Effect of various alkaline binder ratio on geopolymer concrete under ambient curing condition

Abstract

Ground granulated blast furnace slag (GGBFS) was blended with fly ash (FA) to form binder content (B) and combined at different ratios with a solution of various alkaline activators (ALA) to make Geopolymer concrete (GPC). The ALA solution consisted of a mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH), with a stable NaOH concentration of 12 M & 14 M (Molarities) and a Na2SiO3/NaOH mass ratio from 2.5 to 3.5. The GPC mixes were prepared with different ALA/B ratios (0.3, 0.35 & 0.40). All of the mixes were cured under ambient conditions. To analyses, the impact of the ALA/B ratio on the GPC, the compressive, flexural strength and splitting tensile strengths of hardened GPC were investigated at the ages of 7, 28 and 90 days. The experimental results showed that varying the ALA/B ratio had an influence on the compressive strength of GPC. The Compressive strength was higher at an ALA/B ratio of 0.4 than at both higher and lower ratios. At this optimum ALA/B ratio, the compressive strength of up to 64.13 N/mm2 was recorded at 90 days.