Sustainable approach to road construction: Utilizing sand asphalt and lateritic gravel for the base course of the Daloa–Issia Road (Cote D'ivoire)

The scarcity of natural aggregates necessitates new solutions for sustainable road construction. This work evaluates the feasibility of reusing a blend of degraded sand asphalt and lateritic gravel (MESAGLA), sourced from the Daloa–Issia road (Côte d’Ivoire), as a base course material. Geotechnical tests (grading curve, Atterberg limits, Modified Proctor, CBR) were conducted to characterize this material. The results show that MESAGLA has a particle size distribution well-suited to road specifications and a satisfactory plasticity index (PI = 18.88). The optimum water content (6.21 %) and the maximum dry density (2.30 t/m³) indicate good compaction conditions. However, the measured CBR value (59 at 99 % compaction) remains insufficient for direct use in a base course, in accordance with current standards (CBR $\geq 80$). It is therefore necessary to resort to hydraulic binder stabilization or the addition of crushed aggregates to improve its mechanical performance. This approach illustrates the potential for utilizing recycled materials within a perspective of the circular economy and sustainability in highway engineering.