Sustainable Performance Optimization of Lateritic Soil Stabilized With Rice Husk Ash and Cow Bone Ash using Response Surface Methodology

Abstract

Lateritic soils, common in tropical regions and widely used in roadworks, often exhibit high plasticity, low strength, and volume instability, which restrict their direct use in load-bearing applications. The aim of this study is to optimize the sustainable performance of lateritic soil stabilized with rice husk ash (RHA) and cow bone ash (CBA) using response surface methodology (RSM). This study involved the collection and characterization of lateritic soil, RHA, and CBA, followed by evaluating the geotechnical performance of the stabilized soil. Furthermore, statistical optimization was conducted to determine optimal stabilization conditions using response surface methodology (RSM). The natural moisture content and geotechnical properties for the natural soil showed LL, PL, PI, SL, MDD OMC, CBR, UCS, and shear strength values of 47%, 25%, 22%, 5.5%, 1.65 g/cm³, 9.12%, 33.15%, 132 kN/m², and 67 kN/m², respectively. The properties of the modified soil include LL, PL, PI, and SL values ranging from 46–57%, 25–44%, 5–22%, and 5.5% respectively. The MDD and OMC values ranged from 1.32–1.65 g/cm³ and 9.12–25.19%. Furthermore, the CBR values ranged from 33.15–122.14%, UCS values from 132–264 kN/m², and shear strength values from 67–132 kN/m². The stabilization of lateritic soil with RHA and CBA significantly enhanced its strength, compaction, and load-bearing properties compared to the natural soil. Improvements in CBR, UCS, and shear strength demonstrate their effectiveness as sustainable stabilizers. It is recommended that RHA and CBA be adopted in pavement and subgrade applications, with optimal mix ratios carefully considered.