Effect of waste glass fine aggregate on the strength, durability and high temperature resistance of alkali-activated fly ash and GGBFS blended mortar

Abstract

Properties of alkali-activated fly ash and GGBFS blended mortar using waste glass cullet were investigated. Workability of mortar was found to increase by glass aggregate due to its lower absorption than sand. Compressive strength decreased from 77 MPa to 73 MPa at 90 days of age for replacing 100% sand by glass aggregate. Though porosity increased by 1.5% to 13% for using 25% to 100% glass aggregate, reductions were observed in drying shrinkage, sorptivity and chloride permeability. The minor variations in mortar properties are attributed to the lower permeability and irregular shape of glass aggregate. Mortars using glass aggregate showed similar trend of residual strength as compared to that using natural sand after 200°C–800°C temperature exposures. Microstructural studies revealed that mortars using glass aggregate had less microcracks and enhanced bond at the interfacial transition zone (ITZ) after elevated temperature exposures. Moreover, the findings of this study suggests that the replacement of natural sand by using various percentages of waste glass cullet in alkali-activated mortar offers comparable properties to those using natural sand.