Carbon sequestration in cement-based materials: Fundamentals, techniques and challenges

As a major contributor to global carbon dioxide emissions, the cement industry urgently requires decarbonization. While traditional strategies primarily focus on cement substitution and energy process optimization, the relationship between carbonation potential, material performance and life-cycle climate benefits remains insufficiently integrated across applications. Carbonation offers a complementary pathway by binding CO 2 in reactive cement-based materials. Effectively harnessing this potential could enable selected cement-based systems to achieve theoretical net-zero or net-negative life-cycle carbon balances under defined system boundaries, provided that verified CO 2 uptake and substantiated substitution benefits match or exceed all associated emissions. This narrative review examines carbonation mechanisms, reactor systems and applications across raw material processing, concrete production, service and recovery. Specifically, the latest advances are elaborated from three interrelated perspectives: elucidating carbonation mechanisms, integrating technological innovations (including solid waste utilization) to expand CO 2 utilization, and assessing the life-cycle sustainability of systems with theoretical net-negative carbon potential under explicitly defined system boundaries and accounting assumptions. It connects uptake measurements with material performance, process requirements and environmental assessment. Particular attention is given to native-carbonate interference, functional equivalence, upstream processing burdens and the timing of emissions and uptake. These relationships provide a basis for evaluating carbonation pathways under practical engineering and accounting constraints.