Investigations on Micro Silica (Silica Fume) as Partial Replacement of Cement in Concrete

Now a day, we need to look at a way to reduce the cost of building materials, particularly cement is currently so high that only rich people and governments can afford meaningful construction. Studies have been carried out to investigate the possibility of utilizing a broad range of materials as partial replacement materials for cement in the production of concrete. This study investigated the strength properties of Silica fume concrete. Micro silica or silica fume is very fine non crystalline material. Silica fume is produced in electric arc furnace as a by product of the production of elemental silicons or alloys containing silicon. It is usually a white coloured powder somewhat similar to Portland or some fly ash. silica fume is generally categorized as a supplementary cementitious material. Silica fume or micro silica was initially view as cement replacement material and can be used as pozzolanic admixtures. Admixture is defined as a material other than cement water and aggregate that is used as ingredient of concrete and is added to the batch immediately before or during mixing. Pozzolanic admixtures are siliceous or aluminous material which is themselves posses little or no cementitious value but will in finely divided form and in the presence of water chemically react with calcium hydroxide liberated on hydration at ordinary temperature to form compounds possessing cementitious properties. In our experiment we are using micro silica an artificial pozzolans. We are partially replacing cement with silica fume by adding 0 %, 5 %, 7.5 %, 10 %, 12.5 % by weight of cement in concrete and comparing the compressive strength of normal concrete with silica fume replaced concrete. This study has shown that Between 5 to 10 % replacement level of cement by silica fume in concrete will develop strength sufficient for construction purposes. Its use will lead to a reduction in cement quantity required for construction purposes and hence sustainability in the construction industry as well as aid economic construction.