ABSTRACT
Non-expansive soils can exhibit significant swelling when exposed to high concentrations of alkali. This study investigates the potential of novel nano calcium silicates (NCS), synthesized from granite and marble processing waste, to mitigate alkali-induced swelling in red soil (RS). Red soil, a non-swelling soil (1% swell in water), showed pronounced swelling (~15%) under 4N NaOH exposure, primarily due to clay dispersion and in-situ mineral formation. While conventional stabilizers such as fly ash (FA) and ground granulated blast furnace slag (GGBS) reduced swelling to 5% at high dosage (30%), NCS achieved superior performance with just 1.5% addition, lowering the swell to 3%. The enhanced efficacy of NCS is attributed to its high reactivity promoting pozzolanic binding and mineral polymerization, as confirmed by XRD and SEM analysis. This work introduces a sustainable and low-dosage nano-material-based solution for alkali-contaminated soil stabilization, offering a novel pathway for addressing emerging geo-environmental challenges.
