Feasibility Study of Fiber-Reinforced Dredged Reservoir Sediment for Landfill Cover Applications

Dredged reservoir sediments (DRS), generated in large volumes during dam desilting operations, pose significant stockpiling and land-use challenges in Mediterranean regions. Owing to their high fines content and moderate plasticity, these sediments present potential for reuse as compacted hydraulic barrier materials. This study evaluates the feasibility of using DRS as a liner material and, for the first time, provides a direct comparative assessment of natural (wheat straw fibers, WSF) and synthetic (polypropylene fibers, PPF) reinforcement within the same sediment matrix under liner-relevant conditions. Fiber contents of 0–0.9% (by dry mass) were investigated. Mechanical and consolidation behaviors were assessed using direct shear and oedometer tests. Fiber inclusion significantly improved shear strength, with an optimal response at 0.6%. At this dosage, PPF reduced the compression index by ~50%, while WSF provided moderate but consistent improvement. Estimated hydraulic conductivity increased slightly with fiber addition but remained within the range typically reported for compacted barrier materials. FTIR analysis indicated distinct reinforcement mechanisms, with lignocellulosic interactions for WSF and mechanical bridging for PPF. These results demonstrate that DRS can be effectively valorized as liner materials, while highlighting the contrasting performance of biodegradable and synthetic fibers, with 0.6% identified as a balance between mechanical efficiency and material sustainability.