cylinders Air stream of 41°C (UV)
	Huveem et al. (1963)	60	24 h	305mm long semi-cylindrical specimens	Cohesiograph test (SH)
	Traxler (1963)	-	-	-	UV-SH (Several methods)
	Plancher et al. (1976)	150	5 h	25 x 40 mm2 ∅	EH
	Kumar and Goetz (1977)	60	1,2, 4, 6, 10 days Compacted specimens Air at 0.5 mm of water (O)
	Ottawa sand mixtures (Kemp and Prodoehl, 1981)	60	1,200 h	-	EH
	Kemp and Prodoehl, (1981)	35	18 h	-	1,000 MW/cm 2 Amgtrôm actinic radiation (UV)
	Hugo and Kennedy (1985)	100	4 or 7 days	-	80% relative humidity (EH)
	Hugo and Kennedy (1985)	-	54 h	-	Actinic light (UV)
	Hugo and Kennedy (1985)	-	14 days	-	Atlas weathometer
	Oregon mixtures	60	0, 1, 2, 3, 5 days Compacted specimens 0.7 MPa -air (O)
	Production ageing (Von Quintas, 1988)	135	8, 16, 24, 36 h	Loose material	EH
	Long-term ageing (Von	60	2 days	Compacted specimens EH
	Quintas, 1988)	107	3 days	Compacted specimens EH
	Long-term ageing (Von Quintas, 1988)	60	5 to 10 days	Compacted specimens 0.7 MPa -air (O)
		135	2 h	Loose material	EH
	Bitutest protocol
		85	5 days	Compacted specimens EH
	SHRP short-term oven ageing (STOA)	135	4 h	Loose material	EH

Physico-chemical study of bitumen Résumé du chapitre

	Comme cela a été décrit dans la littérature (Chapitre 2), la composition élémentaire du bitume
	est la suivante : le carbone, l'hydrogène, puis le soufre, l'oxygène, l'azote et des traces de
	différents métaux comme le calcium, le fer, le magnésium, le nickel ou le vanadium. Le degré de
	stabilité chimique du bitume est déterminé par les caractéristiques chimiques des différentes
	molécules et le rapport des composants réactifs et non réactifs. Par conséquent, il est
	généralement admis de subdiviser les bitumes en asphaltènes et maltènes, puis les maltènes en
	résines, aromatiques et saturés, par affinité polaire. Ces fractions correspondent au modèle
	colloïdal (dispersions d'asphaltènes dans les maltènes), qui explique bien les propriétés
	physiques et mécaniques du bitume.

Dans ce chapitre, l'objectif est de déterminer l'influence de la fraction d'asphaltènes sur la réponse physico-chimique du mélange. Les bitumes utilisés sont présentés. Le protocole de séparation des phases d'asphaltènes et de maltènes pour une recomposition ultérieure est également montré. Ensuite, des bitumes contenant différentes proportions d'asphaltènes sont recomposés et étudiés. De plus, dans le but de comprendre les effets du vieillissement sur les espèces chimiques et sur l'organisation physico-chimique du bitume, des procédures de vieillissement en laboratoire sont appliquées aux échantillons à des fins de comparaison. Le comportement mécanique des bitumes est habituellement évalué par des tests empiriques de consistance (pénétrabilité et température de ramollissement). Néanmoins, ces tests ne fournissent ni les propriétés rhéologiques des bitumes, ni ses caractéristiques chimiques, ni ses performances mécaniques. Pour ces raisons, une caractérisation chimique et physique est réalisée. Pour chaque bitume, on effectue une analyse infrarouge par transformée de Fourier, une analyse thermogravimétrique, une chromatographie en couche mince (fractions SARA), une solubilité du bitume dans le n-heptane, une chromatographie par perméation de gel, une microscopie à force atomique et les tests rhéologiques. Enfin, à partir des tests rhéologiques et de l'application de la -méthode, on étudie la corrélation entre le vieillissement du bitume et le taux d'asphaltènes. La capacité de la -méthode pour suivre le vieillissement du bitume est ainsi évaluée.

Table 3

 3 -1. Additionally, following the EN 12592 standard, asphaltene content is determined by n-heptane precipitation, denominating this type of asphaltenes as c7-asphaltenes.

Table 3 -1 Base bitumens of the study

 3

	Bitumen	Penetration (1/10 mm)	Softening Point (°C)	c7-Asph (%)
	35/50	40 ± 3	52.6 ± 2.5	14.7 ± 0.5
	50/70	58 ± 3	49.0 ± 2.5	14.3 ± 0.5

Table 3

 3

	-2 summarizes the principal

Table 3 -2 Aged bitumens stud ied by malthenes and asphaltenes content

 3

	Bitumen denomination	% Malthenes	% c7-Asphaltenes
	35/50 RTFOT	82.2 ± 0.5	17.8 ± 0.5
	35/50 PAV	78.6 ± 0.5	21.4 ± 0.5
	50/70 RTFOT	84.1 ± 0.5	15.9 ± 0.5
	50/70 PAV	79.4 ± 0.5	20.6 ± 0.5

Table 3 -

 3 3 summarizes the ratio of malthenes and asphaltenes of each neat bitumen. 35/50 Neat bitumen has an asphaltene content of 14.7% and 50/70 Neat bitumen has an asphaltene content of 14.3%.

