Strength improvement of recycled aggregate concrete through silicon rich char derived from organic waste

Recycled aggregates obtained from construction and demolition waste is known to have lower strength performance than natural aggregate concrete. Several studies have been conducted during the past decade to reduce the adverse effects of recycled aggregates on the strength properties of recycled aggregate concrete. The present study is in continuation of the similar approach, contributing towards the improvement of the recycled aggregate concrete properties with waste derived silicon rich char as a cement replacement from 0.1 to 0.75% of total volume of concrete. Concrete was produced with 100% recycled coarse aggregates and wash-mix sand. It was observed that rice husk and enhanced poultry litter char; both improved the compressive and splitting tensile strength at 0.1% of total volume. Rice husk char at 0.1% produced highest compressive and splitting tensile strength with 17% and 3% increment respectively. On the other hand, enhanced poultry litter and rice husk at 0.75% replacement produced optimum flexural strength than the rest of char mixes. Char was also found to reduce water absorption up to 0.5% of total volume and reduced the permeable voids in recycled aggregate concrete by creating dense structure. Based on the findings, we conclude that waste derived char can potentially enhance the properties of recycled aggregate concrete with marginal amount of cement content replacement while simultaneously acting as carbon storage. (C) 2018 Elsevier Ltd. All rights reserved.