Coovi rocambols Thède AGBELELE^1,, Valéry k. DOKO¹, Edem CHABI², Boris GANMAVO¹, Mohamed GIBIGAYE¹

In Benin, the expansion of road infrastructure projects has led to a growing demand for quality construction materials, while conventional resources are becoming increasingly scarce. In this context, the valorization of local materials such as bar soil—which is abundant but mechanically weak—has become essential. This study investigates the geotechnical enhancement of Tori-Dokanmey bar soil through lithostabilization using crushed granite aggregates sourced from Dan. Bar soil and granite aggregate samples were collected and characterized in accordance with applicable geotechnical standards. Five mixtures were formulated with granite contents of 30%, 40%, 50%, 60%, and 70%. The results indicate that the addition of granite aggregates improves particle size distribution, lowers the liquid limit and plasticity index, increases maximum dry density, and reduces optimum moisture content. The California Bearing Ratio (CBR) shows a significant increase with higher granite contents, reaching values that meet the requirements for sub-base layers in all mixtures, and for base layers in mixtures with 60% or more granite. These findings confirm that lithostabilization of bar soil with crushed granite is an effective, economical, and sustainable solution for road construction in Benin.

Bar soil, Lithostabilization, CBR index, Granite aggregate, Plasticity