	Durabilité des enrobés tièdes intégrant des recyclés

Table 3 -3 Neat bitumens a/m ratio

 3

	Bitumen	% Malthenes	% c7 -Asphaltenes
	35/50 Neat	86.6 ± 0.5	14.7 ± 0.5
	50/70 Neat	85.4 ± 0.5	14.3 ± 0.5

Table 3 -4 SARA fractions of malthenes and asp haltenes of 35/50 and 50/70 bitumens

 3

	Bitumen / Parameter Saturates (%) Aromatics (%) Resins (%)	i-Asph (%)	Ic
	35/50 100M	3.04 ± 0.43	73.43 ± 4.31 17.44 ± 3.14	6.09 ± 1.09	0.10
	50/70 100M	1.95 ± 0.12	86.43 ± 1.35	8.41 ± 1.20	3.21 ± 0.31	0.05
	35/50 100A	0.10 ± 0.17	1.91 ± 0.33	7.10 ± 2.73	90.89 ± 2.67	10.11
	50/70 100A	0.04 ± 0.04	1.65 ± 0.71	5.86 ± 0.45	92.44 ± 0.82	12.32

Table 3 -5 Neat and model bitumens a/m ratio

 3

	Bitumen	Malthenes (%)	c7 -Asphaltenes (%)
	35/50 Neat	85.3 ± 0.5	14.7 ± 0.5
	35/50 85M+15A	85.0	15.0
	50/70 Neat	85.7 ± 0.5	14.3 ± 0.5
	50/70 86M+14A	86.0	14.0

Table 3 -

 3

[START_REF] Newcomb | An introduction to warm-mix asphalt[END_REF]

summarizes the ratio of malthenes and asphaltenes of each bitumen. 35/50 Neat bitumen is recomposed with 15% of c7-asphaltenes content. On the other hand, 50/70 Neat recomposition is rounded down to 14% of c7-asphaltenes in order to differentiate both recomposed bitumens.

Table 3 -6 ATR-FTIR analysis of Ico and Iso values

 3

	Bitumen / Parameter	Ico (%)	Iso (%)
	35/50 Neat	0.00	5.71
	35/50 85M+15A	0.27	9.46
	50/70 Neat	0.00	4.86
	50/70 86M+14A	0.00	7.84

Table 3 -7 SARA fractions of neat and recomposed bitumens

 3

	Bitumen / Parameter Saturates (%) Aromatics (%) Resins (%)	i-Asph (%)	c7 Asph (%)	Ic
	35/50 Neat	2.99 ± 0.68	66.03 ± 5.02 12.84 ± 2.02 18.14 ± 4.15	14.7	0.27
	35/50 85M+15A	3.66 ± 0.67	66.76 ± 5.22 13.57 ± 2.38 16.02 ± 3.04	15.0	0.25
	50/70 Neat	2.08 ± 0.11	65.07 ± 1.98 12.36 ± 1.04 20.49 ± 1.40	14.3	0.29
	50/70 86M+14A	2.12 ± 0.41	68.27 ± 4.77 10.26 ± 1.25 19.36 ± 4.35	14.0	0.27

Table 3 -8 Molecular weights of 35/50 bitumens

 3

		Mn (g/mol)	Mw (g/mol)	MP (g/mol)	Mz (g/mol) Mz+1 (g/mol)	PDI
	35/50 Neat	664	949	876	1,275	1,571	1.43
	35/50 85M+15A	857	1,162	1,061	1,509	1,853	1.36

Table 3 -9 ATR-FTIR analysis of Ico and Iso values of 35/50 model bitumens

 3

	Bitumen / Parameter	Ico (%)	Iso (%)
	35/50 90M+10A	0.75	9.74
	35/50 85M+15A	0.27	9.46
	35/50 80M+20A	0.09	12.60
	50/70 91M+9A	0.00	29.54
	50/70 86M+14A	0.00	7.84
	50/70 81M+19A	0.00	12.92

Table 3

 3

	-7 summarizes the SARA fraction results. It differentiates
	i-asphaltenes and c7-asphaltenes for all model bitumens. Figure 3-30 represents graphically
	those results.

Table 3 -10 SARA fractions and colloidal indexes of 35/50 and 50/70 model bitumens

 3

	Bitumen / Parameter Saturates (%) Aromatics (%) Resins (%)	i-Asph (%)	c7 Asph (%)	Ic
		100M	3.04 ± 0.43	73.43 ± 4.31 17.44 ± 3.14	6.09 ± 1.09	0	0.10
	35/50	90M+10A 85M+15A	3.90 ± 1.79 3.66 ± 0.67	61.87 ± 8.63 17.16 ± 4.75 17.07 ± 3.72 66.76 ± 5.22 13.57 ± 2.38 16.02 ± 3.04	10 15	0.27 0.25
		80M+20A	1.74 ± 0.39	43.05 ± 9.85 23.61 ± 9.59 31.60 ± 8.09	20	0.50
		100A	0.10 ± 0.17	1.91 ± 0.33	7.10 ± 2.73	90.89 ± 2.67	100	10.11
		100M	1.95 ± 0.12	86.43 ± 1.35 8.41 ± 1.20	3.21 ± 0.31	0	0.05
	50/70	91M+9A 86M+14A	1.95 ± 0.71 2.12 ± 0.41	73.92 ± 4.81 11.79 ± 1.43 12.34 ± 2.69 68.27 ± 4.77 10.26 ± 1.25 19.36 ± 4.35	9 14	0.17 0.27
		81M+19A	1.38 ± 0.11	64.19 ± 3.55 8.17 ± 1.46	26.26 ± 3.83	19	0.38
		100A	0.04 ± 0.04	1.65 ± 0.71	5.86 ± 0.45	92.44 ± 0.82	100	12.32

