Investigation on Fly ash based geopolymer concrete for an alternative of Ordinary Portland Cement Concrete

Abstract

Current concerns about global warming, due to the buildup of greenhouse gases in our Atmosphere, have prompted the cement industry to investigate alternatives to ordinary Portland Cement (OPC). One ton of carbon dioxide is produced for every ton of OPC. A sustainable alternative to this OPC is low CO2 producing Geopolymer concrete (GPC). Geopolymers produce no CO2 in chemical reactions and less emitted carbon dioxide due to manufacturing techniques. Hence, GPC's have emerged as a promising alternative to conventional cement concrete in this scenario. Fly ash based Geopolymer concrete is a special type of concrete where in the C-S-H gel of cement is replaced by an inorganic polymer of alumino silicates as the binder to bind the loose aggregates and other un-reacted material together. The two main constituents of GPC are Fly ash and an alkaline activator solution (AAS) which is a combination of Sodium silicate and Sodium hydroxide. The role of AAS is to activate the geopolymeric source material and conduct the polymerization. This article discusses the detailed preparation method of Fly ash based Geopolymer concrete and comparison of GPC with Ordinary Portland Cement Concrete for their compressive strength is done. Resistance of these concretes to Acid and Sulphate environments is investigated. The results have shown that Geopolymer concrete has strengths comparable to that of cement concrete and has excellent resistance to acid and sulphate solutions.