Emerging CO₂ utilization technologies for construction materials: A review

The construction industry is a major contributor of CO₂ emissions. Carbonation, involving the reaction of CO₂ with alkaline reactants, immobilizes CO₂ into thermodynamically stable carbonates used in construction materials such as concrete and aggregates. The utilization of CO₂ in construction materials is considered as one of the most promising routes for carbon sequestration, with a $400 billion market opportunity and a potential to reduce annual CO₂ emissions by up to 3 Gt by 2030. This paper reviews the current status of the utilization of CO₂ in construction materials from the perspective of scientific research and commercial applications. The explanation of the fundamental carbonation reaction mechanisms was extended to cover different binder systems involving Portland cement, non-hydraulic calcium silicate, industrial solid wastes and magnesium-based materials. Factors affecting the kinetics of the carbonation reaction and properties of the final products were reviewed. Furthermore, the current state of research and commercial initiatives involving the utilization of CO2 in the production of various building components were presented. Finally, key issues regarding the challenges faced in the scaling up of CO₂ utilization technologies from the perspective of academia, industry and relevant regulatory bodies were highlighted. Recommendations to address the current utilization dilemma and promote large-scale application of CO₂ in the production and development of construction materials were provided.