Effect of calcium nitrate on the pozzolanic properties of high early strength concrete

Abstract

Flyash based concrete poses constraint on the early strength gain and resulted in restriction for large scale utilization. The effect of accelerator on the improvement of setting properties is of much concern in recent years. In the present study the effect of calcium nitrate on setting properties of flyash concrete was investigated. Effect of accelerators on compressive, split tensile strength and flexural behavior of various concrete mixes was studied. For this purpose, four different variables of concrete mixes were considered namely F/C ratio (0.4, 0.5, 0.6 and 0.7), w/c ratio (0.3 and 0.4), replacement levels of flyash (5, 10, 15, 20, 25 and 30%), respectively and accelerator dosage (0.5 and 1%). The experimental studies showed that the effect of calcium nitrate on the setting properties was greatly improved due to increased reactivity. Further the results on the experimental investigation carried out in the laboratory on the performance indicated that high strength of concrete (52.1 MPa at 28 days) was obtained for F/C ratio of 0.6 at w/c ratio of 0.3 and an accelerator dosage of 1%. It can be also concluded that 20% of flyash with a w/c of 0.4 the strength gain results improved remarkably. Also, the water absorption test results showed a considerable reduction for the flyash based concrete specimens compared to reference concrete.© Maxwell Scientific Organization, 2013.