Optimization of Clayey Ferralitic Soil Stabilization with Crushed Granite and Pulverized Ceramic Waste Through a Comparative Experimental Approach

This study investigates the synergistic stabilization of clayey ferralitic soil (bar soil) from southern Benin using a combination of crushed granite (CG) and pulverized ceramic waste (PCW). The aim was to develop a sustainable alternative to conventional high-percentage granite stabilization by valorizing industrial waste. Twelve soil mixtures were formulated with varying proportions of CG (10–25%) and PCW (7.5–12.5%). Their performance was evaluated through standardized geotechnical tests, including particle size distribution, Atterberg limits, Modified Proctor compaction, and California Bearing Ratio (CBR). The results indicate that the incorporation of PCW significantly improves the soil's properties: it reduces the fines content and plasticity index, lowers the optimum moisture content, and increases the maximum dry density and bearing capacity, yielding a CBR value as high as 78%. The optimal mixture (25% CG + 12.5% PCW) exceeded the performance of a conventional mix with 70% CG, enabling a 64% reduction in granite consumption. This approach demonstrates a technically sound and sustainable stabilization strategy, enhancing particle size distribution and hydraulic stability while providing an eco-friendly and economical solution for constructing pavement foundation and base layers in tropical regions.