This study investigates the influence of the water-to-cement ratio (W/C) on the physical, mechanical, and hydraulic properties of permeable concrete. The raw materials Portland cement, clean lagoon sand, and 5/15 mm gravel were characterized through granulometric analysis, sand equivalent tests, Los Angeles and Micro-Deval resistance, and density measurements. The sand exhibited a fineness modulus of 2.33, a curvature coefficient of 1.02, and a uniformity coefficient of 2.72, confirming its suitability for concrete production. Aggregate resistance values (Los Angeles = 28; Micro-Deval = 5) indicated satisfactory durability. Concrete mixtures were prepared with constant proportions of sand, cement, and gravel, while varying water content to achieve W/C ratios between 0.30 and 0.68. Fresh concrete properties were assessed using the Abrams cone slump test, while hardened concrete was evaluated for porosity, density, compressive strength, tensile strength, and permeability. Results showed that slump increased with W/C, ranging from stiff (0–5 cm) to fluid (>20 cm). Porosity decreased with increasing W/C, stabilizing around 12% at W/C ≥ 0.52, while density peaked at 2.43 g/cm3. Mechanical strength was maximized at intermediate ratios (0.43–0.52), with compressive strength reaching 25.8 MPa and tensile strength 3.24 MPa. Conversely, permeability was highest at low ratios (0.30–0.34, ≈10⁻6 m/s) and dropped to ≈10⁻8 m/s at higher ratios. These findings highlight a fundamental compromise between permeability and strength. For drainage applications such as sidewalks and pavements, low W/C ratios (0.30–0.34) are optimal, while intermediate ratios (0.43–0.52) are preferable for structural performance. The study confirms that tailoring W/C ratios is essential for balancing hydraulic efficiency and mechanical durability, paving the way for future optimization using alternative binders and sustainable materials.

The fundamental tool of this study is the two and three-dimensional modeling software DELFT 3D. It was used to model the hydrodynamic processes of the harbor of San-Pédro (Côte d’Ivoire) and its immediate marine environment, with the input parameters such as tidal variations in tides and river flows, as well as average annual wind speeds. Studies focused on the behavior of current fields, water level variation, and the nature of the tidal wave. The calibration of the model followed by an analysis of the literature led us to choose a coefficient of 0.03 m-1/3.s, with which the model performs very well. Current fields tend to follow the wind direction, parallel to the coast at sea, while they fit the morphology of the roadstead. At sea, currents are exclusively linear at low water, and exceptionally gyratory at flood stage in front of the San-Pedro river outlet. In the roadstead, they are gyratory and linear, alternating in some places and permanently gyratory in others. The shape of the current also depends on its speed, with a limit of 1.5 cm/s for the appearance of gyratory currents at lower speeds. The current speeds in the roadstead are between 0 and 6 cm/s while at sea they are between 5 and 11 cm/s, exceptionally between 10 and 34 cm/s in front of the outlet. As water level variations are highly dependent on tide and season, they are greater in the roadstead (4cm on average) than at sea. The wave is stationary in roadstead, with the existence of the seiche phenomenon, and progressively dominant at sea. The seiche wave determines the directions of entry and exit of water from the roadstead, with low tide corresponding to an outflow of water and high tide, a period of transition between the ingress and egress of water from the roadstead.