Stability Improvement of Oil Contaminated Soil Using Cement and Rice Husk Ash

Oil spills severely degrade soil engineering properties, reducing shear strength and making it unsuitable for construction. This study investigates stabilizing oil-contaminated clayey soils using a Portland Limestone Cement (PLC) and Rice Husk Ash (RHA) blend. Results showed optimal strength at 8% PLC with 4% RHA, improving undrained shear strength from 32.24 to 140.77 kN/m² and bearing capacity from 67.40 to 244.86 kN/m², while 8% PLC with 2% RHA optimally reduced settlement from 117 mm to 11 mm. For cost-effectiveness, 6% PLC with 8% RHA is recommended as the most economical and environmentally sustainable solution for foundation applications.