Is CO₂ utilization in cement and concrete ready for scale-up? Mechanisms, quantification, and policy pathways

The cement industry accounts for between 5 and 8 percent of global CO₂ emissions. These emissions are difficult to cut. The base material is alkaline. This causes carbonation reactions. These reactions are converting calcium hydroxide and calcium silicate hydrate into stable carbonates. Cement helps to both emit and store carbon. In an effort to see just how prepared CO₂ use in cement and concrete is for large-scale applications, this review sets out. We look at basic processes, how well it works, and policies. At the material level, quick carbonation curing, recycling waste from industry, and creating new binders all tend to increase strength, durability, and the permanence of CO₂. Modeling, microstructure studies, and AI produce better models, overall, to better predict carbonation. CO₂ use is still challenging to quantify and verify on the systems level. This is especially concerning for service life carbonation and durability problems. For example, the EU Net Zero Industry Act, U.S. 45Q tax credits, and Green Procurement change market incentives. Such efforts in Asia show even further global reach. Carbonation can make concrete less polluting and advance net-zero goals by bridging basic science and policies.