# Short-term durability and environmental integration of dredged sediment-based concrete in seawater

Habiba Lharti, Mahmoud Hayek, Tara Soleimani, Marie Salgues, Klaartje de Weerdt, Ammar Yahia, Jean-Claude Souche

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Habiba Lharti, Mahmoud Hayek, Tara Soleimani, Marie Salgues, Klaartje de Weerdt, et al. Short-term durability and environmental integration of dredged sediment-based concrete in seawater. Construction and Building Materials, 2025, 492, pp.143104. 10.1016/j.conbuildmat.2025.143104. hal-05208939

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# Short-term durability and environmental integration of dredged sediment-based concrete in seawater

Habiba Lharti<sup>a, *</sup>, Mahmoud Hayek<sup>b, D</sup>, Tara Soleimani<sup>c, D</sup>, Marie Salgues<sup>a</sup>, Klaartje de Weerdt<sup>d, D</sup>, Ammar Yahia<sup>b, e, D</sup>, Jean-Claude Souche<sup>a</sup>

## ARTICLE INFO

Keywords:

Dredged marine sediments

Durability

Chloride ingress

Biocolonization

Life cycle assessment (LCA)

Eco-engineering

Circular economy

## ABSTRACT

The increasing demand for natural sand in construction and tightening environmental regulations have prompted interest in alternative materials for concrete production. This study explores the use of untreated dredged marine sediments as a 30 % partial sand replacement in marine concrete. Two mixtures, a reference concrete (RC) and a marine sediment concrete (MSC), were evaluated before and after 70 days of seawater immersion. The experimental program evaluated compressive strength, durability (porosity, permeability, and chloride ingress), biocolonization potential, and environmental and economic viability through Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA). The results indicate that MSC achieves compressive strength comparable to RC (58.6 MPa vs. 59.7 MPa at 28 days) with lower gas permeability (64.3 × 10⁻¹⁸ m² for MSC vs. 88.9 × 10⁻¹⁸ m² for RC), suggesting a denser microstructure. Although MSC showed a higher initial chloride content (0.11 % vs. 0.05 %), this is attributed to the chloride-bearing sediment. Notably, MSC demonstrated faster biocolonization, indicating stronger ecological integration in marine environments. From a sustainability perspective, MSC reduces environmental impacts associated with sand extraction, promotes the reuse of dredged sediment, and lowers production costs. These findings suggest that MSC could be a promising material for eco-designed coastal infrastructure such as reefs, breakwaters, and offshore foundations. However, further research is needed to evaluate long-term performance, optimize mix design, and validate large-scale applications for sustainable marine construction.

## 1. Introduction

Globally, urbanization and infrastructure development require a substantial quantity of construction materials, particularly concrete. Renowned for its versatility, durability, and cost effectiveness, concrete is the most widely used material in civil engineering, with an estimated annual production of 6 billion cubic meters. This volume is projected to increase due to population growth and the need for resilient infrastructure.

Concrete is typically composed of a binder, aggregates (such as sand and gravel), water, and chemical additions. Among these components, sand plays a crucial role by filling voids between coarse aggregates, ensuring a dense and cohesive mix and contributing to concrete

durability. However, the availability of natural sand, particularly river sand, has become increasingly limited owing to over-extraction and environmental regulations, leading to a global crisis in sustainable sand sourcing [1]. In response, research over the past decade has intensified to identify viable alternatives to natural sand in concrete production [2–4]. Manufactured sand (M-sand) has shown superior early age strength (7 days of curing) compared to natural sand [5]. Similarly, eco-sand, a by-product of cement manufacturing, has proven effective as a partial replacement for M-sand, with an optimal replacement rate of 18 % [6]. Crushed sand from coal mine waste rock (CSM), when combined with fly ash and nano-silica, achieves mechanical and durability properties comparable to those of conventional concrete [7]. Numerous studies also support the replacement of sand with various industrial

<footnote><sup>a</sup> LMGC, University of Montpellier, IMT Mines Ales, CNRS, Ales 30100, France</footnote>

<footnote><sup>b</sup> Department of Civil and Building Engineering, Université de Sherbrooke, 2500 Blvd. de l'Université, Sherbrooke, QC J1K 2R1, Canada</footnote>

<footnote><sup>c</sup> HSM, University of Montpellier, IMT Mines Ales, CNRS, IRD, Ales 30100, France</footnote>

<footnote><sup>d</sup> Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway</footnote>

<footnote><sup>e</sup> Canadian University Dubai, Dubai, United Arab Emirates</footnote>

<footnote>* Corresponding author.
E-mail address: Habiba.Lharti@mines-ales.fr (H. Lharti).</footnote>
wastes, such as granite fine, quarry dust, marble powder and blast
furnace slag, at levels of up to 25 % depending on the raw material
characteristics, contributing to a potential 20 % reduction in the envi-
ronmental impact of concrete [8,9]. Dredged marine sediment (DMS)
has also been identified as a promising sustainable alternative to natural
sand in concrete production [10–13].

In marinas and fishing ports, boat-related activities lead to the
accumulation of polluted sediments, posing a major challenge. To
maintain smooth access and functionality, regular dredging of ports and
waterways is essential, generating over one billion cubic meters of
dredged sediment globally each year [14]. In France alone, approxi-
mately 50 million cubic meters are dredged annually [15], most of
which are redeposited at sea or in estuaries, with only a small portion
treated on land. However, increasing stringent on oceans disposal have
led to the accumulation of dredged marine sediments (DMS) in open
areas [16], resulting in significant economic, environmental, and social
concern [17].

Recycling DMS as a partial sand substitute in concrete presents a
promising solution to address sediment management challenges and
reduce reliance on natural sand. Research indicates that untreated DMS
can replace up to 30 % of sand without significantly compromising
concrete properties [12], although more conservative estimates suggest
an optimal replacement range of 10–20 % [18]. The variability in these
findings is likely due to differences in sediment composition, treatment
processes, and concrete mix designs. The optimal replacement level and
treatment approach must be tailored to the specific properties of the
DMS and the concrete’s intended application [19–21]. Moreover, both
the fresh and hardened properties of DMS-modified concrete are
strongly influenced by mixture design parameters [10,22,23]. Hayek
et al. [22] demonstrated that optimizing the concrete mix design, by
lowering the water-to-binder ratio (w/b) ratio, refining the granular
packing, and using an efficient and compatible superplasticizer, can
increase the feasible DMS replacement level from 10 % to 30 % without
compromising performance. Similarly, Heidari et al. [10] showed that
advanced techniques, such as particle packing optimization and
response surface methodology can further enhance DMS incorporation
up to 38 %, while maintaining fresh and hardened properties compa-
rable to those of the reference mixture without DMS.

Beyond technical feasibility, evaluating the sustainability of sedi-
ment valorization strategies is essential for large-scale implementation.
The environmental implications of these practices must be thoroughly
evaluated using robust decision-making tools. Life Cycle Assessment
(LCA) has emerged as a crucial methodology for evaluating the envi-
ronmental impacts of various management options for dredged marine
sediments [24–27]. Several studies applied LCA to compare valorization
scenarios and highlight the varying environmental outcome associated
with each approach [27,28]. However, the combination of LCA and Life
Cycle Cost (LCC) analysis to evaluate sustainable sand replacement
limits in concrete has received limited attention. This gap may be
attributed to the diversity of valorization methods and the heterogenous
nature of sediment from dredging sites [16]. For example, Soleimani
et al. [29] found that while a 40 % replacement level was technically
feasible for predominantly sandy sediment, this decreased to 20 % when
environmental and economic factors, evaluated through LCA and LCC,
were considered. Thus, integrating LCA and LCC analyses with technical
performance assessments is a crucial step toward enabling the sustain-
able and scalable use of dredged sediment in concrete production.

Ensuring the durability and service life of concrete incorporating
dredged marine sediments (DMS) is essential for its sustainable use in
construction and for ensuring long-term structural performance and
safety. While many studies have confirmed the technical feasibility of
using DMS as a partial sand replacement, durability aspects remain
underexplored [23]. Unlike natural sand, DMS typically contain finer
particles and significant amount of calcite, quartz, aluminum oxide,
ferric oxide, organic matter, contaminants, clay, chlorides and sulfates
[14,30–33]. These components can affect fresh concrete properties,

particularly hydration [34], and increase durability concerns, especially
in reinforced concrete where chloride and sulfate ions can promote
corrosion and sulfate attack [31,35].

DMS incorporation often increases water or superplasticizer demand to maintain workability [12,36]. Studies on hardened concrete durability yield mixed results, Limeira et al. [37] reported no negative impact when replacing up to 50 % of natural sand with sediments from the Port of Barcelona, while Achour et al. [38] observed a decrease of both mechanical properties and durability with increased sediment content. Such inconsistencies are largely attributed to variations in sediment composition, exposure conditions, and concrete mix design. To date, few studies have simultaneously examined both the environmental and biological performance of concrete that incorporates dredged marine sediments. Although previous research has confirmed the feasibility of using DMS as a sand replacement from mechanical and environmental perspectives, the ecological behavior of such materials in marine environments remains largely unexplored. Specifically, the potential for biocolonization in sediment-based concrete, including its capacity to support microbial and macro-organism attachment, has not been systematically assessed, despite its significance in designing eco-engineered marine structures.

This study introduces a novel interdisciplinary approach that in-
tegrates short-term durability, biocolonization behavior, and LCA and
LCCA to evaluate the sustainability of concrete containing 30 % un-
treated DMS under seawater exposure. By examining microbial coloni-
zation alongside chloride ingress and mechanical performance, the
research provides new insights into the ecological integration and
functional performance of sediment-based concrete in marine environ-
ments. This research contributes to more sustainable resource manage-
ment by promoting a circular economy approach, reducing dependence
on natural sand, minimizing industrial waste, lowering the carbon
footprint of marine construction materials, and enabling the large-scale
reuse of dredged sediments.

