Impact of Biocompatible Nanosilica on Green Stabilization of Subgrade Soil

This study reports the synthesis and potential application of biocompatible silica nanoparticles for subgrade soil stabilization. Nanosilica preparation as a major component from wheat husk ash is systematically studied and confirmed by FTIR, ICP, XRD, and TEM analyses. The produced biogenic nanosilica showed an amorphous structure with an average size of 20 nm. Upon loading various green nanosilica contents, our results show an improvement in the key parameters including Atterberg’s limits, maximum dry density, optimum water content, and shear strength of treated soil. Under optimal loading condition, the nanosilica-mediated soil analyses reveal a significant increase in the plastic and liquid limits by factors of 1.60 and 1.24 whereas plasticity index is declined by a factor of 0.78 rather than untreated soil specimen. The treated soil demonstrates a superior increase in the angle of internal friction, cohesion, shear strength, and maximum dry unit weight by factors of 2.17, 3.07, 2.21 and 1.5, respectively. The California Bearing Ratio (CBR) strength of nanosilica-cured soil presents a substantial increase by a factor of 5.83 higher than the corresponding original subgrade soil. We obtained the maximum increase in strength parameters of modified soil at the optimum biogenic nanosilica content of 1.5%.