Effect of Alkali-Activated Waste Glass Powder on the Compaction Characteristics of Synthetic Expansive Soil

This study addresses the sustainable stabilisation of expansive soil through the alkali activation of waste glass powder (WGP), aiming to enhance geotechnical performance while reducing environmental burden. A synthetic expansive soil was formulated using bentonite and calcareous soil to replicate the plasticity behaviour of Al-Qatif clay. Waste glass powder was incorporated at varying contents (0-30%) and activated with 5M sodium hydroxide to evaluate its influence on soil compaction. Standard proctor tests were performed to determine maximum dry density (MDD) and optimum moisture content (OMC). The 20% WGP dosage was identified as optimal, achieving the highest density and lowest moisture demand. The improvement was attributed to both the filler effect of fine glass particles and the geopolymerisation reactions. These findings highlight the potential of alkali-activated waste glass powder as a sustainable and effective alternative to conventional soil stabilisers. The study contributes to the broader effort to incorporate waste materials into geotechnical engineering and provides a foundation for future evaluation of strength and durability performance.