## 2. Research significance

Recycling dredged marine sediment (DMS) as a sand substitute in concrete presents a promising solution to both sediment management challenges and the depletion of natural sand sources. While recent studies have focused on optimizing mix design using DMS, there remains a lack of comprehensive data on the durability of such concrete, especially under harsh marine conditions. Furthermore, the ecological integration of this material, specifically its biocolonization in seawater, has yet to be explored. This study addresses these gaps through a multidisciplinary investigation ranging from laboratory experiments to full-scale in-situ testing. Concrete incorporating 30 % DMS as sand substitution was assessed over 70 days for short-term durability and by biocolonization. The research also includes a life cycle assessment (LCA), life cycle cost analysis (LCC), and field deployment of ballast units in the port of Sète, France. Results highlight the potential of DMS for the eco-design of marine infrastructure. However, further research is necessary to evaluate long-term performance and ecological integration.

## 3. Experimental program

The experimental program was designed to assess the feasibility and
performance of incorporating dredged marine sediments as a partial
sand replacement in marine concrete, using a multidisciplinary
approach encompassing mechanical characterization, durability
assessment, and environmental and economic analyses (Fig. 1). Section
4 presents the study site and concrete mix design, followed by the
experimental setup aimed at assessing the durability of DMS-based
concrete under marine conditions. Section 5 presents the mechanical
and physical properties obtained of both the reference concrete (RC) and
the marine sediment concrete (MSC), before and after immersion in
seawater and filtered seawater. The study also investigates the
<figure><img src="image_2.png" /><figcaption>**Fig. 1.** Experimental program applied in this study. Characterization of RC and MSC. LCA analysis and durability in seawater and filtered seawater.</figcaption></figure>

biocolonization potential of MSC and examines the penetration and accumulation of key elements post-exposure. Life Cycle Analysis (LCA) and Life Cycle Cost Analysis (LCC) are integrated to evaluate the environmental impacts of replacing natural sand with DMS.

# 4. Materials and methods

## 4.1. Dredged marine sediments site

The study site is Port Camargue (Fig. 2), located in the southern region of France within the Rhône River delta. This area is characterized by extensive wetlands, salt marshes, and a network of interconnected water bodies, serving it as an important center for fishing and recreational boating activities. Due to the on-going sediment deposition from

the Rhône River and coastal processes, regular dredging is necessary to ensure navigability and maintain port activities. The sediments used in this study originate solely from such mandatory maintenance operations. Their reuse is explored here as a sustainable solution for materials already dredged, not as a justification for increasing or encouraging additional dredging activities [15].

In 2021, a dredging operation was conducted at Port Camargue (Fig. 3a), during which approximately 4000 m³ of sediment was extracted using a hydraulic suction dredging method (Fig. 3b). The dredged material was primarily composed of silty sand, with approximately 80 % of particles smaller than 80 microns and the remaining 20 % consisting of fine sand. The extracted sediments were stored in geotextile tubes (Fig. 3c) for dewatering and further processing. Of the total dredged material collected, about 3500 m³ of the coarser fraction

<figure><img src="image_3.png" /><figcaption>**Fig. 2.** Study site location, aerial view of Port Camargue, and experimental setup for concrete analysis.</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>Fig. 3. Sediment sampling and dredging operations at Port Camargue, France. (a) Aerial map of the sampling area; (b) Dredging equipment in operation; (c) Sediment collection and containment; (d) Sediment sample.</figcaption></figure>

was utilized for beach nourishment, while the remaining 500 m³ of finer sediments, primarily composed of silt and fine sand, were stored on land for future valorization (Fig. 3d). This fine sediment fraction was chosen for valorization in the current concrete study. The sediments were deposited on a dedicated platform, shielded from direct runoff and contamination. Before being incorporated into concrete, the sediment underwent a preparation protocol to ensure uniformity: it was air-dried, sieved at 2 mm, and mechanically homogenized using rotary mixing equipment. The entire volume prepared for the test campaign was then stored in sealed plastic containers and maintained at 20°C in a climate-controlled room to ensure sampling consistency and material stability throughout the experimental phase.

## 4.2. Physico-chemical properties and concrete mix designs

The chemical and physical properties of the dredged marine sediments used in this study are summarized in Table 1. Some sediment

properties may influence concrete behavior. The fine particle size contributes to matrix densification but may also increase water demand. The presence of organic carbon could enhance biocolonization by providing nutrients for microbial growth, while potentially interfering with cement hydration [21,39]. Sediment samples (Fig. 3d) were stored in the laboratory at 20°C in hermetically sealed plastic bags to prevent contamination and moisture loss. Prior to incorporation into the concrete mix, the sediments underwent a 48-hour air-drying, reducing their moisture content to approximately 10 % [12].

The concrete mix design was established following the Dreux-Gorisse method [40], as described by Hayek et al. [22]. The binder phase consisted of a fixed combination of Portland cement (CEM I 52.5 N) and ground granulated blast-furnace slag (GGBS, Ecocem®) in equal proportions (174 kg/m³ each), with a water-to-binder ratio of 0.5. The aggregate included locally sourced natural silica-limestone gravel (6.3/14 mm) and sand (0/4 mm). A polycarboxylate superplasticizer (SP) was incorporated to enhance flowability and reduce water demand.

Two distinct concrete mix-designs were evaluated. The reference mix (Table 2) contained no marine sediment, while the second mix replaced 30 % (by mass) of the sand with DMS. To maintain equivalent workability the amount of added SP was adjusted when a higher dosage was

<table><caption>**Table 1**

Physico-chemical properties of the marine sediments from Port-Camargue [12].</caption><thead><tr><th>Property</th><th>Value</th></tr></thead><tbody><tr><td>Water content</td><td>17.70 ± 5.60 %</td></tr><tr><td>Average diameter</td><td>117.50 µm ± 25 µm</td></tr><tr><td>Median diameter</td><td>94.40 µm ± 27 µm</td></tr><tr><td>Density</td><td>2.66 ± 0.01 g/cm³</td></tr><tr><td>Specific surface area</td><td>3.13 ± 0.82 m²/g</td></tr><tr><td>pH</td><td>8.67 ± 0.13</td></tr><tr><td>Clay content</td><td>0.81 ± 0.25 %</td></tr><tr><td>Chloride content</td><td>0.67 ± 0.15 %</td></tr><tr><td>Total organic carbon</td><td>2.69 ± 0.26 %</td></tr><tr><td>Morphology</td><td>Angular shape</td></tr><tr><td>Major mineral elements</td><td>Calcite (CaCO₃), Quartz (SiO₂), Anhydrite (CaSO₄)</td></tr><tr><td>Major chemical composition</td><td>SiO₂ (52.84 %), Al₂O₃ (9.56 %), Fe₂O₃ (3.15 %), CaO (13.25 %), K₂O (3.30 %), Na₂O (1.48 %), MgO (1.40 %), SO₃ (0.92 %)</td></tr></tbody></table>

<table><caption>**Table 2**

Mix designs (kg/m3) of concrete samples.</caption><thead><tr><th>Material</th><th>Reference concrete (RC) (0 %)</th><th>Marine sediment concrete (MSC) (30 %)</th></tr></thead><tbody><tr><td>Gravel 6.3/14</td><td>580</td><td>580</td></tr><tr><td>Gravel 4/6.3</td><td>300</td><td>320</td></tr><tr><td>Sand 0/4 or F</td><td>1020</td><td>658</td></tr><tr><td>Marine sediment</td><td>0</td><td>282</td></tr><tr><td>CEM1 52.5</td><td>174</td><td>174</td></tr><tr><td>GGBS, Ecocem@ w/b ratio</td><td>174</td><td>174</td></tr><tr><td>Water</td><td>0.5</td><td>0.5</td></tr><tr><td>Superplasticizer (%)</td><td>186</td><td>173</td></tr><tr><td></td><td>0.2</td><td>2</td></tr></tbody></table>
required due to the fine particle size of DMS. Specifically, the super-plasticizer content was increased from 0.2 % to 2 % (by cement mass) in the sediment-based mix to achieve a target slump of 190 ± 25 mm.

### 4.3. Specimens' preparation and exposure conditions

Following the mixing process [12], cylindrical specimens with dimensions of 11 × 22 cm or 15 × 32 cm (for gas permeability testing) were cast using cardboard molds and covered with plastic lids. After 24 h of initial curing, the specimens were demolded and submerged in water at 20°C for a curing period of up to 90 days. At the end of this curing period, the specimens were cut into 11 × 11 cm sections. To ensure that only the top surface was exposed to seawater, a water repellent coating was applied to both the sides and bottom surfaces. This allowed for a controlled assessment of biocolonization effects on the durability and mechanical properties.

Immersion tests in natural and filtered (using a 0.45 µm membrane filter) seawater were conducted to evaluate the durability of concrete incorporating dredged sediments under marine exposure conditions. These tests also aimed to assess the influence of biocolonization on compressive strength and chloride diffusion, given filtration at 0.45 µm removes most living organisms from seawater. Both reference concrete (RC) and marine sediment concrete (MSC) were subsequently immersed in either natural seawater (Fig. 4a) at the IFREMER Palavas-Les-Flots basin [41] or filtered seawater in a laboratory setting at 20°C (Fig. 4b). After an initial 90-days curing period, the specimen was cut into 11 × 11 cm sections. Each specimen was split in half: one half was immersed in filtered seawater (FSW) in the laboratory conditions, and the other was exposed to natural seawater (SW) on-site (Fig. 4c).

