The study focuses on the characteristics of geopolymer concrete generated by activating fly ash and GGBS as source material. As a substitute for conventional concrete, it is crucial to conduct an experimental investigation to check for long-term development and resistance to various temperatures. However, further research has been conducted on determining strength properties under elevated temperatures. Nevertheless, there is a lack of work in assessing the strength and weight loss of GPC specimens of M25 & M50 grades of concrete at various temperatures (200°C, 400°C, and 600°C) for three different times (30, 60, and 90 minutes) under air-cooling and water quenching which could be the novelty of this work. A detailed experimental program is discussed in this paper. The concentration of sodium hydroxide and SS/SH ratio (8M and 2.5) made constant throughout the work. Overall, 108 cubes were cast and tested after curing for 28 days both curing. The results demonstrated that higher temperature and longer exposure duration (600°C and 90 min) increased weight loss for M25 and M50 grades. In contrast, the compressive strength is significantly reduced at 200°C for 30 minutes for M50 quality concrete. Therefore, it could be concluded that curing and temperature change play a significant role in the strength and weight loss of geopolymer concrete specimens.

alkaline activator, compressive strength, elevated temperature, sodium hydroxide, weight loss.