Table 3 -11 Polydispersity of 35/50 model bitumens

 3

		Mn (g/mol)	Mw (g/mol)	MP (g/mol)	Mz (g/mol) Mz+1 (g/mol)	PDI
	35/50 100M	753	1,012	932	1,275	1,509	1.34
	35/50 90M+10A	785	1,111	994	1,478	1,829	1.42
	35/50 85M+15A	795	1,120	1,052	1,493	1,856	1.41
	35/50 80M+20A	811	1,150	1,042	1,542	1,929	1.42
	35/50 100A	9,472	11,959	10,715	15,096	18,607	1.26

Table 3 -12 Aged bitumens m/a ratio on n -heptane determination

 3

	Bitumen / Parameter	Malthenes (%)	c7-Asphaltenes (%)
	35/50 Neat	85.3	14.7
	35/50 RTFOT	82.2	17.8
	35/50 PAV	78.6	21.4
	50/70 Neat	85.7	14.3
	50/70 RTFOT	84.1	15.9
	50/70 PAV	79.4	20.6
	Ageing on 35/50 Neat bitumen increases the asphaltene content 3.1% after RTFOT, and 3.5%
	more after PAV. Besides, 50/70 Neat bitumen has an asphaltene content augmentation of 1.6%
	and 4.7% respectively.

Table 3 -

 3 [START_REF] Bardesi | Introduccion a las mezclas bituminosas (Spanish)[END_REF] summarized the values of Ico and Iso of all bitumens.

Table 3 -13 ATR-FTIR analysis of Ico and Iso values of aged bitumens

 3

	Bitumen / Parameter	Ico (%)	Iso (%)
	35/50 Neat	0.00	5.71
	35/50 RTFOT	0.88	13.28
	35/50 PAV	3.22	20.10
	50/70 Neat	0.00	4.86
	50/70 RTFOT	0.65	12.46
	50/70 PAV	3.94	16.86

Table 3 -14 SARA fractions and colloidal indexes of 35/50 and 50/70 aged bitumens Bitumen / Parameter Saturates (%) Aromatics (%) Resins (%) i-Asph (%) c7 Asph (%) Ic

 3

	35/50 Neat	2.99 ± 0.68	66.03 ± 5.02 12.84 ± 2.02 18.14 ± 4.15	14.7	0.27
	35/50 RTFOT	1.94 ± 0.60	60.84 ± 6.04 11.46 ± 3.24 25.77 ±3.67	17.8	0.38
	35/50 PAV	1.29 ± 0.45 45.12 ± 12.12 16.69 ±5.42 36.91 ± 9.78	21.4	0.62
	50/70 Neat	2.08 ± 0.11	65.07 ± 1.98 12.36 ± 1.04 20.49 ± 1.40	14.3	0.29
	50/70 RTFOT	6.85 ± 2.53	53.44 ± 5.20 17.68 ± 2.50 22.03 ± 3.36	15.9	0.41
	50/70 PAV	2.96 ± 0.68 50.03 ± 10.30 12.66 ± 2.91 34.35 ± 8.05	20.6	0.60

Table 3 -15 Polydispersity on 35/50 aged bitumens Mn (g/mol) Mw (g/mol) MP (g/mol) Mz (g/mol) Mz+1 (g/mol) PDI 35/50 Neat 664

 3

			949	876	1,275	1,571	1.43
	35/50 RTFOT	753	1,056	969	1,404	1,740	1.40
	35/50 PAV	810	1,087	1,002	1,392	1,682	1.34

Table 3 -16 ATR-FTIR analysis of Ico and Iso values from 35/50 80M+20A and PAV bitumens

 3

	Bitumen / Parameter	Ico (%)	Iso (%)
	35/50 Neat	0.00	5.71
	35/50 80M+20A	0.09	12.60
	35/50 PAV	3.22	20.10

Table 3 -

 3 [START_REF] Read | The Shell Bitumen Industrial Handbook[END_REF] the main bitumens fractions are resumed. Both bitumens present in general similar chemical composition. Still, c7-asphaltene content is 1.4% more in the case of PAV bitumen.

