Effect of Silica Fume and Recycled Coarse Aggregate in Concrete

Abstract

Natural aggregate is being used faster than it is being made available creating a foreseeable shortage in the future. Despite this trend, the availability of demolished concrete for use as recycled concrete aggregate (RCA) is increasing. Using this waste concrete as RCA conserves natural aggregate, reduces the impact on landfills, decreases energy consumption and can provide cost savings. However, there are still many unanswered questions on the beneficial use of RCA in concrete pavements .This report aims to find the possibility of the structural usage of recycled aggregate concrete in lieu or mixed with natural aggregates, based on better understanding of behavior of recycled aggregate in concrete structures experimenting fresh and hardened concrete, mixtures containing recycled aggregates. The literature review provides an overview of sustainability and key performance indicators, the material properties of RCA both as an aggregate and in concrete, concrete mixture and proportioning designs with RCA, performance of existing RCA pavements, and the implementation of RCA highlighting some examples where RCA has been used successfully. Use of recycled aggregate (RA) in concrete can be useful for environmental protection and economical terms. Recycled aggregates are the materials for the future. It is well known fact that it is giving little lower strength than natural aggregate concrete. Though, if it is used up to 20% of replacement by weight, than it can give almost similar strength to that of natural aggregate concrete. Hence it was necessary to improve strength of recycled aggregate concrete for higher recycled aggregate content. Hence silica fume used for strength improvement.