2022 Volume 76 Issue 1 Pages 275-281
This study aimed to evaluate the crystal structure of carbonate ettringite, a material in which the sulfate ion of ettringite is replaced by carbonate ions, and examined the bonding state of atoms, changes in the Al coordination number, and dehydration behavior of carbonate ettringite by comparing to that of ordinary ettringite. As a result, it was found that carbonate ettringite showed a difference in the amount of dehydration up to 200℃ compared to ettringite, and that the Al coordination number changed significantly after heating at 80℃ for 24 hours. In the 11％ RH dried sample, the 27Al NMR peak of carbonate ettringite was similar to that of ettringite, suggesting that carbonate ettringite has the same column structure as ettringite and that the dehydration behavior is due to the difference in ionic properties of sulfate and carbonate ions.
