Comparative study of expansive and non-expansive soils stabilized with lime and rice husk ash (RHA)

The study focusses on comparative analysis of mechanical properties of Bentonite (expansive soil) and Kaolinite (non-expansive soil) treated with Lime and Rice Husk Ash (RHA). Unconfined Compressive Strength (UCS) tests were carried out for different curing periods of 0, 3, 7, 21 and 28 days. X-ray Diffraction and Scanning Electron Microscope tests were carried out to study the mineralogical and microstructural properties of the soil. Beyond optimum content the strength was found to decrease for all cases. In case of Lime the reduction in strength may be due to formation of the silica gel or excess Lime content beyond the optimum content may act as a lubricating agent between two-soil particle and reducing the shear resistance. In case of RHA the reduction in strength may be due to the formation of coarse particles which results in lower densities and more void formation. It was observed that UCS of Lime treatment is approximately 3 times higher than that of RHA treatment. In case of non-expansive soil, it was 3.5 times higher in Lime than RHA treatment.