Assessing the stabilization impact of silica fume and phosphogypsum on hydro-mechanical characteristics of clayey sand

This work investigates the soil stabilization impact of adding silica fume and phosphogypsum on the hydro-mechanical behavior of clayey sand. Laboratory tests were performed on natural soil samples containing 5%, 10%, 15%, and 20% of silica fume and 3%, 6%, 9%, and 12% of phosphogypsum by weight of dry soil. The tests included particle size distribution, compaction characteristics, liquid limit, plastic limit, direct shear test, and hydraulic conductivity. The addition of phosphogypsum from 3 to 6% by weight of dry soil improved the engineering properties of the soil, resulting in an increase in the maximum dry density from 15.73 to 16.22 kN/m³. The highest shear strength of 17.91 kPa was obtained with an addition of 6% of phosphogypsum waste by the weight of dry soil. Similarly, a 10% substitution of silica fume in natural soil resulted in the highest shear strength of 20.37 kPa, providing improved resistance against liquefaction. The results show that the addition of phosphogypsum and silica fume stabilizers can be successfully used to treat clayey sand for various construction activities. The research outcomes will help engineers and construction professionals in implementing cost-effective and sustainable solutions for soil stabilization of clayey sand in practical applications.