## 4.4. Methods

### 4.4.1. Compressive Strength

The compressive strength test is a fundamental assessment of concrete's mechanical performance, particularly for structures exposed to varying environmental conditions. In this study, compressive strength was evaluated in accordance with the French standard for testing hardened concrete [3]. Both reference concrete (RC) and marine sediment concrete (MSC) were tested at 3, 7, 28, and 90 days before seawater immersion to compare their early and long-term strength development. For each concrete type, tests at these curing ages were performed using three cylindrical specimens (Ø 11 cm × 22 cm) to ensure statistical reliability.

Additionally, durability-related strength tests were conducted at 42 and 70 days after immersion in natural seawater (SW) and filtered seawater (FSW) to assess performance under marine exposure.

### 4.4.2. Porosity and water absorption test

Water absorption and porosity tests were performed following the French standard for porosity and density testing [42] to evaluate the percentage of surface-connected pores in RC and MSC after 28 days of curing. Three cylindrical samples (110 mm diameter, 50 mm height) were submerged in water for 48 h to measure water absorption. Porosity was determined by first fully saturating the samples to obtain their water-saturated mass, followed by weighing at atmospheric pressure to quantify air voids, and finally oven-drying at 105°C to determine dry mass. These measurements provided an accurate assessment of porosity before immersion in seawater or filtered seawater.

### 4.4.3. Gas permeability

Gas permeability testing was performed in accordance with the French standard [43], employing the CEMBUREAU method to evaluate the flow of gas through concrete under a constant pressure gradient. Three cylindrical specimens (150 mm diameter, 50 mm height) were placed in a permeameter, where the steady-flow gas flow was measured. From this, the intrinsic permeability was calculated, providing key insight into the material's resistance to gas infiltration, an important parameter for assessing durability in aggressive conditions.

### 4.4.4. Monitoring of biocolonization (image processing technique and wet mass technique)

Biocolonization was assessed to evaluate the interaction between concrete and marine environments, with a focus on marine sediment concrete (MSC). Biofilm formation occurs in a progressive sequence: starting with the formation of a conditioning layer, followed by microbial colonization, and culminating in mature biofilms [44]. In this study, biocolonization was monitored according to Hayek et al. [41] using two complementary techniques. Image processing analysis provided a visual and quantitative assessment of biological growth over time, while the wet mass technique performed at 28, 42, 56, and 70 days after immersion in SW and FSW and filtered seawater (FSW). A total of five specimens per concrete type were used to capture biocolonization development across different orientations and exposure durations. This setup ensured reliable data for both visual and mass-based evaluations.

<figure><img src="image_5.png" /><figcaption>Fig. 4. Experimental setup for concrete immersion in marine environments.</figcaption></figure>
### 4.4.5. Micro-XRF

The interaction between concrete microstructure and seawater can initiate deterioration mechanisms including chloride ingress, and sulfate attack. To assess these phenomena, high-resolution elemental mapping of RC and MSC was performed after 70 days of submersion in SW and FSW using the M4 Tornado µXRF (Bruker). Three specimens per concrete type were analyzed to ensure representativeness and account for possible variability in elemental distributions. This advanced micro-X-ray fluorescence (µXRF) system, equipped with an Ag X-ray tube, a collimator, and dual silicon drift detectors (SDDs), enables precise, non-destructive elemental analysis. Scanning was conducted out under optimized conditions: 50 kV voltage, 600 µA current, 20 mbar vacuum pressure, 20 µm spot size, 50 µm step size, and a collection time of 2 ms per step.

### 4.4.6. Chloride quantification

Chloride content in concrete exposed to seawater was determined using the Mohr titration method, following the procedure described by Berenguer et al. [45]. After 70 days of immersion in natural or filtered seawater, concrete powder samples were extracted at depths of 5, 10, 15, 20, 25 and 30 mm. Each sample was mixed with distilled water, allowed to rest for 24 h, and subsequently titrated with a 0.0141 M silver nitrate (AgNO₃) solution using potassium chromate (K₂CrO₄) as an indicator. The titration endpoint was identified by a brick-red color change, indicating complete chloride reaction with silver nitrate. The chloride content was expressed as a percentage of cement mass, providing a quantitative measure of chloride ingress at varying depths.

### 4.4.7. Life Cycle Assessment (LCA)

A comparative life cycle assessment (LCA) was performed to evaluate the environmental impacts of experimental concrete formulations. Following the methodology described by Soleimani et al. [29], the ReCiPe midpoint (H) method was employed to assess 18 environmental impact categories [46–48]. Life cycle inventories (LCIs) were developed using openLCA v.1.11.0 incorporating data from the ecoinvent v.3.5 database, with allocation at the point of substitution. Field data were used to refine inventory inputs. The environmental impacts of 1 m³ of conventional concrete served as the baseline for comparison. The functional unit was defined as 1 m³ of concrete at the plant gate, with a cradle-to-gate system boundary encompassing raw material extraction through production. For sediment use, the impacts of dredging operations were attributed exclusively to the dredging process, while the sediment itself was treated as a recyclable material with no inherent environmental burden. The normalized impact scores of the experimental concrete scenarios were expressed relative to conventional concrete, and a single aggregated score was calculated to support sustainability decision-making.

### 4.4.8. Life Cycle Cost Analysis (LCCA)

A Life Cycle Cost Analysis (LCCA) was performed to evaluate the economic feasibility of sediment-based concrete. The cost assessments included raw materials, energy consumption, transportation, labor, equipment, and maintenance, with market data sourced from the French construction sector. Total cost per cubic meter of each concrete formulation was calculated using Excel, incorporating material incorporation rates, production processes, and market prices. While untreated raw sediment was assigned a zero-market value, transportation costs were included in the analysis to provide a comprehensive cost assessment.

### 4.4.9. Statistical analysis

GraphPad Prism 10 (GraphPad Software, San Diego, CA, USA) was used to assess the statistical significance of differences in the experimental results. Student's t-test and one-way ANOVA were performed to evaluate the effect of sediment integration on the concrete properties in the hardened state before and after immersion in seawater. Significant differences were denoted in the figures using asterisks, where one

asterisk (*) indicates *p* value < 0.05, two asterisks (**) indicate *p* value < 0.01, and three asterisks (***) indicate *p* value < 0.001.

## 5. Results and discussion

### 5.1. Properties of concrete before immersion

Fig. 5 presents the compressive strength and durability properties of Reference Concrete (RC) and Marine Sediment Concrete (MSC). Fig. 5a shows the evolution of compressive strength over the curing periods of 3, 7, 28, and 90 days. The results indicate that the incorporation of marine sediment into concrete mix had no significant adverse effect on compressive strength. At 3 days, both RC and MSC exhibit comparable strength (17.8 MPa for RC and 17.3 MPa for MSC), indicating that the incorporation of marine sediments has a minimal impact on early-age strength. By 7 days, a slight divergence was observed, with RC achieving 35.0 MPa and MSC reaching 32.4 MPa. At 28 days, MSC slightly outperformed RC, with compressive strength of 59.7 MPa and 58.6 MPa, respectively. However, by 90 days, RC regained a slight increase reaching 67.9 MPa compared to 63.7 MPa for MSC. These results are consistent with the findings of Limeira et al. [37], who reported comparable compressive strength in concrete incorporating dredged marine sand. Moreover, Moradi and Shahnoori [18] support the feasibility of using DMS, noting that partial replacement of up to 15 % can enhance compressive strength due to improved matrix densification.

Fig. 5c shows water porosity and absorption of RC and MSC. No significant differences were observed between the two formulations. For example, the water porosity of RC is 12.9 %, while MSC exhibits a slightly higher porosity of 13.3 %. Similarly, water absorption values were comparable, with RC recording 4.9 % and MSC presenting a marginally lower value of 4.7 %. However, Gas permeability results shown in Fig. 5b indicate a significant difference: MSC exhibits significantly lower intrinsic permeability (64.3 × 10⁻¹⁸ m²) compared to RC (88.9 × 10⁻¹⁸ m²). This reduced permeability suggests a denser microstructure in MSC, potentially due to reduced pore interconnectivity or partial clogging of pore pathways. Consequently, MSC may offer enhanced resistance to gas infiltration, potentially enhancing long-term durability by limiting the ingress of aggressive agents such as carbon dioxide and chloride ions.

Moreover, the chloride content, expressed as a percentage of cement mass, in RC and MSC was analyzed using the Mohr titration method with silver nitrate, following the approach outlined by Berenguer et al. [45]. The results are shown in Fig. 5d. MSC exhibited significantly higher chloride levels (0.11 %) compared to RC (0.05 %). This increase is primarily due to the contribution of chlorides from the marine sediments, which were used as a 30 % sand replacement for natural sand and are known to contain higher chloride concentrations (Table 1). Despite this difference, both concrete formulations remain well below the maximum allowable chloride content of 1 %, by mass of cement, as specified by French standards [49] for non-reinforced concrete or concrete without corrosion-resistant embedded metals.

