TY - JOUR
T1 - α-Dicalcium silicate hydrate
T2 - Preparation, decomposed phase, and its hydration
AU - Ishida, Hideki
AU - Yamazaki, Satoru
AU - Sasaki, Kaori
AU - Okada, Yoshihiko
AU - Mitsuda, Takeshi
PY - 1993/7
Y1 - 1993/7
N2 - α-C2SH can be synthesized by hydrothermal treatment lime and silicic acid for 2 h at 200 °C. When heated to 390-490 °C, α-C2SH dissociates through a two-step process to form an intermediate phase plus some γ-C2S. This appears to be a new dicalcium silicate different from known dicalcium silicates - α, α′L, α′H, β, and γ phase - and is stable until around 900 °C. At 920-960 °C, all the phases are transformed to the α′L phase. The intermediate phase has high crystallinity and is stable at room temperature. 29Si MAS NMR measurements indicate the possibility that it contains both protonated and unprotonated monosilicate anions. The intermediate phase that has passed through the α′ phase at higher temperature yields β-C2S on cooling. The intermediate phase is highly active, and completed its hydration in 1 day (w/s = 1.0, 25 °C). Among the crystalline calcium silicate hydrates with Ca/Si = 2.0, it is hillebrandite that yields β-C2S at the lowest temperature.
AB - α-C2SH can be synthesized by hydrothermal treatment lime and silicic acid for 2 h at 200 °C. When heated to 390-490 °C, α-C2SH dissociates through a two-step process to form an intermediate phase plus some γ-C2S. This appears to be a new dicalcium silicate different from known dicalcium silicates - α, α′L, α′H, β, and γ phase - and is stable until around 900 °C. At 920-960 °C, all the phases are transformed to the α′L phase. The intermediate phase has high crystallinity and is stable at room temperature. 29Si MAS NMR measurements indicate the possibility that it contains both protonated and unprotonated monosilicate anions. The intermediate phase that has passed through the α′ phase at higher temperature yields β-C2S on cooling. The intermediate phase is highly active, and completed its hydration in 1 day (w/s = 1.0, 25 °C). Among the crystalline calcium silicate hydrates with Ca/Si = 2.0, it is hillebrandite that yields β-C2S at the lowest temperature.
UR - http://www.scopus.com/inward/record.url?scp=0027626150&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027626150&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0027626150
VL - 76
SP - 1707
EP - 1712
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
SN - 0002-7820
IS - 7
ER -