Table 3 -17 SARA fractions from model and aged bitumens at the highest asphaltene content

 3

	Bitumen / Parameter Saturates (%) Aromatics (%) Resins (%)	i-Asph (%)	c7 Asph (%)	Ic
	35/50 80M+20A	1.74 ± 0.39	43.05 ± 9.85 23.61 ± 9.59 31.60 ± 8.09	20.0	0.50
	35/50 PAV	1.29 ± 0.45 45.12 ± 12.12 16.69 ±5.42 36.91 ± 9.78	21.4	0.62

Table 4 -1 Mixtures studied and manufacturing temperature

 4

	Mixture	Bitumen Denomination	%RAP	Aggregates (°C)	RAP (°C)	Manufacture (°C)	Ageing Procedure
	Hot Mix	HMA0 HMA0a	0	160	-	160	-
	Asphalt	HMA50 HMA50a	50	210	110	160	-
	Warm Mix	WMA0 WMA0a	0	130	-	130	-
	Asphalt	WMA50 WMA50a	50	150	110	130	-
	Foamed Warm Mix Asphalt	FWMA0 FWMA0a FWMA50 FWMA50a	0 50	130 150	-110	130 130	- -
						Bitumen always at 160°C

Table 4 -2 Base bitumen of the study

 4

	Denomination	Bitumen	Additive Nature	Addition Process	Mixture Manufacture Temperature (°C)
	Hot Mix Asphalt	35/50	None	-	160
	Warm Mix Asphalt	35/50 + 0.5 % Additive	Surfactant	On bitumen	130
	Foamed Warm Mix Asphalt	35/50	1.5% water	Direct Foaming	130

Table 4 -

 4

3 resumes virgin aggregates properties.

Table 4 -3 Virgin aggregates properties Test / Aggregate Type Coarse Aggregate

 4 Reclaimed asphalt pavement comes from the milling operation of an asphalt concrete located on the fatigue carousel track at IFSTTAR[119]. The original bitumen in the RAP is also conventional 35/50. RAP is characterized to guarantee good homogeneity. In order to achieve a continuous gradation for the correct design of the new mixtures, the material is split by sieving in four

	Fine Aggregates	Filler

Table 4

 4

	-4 RAP characteristics

Table 4 -5 RAP bitumen properties

 4 [START_REF] Lopes | Durability of hot and warm asphalt mixtures containing high rates of reclaimed asphalt at laboratory scale[END_REF]

		Bitumen		RAP fraction		Bitumen from RAP
		from RAP	0/2	2/4	4/8	8/12	Recomposition
	Bitumen Content (%) (EN 12697-3)	4.8	8.5	6.2	4.5	3.2	5.45
	Penetration Grade (1/10 mm) confidence interval of +/-3 1/10mm	18	19	19	15	17	P15
	Softening Point (°C) confidence interval of +/-2.5°C	63.0	61.8	62.8	64.4	64.6	S70
	Asphaltene content confidence interval of +/-2.5%	20.2	17.8	19.0	20.0	19.4	-
	Carbonyl Index -Ico (%) confidence interval of +/-SD%	8.60	9.60	9.60	9.10	9.50	-

Table 4 -6 Influence of manufacturing technique on the mechanical performance

 4

			Mixtures				Bitumen
	Technique	|E*| 15°C, 10Hz (MPa)	Phase Angle (°)	ε6c (µdef)	Slope (-1/b)	Pen (1/10 mm)	Soft Point (°C)	Ico (%) Rvalue
	HMA0	12,497	15.0	115	5.99	22	55.0	1.80	1.58
	WMA0	12,498	14.6	100	5.69	26	57.4	1.46	1.58
	FWMA0	10,921	16.1	98	4.82	32	55.6	0.48	1.45
	35/50 Neat					37	53.8	0.00	1.46
	35/50 Foam					34	53.6	0.00	1.46

Table 4 -7 Influence of ageing on the mechanical performance of the different techniques Technique after ageing Mixtures Bitumen |E*| 15°C, 10Hz (MPa) Phase Angle (°) ε6c (µdef) Slope (-1/b) Pen (1/10 mm) Soft Point (°C) Ico (%) Rvalue

 4

	HMA0	12,497	15.0	115	5.99	22	55.0	1.80	1.58
	HMA0a	14,156	10.8	123	8.35	15	65.8	4.96	1.81
	WMA0	12,498	14.6	100	5.69	26	57.4	1.46	1.58
	WMA0a	15,492	10.7	123	7.68	17	65.2	5.40	1.98
	FWMA0	10,921	16.1	98	4.82	32	55.6	0.48	1.45
	FWMA0a	14,448	12.2	113	7.64	18	63.8	5.40	1.73
	35/50 Neat	-	-	-	-	37	53.8	0.00	1.46
	35/50 RAP	-	-	-	-	18	63.0	8.60	1.80
	35/50 Foam	-	-	-	-	34	53.6	0.00	1.46

Table 4 -

 4

8 summarizes the principal results found for the mixtures without RAP (0) and with RAP

[START_REF] Oliver | The Influence of the Binder in RAP on Recycled Asphalt Properties[END_REF]

.