The findings of this study are consistent with those of Hayek et al. [22], who demonstrated that optimizing a concrete mix design with 30 % marine sediments can mitigate potential adverse effects on concrete durability. In terms of durability performance, MSC exhibits increased water porosity, likely due to the finer particle size of marine sediments; however, its reduced water absorption suggests improved water retention capacity. A key advantage of MSC is its significantly lower gas permeability, indicating a denser microstructure that may enhance resistance to environmental degradation. Nonetheless, the higher chloride content observed in MSC compared to RC underscores the necessity for further durability evaluations. To better understand long-term performance, both concrete formulations will be assessed after 42 and 70 days of immersion in seawater and filtered seawater.
<figure><img src="image_6.png" /><figcaption>**Fig. 5.** Compressive strength and durability properties of Reference Concrete (RC) and Marine Sediment Concrete (MSC) before seawater (SW) and filtered seawater (FSW) immersion. (a) Compressive strength development at 3, 7, 28, and 90 days; (b) Gas permeability; (c) Water porosity and absorption at 28 days; (d) Chloride content (% by mass of cement).</figcaption></figure>

## 5.2. Properties of concrete after immersion in seawater (SW) and filtered seawater (FSW)

### 5.2.1. Biocolonization

Biotic and abiotic surfaces immersed in seawater are quickly colonized by bacterial biofilms, which promote the development of marine biofouling within just a few days [41]. This process is influenced by many factors, including exposure conditions and surface properties such as roughness, pH, and nutrient availability [50–52]. In this study, all concrete specimens were prepared, cured, and exposed under identical conditions, and no significant differences were observed in the physical properties of the hardened concrete. The only variable was the incorporation of marine sediments. Therefore, any differences variations in biocolonization behavior can be directly attributed to the presence of marine sediments in the concrete mix.

Under filtered seawater (FSW) laboratory conditions, no bio-colonization was observed on either RC or MSC surfaces, even after 70 days of immersion (Fig. 6c). This outcome highlights the effectiveness of membrane filtration in eliminating marine fouling organisms. In contrast, under natural seawater (in-situ conditions), the results presented in Fig. 6b and c show that both RC and MSC surfaces are bio-colonized after 28 days of immersion. This surface biocolonization, which was assessed using two different techniques, wet biomass measurement and image analysis, showed a growing trend over time,

reaching a maximum at 70 days of immersion. These results are in agreement with the study conducted by Hayek et al. [41], who also observed a plateau of biocolonization after 70 days under similar exposure conditions.

A comparative analysis between RC and MSC revealed that after 70 days of immersion, MSC exhibited significantly higher biocolonization than RC (Fig. 6c). This suggests that the incorporation of marine sediments enhances biocolonization and ecological integration into the marine environment. The marine sediments used in this study contained 2.69 % organic matter, which may contribute essential nutrients that promote microbial growth and surface colonization. Similar findings were reported by Georges et al. [51], who observed enhanced bio-colonization when oyster shells were used as a fine aggregate replacement, with surface growth continuing over 360 days of immersion in natural seawater.

The potential nutrient availability from marine sediments facilitates the attachment of marine fouling organisms and accelerates colonization rates [53]. However, this nutrient enrichment may also influence the development of specific microbial species, thereby modifying natural competition within the bacterial community [54]. The early-stage formation of biofilms observed during the immersion period indicates that microbial colonization commences at an initial stage, potentially influencing the subsequent phases of biocolonization. Further research should focus on characterizing the microbial communities involved and
<figure><img src="image_7.png" /><figcaption>**Fig. 6.** Biocolonization results after immersion in seawater (SW) and filtered seawater (FSW). (a) Wet biomass evolution over time; (b) Surface biocolonization of RC and MSC after 70 days of immersion in FSW; (c) Colonization surface evolution over time for RC and MSC after 70 days of immersion in FSW; (d) Colonization surface evolution over time for RC and MSC after 70 days of immersion in SW.</figcaption></figure>

elucidating their role in biocolonization over extended immersion periods. Previous studies have demonstrated that microbial biofilms are essential for the settlement of larger marine organisms [55], with

macrofouling species such as serpulid tubeworms colonizing submerged concrete surfaces after approximately 90 days [52]. However, biofilm formation may also contribute to concrete biodeterioration, particularly

<figure><img src="image_8.png" /><figcaption>**Fig. 7.** Evolution with time of the compression strength of the reference concrete immersed in the seawater (RC SW) and in the filtered seawater (RC FSW) and the concrete designed with 30 % of marine sediment concrete immersed in the seawater (MSC SW) and in the filtered seawater (MSC FSW) at 42 and 70 days after immersion in SW and FSW.</figcaption></figure>
as concrete alkalinity decreases over time [56]. In this study, durability indicators, including compressive strength, ion accumulation (assessed by micro-XRF), and chloride diffusion, were evaluated after 70 days of immersion in both natural and filtered seawater. This dual approach enables the differentiation of the effects of sediment incorporation and biocolonization on the short-term durability of concrete in seawater (70 days).

### 5.2.2. Compressive strength after immersion in seawater

The compressive strength of concrete subjected to seawater or filtered seawater exposure is influenced by several factors including the duration of exposure, composition of the concrete, and curing conditions. Fig. 7 presents the compressive strength (MPa) of the Reference Concrete (RC) and Marine Sediment Concrete (MSC) after 42 and 70 days of immersion in seawater (SW) and filtered seawater (FSW). Each data point represents the mean value derived from three 11 × 22 cm specimens, offering a comparative evaluation of their performance under both exposure conditions. At 42 days, both RC and MSC demonstrated similar compressive strengths in SW and FSW, with values approximately 60 MPa, comparable to those observed at 28 days prior to immersion (Fig. 7a). This consistency indicates that immersion in seawater, whether filtered or unfiltered, did not significantly affect the compressive strength of either concrete type. This observation is consistent with the findings of Limeira et al. [37], who reported that the incorporation of dredged marine sediments in concrete maintained or enhanced the compressive strength compared to conventional concrete. Furthermore, Ly et al. [57] found that cement-based formulations (CEM III) exhibited superior mechanical properties, including compressive strength, compared to geopolymer-based formulations and also noted that for short immersion periods, there was no significant change in compressive strength. Over 70 days, RC exhibited a moderate increase in compressive strength under both conditions, whereas MSC maintained stable performance over time. Specifically, RC experienced an 11 % increase in compressive strength in SW and a 6 % increase in FSW between 42 and 70 d. In contrast, the MSC showed minimal variation, indicating a more stable mechanical response. This stable performance of MSC aligns with the findings of Margapuram et al. [52], who observed that concrete incorporating supplementary cementitious materials (SCMs), such as slag and fly ash, develops a denser microstructure, leading to better resistance to calcium leaching and improved retention of mechanical properties over time. In our study, MSC showed a similarly denser microstructure, as indicated by its lower permeability, which likely contributes to its stable mechanical performance. Compared to the results at 90 days before immersion (Fig. 5a), the mechanical strength of concrete slightly decreases after immersion. This reduction is more pronounced in RC (from 67.9 MPa after 90 days of curing to 58.2 MPa after 42 days of immersion in seawater). This observation was corroborated by the findings of Zhao et al. [58], who noted that seawater exposure can lead to a reduction in compressive strength, particularly in more permeable concrete types. The higher permeability of RC allows for a greater ingress of seawater ions, which can lead to chemical reactions that weaken the concrete matrix. In contrast, MSC demonstrates a more stable mechanical response, likely owing to the incorporation of marine sediments, which may enhance the resistance of concrete to seawater-induced deterioration. It is important to note that limited scientific studies have exposed concrete made with dredged sediments to seawater. This study provides valuable insights into the performance of concrete under marine conditions. Furthermore, microstructural changes in concrete exposed to seawater are minimal after three months, as observed by Margapuram et al. [52].

The presence of biofilms and macrofouling organisms could exert varying effects on concrete durability. Some studies, such as those of Bone et al. [59] and Georges et al. [60], suggest that biofouling may improve durability by forming a protective biological layer that reduces the penetration of aggressive agents like chloride (Cl⁻) and sulfate (SO₄²⁻) ions. This microbial layer can act as a physical barrier, limiting

ion diffusion and thereby slowing down degradation mechanisms. However, other studies including Hughes et al. [61], highlight the risk of biodeterioration, as certain fouling organisms can produce organic acids and metabolic by-products that alter the pH at the concrete surface. This local acidification may promote decalcification of calcium-rich phases and weaken the cementitious matrix over time. These contradictory effects reflect the complex interplay between biological colonization and chemical degradation. In parallel to biological influences, seawater ions themselves can directly affect the compressive strength of concrete. Sulfate ions (SO₄²⁻) may react with aluminates in the cement paste to form expansive products such as ettringite or gypsum, which can induce internal stresses, microcracking, and long-term strength loss [62]. Chloride ions (Cl⁻), meanwhile, can destabilize hydration products like calcium hydroxide (CH) and contribute to the decalcification of calcium silicate hydrates (C–S–H), the main binding phase of hardened concrete [63,64]. These changes lead to a weaker microstructure and reduced mechanical performance, even in non-reinforced systems.

In this study, biocolonization did not significantly influence the compressive strength of MSC. It would be interesting to monitor bio-colonization and its effect on mechanical strength over the long term to better understand these dynamics and their implications for concrete durability in marine environments.

### 5.2.3. Durability study after exposure to SW and FSW

Understanding the transport mechanisms of critical ions in marine-exposed concrete is essential for assessing its long-term durability. This study analyzed the ingress and accumulation of chloride (Cl), sulfate (S), magnesium (Mg), aluminum (Al), and silicon (Si) in reference concrete (RC) and marine sediment concrete (MSC) after 70 days of immersion in seawater (SW) and filtered seawater (FSW). Micro-XRF mapping and chloride quantification (Mohr method) provided insights into elemental distribution patterns and transport behaviors.

