A Study on the Influence of Fly Ash and Nano-Silica on Strength Properties of Concrete

The cement consumption is directly related to the countrys infrastructure sector and thus growth is paramount in determining the development of the country. With a current production capacity of around 366 million tonnes (MT), India is the second largest producer of cement in the world. Environmental standpoint cement has a negative impact, because manufacturing it emits about a ton of greenhouse gas (CO2) into the atmosphere for every ton of cement manufactured. Production of Portland cement not only releases 7 % of the Worlds carbon dioxide, the cement industry also uses a lot of natural resources such as limestone, clay, petroleum, coal and other substances to preserve the natural resources and to reduce the pollution due to the production of cement is by limiting the cement content in the concrete without compromising the strength. There were efforts before to partially replace cement in concrete with new compounds and industry by-products. The aim of the present experimental investigation is to find the influence of combined application of Nano-Silica (NS) and Fly Ash (FA) on the strength properties of concrete. Fly Ash and Nano-Silica are used as partial replacement of cement. In the present experimental investigation the cement is partially replaced by 20 % and 30 % of Fly Ash and 1.5 %, 3 % and 4.5 % of Nano-Silica by weight. The effect of combined application of Fly Ash and Nano-Silica on compressive strength, split tensile strength, flexural strength and modulus of elasticity of M25 grade of concrete are investigated. The test results of concrete prepared using the combination of different proportions of Fly Ash and Nano-Silica are compared with that of controlled concrete. The variation of different test results of concrete prepared with various proportions of Fly Ash and Nano-Silica indicates the same trend. Based on the test results, it can be observed that concrete prepared with 20 % Fly Ash and 3 % Nano-Silica combination possesses improved strength properties compared to the controlled concrete. The increase in the various strength characteristics of concrete prepared using Fly Ash and Nano-Silica can be attributed to the effective particle packing and also the availability of additional binder in the presence of Fly-Ash and Nano-Silica.