Effect of Olivine Additive on the Shear Resistance of Fine-Grained Soils: A Sustainable Approach for Risk Mitigation and Environmental Impact Reduction

Abstract

Increasing urbanization has also accelerated the potential risks of hazards arising from problematic soils. At this end, it becomes inevitable to apply soil improvement methods, which are the most applicable and economical methods. Increasing the strength of clays, especially in undrained conditions where they exhibit low shear resistance, is essential for mitigating soil-induced hazards. This study aimed to improve the shear resistance of clays with a waste material named olivine, which has rarely been used in soils before. The undrained shear strength of the samples prepared at different curing times was determined at various confining pressures. Both olivine-added and potassium hydroxide (KOH)-activated olivine-added samples were tested in the same manner. It was proven that the olivine contribution alone was not sufficient over time, and higher shear resistance was obtained when olivine was activated with KOH. The samples treated with only olivine added to the resistance with olivine grains, whereas the samples activated with KOH added resistance with both olivine grains and chemical bonds up to a rate of 521% in the case of 20% olivine being used. Morphological and mineralogical analyses were performed to analyze the chemical bonds formed after the reaction. Stabilization with olivine substitutes a sustainable method of improvement that provides benefits such as reducing carbon dioxide emissions and controlling waste.