Experimental Investigation and Modelling of Carbonation Process in Cement Materials

Abstract

Cement mortar and cement paste samples were prepared and subjected to accelerated carbonation test at 20°C, 65% humidity relative, 20% or 50% concentration of CO₂. The carbonation depth was determined using classical phenolphthalein test. The mass fractions of Ca(OH)₂ and CaCO₃ were calculated from thermogravimetric analysis. We studied different factors that influence the carbonation process such as: concentration of CO₂, type of material, surface exposure to CO₂, porosity accessible to water, duration of carbonation. Based on the experimental results, a numerical simulation was developed to predict the carbonation depth. This physicochemical and deterministic model relies upon a detailed description of the carbonation mechanism as it takes into account the chemical kinetics, the microstructural and hydrous evolutions induced.