Experimental Studies and Sustainability Assessments of Quarry Dust for Chemical Treatment of Expansive Soils

Abstract

Civil infrastructure constructed on expansive soils undergoes distress and loss of serviceability because of damage caused by moisture-induced volumetric changes. Traditional stabilization methods that employ calcium-based stabilizers are widely used mitigate the volume change-related distresses, but they increase the carbon footprint and emission of greenhouse gases during production and construction stages, compromising the treatment’s sustainability. This research study was designed to use silica-rich waste products, such as a quarry dust admixture with a calcium-based stabilizer, to enhance the performance of problematic soils and improve the sustainability of the system. An array of engineering tests, including unconfined compressive strength tests before and after moisture conditioning, one-dimensional free swell tests, and linear shrinkage tests, were performed on untreated and treated soils. Test results showed that the utilization of quarry dust as a co-additive significantly improved the strength and durability of the soil and reduced the shrink-swell potential to a greater extent than lime treatment alone. The sustainability assessment was then performed, which showed that the application of quarry dust can be considered a sustainable alternative that helps reduce the geoenvironmental problems related to handling and stockpiling waste products in landfills. Overall, silica-rich waste products have the potential to be appropriate and sustainable additives that work well with a traditional calcium-based stabilizer to modify expansive soil.