Model for predicting compressive strength and elastic modulus of recycled concrete made with treated coarse aggregate: Empirical approach

Utilization of coarse recycled concrete aggregates (CRCAs) in recycled concrete is one of the sustainability measures towards the promotion of a cost-effective, environmentally friendly construction industry. However, recycled concrete typically exhibits relatively inferior mechanical and durability properties. To mitigate inferior characteristics and improve the properties of CRCAs, two treatment approaches, namely: the adhered mortar removal (AMR) and adhered mortar fortification (AMF) techniques, are typically employed. The present study employed vast data from the literature to compare the properties of recycled concrete made with treated CRCAs produced using the two treatment methods. It was found that recycled concrete made with the AMF type of CRCA treatment generally performed better than those prepared using the AMR approach. Treatment of CRCAs using the AMR and AMF techniques enhanced the compressive strength values of recycled concrete by 19.6% and 23.3%, respectively. However, the cost of recycled concrete based on the AMF approach to treating CRCAs was determined to be more costly than the concrete prepared using the AMR type of CRCA treatment. Also in the present study, a new model for predicting the compressive strength and elastic modulus of recycled concrete made with treated CRCA is proposed. Validation of the model using independent data sources from various literature gave realistic predictions. The proposed model can be applied when designing sustainable concrete structures made with treated CRCAs.