Repairing of concrete structures using nano-silica concrete

Abstract

The application of nano-particles have proven their efficacies in different domains of science such as chemial industry, engineering, medicines and many more. Numerous studies have been conducted to enhance cement concrete through various techniques. The incorporation of silica-nano-particles (SNPs) into cement concrete has been shown to be of significant importance, conferring desirable properties. Multiple investigations have been conducted in this regard. This research primarily aims to determine the optimal percentage of SNPs for replacing ordinary portland cement (OPC) in concrete to achieve the most desirable attributes, such as strength, durability, and the production of calcium-silicate-hydrate Gel (C-S-H). Such modified concrete holds substantial potential for use in the retrofitting and repair of critical concrete structures. In this study, OPC 43 grade cement is partially substituted with silica-nano-particles within the range of 2-5% to formulate M30 concrete mix (IS 10262:2009, IS 456:2000) & results are obtained for 3, 7 & 28 days behaviour. The concrete test Samples & control samples are tested for compressive strength, scanning electron microscopy(SEM) has also been performed for the chemistry of C-S-H Gel production and results are compared. As it is very well known that C-S-H’s are the main products of the hydration of portland cement and is primarily responsible factor for the strength in cement concrete. The findings reveal that the partial replacement of OPC cement with 4% SNPs yields the most favorable outcomes in terms of strength and a denser matrix. Considering that cement is the most extensively used material in the construction industry, its replacement is being explored due to the environmental impact associated with cement manufacturing, including the release of CO2 emissions and greenhouse gases (GHG), thereby contributing to global climate change. The estimated carbon footprint is approximately 915 kilograms of CO2 emitted per 1000 kilograms of cement production.