Test methods for CO2 mineralization in cement-based materials: a review by RILEM TC 309-MCP

CO2 can be absorbed and mineralized as solid carbonates in a range of construction materials. Accurate measurement of CO2 content and uptake in cement-based and other construction products is important for the development as well as the certification of novel mineral carbonation products, processes, and practices. However, measurement is complex as samples can range from fine powders to blocks with varying levels of heterogeneity, different solid carbonate phases can be present, and measurement methods may require correction for interferences. When and where the CO2 content is measured is also important. Numerous techniques are available for measuring the solid CO2 content of a sample, from which the CO2 uptake can be calculated. Here, a critical review of the most relevant methods is presented; the most used methods are thermogravimetric and combustion analysis, however, diffraction-based, spectroscopic, wet-chemical, and other methods can also be used for this purpose. Advantages and disadvantages of the various test methods are discussed. Aspects of sample preparation, result interpretation, measurement limitations and possible interferences, as well as the use of complementary methods are highlighted. Important aspects of conversion of measured solid CO2 contents to calculated CO2 uptake are highlighted.