Effects of elevated temperature and water quenching on strength and microstructure of mortars with river sand substitutes

• Manufactured sand and granite powder waste have been employed as river sand substitutes.
• Strength properties have been studied at elevated temperatures.
• Effect of water quenching on mechanical properties and micro structure have been evaluated.

The effect of elevated temperature and water quenching on the strength properties and microstructure of mortars containing manufactured sand (MS) and granite powder (GP) waste as river sand (RS) substitutes has been studied. Two different mortar mixtures with 15% GP waste and 100% MS were exposed to 200 °C, 500 °C, 700 °C and 900 °C for 3 h. The residual strength of these specimens was determined after cooling by water soaking or water quenching (WQ). Micro structures of mortar specimens were investigated by XRD, FT-IR and SEM analysis. Test results show that the mortar incorporating 100% MS as RS substitute exhibits the best performance at all the temperature exposures. All mortar specimens show more loss in terms of splitting tensile strength and flexural strength than compressive strength. However all mortar specimens cooled in water show severe strength loss.