Carbonation curing-driven phase transformation and pore evolution in belite-rich cement incorporating ginkgo and maple leaf ash

This study evaluates ginkgo and maple leaf ash (GMLA), an urban biomass waste, as a supplementary cementitious material in belite-rich cement (BRC) under carbonation curing. BRC pastes incorporating 0–2 wt% GMLA were prepared and cured either in water or under accelerated carbonation for up to 28 days. Key properties including setting time, compressive strength, carbonation degree, phase assemblage, pore structure, and CO 2 uptake were systematically analyzed. The incorporation of GMLA delayed setting due to increased water demand and particle interference effects. Carbonation curing significantly enhanced compressive strength compared to water curing, achieving up to 70.8 MPa at 28 days. GMLA also led to pore coarsening and provided abundant amorphous silica nucleation sites, facilitating deeper CO 2 penetration and increased CO 2 uptake. However, binder dilution reduced calcium availability, limiting C–S–H gel formation and ultimately governing strength reduction. These results highlight a trade-off between mechanical performance and carbon sequestration efficiency.