Total recycling of waste concrete in sustainable concrete production through CO2 mineralization: Strength, durability, and corrosion issues.

CO2 mineralization technology provides a technically feasible strategy to achieve the high-value recycling of waste concrete as a carbon sink, aiming to achieve the carbon neutrality goal in the construction sector. In this study, CO2 mineralization technology was harnessed to enhance recycled aggregate (RA) and recycled powder (RP) to fully replace natural aggregate (NA) and partially replace cement, thereby developing carbonated recycled aggregate concrete incorporating carbonated RP (CRAC-CRP). The results show that the physical and mechanical properties of RA were enhanced after CO2 mineralization due to the reduction of porosity and the refinement of pore size. Furthermore, CRAC-CRP achieved 90-day compressive strength within ∼7% of natural aggregate concrete, together with a ∼16% strength gain from 28 to 90 days. Additionally, CRAC-CRP showed 4.5% lower water absorption and 24.7% lower chloride migration coefficient than recycled aggregate concrete at 90 days. Under chloride exposure, CRAC-CRP maintained more positive open-circuit potential and higher polarization resistance for 200 days, whereas depassivation occurred after 105-180 days in mixes without carbonated constituents. A cradle-to-gate life cycle assessment indicated up to a ∼33% reduction in CO2 emissions and ∼28% lower carbon intensity, together with ∼25% reduced production cost, confirming both environmental and economic advantages of this approach.