Effects of different curing conditions on the long-term properties of alkali activated GBP plus GBFS mortars exposed to high temperatures

This study investigates the effects of Na concentration, steam curing and oven curing conditions on the long-term mechanical and microstructural properties of alkali activated ground basaltic pumice (GBP) and ground blast furnace slag (GBFS) mortars subjected to ambient and high temperatures. The alkali activated mortars are produced with 50% GBP + 50% GBFS as binding material. To bind these materials, liquid Na2SiO3 and solid Na (OH) as activator are used at different Na concentrations. The alkali activated GBP + GBFS mortars subjected to ambient and high temperatures are tested for unit weight, ultrasonic pulse velocity, flexural strength and compressive strength. Additionally, XRD, SEM and EDAX analyses are performed on the alkali activated GBP + GBFS mortars subjected to ambient and high temperatures. The results have shown that the higher strength values can be obtained from alkali activated GBP + GBFS mortars compared to the control mortars. Moreover, the results have shown that the strength values gradually decrease as the temperature exposed to the control mortars increases, but the strength values of alkali activated GBP + GBFS mortars up to 450 degrees C temperature gradually increase, and decrease gradually at later high temperatures.