An experimental investigation on properties of fly ash based geopolymer concrete incorporated with paper sludge ash

Abstract

Concrete is the construction material that is most commonly used worldwide. Among all its constituents, Ordinary Portland Cement (OPC) is the primary ingredient that binds the aggregates together. However, manufacturing OPC is an energy-intensive process. Geopolymer binder is an inorganic binder that has emerged as a new engineering material to replace the conventional Portland cement. This class of binders is termed as geopolymers, a term that was first coined by the French scientist Joseph Davidovits (1979). He defined Geopolymer Concrete (GPC) as an alkaliactivated concrete obtained by a polymeric reaction between alkaline liquids with silicon and aluminium oxides in the source materials of geological origin along with normal aggregates. The most important operation in the manufacture of GPC is curing. GPC requires heat or temperature to activate the chemical reaction that takes place in the geopolymer matrix. Paper sludge is an industrial waste generated from paper-mill industry. The calcination of paper sludge at 700 or 750 °C for two hours produces Paper Sludge Ash (PSA), a highly reactive metakaolin with pozzolanic properties. These outcomes have been affirmed by different creators in their various works.The use of PSA as a construction material is very limited, even though it has pozzolanic properties. In GPC, most of the research works have been conducted on Fly Ash (FA)-based geopolymers and occasionally on Ground-Granulated Blast furnace Slag (GGBS) and Rice Husk Ash (RHA)-based geopolymers. Moreover, current GPC applications are governed by its curing method. To meet the requirement of high temperature during maturity, it is supplied with electrical equipment that could produce hot steam or heat. This method avoids the GPC to be used in a cast in-situ concrete work newline