Development of Cast-in-Place FA-GGBFS-Based Geopolymer Mortar: An Experimental Study

Abstract

With the aim of developing cast-in-place geopolymer mortar hardened under ambient temperature, this study investigated the effects of the composition ratio of fly ash (FA) and ground granulated blast furnace slag (GGBFS) and various alkaline liquids on the compressive strength and density of FA-GGBFS-based geopolymer mortar. Test results clearly show that an increase in GGBFS content in FA-GGBFS-based geopolymer mortar increases the compressive strength, and at least 20% replacement of FA with GGBFS by weight can be sufficiently used as cast-in-place geopolymer mortar under ambient temperature conditions. In this study, various alkaline liquids are characterized by the molar ratios of alkaline metal Na-to-H2O and silicon-to-alkaline metal Na, which are referred to as the alkali/water ratio and silicon/alkali ratio, respectively. In each FA-GGBFS binder mixture, there is a linear relation between the compressive strength and alkali/water ratio if the silicon/alkali ratio within a the certain range.