Du et al. (2025): Multiphase carbonation engineering of RCA via CO₂-enriched cement slurry treatment: Mechanistic insights into carbonation efficiency and asphalt pavement performance enhancement
Xiaotong Du, Kui Hu, Jiahao Zhang, Jia Li, Giuseppe Carlo Marano and Tingyi Zhang, IN: Construction and Building Materials, https://doi.org/10.1016/j.conbuildmat.2025.143722
The growing demand for sustainable pavement materials necessitates innovative approaches to enhance recycled concrete aggregates (RCA), whose surface defects critically undermine asphalt bonding performance. Given its high porosity and loosely bound structure, calcium silicate hydrate (C-S-H) is identified as the primary factor undermining RCA performance and thus the key target of modification. This study proposes a CO₂-enriched cement slurry treatment under ambient conditions to engineer the RCA microstructure through controlled carbonation of C-S-H. The treatment integrates three mechanistic pathways: hydration-induced hardening of unhydrated cement phases, carbonation curing of setting slurry, and targeted carbonation of residual microstructural pores on the RCA surface.