Present study considers structural characterization of sub-grade soil to increase the strength of soil for road. The present investigation has been carried out with agricultural waste materials like Rice Husk Ash individually mixed with soil and also in combination with different percentage of Hydrated Lime. Structural and mechanical characterization of the investigated samples was performed by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Standard Proctor Test, Unconfined Compression Test, California Bearing Ratio (CBR)Test. It was observed that increase of strength may be due to the reduction of mica in the soil sample. Increase of the silica in the soil sample finally increases the strength and stability. Microstructural study revealed that the mica phase may play very important role for maintaining the strength and stability of the soil.
