Geopolymerization of soil by sodium silicate as an approach to control wind erosion

Abstract

Transportation of fugitive dust over long distances because of wind erosion is a severe environmental threat. Different approaches are experienced to control wind erosion, but durability and costs are the main drawbacks of existing techniques. This study hereby investigates sodium silicate usage as an alkaline additive to bind soil particles and control wind erosion. Sodium silicate is an environmentally safe material and the precipitated inorganic silica gel from which has the affinity with soil texture that makes the overall geopolymerization materials and method clean and environmentally friendly. The neutral condition of natural soils can reduce the alkalinity of sodium silicate’s alkalinity upon contact to the silica gel formation and soil geopolymerization. Different water-diluted solutions containing 50, 35, 20 wt% sodium silicate were prepared and sprayed over the soil surface while various specifications of the stabilized part were evaluated. It was found that interparticle cohesion, shear strength, and wind erosion were affected by sodium silicate content, as explained through a series of immersion, direct shear, and wind tunnel tests. A combination of mechanical and chemical forces can explain the interparticle cohesion since no chemical bonding was established between silica gel and soil particles, as described in Fourier-transform infrared spectroscopy analysis. Scanning electron microscopy coupled with energy-dispersive spectroscopy and thermogravimetric experiment displayed soil particles’ aggregation without mineralogical alteration. The achieved results implicate sodium silicate’s promising role as a stabilizer to bind the soil particles and control wind erosion.