Surface Stabilization of Soils Susceptible to Wind Erosion Using Volcanic Ash-Based Geopolymer

This study evaluates the surface application of a volcanic ash-based geopolymer for the stabilization of soils susceptible to wind erosion. To achieve this, the mechanical properties of different soil types treated with various geopolymeric mix designs are evaluated using unconfined compressive strength (UCS) tests. The effects of volcanic ash (VA) and alkaline activator (AA) on the stabilization of silty sand soil are analyzed for two different curing conditions and over an extended curing period of 3 to 100 days. As different types of nonplastic fine-grained soil are vulnerable to various modes of wind erosion. The effectiveness of the geopolymer in the treatment of different types of nonplastic fine-grained soils (with fines content between 0% and 100%) is assessed through the UCS tests. Furthermore, the mechanical strength of soil samples prepared by three different preparation methods is evaluated. The impact of crust thickness, activator solution quantity, and curing conditions on the erodibility and friction velocity of three different soil types (clean sand, silty sand, and silty soil specimens) are measured by wind tunnel experiments. The results show that treatment with the geopolymer can notably increase the threshold friction velocity and reduce the soil wind erodibility. It is concluded that proper determination of the geopolymer mix design requires consideration of the soil type, maximum wind speed, and ambient conditions.