Strength Optimization of Black Cotton Soil Stabilized with Waste Glass Powder and Cement

Abstract

This study investigates the stabilization of black cotton soil (BCS) using waste glass powder (WGP) blended with cement. Black cotton soil is a problematic soil characterized by low bearing capacity and high swelling and shrinkage properties; thus, stabilization is necessary. Many agricultural lands are composed of black cotton soils, which are unsuitable for construction unless replaced or treated with appropriate materials. Civil engineering projects located in areas with soft or weak soils traditionally improve soil properties through stabilization. This study employed waste glass powder (WGP) blended with cement for the stabilization of black cotton soil (BCS) for highway construction. Central composite design (CCD) of response surface methodology was used to design the experiment and perform optimization. The experimental results showed that the optimal mixture consisted of 9.4% WGP and 4% cement, resulting in significant improvements in the soil's geotechnical properties. The optimized mixture achieved an optimum moisture content (OMC) of 11.9%, maximum dry density (MDD) of 1.47 g/cm³, and reduced linear shrinkage of 4.3%. The stabilized soil also exhibited enhanced strength, with unconfined compressive strength (UCS) values of 308.8 N/mm² at 7 days and 770 N/mm² at 28 days. Additionally, the soaked and unsoaked California Bearing Ratio (CBR) values were 42.8% and 78.3%, respectively. The findings of this study demonstrate the potential of using WGP and cement to stabilize black cotton soil, providing a sustainable and effective solution for geotechnical applications.