#### 5.2.3.1. Micro-XRF
Micro-XRF analysis of concrete cross-sections (Fig. 8) revealed distinct accumulation patterns for key elements. As shown in Fig. 8a, Mg was primarily concentrated on the concrete surface which aligns with the findings of De Weerdt et al. [65], who noted that magnesium in seawater interacts with the alkaline concrete matrix to form Mg(OH)₂ (brucite) and M-S-H (magnesium silicate hydrate). However, due to the relatively short exposure period (70 days), distinct Mg(OH)₂ precipitation was not clearly visible in the µXRF images. Slightly higher Mg accumulation was observed in RC samples, as indicated by greenish tones, though no definitive trend emerged. Over longer exposure periods, surface precipitation of Mg(OH)₂ (brucite) may occur; however, its role in influencing concrete durability remains unclear, as brucite is known to have low mechanical resistance, can be easily leached, and does not appear to impede chloride ingress [65,66]. Sulfur (S) distributions (Fig. 8c) do not display a clear diffusion front as would be expected from seawater ingress. Irregular surface concentrations are observed in both RC and MSC samples, without a consistent trend. These patterns may be related to the original material composition or to surface phenomena such as efflorescence during drying, but no definitive interpretation can be made at this stage. The higher Al and Si content in the MSC samples (Fig. 8d) aligns with the aluminosilicate-rich nature of dredged sediments. Silicon (Si) distribution (Fig. 8e) was predominantly localized around aggregates, consistent with its role in calcium-silicate-hydrate (C–S–H) formation. The aggregates particles are rich in Ca which can be expected as it is silica-limestone gravel. The RC concrete is richer in Ca (Fig. 8f) compared to the MSC concrete, which can be expected as more of the limestone rich sand was used in the RC concrete compared to the MSC concrete.

#### 5.2.3.2. Chloride ingress
Micro-XRF analysis (Fig. 8g) revealed that chloride ingress was primarily concentrated at the concrete surface, with significantly higher intensities in Marine Sediment Concrete (MSC)
<figure><img src="image_9.png" /><figcaption>**Fig. 8.** Micro-XRF elemental maps and structural analysis of marine sediments and reference concrete samples. (a) Concrete samples examined: Reference Concrete (RC) and Marine Sediment Concrete (MSC) exposed to Seawater (SW) and Filtered Seawater (FSW). (b, c, d, e, f, g) Elemental maps derived from micro-XRF analysis for key elements (Mg, S, Al, Si, Ca, Cl).</figcaption></figure>

compared to Reference Concrete (RC). This effect was particularly pronounced in samples exposed to natural seawater (SW), where both the elevated chloride content of seawater and the presence of dredged sediments contributed to increased surface accumulation. A similar trend was observed in filtered seawater (FSW), albeit with slightly lower chloride concentrations, likely due to the removal of suspended particulates and microorganisms during filtration. In contrast, RC exhibited lower chloride accumulation in both exposure conditions, indicating a lower susceptibility to chloride ingress, which may be attributed to the absence of sediment-related chlorides. To quantify chloride transport within the concrete matrix, the Mohr method was employed (Fig. 9). Before immersion, MSC exhibited (Fig. 9) a higher initial chloride content (0.114 %) than RC (0.057 %), which is attributed to the natural chlorides present in the dredged sediments used as partial aggregate replacement. After 70 days of immersion, chloride accumulation at the surface was observed in all samples, with MSC (SW) showing the highest concentration (0.1548 %), while RC (SW) exhibited (Fig. 9) a lower

value (0.1187 %). Samples exposed to filtered seawater displayed reduced chloride uptake, with RC (FSW) recording the lowest surface chloride content (0.0927 %). This trend highlights the interplay between sediment incorporation, seawater composition, and bio-colonization, where unfiltered seawater containing suspended particles and microbial communities enhances surface chloride retention, while filtration effectively limits chloride ingress. At greater depths (25–30 mm), chloride concentrations progressively decreased in all samples, confirming a diffusion-controlled transport mechanism. However, MSC (SW) maintained significantly higher chloride levels (0.1087 %) than RC (SW) (0.0556 %), suggesting that sediment incorporation enhances chloride transport and retention. A similar pattern was observed at shallower depths (5–10 mm), where MSC (SW) exhibited a chloride concentration of 0.1216 %, slightly exceeding that of RC (SW) (0.1194 %). These findings align with previous research on chloride ingress in sediment-based concretes, where increased porosity and initial chloride content were found to accelerate transport [45,67].
<figure><img src="image_10.png" /><figcaption>Fig. 9. Chloride ion penetration across depths for reference and marine sediment concrete under different exposure conditions.</figcaption></figure>

Furthermore, the observed zonation of chloride, sulfate, and magnesium ions suggests complex chemical interactions at the concrete surface, which can alter binding mechanisms and impact long-term durability [66,68]. Overall, these results highlight the durability challenges associated with incorporating marine sediments in concrete, particularly in seawater environments where suspended particles and bioactive components may enhance surface chloride retention. Although the chloride concentrations measured in MSC remain relatively low after 70 days (0.1548 % at 1 mm depth), they are approaching values typically associated with the onset of steel corrosion. According to previous studies, corrosion of reinforcement can begin at chloride thresholds ranging from 0.2 % to 0.4 % by weight of cement, depending on factors such as pH and binder composition [69]. While current levels remain below these limits, longer exposure durations could increase the risk of corrosion, particularly in reinforced applications. Future research should focus on long-term chloride transport kinetics, the role of biofilms in modifying ingress mechanisms, and potential mitigation strategies such as optimized mix designs or supplementary cementitious materials to enhance the chloride resistance of sediment-based concrete.

Moreover, the higher content of alumina (Al) and silica (Si) detected in MSC samples reflects the aluminosilicate-rich nature of the dredged sediments. These compounds may react during hydration to form additional calcium-alumino-silicate hydrates (C-A-S-H), which can refine the pore structure and help explain the reduced permeability observed in MSC. However, these same phases may also influence the binding capacity and transport behavior of chlorides and sulfates, potentially contributing to the higher surface ion retention noted in µXRF and Mohr titration analyses. These microstructural features help to explain the dual behavior observed: MSC exhibits a denser and less permeable microstructure, contributing to good short-term mechanical stability and reduced gas permeability; however, its modified chemistry and finer porosity coupled with its ability to biocolonization may increase its vulnerability to surface ion accumulation. A better understanding of these interactions is essential for optimizing mix design and predicting long-term performance in marine environments.

## 5.3. Life cycle assessment

A comparative life cycle assessment (LCA) of Reference Concrete (RC) and Marine Sediment Concrete (MSC) reveals notable differences in environmental impacts across multiple categories (Fig. 10a and b). Cement remains the dominant contributor to environmental burdens, particularly in terms of climate change impact, due to the high energy

consumption associated with clinker production. Given that cement accounts for approximately 60–80 % of concrete’s total carbon footprint, the integration of supplementary cementitious materials (SCMs) remains a pivotal strategy for improving sustainability. The partial substitution of natural sand with dredged sediment in MSC presents potential environmental benefits by reducing resource depletion and mitigating land disturbance associated with aggregate extraction. However, this approach introduces trade-offs, particularly concerning the increased reliance on chemical admixtures, such as superplasticizers, to maintain workability. The higher dosage of these admixtures contributes to elevated impacts on human toxicity and marine eutrophication, highlighting that while sediment valorization reduces aggregate extraction, the additional chemical inputs and transportation demands may offset these gains.

Transportation-related emissions further influence the overall environmental profile of MSC, particularly in categories such as ozone depletion and terrestrial acidification. Additionally, the increased use of superplasticizers in MSC contributes to higher impacts in photochemical oxidant formation and terrestrial ecotoxicity. Overall, while the incorporation of dredged sediment reduces reliance on virgin raw materials, maximizing its environmental benefits requires a holistic approach. Key strategies include localized material sourcing, optimized mix formulations, and the adoption of low-impact chemical admixtures to mitigate potential trade-offs and enhance the overall sustainability of sediment-based concrete.

### 5.3.1. Environmental impact reduction potential of sediment-based concrete

A detailed impact assessment comparing RC and MSC indicates that sediment incorporation yields environmental benefits in specific impact categories, though the magnitude of these improvements varies (Fig. 10c). Notably, the climate change impact remains largely unchanged, underscoring the dominant influence of cement production on the overall carbon footprint of concrete. While the partial replacement of sand with dredged sediment reduces upstream emissions related to aggregate extraction, its limited effect on global warming potential (GWP) highlights the necessity of integrating cement substitution strategies, such as ground granulated blast-furnace slag (GGBS) or fly ash, to achieve significant reductions in CO₂ emissions. MSC exhibits moderate reductions in freshwater eutrophication and human toxicity, suggesting that sediment utilization mitigates some of the environmental burdens associated with natural sand extraction. The most pronounced reduction appears in the marine eutrophication indicator, which in LCA terms refers to nutrient emissions to water during the production phase. In this
<figure><img src="image_11.png" /><figcaption>**Fig. 10.** Life cycle assessment. (a, b) Comparison of environmental impacts contributions between the marine sediment concrete with sand substitution of 30 % sediment (MSC) and the reference concrete (RC); (c) Comparative environmental impacts and cost for MSC (sand substitution by 30 % sediment) and the reference concrete (RC); (d) Comparison between the cost of MSC and RC for 1 m³ concrete.</figcaption></figure>

context, the valorization of dredged sediment helps divert potentially nutrient-rich materials from marine disposal routes. Smaller reductions are noted in photochemical oxidant formation and terrestrial acidification, primarily attributable to the decreased reliance on virgin aggregate extraction. However, MSC demonstrates a higher terrestrial ecotoxicity impact compared to RC, likely due to the presence of contaminants in the dredged sediment and the increased demand for chemical

admixtures, particularly superplasticizers.

Overall, the findings indicate that while sediment incorporation into concrete provides tangible environmental benefits, particularly in reducing marine eutrophication and mitigating the impacts of sand extraction, its limited effect on climate change mitigation and the observed increase in terrestrial ecotoxicity emphasize the need for a comprehensive optimization strategy. Future research should explore
advanced mix designs, alternative binder systems, and long-term performance assessments to further enhance the sustainability of sediment-based concrete.

