Effect of discontinuous curing and ambient temperature on the compressive strength development of fly ash based Geopolymer concrete

In the current study, 6 mixtures of Geopolymer concrete have been studied. The effect of discontinuous curing in oven and in atmosphere ambient temperature has been inspected by exposing the Geopolymer concrete specimens to temperature in the oven for few hours then stopping the oven to let it cool down to the ambient temperature. The compressive strength test of 100x200 mm cylindrical specimens for each mixture has been performed at different ages. It was found that the ambient temperature has vast effect on the compressive strength of the Geopolymer concrete in discontinuous curing. Discontinuous curing saves energy and can be a good replacement to the continuous curing when the ambient temperature is 40°C or more. Specimens that were cured continuously in ambient temperature of 43°C has resulted in compressive strength of 23 MPa at age of 40 days; to enhance the compressive strength, it is advised to impose few hours of discontinuous oven curing. It was also found that the rest period (starts when pouring concrete in forms and ends when imposing oven curing to the Geopolymer) has a positive influence on the compressive strength of Geopolymer concrete, but when no rest period is allowed, the later ages compressive strength is remarkably higher.