Effect of Silica Fume on the Properties of Concrete

This paper deals with the experimental works on the strength of concrete cube specimens with cement replacement by various percentages (0%, 5%, 7.5%, and 10%) of silica fume in concrete mixtures. The use of supplementary cementitious material is gaining much attention owing to its high pozzolanic property and a further improvement in strength properties. Silica-fume is one among the widely used pozzolanic material which exhibits high cementing efficiency due to high silica content. The physical properties of cement with and without silica fume replacement are tested according to ASTM. Mix design calculations for concrete mixtures with 0%, 5%, 7.5% and 10% silica fume content with constant watercement ratio 0.4 are calculated for concrete mixtures according to ACI. The target strength is 34.5 MPa. Three concrete cube specimens for each mix are prepared. After 7 days and 28 days, compressive strengths of the mortar and concrete cubes are tested. According to the test results, the concrete mix with 10% silica fume has the highest compressive strength. Overall, the strength of concrete with various replacement of silica fume enhances greater strength than the normal mix with 0% replacement.