Effect of partial replacement of cement by silica fume on strength of high-strength concrete

Silica fume is a component of high-strength concrete, which is one of the most important factors in concrete strength. Silica fume is a by-product resulting from the reduction of high-purity quartz with coal, coke, and wood chips in an arc furnace during the production of silicon metal or silicon alloys. The effects of silica fume on the strength of concrete have been shown in the results of the research. Many studies have been done on concrete technology, which has led to various advances in this field. The strength of the concrete is greatly influenced by its ingredients, including silica fume. The materials used in this research can be found in Kabul, and these materials have been selected for laboratory work that can be tested by standard laboratories. In this research, the effects of silica fume on the compressive and tensile strengths of concrete have been studied. In the laboratory work, in addition to the basic ingredients such as cement, sand, gravel, and water, additional admixtures such as silica fume and superplasticizer have been used. The concrete specimen tests have been conducted according to ASTM standards. In this research, the cement is partially replaced with Silica Fume. The same concrete mixtures with different amounts of silica fume (0%, 10% and 15%). The objective of this research is to comprehensively determine the effect of silica fume on high-strength concrete. The result shows that as the amount of silica fume increases up to 10%, the compressive and tensile strengths of concrete also increase, but when the amount of silica fume increases to 15%, the compressive strength of concrete decreases but the tensile strength increases.