Evaluation of CO2 Uptake under Mild Accelerated Carbonation Conditions in Cement-Based and Lime-Based Mortars

The industrial production of cement-based and lime-based materials such as mortars contributes significantly to the release of greenhouse gases such as CO2 into the atmosphere. However, a percentage of these emissions is reabsorbed as the mortar hardens, owing to carbonation reactions. This study aims to explore the CO2 sequestration capacity of a cement-based (CM) and a lime-based mortar (LM) over the first 28 days of curing. The CO2 uptake of CM and LM was experimentally evaluated in mildly accelerated conditions by using a volumetric approach. This procedure enabled us to assess the CO2 absorbed after 1, 7 and 28 days from mortar preparation so as to simulate CM and LM behavior during their setting, hardening, and service-life conditions. Through the experimental approach values of 19.1, 25.5 and 26.4 g CO2/kg for CM and 5.0, 11.0 and 16.1 g CO2/kg for LM were obtained. These results, which were validated by means of X-ray diffraction along with calcimetry analysis, confirmed that carbon sequestration by common mortars during their curing time is not negligible.