M Hayek

M Salgues

S Bayle

J.-C Souche

K De Weerdt

S Pioch

INFLUENT PARAMETERS ON THE EARLY BIOCOLONIZATION OF CEMENTITOUS MATERIALS IN SEAWATER

Keywords: Cementitious materials, Marine environment, Eco-design, Biocolonization

The main cause of biodiversity loss is human artificialization on natural environment (IPBES 2019). In marine area, with 39,400 km² of coastal and marine areas already encroached and an increasing demand of infrastructures to support human activities due to the growing of population, projected to reach 9 billion by 2050, it is clear that humanity needs to find ways to prevent its pressure on biodiversity. To this end, since the 1990s the "ecological reconciliation" concept has been trying to develop a win-win approach that unites ecological engineering with civil engineering. Today, civil engineers have a responsibility to incorporate eco-design processes in all construction projects, to ensure common benefits both for humans and the ecosystems. Then, the new challenge of the 21st century is to develop eco-designed concretes that, in addition to their usual properties, provide improved bioreceptivity in order to enhance marine biodiversity. The aim of this study is to clarify the potential release of polluting elements from cementitious materials in seawater and to master and classify the intrinsic parameters that influence the biocolonization of cementitious materials in the marine environment. By using biofilm-culturemethod (biofilm quantification), this study shows that the surface treatment with green formwork oil enhance the biocolonization whereas the application of curing agent has the opposite effect. The use of rough surface or slag cement CEM III increases the bioreceptivity of cementitious materials in the marine environment. Among the influent parameters, surface roughness proved to be the factor that promotes biocolonization most effectively.

INTRODUCTION

In the marine environment, microbial cells are often found in complex, surface-attached communities, known as biofilms. By definition, biofilms are assemblages of single or multiple microbial populations irreversibly attached to a substrate or an interface and included in a coating of extracellular polymeric substances (EPS) [START_REF] Dobretsov | Mini-review: Inhibition of biofouling by marine microorganisms[END_REF]. Biofilms arbor considerable microbial diversity. Bacteria, archaea, algae, fungi, protozoa and viruses all form important components of the biofilm matrix and dominate biogeochemical and bioremediation processes in seawater [START_REF] Besemer | Biodiversity, community structure and function of biofilms in stream ecosystems[END_REF][START_REF] Singh | Biofilms: implications in bioremediation[END_REF]. Then, biofilms contribute to the biodiversity and ecosystem processes of aquatic ecosystems.

Moreover, any surface in the marine environment will be colonized with micro-and macroorganisms leading to biofilm formation [START_REF] Flemming | Biofouling in water systems -cases, causes and countermeasures[END_REF]. This biocolonization process develops via four distinct phases; adsorption of dissolved organic molecules, attachment of bacterial cells, attachment of unicellular eukaryotes and attachment of larvae and spores [START_REF] Lobelle | Early microbial biofilm formation on marine plastic debris[END_REF]. Bacterial attachment is a highly controlled and regulated process whereby attached cells produce EPS to form structured and complex matrixes [START_REF] Donlan | Biofilms: Microbial Life on Surfaces[END_REF]. Then, these pioneer microorganisms facilitate the establishment of the next arrivals, including heterotrophic and photosynthetic microorganisms such as cyanobacteria, fungi, diatoms, barnacles, algae and protozoa [START_REF] Grzegorczyk | Monitoring of Marine Biofilm Formation Dynamics at Submerged Solid Surfaces With Multitechnique Sensors[END_REF].

