Effect of Ternary Cementitious system on compressive strength and resistance to Chloride ion penetration

Portland cement is a highly energy intensive material. Therefore, considerable effort is being made to find substitutes for partial replacement of cement in concrete. This paper reports the results from experimental studies on the compressive strength and resistance to chloride ion penetration of concrete containing ternary blends of Portland cement, silica fume (SF) and wide range of fly ash (FA) Class C fly ash is used in this study in various proportions (i.e.) 30%, 40% and 50% and that of silica fume by 6% and 10% by weight of cement. The mix proportions of concrete had constant water binder ratios of 0.4 and super plasticizer was added based on the required degree of workability. The concrete specimens were cured on normal moist curing under normal room temperature. The compressive strength was determined at various ages and the resistance to chloride-ion penetration was measured at different ages up to 90 days. The results indicate that the concrete made with these proportions generally show excellent fresh and hardened properties since the combination is somewhat synergistic. The addition of silica fume with fly ash was found to increase the compressive strength of concrete at early age when compared to concrete made with fly ash alone. Moreover the incorporation of fly ash and silica fume in concrete increases the resistance to chloride ions and produced concrete with low permeability.