Magnesium oxide carbonation, especially the reactive magnesia (rMgO), is a new paradigm regarded as a green alternative to the traditional Portland cement. The eco-friendly nature of rMgO binder and the ability to consume industry-derived wastes during carbonation have caused it to receive significant attention in recent years as solutions are being sought for the difficulties facing the cement and construction industry. However, the reaction mechanisms and the carbonation conditions required to achieve an optimized carbonation degree and CO₂ uptake are still unclear and not fully understood. This article aimed to review previous studies that investigated the rMgO reaction mechanisms, some factors influencing the carbonation curing of rMgO-based composites, and the application of carbonated rMgO in soil stabilization. Findings revealed that rMgO hydration is a crucial aspect of the reaction process and suggests that factors such as material properties and curing conditions influence the carbonation process. The carbonation treatment utilizes sequestered CO₂ to enhance the mechanical and durability performance of carbonated rMgO composites by refining the pore structure and improving the porosity of the carbonated products. Meanwhile, utilizing hydration agents eliminates delayed hydration and improves the overall carbonation efficiency. Finally, recommendations for future research directions on the carbonation of rMgO-based composites were provided.

Carbonation of MgO-based binder and CO₂ utilization in the construction industry.