2018 Volume 72 Issue 1 Pages 18-24
In order to realize the recycled cement, we are aimed to organize the cycle composed of highly reactive β-C2S and amorphous C-S-H with a high C/S ratio. By using Double-decomposition method, amorphous C-S-H with C/S＝2.0 were synthesized from sodium-ortho-silicate under the samples which might not contain sodium or natrium in the solid phases. Therefore, this study was performed to reveal the hydration mechanisms of C2S, derived by heating amorphous C-S-H samples with a high C/S ratio at low-temperature（600℃）. As a result, it was succeeded to obtain amorphous C-S-H not containing CH through the hydration at 80℃, which were similar to the original sample synthesized by Double-decomposition method. Furthermore, another pattern of amorphous C-S-H samples without CH were composed in the case of using sodium-meta-silicate as a starting material. In this process of hydrations, Wollastonite was hydrated because of its high pH in the solution and high specific surface by N2-BET.
