Aeolian Sand Stabilization using Metakaolin and Calcium Carbide Residue as an Alkaline Activator

Stabilizing weak and poorly graded soils in engineering projects is commonly achieved using lime and cement. However, the cement production process requires significant energy and generates a substantial volume of carbon dioxide, which presents considerable environmental risks. As an alternative to cement and lime, alkali-activated aluminosilicates have gained recognition due to their cost-effectiveness and environmental compatibility. This study aims to investigate the feasibility of utilizing metakaolin as a stabilizing agent for sandy soil, with Calcium carbide residue (CCR) serving as an alkaline activator. To this end, factors such as the concentration of alkaline activator, metakaolin content, curing time, and temperature of treated soil samples were examined through unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests. The results were then compared to those of sand stabilized with Portland cement. Furthermore, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to analyze the microstructures formed during the soil stabilization process. The findings indicate a significant increase in the stabilized soil samples' compressive strength and ductile behavior. Moreover, the analysis of the developed microstructures in the stabilized soil samples demonstrates a noticeable bond between the binding gel and sand particles and the filling of intergranular space with alkali-activated binding gel. Overall, the findings of the present study suggest that the introduced binding gel has the potential to be an environmentally compatible stabilizing agent for stabilizing sandy soils.