This work aims to reveal the effects of zeolite on properties of fly ash based geopolymer under high temperature at 300 °C, 600 °C and 900 °C. The specimens were prepared by alkali activation of fly ash, which was partially replaced by two different types of zeolite at 10%, 20% and 30% by weight. The specimens were analyzed for the maximum compressive strength, weight loss percentage, XRD and SEM. The results highlighted that the percentage of weight loss increased with the ratio of zeolite replacement. The compressive strength of geopolymer with synthetic zeolite and natural zeolite at 7, 28, 60 days were similar. The high-temperature exposure resulted in the reduction in compressive strength in all proportions. At the same temperature, compressive strength of all specimens were not significantly different.
