Influence of different treatment methods on the mechanical behavior of recycled aggregate concrete: A comparative study

Abstract

Recycling of construction and demolition waste in the concrete is considered a sustainable way However, recycled aggregates (RA) with inferior properties are produced after recycling as compared to natural aggregates. This study aims to improve the performance of RA by utilizing different treatment methods and to evaluate the properties of the resulting recycled aggregate concrete (RAC). For this purpose, five different treatment techniques of RA, such as carbonation, acetic acid immersion, acetic acid immersion with mechanical rubbing, acetic acid immersion with carbonation and lime immersion with carbonation are adopted during the study. Different mechanical tests are performed to investigate the effect of different RA treatment techniques on the mechanical properties of RAC with treated and untreated RA. Increase in split tensile strength and flexural strength along with improved stress-strain behavior of RAC is observed for treated RA as compared to untreated RA. The stress-strain behavior of RAC having RA treated through acetic acid immersion with mechanical rubbing and lime immersion with carbonation is observed very close to the stress-strain curves of natural aggregate concrete reflecting the positive impact of these RA treatment techniques on the performance of RAC. Moreover, empirical relations to predict different mechanical properties and stress-strain model of RAC with both treated and untreated RA are also developed in this work. A comparative study of the existing and proposed models with the test results indicates that the proposed relations and model can effectively predict the mechanical behavior of RAC with both treated and untreated RA.