STUDY ON CARBONATED C-A-S-H AND ITS DECARBONATION BEHAVIOR BY HEATING

Abstract

Various analyses were performed on C-A-S-H carbonated by dry or wet process. In case of dry process, C-A-S-H was almost completely carbonated, and vaterite, aragonite, calcite, and silica gel were formed. Electron microscopic observations showed that the calcium carbonate and silica gel were not clearly separated, but were present in a fine mixture. In case of dry process, C-A-S-H was almost completely carbonated, and the phases were calcite and silica gel. Electron microscopic observations showed that the calcite had a size of several micrometers and was clearly distinguishable from silica gel. The decarbonation behavior was different between the two processes, and the C-A-S-H carbonated by dry process showed more significant decarbonation in the lower temperature range （around 400 to 600℃）.