Experimental Investigations on Fly Ash Geopolymer Mortar

Abstract

The industrial waste which is rich in silica and alumina activated with alkaline activators such as sodium silicate (NS) or potassium silicate combined with sodium hydroxide (NH) or potassium hydroxide forms geopolymer cement. The present investigation aims to utilize the fly ash in an innovative way that is to activate it using alkaline activators. The use of environmentally friendly cement can reduce greenhouse effect, solve disposal problems, and improve waste utilization. The main objective of this study was to investigate the effects of activator and curing conditions on the compressive strength and microstructure of alkali-activated fly ash mortar or geopolymer mortar. Two different activators were used to activate the binder such as NS and NH solutions. Six separate mixes were designed with different NaOH concentrations (8M–18M). Furthermore, the effect of the solution-to-binder ratio on the compressive strength (CS) of fly ash (FA) geopolymer mortar (GPM) was investigated. The outcome of the present study revealed that the compressive strength was found to be enhanced with NaOH concentration up to 14M, and after that, this strength reduced. Further, the compressive strength was increased up to solution-to-binder ratio of 0.6, and beyond that, this strength decreased. Heat-cured specimen was more strengthened than ambient-cured specimen.