However, in alignment with the global attention to environmental protection and biodiversity restoration in the marine environment [START_REF] Bai | IPBES Global Assessment on Biodiversity and Ecosystem Services Chapter 1. Assessing a planet in transformation: Rationale and approach of the IPBES Global Assessment on Biodiversity and Ecosystem Services[END_REF], the number of studies about the biocolonization of submerged materials and their effects on marine ecology and biodiversity has increased in the last decade. Indeed, in the marine environment, urban, coastal and offshore structures provide an important protective function, but can also have unintended ecological consequences, such as the loss or modification of habitat and the alteration of hydrological and ecological flows [START_REF] Heery | Identifying the consequences of ocean sprawl for sedimentary habitats[END_REF][START_REF] Waltham | Ecological engineering in the coastal seascape[END_REF]. The new challenge of the 21st century for managers is to eco-design marine infrastructure in a way that minimizes its ecological impact and increases its bioreceptivity (the ability to be colonized by living organisms) in order to enhance marine biodiversity without losing the structure durability [START_REF] Browne | Ecologically Informed Engineering Reduces Loss of Intertidal Biodiversity on Artificial Shorelines[END_REF].

Knowing that concrete is one of the materials most widely used for the construction of marine infrastructure such as ports and coastal defences [START_REF] Khanzadeh Moradllo | Time-dependent performance of concrete surface coatings in tidal zone of marine environment[END_REF], cementitious materials have a negative image with regard to environmental pollution. Depending on its chemical composition, a cementitious material may contain substances that promote or inhibit the development of microorganisms by the presence of some heavy metals, in sufficient quantity in the cement [START_REF] Dubosc | Characterization of biological stains on external concrete walls and influence of concrete as underlying material[END_REF]. Trace metal contamination in marine coastal areas is a worldwide threat for aquatic communities and a multi-chemical contamination influence both marine biofilm communities' structure and functioning [START_REF] Coclet | Trace Metal Contamination Impacts Predicted Functions More Than Structure of Marine Prokaryotic Biofilm Communities in an Anthropized Coastal Area[END_REF]. Some studies assess that transport of drinking water via pipelines composed of cement mortar is not detrimental for health according to the European Union (EU, 98/83/CE) and the World Health Organization (WHO) recommendations. Moreover, concrete matrices are complex and possess the capacity to store trace toxic metals [START_REF] Elkadi | Depth Profiling (ICP-MS) Study of Toxic Metal Buildup in Concrete Matrices: Potential Environmental Impact[END_REF] and to stabilize heavy metals [START_REF] Latifa | Piégeage des métaux lourds dans le mortier à court terme[END_REF][START_REF] Al-Kindi | Evaluation the Solidification/Stabilization of Heavy Metals by Portland Cement[END_REF], even in marine environment [START_REF] Webster | Long-Term Leaching of Metals from Concrete Products[END_REF].

Leaching tests are used to study the durability of concrete in aggressive environments but few studies deal with the environmental impact of immersed concrete. In 1996, SERCLERAT performed semi-dynamic tests on CEM I concretes and highlighted that heavy metals are almost undetectable in leachate water, even using cements spiked to 1000 -2000 mg / kg [START_REF] Serclerat | Les métaux traces dans le clinker de ciment Portland : rétention dans les mortiers et fixation dans les hydrates[END_REF]. In 1999, HILLIER et al. are also studying the leaching of toxic heavy metals by trace in CEM I concretes by integrating a longer exposure time of 254 days into deionized water. Based on the results of studies from the 1990s [START_REF] Rankers | Leaching tests for concrete containing fly ash -evaluation and mechanism[END_REF], he confirms that heavy metals are undetectable even at very low thresholds [START_REF] Hillier | Long-term leaching of toxic trace metals from Portland cement concrete[END_REF]. Then, the normative leaching tests do not make it possible to follow and quantify the releases of heavy metals.

The use of deionized water results in slow dissolution of hydration products (portlandite, ettringite and C-S-H), so that heavy metal leaching from concrete is sustained [START_REF] Hartwich | Influence of leachate composition on the leaching behaviour of concrete[END_REF]. Therefore, the pH has always been a real issue in leaching. Then, some scientists are studying leaching phenomena at constant pH [START_REF] Berthomier | Leaching of CEM III paste by demineralised or mineralised water at pH 7 in relation with aluminium release in drinking water network[END_REF] and advise to know in what form the metals will be present [START_REF] Moudilou | RELARGAGE DES METAUX LOURDS PRESENTS EN TRACES DANS LES MATRICES CIMENTAIRES[END_REF] since some elements are only soluble in a pH range [START_REF] Serclerat | Les métaux traces dans le clinker de ciment Portland : rétention dans les mortiers et fixation dans les hydrates[END_REF].

