Blast furnace slag-based geopolymer mortars cured at different conditions: modeling and optimization of compressive strength

Abstract

The sustainable growth in construction industry is moving towards exploration of alternative cements. The current research deals with preparation of geopolymer mortars based on granulated blast furnace slag as partial replacement of cement based on using central composite experimental design. The effect of the activated alkaline binder (geopolymer/cement ratio, 8.6–86.4 wt.%) and the alkaline liquid/solid proportion (0.38–0.45) on the compressive strength and density of geopolymer mortars of age 7 days were investigated. The geopolymer mortars were cured at different conditions (ambient temperature, water curing for 6 days followed by 1 day heat curing at 80 °C and heat curing for 1 day at 80 °C after 6 days air curing at ambient temperature). The compressive strength was modeled and optimized by analyzing the experimental data using response surface methodology. The results obtained confirmed that optimum compressive strength was achieved with geopolymer/cement ratio 8.6% and liquid activator/solid 0.52. The heat curing seemed to associate with the higher compressive strength and density. New geopolymer mortars cured by heating for 1 day could be prepared with an increase of 26.6% in compressive strength compared to conventional Portland cement mortars.

Keywords:

• Geopolymer mortar
• blast furnace slag
• curing
• density
• compressive strength
• modeling
• optimization

Disclosure statement

No potential conflict of interest was reported by the author.