Experimental Investigations of Mechanical properties on Micro silica (Silica Fume) and Fly Ash as Partial Cement Replacement of High Performance Concrete

Abstract

The 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 and fly ash concrete. This work primarily deals with the strength characteristics such as compressive, Split tensile and flexural strength. High performance concrete a set of 7 different concrete mixture were cast and tested with different cement replacement levels (0%, 2.5%, 5%, 7.5%, 10% 12.5% and15%) of Fly ash (FA) with silica fume (SF) as addition ( 0%,5%,10 % ,15% ,25and 30%) by wt of Cement and/or each trial super plasticizer has been added at constant values to achieve a constant range of slump for desired work ability with a constant water-binder (w/b) ratio of 0.30.Specimens were produced and cured in a curing tank for 3, 7, 14 and 28 days. The cubes were subjected to compressive strength tests after density determination at 3,7,14 and 28 days respectively. The chemical composition and physical composition of micro silica, FlyAsh and cement were determined. The density of the concrete decreased with increased in percentage of micro silica and Fly ash replacement up to 15%. Increase in the level of micro silica fume and Fly ash replacement between 30% to 45% led to a reduction in the compressive strength of hardened concrete. This study has shown that between 15 to 22.5% replacement levels, 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.