Effects of mix design parameters on compressive strength of high calcium fly ash geopolymer concrete

Recently, geopolymer concrete has gained much attention among researchers due to its lesser carbon footprints and better mechanical properties compared to conventional concrete. Hence, this paper aims to evaluate the compressive strength behavior of high calcium fly ash geopolymer concrete that is prepared using high calcium fly ash collected from Manjung power plant in Perak Malaysia. The test parameters included alkaline activator to binder ratio (a/b), water to binder ratio (w/b), curing condition, and curing age. The results indicated that when the alkaline activator to binder ratio (a/b) and the water to binder ratio (w/b) increased, the compressive strength of high calcium fly ash decreased. It was also found that increasing the fly ash content resulted in higher compressive strength. Furthermore, this study demonstrated that oven curing at 65 °C for 24 hours increased the compressive strength by two times than that of the compressive strength of specimens cured using the ambient temperature of (25 °C ± 2 °C). In conclusion, this study revealed that high calcium fly ash geopolymer concrete can be potentially used in civil engineering applications with economic and environmental benefits.