2022 Volume 76 Issue 1 Pages 528-536
In this study, the interlayer structure was evaluated by obtaining the water vapor adsorption isotherms from low relative pressure and the isotopic differential heat of adsorption calculated by the Clausius-Clapeyron equation for heat treated 1.4nm tobermolite, which was changed to 1.1nm, without Si-Q3 bond. The low crystallinity C-S-H was also evaluated using 1.4nm tobermorite with heat treatment as a comparison. As a result, characteristic bimodal peaks appeared in the heat of adsorption change in the low humidity range, and the behavior up to the first and second peaks were attributed to adsorption in the interlayer and on the outer surface of the interlayer, respectively. Also, the increase of the first peak in the heat of adsorption of 1.4nm tobermorite was attributed to the hydration of Ca2＋ ions bridging the interlayer.
