Sustainable Soil Reinforcement by Maximizing Geotechnical Performance with Rice Husk Ash in Subgrade Layers

Soil reinforcement using rice husk ash and cement is emerging as an effective method for enhancing geotechnical performance in subgrade layers, offering an environmentally friendly, stable, durable, and cost-efficient solution. This study investigates sustainable soil reinforcement by maximizing geotechnical performance by applying RHA in subgrade layers. Experimental evaluations were conducted using California Bearing Ratio tests, Scanning Electron Microscopy, and Energy-Dispersive X-ray Spectroscopy. The research focused on three subgrade configurations: upper, lower, and double subgrade layers, each treated with varying proportions of cement (2%, 4%, 6%) and RHA (2%, 4%, 6%). The findings demonstrated significant improvements in bearing capacity across all subgrade layers and combinations compared to untreated control specimens. Notably, the double subgrade layer with 6% RHA + 6% cement achieved the highest CBR value of 21.30 KPa, followed by the configuration with 2% RHA + 6% cement, which recorded a CBR value of 19.62 KPa. The specimen containing 4% RHA + 6% cement achieved a CBR value of 18.62 KPa. These results highlight the effectiveness of RHA as a sustainable material for enhancing geotechnical performance in soil enhancement applications.