Improving the physical and mechanical properties of recycled concrete aggregate: A state-of-the-art review

The current state-of-the-art review indicates the need for future research to develop recycled concrete aggregate (RCA) properties like natural aggregate (NA) as specified by Indian or international codes. By improving the physical and mechanical properties of RCA, recycled aggregate concrete (RAC) may achieve more similar performance to natural aggregate concrete (NAC). RCA's physical and mechanical properties are enhanced by mechanical treatments, chemical treatments, chemical-mechanical treatments, thermal treatments, and thermomechanical treatments. Additionally, RCA is coated with supplementary cementitious material (SCM) and nanomaterials to increase its properties. RCA can be thermally treated to improve its properties while lowering its energy consumption by adjusting the treatment duration. RCA properties are altered by mechanical treatment when charges and revolutions are changed. It is possible to determine the set of charges and drum revolutions that may produce the RCA with optimal physical and mechanical properties using decision-making statistical techniques. A specific weight can be given to each physical or mechanical property of a treated RCA when evaluating its performance. The same procedure can be used for chemical-mechanical and thermomechanical treatments. It is possible to manufacture industrial RAC from the RCA produced by this procedure. It may be anticipated that RAC composed of RCA with optimized physical and mechanical properties will be more similar to NAC in terms of its physical, mechanical, and durability properties. It is also possible to improve the material properties of the treated RCA by coating them with SCMs or nanomaterials even more. The effect of SCM, nanomaterial, and fiber on the physical, mechanical, and durability properties of RAC composed of treated RCA could be studied in the future.