Carbonation reaction of hardened low-heat cement

Carbonation reaction of low-heat cement was investigated in order to develo p practical applications for the hardened cement, such as to building mater ials and concrete products. The measurement results for the pore volume and specific surface area of the hardened low-heat cement indicated that the p ore volume was considerably reduced and the specific surface area of the ce ment was increased after the carbonation. The calcium carbonate and the rea ction ratios of the compounds in the cement were examined by X-ray diffract ion (XRD) quantitative analysis and thermogravimetry-differential thermal a nalysis (TG-DTA). The hydration of alite and belite were accelerated by car bonation. The composition change in the hardened low-heat cement, which was caused by the carbonation, was studied using the results of the quantitati ve analysis. The mechanism which enables carbon dioxide to permeate hardene d cement was examined by comparing the pore volume of hardened cement measu red using a mercury porosimeter, with the pore volume of hardened cement de termined from the composition change.