Only one study establishes conclusions on a significant absence of metal leaching into seawater [START_REF] Mcmanus | Partial replacement of cement for waste aggregates in concrete coastal and marine infrastructure: A foundation for ecological enhancement?[END_REF]. This lack of study in seawater is relative to the difficulty to analyze the leachate in a strong ionic activity. No differences were noticed between Portland cement and slag cement concretes, a very low heavy metals release is measured. In the natural environment, measures are not relevant because the infinite rate of dilution. On top of the material impact on the environment, cementitious materials are colonized after immersion in seawater. The intrinsic parameters that influence the bioreceptivity of cementitious materials in the marine environment are crucial and constitute a fundamental step towards more green and eco-designed marine artificial structures.

Generally speaking, the intrinsic parameters that influence the biocolonization (biofilm formation) of cementitious materials are the nature and the physicochemical properties of the surface: chemical composition, roughness, porosity, hydrophobicity and pH [START_REF] Lors | Interactions Materials -Microorganisms: Concrete and Metals more Resistant to Biodeterioration[END_REF][START_REF] Dubosc | Characterization of biological stains on external concrete walls and influence of concrete as underlying material[END_REF][START_REF] Manso | Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth[END_REF][START_REF] Hayek | La bioréceptivité de matériaux cimentaires dans l'eau de mer : mécanismes, facteurs agissants et conséquences[END_REF][START_REF] Souche | De la conception à l'écoconception des ouvrages maritimes : intégrer la nature au projet d'aménagement maritime[END_REF][START_REF] Salgues | L'écoconception maritime : une révolution pour les maitres d'ouvrages[END_REF][START_REF] Tran | Influence of the intrinsic characteristics of mortars on their biofouling by pigmented organisms: Comparison between laboratory and field-scale experiments[END_REF]. However, these factors are less well known in the marine environment. We showed in a previous study that the bacterial colonization of cementitious materials in seawater is influenced by the pH and the type of cement [START_REF] Hayek | In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment[END_REF][START_REF] Hayek | L'influence de la carbonatation sur la biocolonisation de matériaux cimentaires dans le milieu marin[END_REF].

In order to help engineers in their new challenge of designing marine infrastructures using ecodesigned concrete, the main objective of this present study is to determine the effect of two products which are widely used during concrete production on the biocolonization of cementitious materials in the marine environment. These products are the curing compound and the green formwork oil. Moreover, in order to select the parameter that promotes biocolonization most effectively, we also tested in this study the effect of surface roughness and type of cement. In addition, this paper proposes a short-term preliminary study to evaluate the potential release of heavy metals from mortar to deionized water and conclude on the environmental impact of the cementitious materials immerged into seawater.

MATERIALS AND METHODS

Preparation of Mortar Specimens

Ordinary Portland Cement (OPC) CEM I cement 52.5 N CE CP2 NF "SB" (provided by Ciments Calcia) and blastfurnace slag cement CEM III (composed of 60% ground granulated blastfurnace slag NF EN 15167-1, provided by ECOCEM (CAS no.: 65996-69-2) were used in this study to produce six types of mortar specimens (Table I). The mortar had a water/cement ratio (w/c) of 0.5 and was composed of 450 g cement and 1350 g sand (sand 0/4 EN 196-1). After mixing, the mortars were cast in cylindrical molds measuring 2.7 cm in diameter and 2.9 cm high. After 24 h of hardening, the mortar specimens were removed from the molds and placed in a laboratory room at 20 °C for 30 days. Formwork oil (vegetable oil, BIODEM SI 3) was spread on the molds, using absorbent paper to avoid any surplus, before the mortar was poured.

