Stabilization of Expansive Clayey Soil with Alkali Activated Binders

Expansive soil is predominantly impervious and exhibits dual nature (swelling/shrinkage) when exposed to moisture fluctuation. It is difficult to control the heave action which renders the loss of mechanical strength of such soils. The present study emphasizes on the stabilization of black cotton soil (BCS) using envirosafe alkali-activated binders (AAB) instead of traditional cement-based binders. Mineralogical and microstructural characterization for both untreated BCS and AAB-treated BCS are performed through X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier-transform infrared (FTIR) spectroscopy, and energy dispersive X-ray spectroscopy (EDS). The influences of varying percentages of AAB at different curing periods are investigated through index and shear strength properties of treated BCS. The binder treatment shows a significant improvement in geoengineering properties and aids in enhancing the CBR and unconfined compressive strength (UCS) values of BCS. The reduction in swelling and plasticity index is attributed to mineral alteration due to treatment of BCS with AAB. This study may prove to be very effective in devising an economic technique to address the problems associated with BCS.