A review of carbon dioxide removal through concrete carbonation: key parameters and life cycle assessment

Abstract Industrial sectors, especially those with significant global CO 2 emissions like the cement and concrete industries, are striving to achieve net-zero emissions by 2050. It is anticipated that carbon dioxide removal will be required to meet these goals. Hydrated cement in concrete can react with atmospheric CO 2 to form carbonate minerals (i.e. carbonation), and in doing so, act as a carbon uptake mechanism. This carbonation process can be accelerated via various engineering interventions, such as crushing concrete after demolition. In this literature review, we examine key parameters, including porosity, exposure conditions, CO 2 concentration, curing methods, coatings, and the use of supplementary cementitious materials, that affect CO 2 uptake in concrete to inform better quantification of life cycle emissions. These findings can inform the feasibility of implementing carbonation as a method for reducing emissions from cement-based materials and identify data limitations that need further study for future modeling efforts. Presently, it has been estimated that 9%–17% of concrete production emissions could be re-adsorbed during use and end of life. However, such estimates of uptake have only considered limited data sets, without fully addressing the comingled effects of the parameters impacting carbonation. Further, some carbon uptake modeling efforts may require input values that are not readily available, or may be challenging to repeat, and do not accurately account for carbon fluxes over the life cycle. Findings from this review highlight the importance of development of systematic approaches to assess cradle-to-grave life cycle assessments using dynamic carbon accounting when measuring concrete carbonation.