Curing compound (SikaCem®Cure) was added to the top of the specimens in accordance with the supplier's instructions 1 h after stripping. The rough mortars were prepared with a rough silicone skin; no release agent was needed. The cylindrical molds filled with mortar were poured on the silicone skin and held in place with a weight.

Immersion conditions

An immersion test in seawater was carried out using flat-bottomed basins (polyester, 6 m long, 0.6 m high and 2 m wide) located at the IFREMER station (biology of exploited marine organism's research unit in Palavas, France). The basins featured a seawater inlet and outlet allowing for an open seawater circuit. To ensure that the experiment would be completed smoothly and avoid contamination of any type, the basins were cleaned before the cementitious material specimens were placed in them.

Quantification of bacterial colonization

Quantification of the bacterial biofilm adhered to the surface of the mortar specimens was performed using the protocol described by Hayek et al., (culture-based methods) [START_REF] Hayek | In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment[END_REF]. This quantification was carried out after 0, 1, 2, 6, 8, 15, 24, 26 and 28 days of immersion in seawater.

After each incubation period, three specimens of each mortar type were placed in three sterile tubes containing 10 mL of sterile seawater. Bacteria adhering to the mortar surface were detached by immersing the tubes in an ultrasonic bath (Bandelin SONOREX™) for 10 min at 20 °C. The solution obtained was diluted using sterile seawater and 100 µl of diluted solution were spread on plates containing marine agar (MA, Dutscher, 490614). The plates were then incubated at 20 °C, and a colony count was performed at least 72 h after incubation. The results are expressed as colony-forming units per cm3 of mortar (CFU/cm 3 ).

Statistical analyses

In order to evaluate the significance of the various biocolonization obtained, statistical analysis was performed using GraphPad Prism 5 (GraphPad Software, San Diego, CA, USA) and oneway ANOVA tests. Statistical significance was accepted by p-value <0.05 obtained using Bonferroni or Tukey's multiple comparison post hoc tests.

Contaminant release evaluation

To assess whether inorganic contaminants have been leached from the cements, the concentration of copper and lead was measured in the water. All dishes were previously washed with a solution of HNO3 at 2N. A 4 cm square cube piece of mortars have been placed under slight agitation (30 rpm -rotation per minute) in deionized water at 20 ° C. A solid-liquid ratio of 1:8 was observed in this test. After leaching, 20 ml of samples were filtered using a 0.45 μm filter. Then the pH of sample was adjusted to 2 using 1N nitric acid before ICP-AES analysis. The detection limit for our method is 10 µg/L.

RESULTS AND DISCUSSION

The biological colonization of cementitious materials is affected according to the literature by many factors, including the environmental conditions, the bacterial properties and the physical/chemical characteristics of the material surface [START_REF] Hayek | La bioréceptivité de matériaux cimentaires dans l'eau de mer : mécanismes, facteurs agissants et conséquences[END_REF][START_REF] Karthick Raja Namasivayam | Bacterial biofilm or biofouling networks with numerous resilience factors from real water supplies of Chennai and their enhanced susceptibility to biocompatible nanoparticles[END_REF]. To avoid the effect of the environmental conditions and bacterial parameters on the biocolonization results, the mortar specimens were incubated at the same time under the same environmental conditions in the presence of the same marine bacteria. Therefore, only the physicochemical properties of the mortar surfaces could generate a different rate of bacterial colonization.

Effect of the curing compound and the green formwork oil on the biocolonization of mortar specimens

Generally, the curing compound and the green formwork oil are used during manufacturing to improve the durability of concrete; the curing agent is a liquid applied to the concrete or mortar surface to protect the material from water evaporation and give it greater aesthetic and mechanical durability, preventing early-age surface cracking [START_REF] Dang | Curing cement concrete by using shrinkage reducing admixture and curing compound[END_REF]. Formwork oil is a moldrelease agent that is applied to a wall of a mold to ensure easy separation of the hardened concrete from the mold by reducing the adhesion forces at the concrete/mold interface [START_REF] Djelal | Role of demoulding agents during self-compacting concrete casting in formwork[END_REF]. This oil forms a well-adsorbed and stable "lubricant monolayer" on the surface of cementitious materials, leading to improved release performance [START_REF] León-Martínez | Laboratory and field performance of biodegradable release agents for hydraulic concrete[END_REF].