Table 4 -8 Influence of RAP addition on the mechanical perf ormance of the different techniques Technique with 50% RAP Mixtures Bitumen |E*| 15°C, 10Hz (MPa) Phase Angle (°) Corrected ε6 (µdef) Slope (-1/b) Pen (1/10 mm)

 4

	Soft Point (°C)	Ico (%)	Rvalue

Table 4 -9 Influence of ageing on the characteristics of the mixtures with RAP Technique with 50% RAP Mixtures Bitumen |E*| 15°C, 10Hz (MPa) Phase Angle (°) ε6c (µdef) Slope (-1/b) Pen (1/10 mm) Soft Point (°C) Ico (%) Rvalue

 4

	HMA50	14,590	12.2	127	7.08	19	62.8	4.08	1.71
	HMA50a	15,847	11.3	122	6.99	15	66.0	8.27	1.84
	WMA50	13,721	12.7	119	5.55	19	61.6	3.74	1.74
	WMA50a	16,035	11.0	108	16.70	14	66.8	8.39	1.98
	FWMA50	13,122	14.0	106	5.12	24	60.4	5.47	1.68
	FWMA50a	15,460	11.5	115	5.49	17	66.0	10.35	1.99
	35/50 Neat	-	-	-	-	37	53.8	0.00	1.46
	35/50 RAP	-	-	-	-	18	63.0	8.60	1.80
	35/50 Foam	-	-	-	-	34	53.6	0.00	1.46

Table 4 -

 4 9 is a synthesis of the results, in terms of complex modulus, fatigue resistances, penetration depth, softening point temperature, carbonyl index and Rvalue for the mixtures with 50% of RAP, submitted to the RILEM ageing protocol. As well, 35/50 Neat bitumen, RAP bitumen and Foam bitumen are also presented.

Table 5 -1 Materials and results selected from Chapter 3

 5

	Denomination		Data from
	35/50		c7-Asphaltenes
	35/50 RTFOT
		TLC-FID (SARA fractions)
	35/50 PAV
	35/50 100M	𝐼𝑐 =	𝑖 -𝐴𝑠𝑝ℎ𝑎𝑙𝑡𝑒𝑛𝑒𝑠 + 𝑆𝑎𝑡𝑢𝑟𝑎𝑡𝑒𝑠 𝐴𝑟𝑜𝑚𝑎𝑡𝑖𝑐𝑠 + 𝑅𝑒𝑠𝑖𝑛𝑠
	35/50 90M+10A		GPC (Polydispersity)
	35/50 85M+15A
		Huet-Such model parameters
	35/50 80M+20A

Table 5 -2 Resume of results for Chapter 3 bitumens Bitumen c7-Asph

 5 On Chapter 3, 35/50 neat and model bitumens are submitted to DSR testing. Bitumen samples are tested from -20°C to 60°C at frequency range from 10 Hz to 0.01 Hz. Master curves for the norm of the complex modulus and phase angle are built at T = 0°C, where TTSP is verified. Such modelling, experimental data from the frequency and temperature sweeps are concentrated in the 6 model parameters (G∞, , k, h, β and τ), describing the properties of the bitumen in the whole time-temperature domain. All bitumen master curves, shift factors aT, Black space, Cole-Cole plan and Huet-Such model curves are reported in Annexes 2 and 3.

			(%)	Sat (%)	Arom (%)	Res (%)	i-Asph (%)	Ic	PDI	Rvalue	w(co) (Hz)
	aged	Neat	14.70	2.99	66.03	12.84	18.14	0.27	1.43	1.81	2.14E-02
	35/50	RTFOT PAV	17.80 21.40	1.94 1.29	60.84 45.12	11.46 16.69	25.77 36.91	0.38 0.62	1.40 1.34	2.06 2.45	4.03E-03 5.85E-05
		85M+15A	15.00	3.66	66.76	13.57	16.02	0.24	1.41	1.66	5.23E-02
	model	90M+10A	10.00	3.90	61.87	17.16	17.07	0.27	1.42	1.55	4.20E-01
	35/50	80M+20A	20.00	1.74	43.05	23.61	31.60	0.50	1.42	2.42	1.52E-04
		100M	0.00	3.04	73.43	17.44	6.09	0.10	1.34	1.12	5.63E+00
		Parameters from Huet-Such modelling

Table 5 -3 Chapter 3 bitumen parameters

 5

		Bitumen G∞ (MPa)		k	h	β	τ (s)	C1	C2
	aged	Neat	835.55	3.47	0.23	0.59	186.19	1.90E-02	22.52	137.35
	35/50	RTFOT PAV	788.30 813.48	3.59 5.88	0.22 0.23	0.57 0.56	557.42 1576.50	3.62E-02 3.05E-01	25.59 32.89	168.00 206.87
		85M+15A	879.43	3.75	0.24	0.60	222.56	6.74E-03	23.59	151.48
	model	90M+10A	870.76	3.80	0.24	0.61	102.53	1.53E-03	20.47	133.32
	35/50	80M+20A	875.79	7.35	0.25	0.60	1033.60	2.65E-01	26.92	162.99
		100M	601.61	0.01	0.84	0.37	402.05	3.22E-05	18.18	122.74

Table 5

 5

	-5 summarizes the principal results obtained for asphalt mixtures
	and extracted bitumens.

