A Study on Partial Replacement of Cement by Micro Silica and Sand by Copper Slag in Self Compacting Concrete

The extensive use of concrete in infrastructure leads to depletion of natural resources and also effects the environment. The aim of the present study is to evaluate the effect of replacing cement with micro silica and fine aggregate with copper slag in self compacting concrete. For this study M30 grade self compacting concrete is prepared and is evaluated for fresh concrete properties and hardened concrete properties like compressive, split tensile and flexural strength. Ordinary portland cement is replaced with micro silica at 0, 4, 8 and 12 %, while the fine aggregate is replaced with copper slag at 0, 20, 40 and 60 % by weight. The compressive, split tensile and flexural strength properties are compared among all the mixes at periods of 7, 28 and 56 days. The results show that the use of micro silica and copper slag improves the mechanical properties of concrete. The optimum results were observed at 8 % and 40 % replacements of micro silica and copper slag respectively. The increase in compressive strength at 28 and 56 days was found to be 14.9 % and 10.8 %, which is 42.4MPa and 45.1MPa when compared to the nominal mix which is 36.9MPa and 40.7MPa respectively.