Durability of fly ash based geopolymer concrete in the presence of silica fume

Geopolymer is a green cementitious material and has excellent mechanical properties, low energy in its production and emits less carbon dioxide. In this paper, the effect of silica fume on durability properties of fly ash based geopolymer concrete have been investigated by immersing the cubes in 2% sulphuric acid and 5% sodium chloride solutions. The resistance of specimens to chemical attack was evaluated visually, measuring change in the weights and percent losses in compressive strength at different intervals of time. A control mix was also cast as M40 with ordinary Portland cement concrete for comparison. Percent losses in compressive strengths in the case of control (M40) and GPC3 in 2% H2SO4 at 90 d were found 36 and 8%. Percent losses in compressive strengths in the case of control (M40) and GPC3 in 5% NaCl at 90 d were 18% and about 0%.Thus the resistance of geopolymer concrete incorporating silica fume in sulphuric acid and chloride solution was significantly higher than that of the control.