The Effects of Soil Porosity and Mix Design of Volcanic Ash-Based Geopolymer on the Surface Strength of Highly Wind Erodible Soils

Abstract

Surface stabilization of loose, non-cohesive, and fine soils has always been a challenging task for geotechnical engineers. These soils show meager mechanical behavior and are very vulnerable to wind erosion. Many attempts have been made to combat wind erosion of soils. These attempts, including a variety of soil surface amendment methods, have faced complications in terms of financial efficacy, reduced long-term behavior at elevated temperatures, and limitations in stabilization of a wide range of soil types. The application of geopolymers for surface stabilization is a novel approach, which has its own challenges in terms of selecting an appropriate precursor type, mix design, and preparation method. This study evaluated the challenges of using volcanic ash (VA)-based geopolymer, through the 1 Phase (1P) method for stabilization of two silty and sandy soils. A series of uniaxial compressive strength (UCS) and penetrometer tests were performed on cylindrical specimens and soil surface-treated samples, respectively, to evaluate the resistance of treated samples with different porosities. Moreover, the rheological behavior of geopolymer paste having various binder-to-activator ratios is discussed. The available rheological characteristics of geopolymer in this study fit well with the Bingham model. It was found that, despite the minimal crust thickness formed on the topsoil, significant surface resistance is acquired. The results show notable performance of the 1P method for surface amendment of both the silty and sandy soil samples.