### 5.3.2. Economic viability of sediment-based concrete

A life cycle cost (LCC) analysis reveals that the total production cost of 1 m³ of MSC is lower than that of RC (Fig. 10d). This cost reduction is primarily attributed to the partial substitution of natural sand with dredged sediment, which reduces material acquisition and processing expenses. The procurement of commercial sand involves extraction, transportation, and regulatory compliance costs, particularly in regions where sand mining is restricted. By utilizing dredged sediment—a byproduct of waterway maintenance with minimal market value—MSC reduces dependency on high-cost raw materials, leading to direct financial savings.

The economic feasibility of MSC, however, is influenced by logistical and processing factors. Although sediment itself represents a lower-cost alternative to natural sand, its overall economic viability depends on transportation distances, handling requirements, and potential pre-treatment expenses. Transport costs play a critical role in determining overall savings, as the economic advantage of sediment incorporation may be offset if sources are located far from production sites. Additionally, variations in sediment composition may necessitate higher dosages of superplasticizers, thereby increasing chemical admixture costs in MSC. These factors suggest that the economic viability of sediment incorporation is highly context-dependent, requiring careful regional supply chain assessments and mix design optimizations. Despite these considerations, the observed reduction in overall production costs indicates that sediment valorization presents a financially viable strategy for lowering concrete manufacturing expenses. Furthermore, the economic benefits of sediment utilization align with broader sustainability objectives, including resource conservation and waste minimization.

## 5.4. Eco-design of a ballast for the port of Sète

Dredged sediments are increasingly being utilized in civil engineering applications, particularly in road construction, as a sustainable alternative to traditional materials. The dredged sediments treated with Portland cement can be used as a road foundation layer [70]. In our study, we investigated the use of untreated dredged sediments. However, our research extends beyond previous work by exploring a novel application for dredged sediments: This investigation led to the design and ecological integration of an innovative ballast (Fig. 11), combining a primary structural function as a dead body for boats and an ecological function as a habitat for a target species. The image (Fig. 11) illustrates the manufacture and installation of this ballast in the port of Sète. It comprises several concrete elements, each utilizing a specific formulation. The structural components, such as the central cross, were constructed using a standard CEM I 52.5 PM, XS2, C30/37, S4 concrete, ensuring optimal resistance in demanding marine conditions.

The bottom sections, including the slabs and interlayers (Fig. 11a, b and c), incorporate MSC formulated with 30 % marine sediment in place of sand. This XS2 C30/37 concrete with S4 slump combines mechanical performance adapted to marine constraints with a circular economy approach, maximizing the utilization of local resources.

The ballast includes reinforced concrete elements and has been submerged since May 2023. It is currently monitored in situ to evaluate long-term performance under marine exposure, including potential chloride ingress and its implications for reinforcement durability. This real-scale deployment provides valuable insight into the behavior of sediment-based concrete in structural applications, particularly regarding the risk of corrosion initiation associated with exogenous chlorides present in the dredged sediment.

For the ecological aspect, the design of the ballast adheres to the principles of hydraulic transparency, bio-mimetic geometry (low height and curved shapes), and stability [71]. The concrete surfaces have been textured with silicone skins (Fig. 11a), replicating the roughness and appearance of natural rock. This biomimetic design work reproduces the

<figure><img src="image_12.png" /><figcaption>Fig. 11. Manufacture and immersion of eco-designed ballast for the port of Sète Design. (a) Manufacture and application of silicone skins to reproduce natural roughness; (b) Crosses ready for assembly; (c) Ballast ready for immersion in seawater; (d) Deployment in the port of Sète; (e) Integration and biocolonization in a marine environment; (f) Focus on cavities providing habitats for marine fauna.</figcaption></figure>
complexity of the natural environment biocolonization (Fig. 11e), while simultaneously creating habitats (Fig. 11f) that are adapted to the target species, such as sars, bass, and sea bream, identified as priority species for the region. Following production (Fig. 11c), the ballast was transported and immersed with precision (Fig. 11d). Its geometry was optimized to reduce hydrodynamic disturbance, incorporates cavities that facilitate water circulation, ensure substantial structural stability, and limit scouring of the seabed. These cavities also contribute to hydraulic transparency, essential for preserving marine currents and reinforcing the anchoring structures (Fig. 11f). Three weeks post-immersion, significant colonization of the textured surfaces by macroalgae and target species was observed, underscoring their ecological attractiveness. These results confirm that the ballast promotes early surface biocolonization under marine exposure, suggesting favorable conditions for ecological integration. However, the long-term ecological significance, particularly regarding biodiversity enhancement or habitat restoration, remains to be fully assessed.

## 6. Conclusions

The durability and sustainability of marine and coastal infrastructures are influenced by exposure to harsh environmental conditions such as chloride ingress, sulfate attack, and biocolonization. This study assessed the mechanical performance and environmental impact of marine sediment concrete (MSC) incorporating 30 % dredged marine sediments (DMS) as a partial replacement for sand. Based on the results, the following conclusions can be drawn:

* The incorporation of 30 % DMS in MSC maintained mechanical strength comparable to that of reference concrete (RC) before and after seawater exposure, with compressive strengths of 58.6 MPa for MSC and 59.7 MPa for RC at 28 days, confirming its structural viability for marine applications.

* Gas permeability measurements indicated that MSC exhibited a less connected and denser microstructure ($64.3 \times 10^{-18} \text{ m}^2$ vs. $88.9 \times 10^{-18} \text{ m}^2$ for RC), suggesting improved resistance to environmental degradation. However, its increased chloride retention highlights the need for further optimization to enhance long-term durability in aggressive marine environments. Potential effects of sulfate ions such as expansive reactions with aluminates and chloride-induced corrosion should be considered for reinforced structures.

* MSC demonstrated a higher potential for biocolonization than RC, fostering microbial and macro-organism growth. This property is particularly beneficial for eco-engineered marine infrastructures, including artificial reefs, submerged breakwaters, and offshore wind turbine foundations, where ecological integration is a key design criterion.

* Biocolonization of concrete surface at early age (up to 70 days) resulted in an increased chloride amount within the top 20 mm of the surface. Further studies should be focused on the long-term effects of this biocolonization on the chloride diffusion and the long-term durability of concrete exposed to seawater.

* Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) results confirmed that the use of DMS in MSC reduces reliance on virgin aggregates, contributes to waste valorization, and lowers overall production costs. However, the increased demand for superplasticizers and the potential presence of contaminants in the sediments introduce trade-offs that require further investigation.

Looking forward, further research is needed to enhance the long-term durability of MSC, particularly regarding chloride resistance, freeze-thaw cycles, and sulfate attack in highly aggressive environments. The integration of advanced admixtures, mineral additives, or surface treatments could provide additional protection against degradation. Additionally, large-scale field applications and long-term performance monitoring will be essential to validate the feasibility of MSC

in real-world marine infrastructure projects. While this study yields promising short-term results, it is limited by a 70–90-day exposure period. The long-term effects of ion ingress, contaminant leaching, and reinforcement corrosion require further investigation. Moreover, the potential environmental impacts of utilizing untreated sediments and chemical admixtures, particularly in relation to leaching and extended interactions with marine ecosystems, necessitate attention. Incorporating ecotoxicity testing in future research could ensure the environmental safety of large-scale applications. By bridging the gap between structural engineering, materials science, and ecological restoration, the use of marine sediment-based concrete represents a transformative step toward sustainable and resilient coastal construction solutions.

## CRediT authorship contribution statement

**Ammar Yahia:** Writing – review & editing, Conceptualization. **Klaartje de Weerdt:** Writing – review & editing, Visualization, Validation, Formal analysis, Conceptualization. **Jean-Claude Souche:** Writing – review & editing, Validation, Supervision, Resources, Project administration, Funding acquisition. **Mahmoud Hayek:** Writing – review & editing, Validation, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. **LHARTI Habiba:** Writing – review & editing, Writing – original draft, Visualization, Methodology, Formal analysis, Data curation, Conceptualization. **Marie Salgues:** Writing – review & editing, Validation, Supervision, Investigation, Formal analysis. **Tara Soleimani:** Writing – review & editing, Validation, Formal analysis, Data curation.

## Declaration of Competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

## Acknowledgements

The authors express their gratitude to the Occitanie Region (France), the Prefecture of the Occitanie Region, and the European Union for their financial support. They also extend their appreciation to IMT Mines-Alès and the University of Montpellier for their involvement and support. Special thanks go to Florian Stratta and the civil engineering internship students of IMT Mines-Alès for their valuable contributions. The authors are also thankful to Ad-OCC, as well as the staff of the ports of Camargue and Pérols, particularly Yan Roux and Willy Paramé. Lastly, they acknowledge the collaborative support of Eurovia, DTE, LRM, HSM, Microbia Environnement, and LIB Industry.

## Data Availability

The authors do not have permission to share data.

## References

[1] E. Park, Sand mining in the Mekong delta: extent and compounded impacts (mai), Sci. Total Environ. 924 (2024) 171620, https://doi.org/10.1016/j.scitotenv.2024.171620.

[2] S. Singh, R. Nagar, V. Agrawal, A. Rana, et al. Tiwari, Sustainable utilization of granite cutting waste in high strength concrete (mars), J. Clean. Prod. 116 (2016) 223–235, https://doi.org/10.1016/j.jclepro.2015.12.110.

[3] X. Meng, X. Jiang, Z. Li, J. Wang, K.M. Cooper, et Z. Xie, Responses of macroinvertebrates and local environment to short-term commercial sand dredging practices in a flood-plain lake, août, Sci. Total Environ. 631-632 (2018) 1350–1359, https://doi.org/10.1016/j.scitotenv.2018.03.086.

