Carbonation reaction of low-heat cement was investigated in order to develop practical applications for the hardened cement, such as to building materials and concrete products. The measurement results for the pore volume and specific surface area of the hardened low-heat cement indicated that the pore volume was considerably reduced and the specific surface area of the cement was increased after the carbonation. The calcium carbonate and the reaction ratios of the compounds in the cement were examined by X-ray diffraction (XRD) quantitative analysis and thermogravimetry-differential thermal analysis (TG-DTA). The hydration of alite and belite were accelerated by carbonation. The composition change in the hardened low-heat cement, which was caused by the carbonation, was studied using the results of the quantitative analysis. The mechanism which enables carbon dioxide to permeate hardened cement was examined by comparing the pore volume of hardened cement measured using a mercury porosimeter, with the pore volume of hardened cement determined from the composition change.
