CO₂ sequestration pathways in cementitious materials: Mechanisms, material synergies, and deployment challenges for low-carbon construction

• Comprehensive review of CO₂ sequestration in cementitious materials via accelerated carbonation curing (ACC) and mineral carbonation of alkaline by-products such as cement kiln dust (CKD). • ACC performance is typically enhanced under CO₂ concentrations ≥20%, relative humidity of 60–80%, temperatures of 20–30°C, and curing durations of 4–24 h, as reported across experimental studies. • Reactive binders (e.g., MgO), biochar additives, and FRP reinforcement enhance CO₂ uptake and durability performance. • Policy and market mechanisms are mapped to distinct CO₂ sequestration pathways to support industrial deployment and certification. The cement industry accounts for approximately 8% of global anthropogenic carbon dioxide emissions, underscoring the need for scalable in-material sequestration strategies. This study reviews current and emerging pathways for carbon dioxide sequestration in cement-based systems, focusing on process-based approaches such as accelerated carbonation curing and material-based strategies including mineral carbonation of alkaline byproducts like cement kiln dust and fly ash. The discussion is structured around three guiding questions: (1) how these approaches affect durability, strength development, and pore structure; (2) their economic feasibility and the role of enabling policy frameworks; and (3) optimal carbon dioxide incorporation levels that balance structural performance and environmental impact. Key findings include early-age strength gains from accelerated carbonation curing, pore densification with limited carbon dioxide diffusion, and corrosion risks in reinforced systems. Economic assessments estimate sequestration costs in the range of 25–56 United States dollars per metric ton of carbon dioxide, with particularly strong feasibility in precast concrete applications. Policy mechanisms such as carbon pricing, durability certification, and deployment subsidies are identified as critical enablers. Future opportunities include cast-in-place carbonation, low-purity carbon dioxide utilization, and life cycle-integrated curing strategies. By linking material science, engineering integration, and policy instruments, the paper outlines a comprehensive framework for advancing carbon-sequestering cement technologies in low-carbon construction.