[4] K. Strukar, T. Kalman Sipoš, I. Miličević, et R. Bušić, Potential use of rubber as aggregate in structural reinforced concrete element – a review (juin), Eng. Struct. 188 (2019) 452–468, https://doi.org/10.1016/j.engstruct.2019.03.031.

[5] A. Kavya, et A. Venkateshwara Rao, Experimental investigation on mechanical properties of concrete with M-sand, Mater. Today. Proc. 33 (2020) 663–667, https://doi.org/10.1016/j.matpr.2020.05.774.
[6] C. Vinodhini, et al., Behaviour of concrete by partial replacement of fine aggregate with eco sand, Mater. Today. Proc. 52 (2022) 1986-1990, https://doi.org/10.1060/j.matpr.2021.11.626.

[7] V.M. Nguyen, T.B. Phung, D.T. Pham, et L.S. Ho, Mechanical properties and durability of concrete containing coal mine waste rock, F-class Fly ash, and nano-silica for sustainable development, J. Eng. Res. 11 (3) (sept. 2023) 75-86, https://doi.org/10.1016/j.jer.2023.100097.

[8] Z. Li, J. Lao, L. Wang, N.S. Lim, K.H. Tan, et S. Qian, A review on substitution of natural sand with granite fines in sustainable concrete, Constr. Build. Mater. 346 (sept. 2022) 128417, https://doi.org/10.1016/j.conbuildmat.2022.128417.

[9] B. Arulmoly, et C. Konthesingha, Pertinence of alternative fine aggregates for concrete and mortar: a brief review on river sand substitutions (juill), Aust. J. Civ. Eng. 20 (2) (2022) 272-307, https://doi.org/10.1080/14488353.2021.1971596.

[10] P. Heidari, P. Rivard, et W. Wilson, Multi-objective optimization of cement-based systems containing marine dredged sediment, août, Constr. Build. Mater. 439 (2024) 137228, https://doi.org/10.1016/j.conbuildmat.2024.137228.

[11] P. Heidari, W. Wilson, et P. Rivard, Marine dredged sediments as a partial alternative to sand in cementitious systems using particle packing optimization », Symp. Pap. 362 (juin 2024) 639-650, https://doi.org/10.14359/51741018.

[12] M. Hayek, T. Soleimani, M. Salgues, et J.-C. Souche, Utilizing fine marine sediment as a partial substitute for sand in Self-Compacting concrete specially designed for application in marine environments (mars), Sustainability 16 (6) (2024) 2538, https://doi.org/10.3390/su16062538.

[13] T. Soleimani, M. Hayek, G. Junqua, M. Salgues, et J.-C. Souche, Environmental, economic and experimental assessment of the valorization of dredged sediment through sand substitution in concrete, févr, Sci. Total Environ. 858 (2023) 159980, https://doi.org/10.1016/j.scitotenv.2022.159980.

[14] M. Benzerzour, M. Amar, et N.-E. Abriak, New experimental approach of the reuse of dredged sediments in a cement matrix by physical and heat treatment (juin), Constr. Build. Mater. 140 (2017) 432-444, https://doi.org/10.1016/j.conbuildmat.2017.02.142.

[15] G. Dorleon, S. Rigaud, et I. Techer, Management of dredged marine sediments in Southern France: main keys to large-scale beneficial re-use (avr), Environ. Sci. Pollut. Res. (2014), https://doi.org/10.1007/s11356-024-33129-9.

[16] A.E.M. Safhi, Dredged materials as construction Resource—Up-to-Date review », in Valorization of Dredged Sediments as Sustainable Construction Resources, 1st Edition., Taylor & Francis Group., CRC Press, 2022, p. 22.

[17] H. Beddaa, A.B. Fraj, et S. Ducéléroir, Experimental study on river sediment incorporation in concrete as a full aggregate replacement: technical feasibility and economic viability, déc, Constr. Build. Mater. 313 (2021) 125425, https://doi.org/10.1016/j.conbuildmat.2021.125425.

[18] S. Moradi, et S. Shahnoori, Eco-friendly mix for Roller-Compacted concrete: effects of Persian-Gulf-Dredged marine sand on durability and resistance parameters of concrete (avr), Constr. Build. Mater. 281 (2021) 122555, https://doi.org/10.1016/j.conbuildmat.2021.122555.

[19] H.E.L. Moueden, M. Amar, A. Zambon, M. Benzerzour, et N.-E. Abriak, The use of dredged marine sediment in the formulation of Air-Foam concrete (mai), Waste Biomass.. Valoriz. 13 (5) (2022) 2591-2607, https://doi.org/10.1007/s12649-021-01650-4.

[20] A.B. Slama, N. Feki, D. Levacher, et M. Zairi, Valorization of harbor dredged sediment activated with blast furnace slag in road layers, févr, Int. J. Sediment Res. 36 (1) (2021) 127-135, https://doi.org/10.1016/j.ijsrc.2020.08.001.

[21] H. Beddaa, I. Ouazi, A. Ben Fraj, F. Lavergne, et J.-M. Torrenti, Reuse potential of dredged river sediments in concrete: effect of sediment matrix, août, J. Clean. Prod. 265 (2020) 121665, https://doi.org/10.1016/j.jclepro.2020.121665.

[22] M. Hayek, Tara Soleimani, Marie Salgues, Jean-Claude Souche, et E. Garcia-Diaz, Valorization of uncontaminated dredged marine sediment through sand substitution in marine grade concrete, Eur. J. Environ. Civ. Eng. 27 (13) (oct. 2023) 4008-4025, https://doi.org/10.1080/19648189.2023.2168765.

[23] J.J. Yao, et S.H. Chu, Durability of sustainable marine sediment concrete (mars), Dev. Built Environ. 13 (2023) 100118, https://doi.org/10.1016/j.dibe.2022.100118.

[24] J. Bai, V. Chatain, et V. Laforest, Analyse du cycle de vie (ACV) d'une filière de valorisation terrestre de sediments de drainage marins variabilis, janv. 2017, Environ. Ing. énierie D. éveloppement N°73-mai (2017) 7783, https://doi.org/10.4267/dechets-sciences-techniques.3564.

[25] Md.U. Hossain, et al., Evaluating the environmental impacts of stabilization and solidification technologies for managing hazardous wastes through life cycle assessment: a case study of Hong Kong, déc, Environ. Int. 145 (2020) 106139, https://doi.org/10.1016/j.envint.2020.106139.

[26] N. Svensson, et al., Integrated cost and environmental impact assessment of management options for dredged sediment, févr, Waste Manag. 138 (2022) 30-40, https://doi.org/10.1016/j.wasman.2021.11.031.

[27] H. Zhou, W. Zhang, L. Li, M. Zhang, et D. Wang, Environmental impact and optimization of lake dredged-sludge treatment and disposal technologies based on life cycle assessment (LCA) analysis, Sci. Total Environ. 787 (sept. 2021) 147703, https://doi.org/10.1016/j.scitotenv.2021.147703.

[28] R. Hadj Sadok, N. Belas Belaribi, R. Mazouzi, et F. Hadj Sadok, Life cycle assessment of cementitious materials based on calcined sediments from chorfa II dam for low carbon binders as sustainable building materials (juin), Sci. Total Environ. 856 (2022) 154077, https://doi.org/10.1016/j.scitotenv.2022.154077.

[29] T. Soleimani, M. Hayek, G. Junqua, M. Salgues, et J.-C. Souche, Environmental, economic and experimental assessment of the valorization of dredged sediment through sand substitution in concrete, févr, Sci. Total Environ. 858 (2023) 159980, https://doi.org/10.1016/j.scitotenv.2022.159980.

[30] A.S. Hurshouse, The relevance of spection in the remediation of soils and sediments contaminated by metallic elements-an overview and examples from central scotland, UK, J. Environ. Monit. 3 (1) (2001) 49-60, https://doi.org/10.1039/b006132h.

[31] M. Amar, M. Benzerzour, N.-E. Abriak, et Y. Maminday-Pajany, Study of the pozzolanic activity of a dredged sediment from dunkirk harbour, Powder Technol. 320 (oct. 2017) 748-764, https://doi.org/10.1016/j.powtec.2017.07.055.

[32] M. Hayek, T. Soleimani, M. Salgues, Y.E. Bitouri, J.-C. Souche, et E. Garcia-Diaz, « La possibilité de valorisation des sédiments marins fins dans le matériau béton », 2022.

[33] K. Millrath, S. Kozlova, C. Meyer, et S. Shimanovich, New approach to treating the soft Clay/Silt fraction of dredged material, in Dredging '02, Orlando, Florida, United States, American Society of Civil Engineers, oct. 2003, pp. 1-10, https://doi.org/10.1061/40680(2003)138.

[34] A. Abdallah, H. Kada, et A. Amrouche, « Evaluating the Effects of Uncontaminated Marine Sediments on Hydration Kinetics and Thermo-Physical Properties of Mortars for Sustainable Construction », 2011.

[35] B.M. Sindhurashmi, G. Nayak, N.D. Adesh, V. Rao, et S.P. Dubey, Incorporating sea sand into self-compacting concrete: a systematic review (avr), Discov. Appl. Sci. 6 (4) (2024) 194, https://doi.org/10.1007/s42452-024-05826-0.

[36] A. Dehouck, R. Almar, Y. Balouin, M. Jaud, et C. Delacourt, Bathymétrie littorale par télédétection: méthodes, précision et finalités, XIèmes Journées, Les Sables d'Olonne, Editions Paralia, 2010, pp. 457-468, https://doi.org/10.5150/jngcgc.2010.054-D.