Table 5 -5 Principal results from asphalt mixtures and extracted bitumens testing

 5

	Parameter	|E*|	Phase Angle (°)	ε6c	Slope	Pen	Soft Point	ICo	R value	w(co)	Tc Rutting	Tc Fatigue	G* Sin (δ) G*/Sin (δ)
		15°C, 10Hz (MPa)		(µdef)	(-1/b)	(1/10 mm)	(°C)	%		(Hz)	(°C)	(°C)	30°C, 10rad/s	30°C, 10rad/s
	35/50 Neat	-	-	-	-	37	53.8	0	1.46	1.49E-02	72.1	21.2	1.10E+06 1.28E+06
	35/50 RAP	-	-	-	-	18	63.0	8.6	1.80	1.34E-03	85.2	26.8	9.40E+05 1.07E+06
	35/50 Foam	-	-	-	-	34	53.6	0	1.46	1.63E-02	67.8	19.2	2.55E+06 3.97E+06
	HMA0	12,497	15.0	115	5.99	22	55.0	1.8	1.77	4.71E-04	77.6	27.7	3.40E+06 5.39E+06
	HMA0a	14,156	10.8	123	8.35	15	65.8	4.96	1.81	4.31E-04	80.7	28.0	3.64E+06 6.16E+06
	HMA50	14,590	12.2	127	7.08	19	62.8	4.08	1.71	1.46E-03	78.1	26.8	2.62E+06 3.99E+06
	HMA50a	15,847	11.3	122	6.99	15	66.0	8.27	1.84	2.24E-04	83.5	27.3	3.34E+06 5.75E+06
	WMA0	12,445	14.6	100	5.69	26	57.4	1.46	1.73	8.81E-04	77.8	26.1	2.64E+06 4.01E+06
	WMA0a	15,343	10.7	123	7.68	17	65.2	5.4	1.98	3.01E-04	83.0	26.6	3.09E+06 5.40E+06
	WMA50	13,688	12.7	119	5.55	19	61.6	3.74	1.74	1.65E-03	77.3	26.1	2.49E+06 3.67E+06
	WMA50a	15,851	11.0	108	16.70	14	66.8	8.39	1.98	2.30E-04	84.1	27.7	3.41E+06 5.96E+06
	FWMA0	10,921	16.1	98	4.82	32	55.6	0.48	1.64	4.67E-03	68.0	20.7	1.33E+06 1.71E+06
	FWMA0a	14,448	12.2	113	7.64	18	63.8	5.4	1.73	1.09E-03	80.7	26.2	2.85E+06 4.97E+06
	FWMA50	13,122	14.0	106	5.12	24	60.4	5.47	1.68	3.27E-03	73.4	24.1	1.92E+06 2.66E+06
	FWMA50a	15,460	11.5	115	5.49	17	66.0	10.35	1.99	3.01E-04	81.0	24.2	2.79E+06 4.90E+06

Table 5 -8 Asphalt mixtures parameters from complex modulus 2S2P1D modelling

 5

	Bitumen	E0 (MPa)	E∞ (MPa)		k	h	β	τ (s)	C1	C2
	HMA0	67.73	30,626	1.68	0.19	0.56	26.40	3.01E+01 34.30 200.90
	HMA0a	40.28	31,010	2.02	0.17	0.54	64.08	1.79E+02 34.53 196.87
	HMA50	74.34	32,584	1.79	0.18	0.54	36.23	6.43E+01 33.89 202.76
	HMA50a	77.77	34,874	2.00	0.18	0.54	47.58	1.22E+02 32.56 192.54
	WMA0	67.31	29,653	1.52	0.18	0.55	26.31	2.97E+01 33.25 193.39
	WMA0a	74.72	33,740	1.99	0.17	0.54	47.06	1.84E+02 35.26 200.53
	WMA50	77.59	31,154	1.84	0.18	0.56	26.91	5.51E+01 33.10 200.60
	WMA50a	56.05	34,903	2.03	0.18	0.55	53.52	1.43E+02 30.72 179.00
	FWMA0	43.16	27,155	1.80	0.21	0.61	25.57	2.32E+01 35.15 213.36
	FWMA0a	85.82	33,111	1.86	0.18	0.53	41.07	8.97E+01 31.61 177.95
	FWMA50	60.36	30,823	1.96	0.20	0.59	24.94	4.34E+01 32.43 196.21
	FWMA50a	84.65	34,087	1.98	0.18	0.55	41.77	1.09E+02 30.28 176.96
	Mean	67.48	31,977	1.87	0.18	0.55	38.45	8.94E+01 33.09 194.26
	Standard Dev	14.93	2,327	0.16	0.01	0.02	12.93	5.78E+01	1.64	11.17

Table 5 -9 SHRP bitumens tested and compared

 5

	Bitumen	State	Bitumen	State	Bitumen	State
	35/50 Neat	NEAT	35/50 Neat	NEAT	35/50 Foam	NEAT
	HMA0	RTFOT	WMA0	RTFOT	FWMA0	RTFOT
	HMA0a	PAV	WMA0a	PAV	FWMA0a	PAV
	HMA50	RTFOT	WMA50	RTFOT	FWMA50	RTFOT
	HMA50a	PAV	WMA50a	PAV	FWMA50a	PAV
	Rutting criterion
	On

