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 mate-rials 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. Further-more, 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 appli-cation of CO2 in the production and development of construction materials were provided.