Effect of magnesium silicate hydrate (M-S-H) formation on the local atomic arrangements and mechanical properties of calcium silicate hydrate (C-S-H); In situ X-ray scattering study

ケイ酸カルシウム水和物(C-S-H)の局所原子配列と力学特性に及ぼすケイ酸マグネシウム水和物(M-S-H)生成の影響; X線散乱法によるその場観察

Kim, G.*; Im, S.*; Jee, H.*; Suh, H.*; Cho, S.*; 兼松 学*; 諸岡 聡  ; 小山 拓*; 西尾 悠平*; 町田 晃彦*; Kim, J.*; Bae, S.*

Kim, G.*; Im, S.*; Jee, H.*; Suh, H.*; Cho, S.*; Kanematsu, Manabu*; Morooka, Satoshi; Koyama, Taku*; Nishio, Yuhei*; Machida, Akihiko*; Kim, J.*; Bae, S.*

This study explored the effect of M-S-H formation on the local atomic arrangements and mechanical properties of C-S-H. The elastic moduli of the samples were calculated using shifted atomic distances (r) and d-spacings (d) acquired by applying an external load on the pastes during X-ray scattering experiments. The experimental results indicated that the crystal structure of C-S-H remained intact with MgCl addition. At the highest Mg/Si ratio (Ca/Si = 0.6, Mg/Si = 0.2), change in the dominant phase occurred from C-S-H to M-S-H because the low pH environment hindered the formation of C-S-H and facilitated the formation of M-S-H. The elastic modulus decreased with increasing Mg/Si ratio up to 0.1 owing to both C-S-H destabilization and low M-S-H content in the samples. Conversely, the elastic modulus increased in the paste synthesized with the highest Mg/Si ratio because considerable M-S-H had formed, which exhibited a higher elastic modulus than C-S-H.