The effect of these two products (curing compound and green formwork oil) is poorly understood to date. Figure 1 shows that the curing compound inhibits the bacterial colonization of mortar submerged in seawater whereas green formwork oil has the opposite effect. Figure 1 shows that the bacterial colonization of mortar surfaces started with a latency phase, followed by a phase of cell growth and accumulation on the surfaces and ending with a plateau phase. These colonization kinetics were also observed in most of the studies quantifying bacterial-biofilm formation on cementitious-material surfaces or on other surface types [START_REF] Tran | Influence of the intrinsic characteristics of mortars on their biofouling by pigmented organisms: Comparison between laboratory and field-scale experiments[END_REF][START_REF] Hayek | In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment[END_REF].

Figure 2 shows that the curing compound significantly inhibits the bacterial colonization of mortar submerged in seawater. Cells accumulated and grew faster and more extensively on an untreated surface. The compositions of curing compound used in this study indicate the presence of alkyl (C14-C18) bis (2-hydroxyethyl) amine, 5-chloro-2-methyl-2H-isothiazol-3-one and 2methyl-2H-isothiazol-3-one (FDS Sikacem cure). These elements or their derivatives have been cited as an anti-biofilm molecules that inhibited the formation and the accumulation of bacterial biofilm [START_REF] Andjouh | Screening of bromotyramine analogues as antifouling compounds against marine bacteria[END_REF][START_REF] Andjouh | Click-based synthesis of bromotyrosine alkaloid analogs as potential antibiofilm leads for SAR studies[END_REF]. Moreover, the treatment of the material by an hydrophobic surface coating is cited as one of the anti-biofilm strategies used to inhibit bacterial and other organisms adhesion on the surface [START_REF] Huggett | Effects of initial surface wettability on biofilm formation and subsequent settlement of Hydroides elegans[END_REF][START_REF] Blainey | The use of block copolymers to inhibit bacterial adhesion and biofilm formation on hydrophobic surfaces in marine habitats[END_REF][START_REF] Razavi | Environment-Friendly Antibiofouling Superhydrophobic Coatings[END_REF]. To verify the effect of the curing film on the hydrophobicity of the mortar surface, the contact angle with a drop of water was measured for the treated and untreated surface using a drop-shape scanner. From their preparation until the start of the immersion test, the mortars treated with the curing compound presented a contact angle greater than 110° (40° in the case of untreated mortars), indicating a hydrophobic surface [START_REF] Bixler | Biofouling: lessons from nature[END_REF]. After immersion and under the action of seawater, the contact angle gradually decreased with time and became equal to that of the control mortar at 28 days of immersion (data not shown). Therefore, we propose that the curing compound inhibited the biological colonization of mortar surfaces in seawater because of its chemical composition (anti-biofilm) and its effect on surface hydrophobicity. However, Figure 2 shows that the formwork oil significantly promotes the bacterial colonization of mortar submerged in seawater. The composition of the green formwork oil used in this study is not given. Detailed information is given neither in the technical product information nor in the bibliography. Therefore, knowing that green formwork oil is biodegradable, we propose that this oil applied on the surface of the mortar specimens was used as a carbon source by marine bacteria, according to the study and the results of [START_REF] Li | Anaerobic biodegradation of vegetable oil and its metabolic intermediates in oil-enriched freshwater sediments[END_REF][START_REF] Mehdi | Investigation of alkane biodegradation using the microtiter plate method and correlation between biofilm formation, biosurfactant production and crude oil biodegradation[END_REF]. Dusane et al. showed by a laboratory test that the biofilm formation is affected by the carbon sources. Lactic acid, erythritol, glycerol, glucose and edible oils increase this process [START_REF] Dusane | Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589[END_REF]. Therefore, we propose that the surface treatment with this type of formwork oil increased the biological colonization of cementitious materials in the marine environment because it is used as a nutrients source by marine microorganisms.

