Effect of pre-conditioning on the carbonation curing characteristics of belite-rich cement paste

This study investigated the effect of pre-conditioning on the carbonation curing characteristics of belite-rich cement (BRC) paste. Before carbonation curing, the BRC paste was pre-conditioned under ambient dry and oven-dry conditions, and its physicochemical and mechanical properties were subsequently evaluated. The highest compressive strength was observed when the moisture content before carbonation curing was approximately 50%. The results suggest that CO 2 penetration alters the hydration mechanism of BRC paste and that pre-conditioning enhances both carbonation curing efficiency and overall physicochemical properties. Compared to untreated samples, pre-conditioned specimens exhibited higher compressive strength, primarily due to the removal of internal moisture, which increased the reactive surface area for CO 2 , facilitated its rapid diffusion, and promoted more uniform carbonation. Furthermore, XRD, TG/DTG, and MIP analyses revealed that pre-conditioned BRC paste contained higher amounts of ettringite and calcite after 28 days of curing, further improving its physicochemical performance. • Pre-conditioning enhances CO 2 uptake and strength of BRC paste. • BRC shows optimal carbonation at 40–50% moisture content. • Calcite formation densifies BRC pore structure and improves performance.