Mechanical properties of silica fume concrete designed as per construction practice

Abstract

The effect of silica fume (SF) on the compressive, flexural and tensile splitting strengths of hardened concrete is studied. Seven concrete mixes are prepared using Portland slag cement (PSC) partially replaced with SF ranging from 0 to 30%. The mix proportions were obtained as per the construction practice at the site with 10% excess cement when SF is used. The optimum doses of SF for the maximal values of compressive, tensile splitting and flexural strengths at 28 d are determined. The results of this study are compared with similar results associated with the Portland cement available in the literature. A correlation, in the form of simplified equations, between the compressive, tensile splitting and flexural strengths of SF concrete and PSC is obtained. Ultrasonic pulse velocity (UPV) tests are carried out on all concrete specimens at 28 d before conducting the compression test. A relationship between UPV values and compressive strengths is proposed for SF concrete with PSC based on the experimental data.