Utilization of CO2 curing to enhance the properties of recycled aggregate and prepared concrete: A review

In recent years, the CO2 curing technique has been developed to enhance the properties of recycled aggregate (RA) and recycled aggregate concrete (RAC), materials that can absorb the CO2 gas and are more sustainable for the construction industry. A body of literature on the CO2 curing of RA and RAC is currently available, but a systematic review is lacking. Therefore, this paper reviewed the published literatures on the use of CO2 curing to enhance the properties of the RA and prepared RAC. The studies on CO2 curing technology, the properties of carbonated recycled aggregate (CRA), and the micro-properties, workability, mechanical properties and durability performance of concrete with CRA are respectively reviewed. The results showed that the RA properties, CO2 concentration and pressure, relative humidity and curing time all had a significant impact on the properties of CRA. Carbonation treatment improved the pore structure of RA and reduced its porosity, and the workability, mechanical properties and durability performance of prepared RAC were also improved. In addition, an outlook on the CO2 curing of RA and prepared concrete was presented, and we expected that this work may inform further investigation of the use of CO2 curing to enhance the properties of concrete and cement products.