The effect of high temperature on the compressive strength of mortars

In this study, the effect of elevated temperature on the compressive strength of mortars containing fly ash, silica fume and pumice was investigated. Thirteen mortar mixtures were produced by replacing 0%, 5%, 10%, 15% and 20% of cement with a fly ash, silica fume and pumice. Totally, 3900 cube (50 × 50 × 50 mm) mortar specimens were prepared from these mortar mixtures and cured at 7, 28 and 90 days. After standard curing period, specimens were dried in a room temperature for 7 days and then exposed to temperature of 20, 150, 300, 450, 600 and 750 °C for 1 h in ceramic furnace. Afterwards, the compressive strengths of the specimens were determined. It was concluded that, compressive strengths of mortars containing pozzolan were less affected high temperature than that of control mortars.

► Compressive strengths of pozzolanic mortars (PMs) were less affected by high temperature.
► Compressive strength losses of PMs were increased with increasing temperature level.
► Strength losses of PMs under high temperature were not markedly changed with remaining time.