Miguel Perez Martinez Titre de la thèse: Durabilité des enrobés tièdes intégrant des recyclés Title of thesis: Long term performance of low temperature asphalt pavements containing reclaimed asphalt Résumé Les

  routes sont le moyen de transport le plus utilisé dans le monde et le développement d'un pays est souvent mesuré en termes de kilométrage total des routes revêtues. Les chaussées sont essentielles à notre réseau social et l'enrobé bitumineux est le matériau le plus utilisé pour leur fabrication. À l'heure actuelle, le réseau routier européen n'est plus en forte croissance et nécessite surtout un entretien. Dans un contexte de développement durable de plus en plus exigeant, la route pourrait donc représenter sa propre source d'approvisionnement en tirant parti du recyclage. Elle doit aussi limiter les quantités d'énergies et de ressources naturelles nécessaires à sa propre maintenance. La combinaison des techniques d'enrobés tièdes (WMA) et de taux de recyclage élevés d'agrégats d'enrobés (RAP) apparaît comme une solution permettant d'économiser à la fois l'énergie et les ressources naturelles. Mais sa durabilité doit être éprouvée. Un programme expérimental a donc été mis en place pour montrer l'évolution des performances de ces enrobés bitumineux avec le temps, mettant en évidence la notion de vieillissement essentiellement lié à la fraction bitumineuse. A l'échelle du bitume, l'évaluation à long terme est effectuée notamment en appliquant la δ-méthode et en comparant avec les mesures de masses moléculaires par GPC à la fois sur des échantillons modèles à teneur en asphaltènes controllée et sur des échantillons de laboratoire. A l'échelle de l'enrobé bitumineux, une étude comparative a été réalisée entre un enrobé à chaud traditionnel et des WMAs incluant 0% ou 50% de RAP soumis à une procédure de vieillissement en laboratoire. Les performances à long terme des mélanges sont comparées au moyen d'essais de module complexe et de fatigue. Les résultats montrent une relation entre l'évolution de la structure des bitumes par vieillissement et les performances mécaniques. Le vieillissement à court terme au moment de la fabrication est beaucoup moins marqué pour les procédés tièdes. Après vieillissement à long terme, les tendances générales sont similaires pour tous les procédés.

		Bitumen	E0 (MPa) E∞ (MPa)		k	h	β	τ (s)
		HMA0	67.73	30,626	1.68	0.19	0.56	26.40	3.01E+01
		HMA0a	40.28	31,010	2.02	0.17	0.54	64.08	1.79E+02
		HMA50	74.34	32,584	1.79	0.18	0.54	36.23	6.43E+01
		HMA50a	77.77	34,874	2.00	0.18	0.54	47.58	1.22E+02
		WMA0	67.31	29,653	1.52	0.18	0.55	26.31	2.97E+01
		WMA0a	74.72	33,740	1.99	0.17	0.54	47.06	1.84E+02
		WMA50	77.59	31,154	1.84	0.18	0.56	26.91	5.51E+01
		WMA50a	56.05	34,903	2.03	0.18	0.55	53.52	1.43E+02
		FWMA0	43.16	27,155	1.80	0.21	0.61	25.57	2.32E+01
		FWMA0a	85.82	33,111	1.86	0.18	0.53	41.07	8.97E+01
		FWMA50	60.36	30,823	1.96	0.20	0.59	24.94	4.34E+01
		FWMA50a	84.65	34,087	1.98	0.18	0.55	41.77	1.09E+02
	Mixture	C1	C2		Mixture	C1	C2	Mixture	C1	C2
	HMA0	34.30	200.90	WMA0		33.25	193.39	FWMA0	35.15	213.36
	HMA0a	34.53	196.87	WMA0a	35.26	200.53	FWMA0a	31.61	177.95
	HMA50	33.89	202.76	WMA50	33.10	200.60	FWMA50	32.43	196.21
	HMA50a Mots-clés	32.56	192.54	WMA50a	30.72	179.00	FWMA50a	30.28	176.96
	Durabilité,	Recyclage,	Agrégats	d'enrobé,	Performance
	mécanique,

moussage du bitume, enrobé tiède, vieillissement

Acknowledgements

~ iii ~

Acknowledgements

The research presented in this document has been carried out as part of the Marie Curie Initial Training Network (ITN) action, FP7-PEOPLE-2013-ITN. This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement number 607524. Cette étude a été principalement réalisée au sein de l'équipe Matériaux pour les Infrastructure de Transport à l'IFSTTAR Nantes ainsi qu'au sein de l'équipe d'ingénierie chimique de l'Université de Huelva. Je tiens vivement à remercier M. Paul Marsac qui m'a choisi pour cette thèse à l'issu du projet SUP&R ITN. Je lui suis profondément reconnaissant pour sa disponibilité permanent, ses encouragements, son aide et sa confiance en ma réussite au cours de ces trois années de thèse. Je tiens également à remercier sincèrement M. Ferhat Hammoum qui a acceptée de diriger cette thèse. Son aide précieuse pour la recherche des matériaux bitumineux et tous ses conseils qui m'ont permis d'évoluer tout au long de cette thèse. Je remercie vivement M Thomas Gabet qui a également acceptée de co-encadre cette thèse. Son regard sur ce travail a été d'une grande aide tout au long de la thèse. remerciements à M. Emmanuel Chailleux et M. Vincent Gaudefroy pour

