Early strength development of self-compacting geopolymer mortar using binary and tertiary blends of industrial wastes

Abstract

The use of self-compacting concrete in construction has become unavoidable due to massive infrastructure requiring heavy reinforcement. Sustainable concrete using industrial waste as its source material proves to be a boon to any nation. This paper evaluates the effect of variation of alkaline activators like sodium hydroxide and sodium silicate on the early strength development of self-compacting geopolymer mortar. Two blends were selected for the study. The focus was on the flowability of self-compacting geopolymer mortar using binary blends of fly ash (FA) and ground granulated blast furnace slag (GGBFS) and tertiary blends of fly ash, GGBFS with Metakaolin (MK) and silica fumes (SF) at replacement of 5, 10 and 15 % with fly ash. The binary blend at 10 M NaOH gave the highest compressive strength of 22.6 MPa at 7 days of ambient curing with both the hydroxide-silicate ratios. While for the tertiary blend, the combination of FA, GGBFS and 15% SF gave the highest compressive strength of 16 MPa at 7 days at ambient curing. The early strength is most crucial factor when the said mortar is to be used for repair works. As there is lot of research going on, for use of geopolymer mortar for repair work, both binary and tertiary blends can be used as a repair materials due to early strength gain.