Improving the Engineering Properties of Sandy and Calcareous Soils Using Basalt Powder

Soil stabilization has become a crucial concern in geotechnical engineering due to the growing demand for sustainable construction practices. Conventional stabilizers such as cement and lime, although effective, are associated with significant carbon emissions and high production costs. In recent years, the utilization of industrial by-products and natural minerals has attracted considerable attention as eco-friendly alternatives. Basalt rock powder (BRP), a by-product of quarrying and stone cutting, possesses favorable physical and mineralogical characteristics that make it a potential soil stabilizer. This study investigates the effectiveness of BRP in improving the engineering behavior of sandy and calcareous soils, which are widely distributed in arid and semi-arid regions but typically lack adequate bearing capacity and stability for construction applications. Laboratory experiments, including standard Proctor compaction, unconfined compressive strength (UCS), California Bearing Ratio (CBR), and direct shear tests, were carried out on soil samples treated with different percentages of BRP (0–15%) under varying curing periods. The results demonstrated that BRP significantly enhanced soil strength, stiffness, and resistance to deformation, with optimum performance observed at around 10% replacement. In particular, UCS and CBR values increased by 20–40% after 28 days of curing, while friction angle and cohesion also exhibited noticeable improvements. These findings confirm the potential of BRP as an environmentally sustainable stabilizer that not only improves soil performance but also contributes to recycling quarry wastes and reducing the carbon footprint of geotechnical practices.