Highly Reactive β-C₂S from Hillebrandite

This paper reviews the field indicated by the title, with emphasis on the recent work by author s group. The topics are as follows: hydrothermal synthesis of hillebrandite, Ca₂(SiO₃)(OH)₂, using silica and lime with Ca/Si=2.0 at 200∼250℃ ; thermal decomposition of hillebrandite into β-C₂S at 600℃ ; stable form of β-C₂S having 7∼8 ㎡/g BET at room temperature without stabilizer; hydration behavior of β-C₂S at 25∼80℃ ; Ca-rich C-S-H gels with Ca/Si=1.9∼2.0; silicate anion structure of C-S-H gels by using TMS and NMR methods; electron. diffraction of C-S-H gels; thermal behavior of C-S-H gels by using NMR and X-ray methods. This study investigates the low temperature synthesis of highly reactive β-C₂S from calcium silicate hydrate produced by hydrothermal preparation, and clarifies its hydration behavior.