Effect of the type of cement and the surface roughness on the biocolonization of mortar specimens

In order to compare and classify the intrinsic parameters that influence the biocolonization of cementitious materials in the marine environment, we also tested in this study under the same conditions the effect of the type of cement (the use of CEM III) and the surface roughness on the biofilm formation at the surface of mortar specimens. Figure 3 shows that the bacterial colonization of mortar surfaces in the case of OM3, BM1 and BM3 has the same kinetic observed in the case of Ref, CM and OM1 (cf. Figure 1). However, the formation of bacterial biofilm was much greater in the case of CEM III mortars, regardless of the surface topography (BM1 vs. BM3) or whether formwork oil (OM1 vs. OM3) was applied. These results were in keeping with the literature, in which a similar effect of cement type on the biological colonization of cementitious materials has been reported [START_REF] Hayek | In vitro and in situ tests to evaluate the bacterial colonization of cementitious materials in the marine environment[END_REF][START_REF] Voegel | Evaluation of microbial proliferation on cementitious materials exposed to biogas systems[END_REF][START_REF] Ly | Optimisation of 3D printed concrete for artificial reefs: Biofouling and mechanical analysis[END_REF]. In addition, a rough mortar surface significantly increased bacterial colonization in comparison with a smooth surface (Ref). This influence of surface roughness was identified in several studies concerning the biological colonization of cementitious materials [START_REF] Tran | Influence of the intrinsic characteristics of mortars on their biofouling by pigmented organisms: Comparison between laboratory and field-scale experiments[END_REF][START_REF] Voegel | Evaluation of microbial proliferation on cementitious materials exposed to biogas systems[END_REF].

Therefore, based on the rate of biological colonization (Figure 3), the mortar types can be classified from less to more bioreceptive in the following order: CM< Ref < OM1 < OM3 < BM1 < BM3. Then, the intrinsic parameters that promote the biocolonization of cementitious materials in the marine environment can be classified from more to less effectively in the following order: surface roughness > the use of CEM III (type of cement) > surface treatment with green formwork oil.

However, the main cause of concrete structure deterioration in the marine environment is the chemical attack caused by seawater ions such as chloride and magnesium sulfate attack [START_REF] Yi | A review on the deterioration and approaches to enhance the durability of concrete in the marine environment[END_REF].

According to the literature, the biological colonization of immerged concrete structure can have a protective effect (bioprotection) against chemical attack in seawater, leading to improved structure durability [START_REF] Soleimani | Growth and characterization of Escherichia coli DH5α biofilm on concrete surfaces as a protective layer against microbiologically influenced concrete deterioration (MICD)[END_REF][START_REF] Perkol-Finkel | Ecologically Active Concrete for Coastal and Marine Infrastructure: Innovative Matrices and Designs[END_REF]; the marine organisms adhered to the concrete surface form a physical barrier that reduces surface permeability. The decrease in surface permeability leads to lessefficient diffusion of aggressive ions (Cl-, Mg 2+ and OH -), which can increase the durability of a concrete structure in the marine environment. Furthermore, Lv et al. demonstrate that the presence of the Crassostrea gigas coating (biological coating) on the surface of marine concrete can reduce the water absorption of concrete, and enhance the resistance of concrete to chloride penetration and carbonation [START_REF] Lv | Effect of biological coating (Crassostrea gigas) on marine concrete: Enhanced durability and mechanisms[END_REF]. Then, improving the biological colonization of concrete structure in the marine environment can have a positive effect both for the environment (biodiversity restoration) and for the concrete structure (bioprotection).

