Effect of elevated temperature on the mechanical strength of glass mortar

Abstract

This experimental study aimed to investigate the elevated temperature behavior of glass powder (GP) as a partial replacement of Portland cement. The residual compressive strength is an essential consideration for the sustainability of newly introduced supplementary cementitious material at elevated temperatures. For this study, the powder of waste glass was used to replace portland cement in the proportion of 0%, 10%,20%, and 30%. For fundamental understanding, the compressive strength test was carried out on samples after exposure to high temperature with two different cooling regimes. The experimental result reveals that the mortar mix with cement replaced by 20% GP for both cooling conditions retained more relative residual strength and showed sound behavior compare to the reference sample. The mortar sample with 20% glass powder replacement shows better performance with lower strength loss for both cooling regimes. For air cooling samples, the average strength loss was 27.0% compared to 31.2% of the reference sample. In water cooling samples, the average strength loss was 25.4% compared to the 30.7% reference sample. The two distinct temperature ranges were observed regarding the effect of glass powder replacement on mortar strength under elevated temperature. For temperature above 400 °C average strength loss was 38.62% in the mortar with glass powder and 35.60%in reference sample for water cooling condition. Similarly, for air-cooling samples, the average strength loss was 51.8% compared to 48.90% of the reference sample. Therefore, the lesser strength loss of mortars containing glass powder may be related with their low calcium hydroxide content.