Acid Resistance of Alkali Activated Composites Containing Waste Glass Fine Aggregate

This study examined the efficacy of waste glass cullet as a substitute materials to natural fine aggregate in alkali activated composites when exposed to H2SO4 and HCl acid solutions for one year. The changes in physical appearance, surface alkalinity, mass, mechanical strength and microstructure of the hardened samples before and after immersion in acid solutions were investigated. The findings of the experimental work indicated that the physical, mechanical and microstructural damages of the specimens due to acid attacks increased with the rise of glass aggregate percentages. This is attributed to the smooth surface texture and angularity of the glass cullet which affected the bond with the damaged paste matrix at the interfacial transition zone (ITZ) and increased the porosity. However, the acid resistance performance of the mortars containing up to 50% glass aggregate was found satisfactory when compared with the mortar without glass fine aggregate. Therefore, the use of waste glass cullet as a partial replacement of natural sand by up to 50% is considered feasible in alkali activated systems against acid exposures.