VALORIZATION OF ROAD CONSTRUCTION WASTE: CASE OF THE MBORO-DIOGO ROAD SECTION (SENEGAL)

Given the growing scarcity of high-quality road construction materials and persistent budgetary constraints, recycling materials from road demolition represents a relevant technical and economic alternative in Senegal. This study assesses the feasibility of separately recycling lateritic gravels from the base and sub-base layers of a pavement to be rehabilitated, with a view to reusing them as a sub-base layer in a context of expanding transport infrastructure. The materials were sampled at three boreholes (S1, S2, S3) on the Mboro–Diogo Road in Senegal and blended with raw lateritic gravels from the Keur Samba Kane quarry at three incorporation rates: 30%, 50%, and 70%. A comprehensive set of identification tests was carried out, including particle-size distribution analysis, Atterberg limits, the Proctor test, and California Bearing Ratio (CBR) index measurement. The results show that incorporating Keur Samba Kane lateritic gravels (LKSK) significantly improves the mechanical performance of the blends. The fines content decreases progressively as the incorporation rate increases, while the CBR index improves steadily, reaching up to 77 for lateritic gravels from S1 (LS1) at a 70% incorporation rate. With respect to the specifications required for a sub-base layer, the blend with 50% of LKSK appears to be the most suitable. It offers an optimal compromise between mechanical performance and plasticity stability and thus constitutes a viable solution for reusing reclaimed lateritic gravels.