Effect of Micro Silica on The Strength of Concrete with Ordinary Portland Cement

Abstract

Concrete is the most important engineering material and the addition of some other materials may change the properties of concrete. With increase in trend towards the wider use of concrete for prestressed concrete and high rise buildings there is a growing demand of concrete with higher compressive strength. Mineral additions which are also known as mineral admixtures have been used with cements for many years. There are two tpes of materials crystalline and non crystalline. 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 gray coloured powder somewhat similar to portland or some fly ashes silica fume is generally categorized as a supplymentry cementitious material. Silica fume or micro silica was initially vied as cement rplacement material and in some area it is usually used as replaced by much smaller quantity of silica fume micro silica may 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 as a artificial pozzolans. We are adding 0%, 5%, 10%, 15% by wt of cement in concrete.