STUDY OF THE EFFECTS OF PARTIAL REPLACEMENT OF CEMENT BY SILICA FUMES ON THE PROPERTIES OF CONCRETE

Abstract

Infrastructure development for a country is a principle development and concrete plays a vital role. Concrete is the world’s largest consuming material in the field of construction. From time immemorial research over concrete has been going on to enhance its performance and strength. Nowadays, most concrete mixture contains supplementary cementitious material (SCM) which forms part of the cementitious component. These materials are majority byproducts from other processes. The main benefits of SCMs are their ability to replace certain amount of cement and still able to display cementitious property, thus reducing the cost of using Portland cement. The fast growth in industrialisation has resulted in tons and tons of byproduct or waste materials, which can be used as SCMs such as fly ash, silica fume, ground granulated blast furnace slag, steel slag etc. The use of these byproducts not only helps to utilize these waste materials but also enhances the properties of concrete in fresh and hydrated states. Micro silica or silica fumes, a very fine non-crystalline material is very good as filler material to provide good strength In the present study, an attempt has been made to investigate the strength parameters of concrete made with partial replacement of cement by Silica Fumes. Here in the experiment an attempt has been made to increase the strength of concrete by replacing cement with 0%,5%,10%,15% and 20% of Micro silica fumes in a design mix of M35 and M40.The materials are taken from the locally available sources. Properties of hardened concrete viz Ultimate Compressive strength, Flexural strength, Splitting Tensile strength has been determined for different mix combinations of materials and these values are compared with the corresponding values of conventional concrete. The compressive strengths are checked for the mentioned design mixes. It is found that an optimum replacement of 15% of Micro silica to that of cement (by weight) increases the strength of concrete to 30%.Further addition of micro silica shows a decreasing trend.