Thermal insulating and fire resistance performances of geopolymer mortar containing auto glass waste as fine aggregate

Abstract

This research investigates the use of auto glass waste (AGW) as fine aggregates to improve the thermal insulation and fire resistance properties of the high-calcium fly ash geopolymer mortar. The AGW was used to replace natural sand (NS) at 0%, 20%, 40%, 60%, 80%, and 100% by volume. The physical and mechanical properties of geopolymer mortars containing AGW before and after elevated temperature exposure at 300, 600, and 900 °C were evaluated. The results indicated that the incorporation of AGW had a slight effect on the workability and strength of geopolymer mortars, but a significant improvement in the thermal insulating and fire-resistant characteristics. Although the increase in AGW volume led to a decrease in the compressive strength, the use of 100% AGW provided an acceptable 28-day compressive strength of 84% compared with the geopolymer mortars containing only NS. The incorporation of 100% AGW resulted in the thermal insulating mortar which was a very low thermal conductivity of 64% of NS mortar. The fire-resistant mortar at 900 °C exposure with the highest relative compressive strength of 218% and compressive strength of 113 MPa was obtained with 100% AGW. This research provides the reference for the application of AGW as a fine aggregate replacement to produce fly ash geopolymer mortar as green building materials with excellent thermal insulating and fire-resistant applications.