Improving the Shear Strength and Compressibility of Sandy Soil by Utilizing Calcined Shale and Cement

Sandy soil is one of the problematic soils due to the uniform distribution of the particles and the rounded shape of particles. These properties of soils lead to low shear strength, high compressibility, high collapsibility potential, and hard compaction. For that, Soil stabilization is mandatory for these kinds of soils. Calcium-based stabilizers have been used widely to stabilize these kinds of soils. Despite that, these materials have some challenges regarding environmental matter and possess numerous shortcomings, leading to the exploration of more effective stabilizers. Calcined shale has been used for concrete modification as a supplementary cementitious materials SCMs but never been used for soil stabilization. This study uses calcined shale as a partial replacement for cement to stabilize sandy soil. This research consists of two parts; the first part evaluates the optimum percentage of cement to stabilize the sandy soil used in this study. The second part is determining the optimum amount of calcined shale used to partially replace cement. The results revealed that 10% is the optimum dose of cement and 30% of CS is the best percentage to partially replace cement. 10% of cement reduced the consolidation by 98%. Using 30% of calcined shale as a partial replacement for cement increased the consolidation by 29% at a curing time of 7 days and reduced it by 9.2% when cured for 28 days.