[37] J. Limeira, M. Etxeberria, L. Agulló, et D. Molina, Mechanical and durability properties of concrete made with dredged marine sand, Constr. Build. Mater. 25 (11) (nov. 2011) 4165-4174, https://doi.org/10.1016/j.conbuildmat.2011.04.053.

[38] R. Achour, R. Zentar, N.-E. Abriak, P. Rivard, et P. Gregoire, Durability study of concrete incorporating dredged sediments, déc, Case Stud. Constr. Mater. 11 (2019) e00244, https://doi.org/10.1016/j.csmc.2019.e00244.

[39] M. Amar, M. Benzerzour, J. Kleib, et N.-E. Abriak, From dredged sediment to supplementary cementitious material: characterization, treatment, and reuse, févr, Int. J. Sediment Res. 36 (1) (2021) 92-109, https://doi.org/10.1016/j.ijsrc.2020.06.002.

[40] G. Dreux, et J. Festa, Nouveau guide du béton et de ses constituants, Eyrolle, 1998.

[41] M. Hayek, M. Salgues, J.-C. Souche, E. Cunge, C. Giraudel, et O. Paireau, Influence of the intrinsic characteristics of cementitious materials on biofouling in the marine environment (mars), Sustainability 13 (5) (2021) 2625, https://doi.org/10.3390/su13052625.

[42] « NF P18-459 - Béton - Essai pour béton durci - Essai de porosité et de masse mensionale », août 2022.

[43] XP P18-463, « Bétons - Essai de permeabilité aux gaz sur béton durci », décembre 2023.

[44] M. Grzegorczyk, S.J. Pogorzelski, A. Pospiech, et K. Boniewicz-Szmyt, « monitoring of marine biofilm formation dynamics at submerged solid surfaces with multitchnique sensors », Front. Mar. Sci. 5 (oct. 2018) 363, https://doi.org/10.3389/fmar.2018.00363.

[45] R. Berenguer, et al., Verificação de penetração de cloretos em corpos de prova parcialmente imeros em água do mar em recife, pernambuco (avr), Rev. De. la Asoc. óN. Latinoam. De. Control De. Calid. Patol. ía Y. Recuper. óN. De. la ConstruçãoN. 8 (2) (2018) 108-122, https://doi.org/10.21041/ra.v8i2.195.

[46] M. Gorree et al., Handbook on Life Cycle Assessment: Operational Guide to the ISO Standards, in Eco-Efficiency in Industry and Science, no. 7. Dordrecht: Kluwer Academic Publishers, 2004, doi: 10.1007/0-306-48055-7.

[47] M.A.J. Huijbregts, et al., ReCiPe2016: a harmonised life cycle impact assessment method at midpoint and endpoint level, févr, Int J. Life Cycle Assessment. 22 (2) (2017) 138-147, https://doi.org/10.1007/s11367-016-1246-y.

[48] A. Mehmeti, A. Angelis-Dimakis, G. Arampatzis, S. McPhail, et S. Ulgiati, Life cycle assessment and water footprint of hydrogen production methods: from conventional to emerging technologies, févr, Environments 5 (2) (2018) 24, https://doi.org/10.3390/environments5020024.

[49] NF EN 206-1, « Béton Partie 1: Spécification, performances, production et conformité », avr. 2004.

[50] M. Hayek, M. Salgues, J.-C. Souche, K.D. Weerdt, et S. Pioch, « How to Improve the Bioreceptivity of Concrete Infrastructure Used in Marine Ecosystems? Literature Review for Mechanisms, Key Factors, and Colonization Effects », coas, vol. 39, n° 3, p. 553-568, mars 2023, doi: 10.2112/JCOASTRES-D-21-00158.1.

[51] L. Stohl, T. Manninger, J. von Werder, F. Dehn, A. Gorbushina, et B. Meng, Bioreceptivity of concrete: a review, J. Build. Eng. 76 (oct. 2023) 107201, https://doi.org/10.1016/j.jobe.2023.107201.

[52] D. Margapuram, et al., Short-term interactions of concrete, biofilm, and seawater in the submerged zone of marine environments for sustainable floating offshore wind turbines, Constr. Build. Mater. 451 (nov. 2024) 138840, https://doi.org/10.1016/j.conbuildmat.2024.138840.

[53] M. Salgues, M. Hayek, J.-C. Souche, et S.P. Lagam, Discussion on "Living on the rocks: substrate mineralogy and the structure of subtidal rocky substrate communities in the Mediterranean Sea, août, Acad. Lett. (2021), https://doi.org/10.20935/AL2905.

[54] R.S. McManus, N. Archibald, S. Comber, A.M. Knights, R.C. Thompson, et L. B. Firth, Partial replacement of cement for waste aggregates in concrete coastal and marine infrastructure: a foundation for ecological enhancement? Ecol. Eng. 120 (sept. 2018) 655-667, https://doi.org/10.1016/j.ecoleng.2017.06.062.

[55] P.-Y. Qian, A. Cheng, R. Wang, et R. Zhang, Marine biofilms: diversity, interactions and biofouling, Nat. Rev. Microbiol 20 (11) (nov. 2022) 671-684, https://doi.org/10.1038/s41579-022-00744-7.
[56] C.C. Gaylarde, et B.O. Ortega-Morales, Biodeterioration and chemical corrosion of concrete in the marine environment: too complex for prediction, Art. n° 10, Microorganisms 11 (10) (oct. 2023), https://doi.org/10.3390/microorganisms11102438.

[57] O. Ly, et al., Optimisation of 3D printed concrete for artificial reefs: biofouling and mechanical analysis, févr, Constr. Build. Mater. 272 (2021) 121649, https://doi.org/10.1016/j.conbuildmat.2020.121649.

[58] Y. Zhao, X. Hu, C. Shi, Z. Zhang, et D. Zhu, A review on seawater sea-sand concrete: mixture proportion, hydration, microstructure and properties, août, Constr. Build. Mater. 295 (2021) 123602, https://doi.org/10.1016/j.conbuildmat.2021.123602.

[59] J.R. Bone, A.E. Hall, R. Stafford, et R.J.H. Herbert, Inconsistent bioreceptivity of three mortar mixes in subtidal sites (juill), Ecol. Eng. 204 (2024) 107265, https://doi.org/10.1016/j.ecoleng.2024.107265.

[60] M. Georges, A. Bourguiba, D. Chateigner, N. Sebaibi, et M. Boutouil, The study of long-term durability and bio-colonization of concrete in marine environment (juin), Environ. Sustain. Indic. 10 (2021) 100120, https://doi.org/10.1016/j.indic.2021.100120.

[61] P. Hughes, et al., « microscopic study into biodeterioration of marine concrete (avr), Int. Biodeterior. Biodegrad. 79 (2013) 14–19, https://doi.org/10.1016/j.ibiod.2013.01.007.

[62] A.M. Ragab, M.A. Elgammal, O.A. Hodhod, et T.E. Ahmed, Evaluation of field concrete deterioration under real conditions of seawater attack, août, Constr. Build. Mater. 119 (2016) 130–144, https://doi.org/10.1016/j.conbuildmat.2016.05.014.

[63] J. Xiao, C. Qiang, A. Nanni, et K. Zhang, Use of sea-sand and seawater in concrete construction: current status and future opportunities, Constr. Build. Mater. 155 (nov. 2017) 1101–1111, https://doi.org/10.1016/j.conbuildmat.2017.08.130.

[64] X. Liu, P. Feng, X. Yu, et J. Huang, Decalcification of calcium silicate hydrate (C-S-H) under aggressive solution attack, août, Constr. Build. Mater. 342 (2022) 127988, https://doi.org/10.1016/j.conbuildmat.2022.127988.

[65] K. De Weerdt, W. Wilson, A. Machner, et F. Georget, Chloride profiles – what do they tell us and how should they be used? Cem. Concr. Res. 173 (nov. 2023) 107287 https://doi.org/10.1016/j.cemconres.2023.107287.

[66] U.H. Jakobsen, K. De Weerdt, et M.R. Geiker, Elemental zonation in marine concrete (juill), Cem. Concr. Res. 85 (2016) 12–27, https://doi.org/10.1016/j.cemconres.2016.02.006.

[67] K. De Weerdt, D. Orsáková, A.C.A. Müller, C.K. Larsen, B. Pedersen, et M.R. Geiker, Towards the understanding of chloride profiles in marine exposed concrete, impact of leaching and moisture content, Constr. Build. Mater. 120 (sept. 2016) 418–431, https://doi.org/10.1016/j.conbuildmat.2016.05.069.

[68] K. De Weerdt, Chloride binding in concrete: recent investigations and recognised knowledge gaps: RILEM robert L'Hermite medal paper 2021, déc, Mater. Struct. 54 (6) (2021) 214, https://doi.org/10.1617/s11527-021-01793-9.

[69] P. Castro-Borges, L. Veleva, M. Balancán-Zapata, J.M. Mendoza-Rangel, et L. A. Juárez-Ruiz, Effect of environmental changes on chemical and electrochemical parameters in reinforced concrete. The case of a tropical marine atmosphere (mai), Int. J. Electrochem. Sci. 8 (5) (2013) 6204–6211, https://doi.org/10.1016/S1452-3981(23)14753-5.

[70] A. Loudini, M. Ibnoussina, O. Witam, A. Limam, et O. Turchanina, Valorisation of dredged marine sediments for use as road material », déc, Case Stud. Constr. Mater. 13 (2020) e00455, https://doi.org/10.1016/j.cscm.2020.e00455.

[71] S. Pioch, et al., « enhancing eco-engineering of coastal infrastructure with eco-design: moving from mitigation to integration », Ecol. Eng. 120 (2018) 574–584, https://doi.org/10.1016/j.ecoleng.2018.05.034.