Effect of Partial Replacement of Cement by Mixture of Glass Powder and Silica Fume Upon Concrete Strength

Abstract

All over the world the most common consuming construction material is concrete. It is well know that concrete is the combination of cement, aggregates and water. The production of cement results in the formation of carbon dioxide gas causes the environmental pollution. About 7 percent of carbon dioxide gas is evolved from cement industries to atmosphere. Keeping in view about the environmental pollution which may leads to some serious issues of health, so it is essential to use locally available pozolanic materials as a partial replacement of cement because these materials are economical as compared to Portland cement and also friendly to the environment without compromising on concrete strength. In concrete cement can be partially replaced by different supplementary cementitious materials. In the recent years pozzolonic materials, glass powder and silica fume are used in concrete as a partial cement replacement to improve the strength of concrete. In this research work the mixture of glass powder and silica fume were used in concrete as a partial cement replacement, to study its effect upon concrete strength. The mix proportion of 1:2:4 was selected for all the concrete samples with water to binder ratio of 0.55. For comparison, a control sample of concrete was prepared without mixture of glass powder and silica fume to compare it with the various samples containing different percentages of mixture of glass powder and silica fume as a partial replacement of cement in concrete. Results discovered that the usage of mixture of glass powder and silica fume in concrete as a partial replacement of cement increases the concrete strength. Such as compressive strength increases up to 8.64%, tensile strength increases up to 15% and flexural strength increases up to 7.08% at the age of 28 days. It is concluded that maximum strength is achieved at 28 days by 30 percent replacement of cement through mixture of glass powder and silica fume in concrete and the strength was decreased by increasing the mixture of glass powder and silica fume content beyond 30 percent. Therefore 30 percent replacement of cement is the optimum amount to achieve the higher strength. From the SEM analysis of concrete samples it’s proved that both the pozzolonic materials contribute in hydration process and further validated the strength test results.