Review on fly ash-based geopolymer concrete without portland cement

Abstract

This paper summarizes the factors that affect the properties of fly ash-based geopolymer concrete. Alkaline activator is an important material that controls the properties of geopolymer concrete. The workability of fresh geopolymer concrete was control by alkaline activator concentration. Higher concentration had reduced the workability of geopolymer but it can be obtain again by added extra water to the mix. The range of curing temperature about 60ºC - 90ºC, within time in 24 – 72 hour, the compressive strength of concrete can be obtained about 400 - 500kg/cm2. In addition, compressive strength also can be increased when use the fly ash with higher fineness. Geopolymer concrete also provided better resistance against aggressive environment and elevated temperature compared to normal concrete. Under elevated temperature, geopolymer concrete with potassium silicate can withstand higher temperature (1200ºC) compared to sodium silicate. Size aggregate also affect the behavior of geopolymer concrete under high temperature, where it was found that aggregate with size more than 10mm is more suitable to use.