Shear strength and life cycle assessment of volcanic ash-based geopolymer and cement stabilized soil: a comparative study

There is a growing interest in developing environmentally-friendly substitution for Portland cement in soil stabilization. This study evaluated the feasibility of using volcanic ash (VA)-based geopolymer as an alternative soil stabilizer to cement by comparing their shear strength behavior and life cycle assessment (LCA). The effects of curing conditions, vertical confinements, binder contents, and alkali activator properties were investigated. The results revealed that regardless of the type of binder, increasing binder content changes the structure of clayey soil through aggregation, thus improves the shear resistance. The interparticle bonds developed faster at higher curing temperatures, and the interlocking of the particles increased at higher confining pressures. Based on the determined boundary conditions, the LCA suggested a comparative environmental impact for both binders to stabilize 1 m³ functional unit of clayey soil with similar shear strength.