The processing, characterization, and properties of fly ash based geopolymer concrete

In recent years, attempts to increase the utilization of fly ash as a replacement for ordinary Portland cement (OPC) in concrete have increased in significance. Geopolymer concrete does not need the presence of Portland cement as a binder. Instead, an activating geopolymer can be utilized with an alkaline activator. Moreover, the use of fly ash is more environmentally friendly due to the reduced CO 2 emissions and costs compared to OPC, which requires the burning of large quantities of fuel and the decomposition of limestone and can result in significant CO 2 emissions. The compressive strength increases with the optimum NaOH molarity, fly ash/ alkaline activator ratio, Na 2 SiO 3 /NaOH ratio used, and curing process handled. Fly ash-based geopolymer also provides superior performance givens its better resistance to aggressive environments compared to normal concrete. This paper summarizes the current knowledge about the properties and characteristics of fly ash-based geopolymer by reviewing previous research work.