Contaminant release from mortars to seawater

The obtained results show us that no copper detection occurs in all samples. The presence of lead neither can be affirmed since the measured concentrations are within the tolerances related to the measurement uncertainties (0.01 mg/L). These results are consistent with those of previous studies [START_REF] Hillier | Long-term leaching of toxic trace metals from Portland cement concrete[END_REF][START_REF] Mcmanus | Partial replacement of cement for waste aggregates in concrete coastal and marine infrastructure: A foundation for ecological enhancement?[END_REF] which obtained concentrations is in the order of a few µg / L.

CONCLUSIONS

Eco-design of marine constructions is a major focus for researchers and construction companies working in marine environment, to enhance durability and also, since few years, to minimize and mitigate human impacts toward "no net loss" on biodiversity policies [START_REF] Salgues | L'écoconception maritime : une révolution pour les maitres d'ouvrages[END_REF]. This study tests, compares and classify the intrinsic parameters that influence the biocolonization of cementitious materials in the marine environment. Regarding the parameters tested in the present work, we can summarize that: (i) Work practices such as the use of a curing agent and/or formwork oil have an impact on biocolonization; the surface treatment with green formwork oil enhance the biocolonization whereas the application of curing agent has the opposite effect. (ii) The use of rough surface or slag cement CEM III increases the bioreceptivity of cementitious materials. (iii) Among the parameters examined, surface roughness proved to be the factor that promotes biocolonization most effectively.

This study also concludes that no release of toxic heavy metals was detected during the leaching test in water. Further experiments need to be done using a leaching test in seawater even if the ICP measurement will be complex because of the significant ionic activity of sea water. More precise equipment ICP-MS would be relevant to possibly detect any heavy metals realease.

These results could be taken up in future recommendations to enable engineers to design with the same level of knowledge both technical and ecological concerns, to eco-design marine infrastructure and develop real "win-win" projects.

Figure 1 .

 1 Figure 1. Quantification of bacterial colonization of mortar specimens. Each quantification was performed in triplicate using the culture-based method, and the error bars present the standard deviation from the values obtained. Ref = control mortar; CM = cured mortar; OM1 = oiled mortar prepared with CEM I.

Figure 2 .

 2 Figure 2. Statistical comparison (GraphPad Prism 5) of the biocolonization of mortar surfaces treated and untreated with curing compound or green formwork oil. Each experiment was performed in triplicate, and the error bars present the standard deviation of the values obtained. The experiments highlighted with asterisks differed significantly from the control (Bonferroni; **: p < 0.01, ***: p < 0.001) at the indicated time.

Figure 3 .

 3 Figure 3. Quantification of bacterial-biofilm formation on mortar specimens. Each quantification was performed in triplicate using the culture-based method, and the error bars present the standard deviation from the values obtained. Ref = control mortar; CM = cured mortar; OM1 = oiled mortar prepared with CEM I; OM3 = oiled mortar prepared with CEM III; BM1 = biomimetic mortar prepared with CEM I; BM3 = biomimetic mortar prepared with CEM III.

Table I . Types and compositions of mortar specimens

 I

	Mortar Specimen	Surface Type	Cement	CEM I (g)	CEM III (g)	Water (g)	Sand (g)	Curing Agent	Formwork Oil
	Control mortar	Ref		CEM I	450	0	225	1350	-	-
	Cured mortar	CM	Smooth (SS)	CEM I	450	0	225	1350	+	-
	Oiled	OM1		CEM I	450	0	225	1350	-	+
	mortar	OM3		CEM III 180	270	225	1350	-	+
	Biomimetic BM1 Rough	CEM I	450	0	225	1350	-	-
	mortar	BM3	(RS)	CEM III 180	270	225	1350	-	-

ACKNOWLEDGMENT

The authors thank Emmanuel Rezzouk and Sébastien Triplet (IFREMER, Biology Research Unit for exploited marine organisms) for their welcome at the Palavas-les-Flots oceanographic station and thank LIB industry for the supply of the silicone matrix and their assistance. The authors thank NTNU, IMT Mines Alès and University Montpellier 3 for their participation or support and in particular Hugo Fahy and Thierry Vincent.

FUNDING SOURCES

This work was supported by the IMT Mines Ales.