-Annex 1 -i -35/50 NEAT BITUMEN Overlapping of G'(Pa), G''(Pa) and Tan( ) at T = 30°C Overlapping of G'(Pa), G''(Pa) and Tan( ) at T = 25°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -ii -Overlapping of G'(Pa), G''(Pa) and Tan( ) at T = 15°C Overlapping of (°) for PP25 and PP08 results Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -iii -35/50 85M+15A Overlapping of G'(Pa), G''(Pa ), (°) and Tan() at T = 30°C Overlapping of G'(Pa), G''(Pa ), (°) and Tan() at T = 25°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -iv -Overlapping of G'(Pa), G''(Pa) , (°) and Tan() at T = 15°C 35/50 90M+10A Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -v -Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 15°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -vi -35/50 80M+20A Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -vii -Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 15°C 35/50 100M Overlapping of G'( Pa), G''(Pa), (°) and Tan() at T = 15°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -viii -Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 10°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 0°C Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -ix -35/50 RTFOT Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -x -Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 15°C 35/50 PAV Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -xi -Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 15°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -xii -50/70 NEAT BITUMEN Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -xiii -Overlapping of G'(Pa), G''(Pa) , (°) and Tan() at T = 15°C 50/70 86M+14A Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Durabilité des enrobés tièdes intégrant des recyclés -Annex 1 -xiv -Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 15°C Annex 1 -Overlapping temperatures for model and aged bitumens -Annex 1 -xv -50/70 91M+9A Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 30°C Overlapping of G'(Pa), G''(Pa), (°) and Tan() at T = 25°C

Complex modulus

All mixtures are stiffer after applying the ageing protocol. The highest growth has been for the foaming technique (32%), which is consistent with the decrease of bitumen penetration from 34 to 18.

Fatigue

In the case of fatigue behaviour, from Table 4-7, the increment shown by the ε6 parameter after ageing is linked to an increment of the slope (-1/b) of the fatigue law. Thus, on the foaming process that increase of fatigue life could be explained by the increment of stiffness and reduction of penetration on the bitumen.

In Figure 4-13 the fatigue law for the different aged asphalt mixtures is presented. In general, when ageing takes place the fatigue slope increases. This means that the fatigue resistance of the material is more sensitive to the strain level.

In part (b) of the figure, WMA0a mixture show high level of dispersion. This is represented by the hyperboles of the 95% confidence intervals. With these high levels of dispersion it is difficult to conclude on any real effect of the ageing stage in this case. For example, the hypothesis of 0 slope (no influence of the strain level on the fatigue life) is not rejected for WMA0a results. At the moment, it is not clear whether these high dispersions should be attributed to flaws in the test procedure, test execution or if it reflects the intrinsic properties of the mixtures.

On the other hand, in Figure 4

DSR results

When looking at the rheological master curves plotted in Figure 4

-method analysis

In this case of rheological data superposition, the δ-method could play good role for data treatment. From the last analysis (50% RAP not aged), the changes induced by ageing are different in each case (Curves shown in Annex 5). Through this analysis, ageing of materials could be classified as HMA50a < FWMA50a < WMA50a.

In Figure 4-26 (b), it is highlighted the difference between WMA50a and HMA50a. They have very similar values of penetration (14 and 15), softening point (66.8 and 66°C), Ico (8.39 and 8.27%). However, the difference shown by the -method could explain why stiffness and fatigue performance are different.

Evaluation of materials for recycling

The aim of recycling should not only be to assure certain characteristics and performances of the mixtures, but also to determine the sustainability of these new mixtures for further reuse. There are many questions to answer. Such as: how long can a bitumen be reuse without using rejuvenating agents or if standard indicators as penetration and softening point give the require information.

In this section, an evaluation of our studied materials for further recycling is assessed.

From EN 13108-8 standard, the principal characteristics of previously tested materials are summarized in Table 4-10. According to the standard, all materials are the same, except for the surfactant WMA material which contains of course surfactant. Thus, it is known by us that the manufacturing procedure is a warm procedure. If not, it could be thought that the surfactant is used for other reasons as it could be the improvement of mixture workability. Moreover, in the list of materials (A, B, C, D, E, F and G) there is no specification about the presence of already aged material. The information required be the standard is incomplete. In fact, if it only gives general information, or there is unknown data, RAP addition will still be misused due to the lack of information of the material.

In Table 4-10, the last column includes the letter denomination of the materials tested in previous sections as the standard specifies. Each material has suffered both a short and a long term ageing. The influence of the manufacture procedure is key for determining how is going to age and evolve the material.

Influence of index carbonyl on fatigue life and complex modulus On Figure 5 This leads to the same analysis as in Chapter 4, where FWMA mixtures ages so little during manufacture that they need to achieve certain grade of ageing for a good performance.

In the cases of part (b), the correlation for the norm of the complex modulus is obtained with a logarithmic function of the carbonyl index. It is in this graphic all procedures show good independent correlation with Ico. Chapter 5 -Correlation between structure and mechanical performance -147 -