CO2 mineralization by recycled concrete fines

It is estimated that over 10 billion tons of construction waste are generated globally on an annual basis ( Akhtar and Sarmah, 2018 ). Of this quantity, concrete waste constitutes approximately 60–70% in volume (K. Ouyang et al., 2020 ). The recycling of concrete waste into recycled concrete aggregate (RCA) represents a highly effective technique for addressing the scarcity of aggregate resources and reducing carbon emissions. Dismantled concrete is pulverized and processed into fine powders with particle sizes less than 0.075 mm (Lu et al., 2018), which is known as recycled concrete fines (RCF). Its principal composition comprises hydration products such as C-S-H, Ca(OH) 2 , AFm, and inert quartz sand (Lu et al., 2018; L. Li et al., 2022 ). Its main uses are in the preparation of recycled cement from burnt matrices or as a supplementary cementitious material (SCM) to produce concrete; the latter has been extensively studied. However, the use of RCF as SCM is limited by its rough surface, high number of micropores and microcracks, and low reactivity, which result in deterioration of the matrix microstructure and reduction of mechanical properties (Zhang et al., 2015 ; Wu, Yang et al., 2021).