Mechanical properties of geopolymer concrete reinforced with steel fibers under ambient and elevated temperatures

Abstract— The objective of the current study to study and improve the compressive strength and tensile strength of geopolymer concrete (GPC). Ground granulate blast furnace slag (GGBFS), fly ash (FA) , and ordinary Portland cement (OPC) are used as a binder materials to develop the GPC mixes. The alkaline solution was a mixture of sodium silicate and sodium hydroxide. The binder material ratio was utilized to manufacture GPC 50% GGBFS, 40%FA, and 10% OPC. The total binder weight was 420 Kg/m3, within a constant alkali-binder proportion (0.4%), and with three volumetric ratios of steel fiber (SF). The specimens were cured at ambient temperature. The compressive strength and splitting tensile strength of GPC are evaluated at age 28 days, before and after three levels of fire exposure. The results showed that the mechanical properties enhanced by increasing the replacement ratio of SF from 0%to 1%, show an increasing in the compressive strength and tensile strength by (59% and 150%) respectively. No degradation in the residual mechanical properties was observed when exposed to fire at temperature up to 750˚c.Index Key words: Geopolymer concrete, binder materials, fly ash , ground granulate blast furnace slag, compressive strength and tensile strength.