IN SITU XRD AND supra 29Si SOLID-STATE NMR ANALYSIS ON TOBERMORITE FORMATION:EFFECT OF THE C-S-H STRUCTURE IN CaO-SiO₂-H₂O SYSTEM

放射光その場X線回折と<sup>29</sup>Si固体NMRによるトバモライト生成過程の解析:CaO-SiO<sub>2</sub>-H<sub>2</sub>O系におけるC-S-H構造の影響

To clarify the formation mechanism of tobermorite(5CaO・6SiO₂・5H₂O), one of the crystalline calcium silicate hydrates, the authors have investigated the formation of tobermorite during hydrothermal processing by in situ X-ray diffraction analysis using high-energy X-rays from a synchrotron radiation source and supra 29 Si solid state nuclear magnetic resonance (NMR). Specifically, the effects of the particle size of quartz, one of the starting materials, and a water/solid ratio on tobermorite formation in the CaO-SiO₂-H₂O system were studied. In the system where semi-crystalline C-S-H formed, an amorphous C-S-H which formed in the heating process had a longer chain length and a cross-link(Q³) of the Si-tetrahedron. On the other hand, in the system where tobermorite formed, the chain length was almost constant and the cross link(Q³) slightly formed in the heating process. The two types of amorphous C-S-H mentioned above had a same chemical composition, but different structures. The authors assumed as the mechanism that the concentration of the silicate anion consisting of about five units in the liquid phase was an important factor determining the tobermorite formation.結晶性ケイ酸カルシウム水和物であるトバモライトの生成機構を解明することを目的に、CaO-SiO₂-H₂O系における原料珪砂の粒径と、水/固体比がトバモライト生成に及ぼす影響を、in situ XRDと supra29Si固体NMRを用いて検討した。昇温過程で生成する非晶質C-S-Hは、擬結晶C-S-Hが生成する系ではシリケートアニオンの鎖長が長くQ³が多く生成した。一方、トバモライトが生成する系ではその鎖長はほぼ一定でQ³はわずかしか生成しなかった。この非晶質C-S-HのCa/Si比がほぼ同一であるのに関わらず、異なった構造を有するのは、昇温過程において生成する液相中のシリケートアニオンの鎖長が5程度の非晶質C-S-H濃度が関係していると推察した。

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  • Accession Number: 01561250
  • Record Type: Publication
  • Source Agency: Japan Science and Technology Agency (JST)
  • Files: TRIS, JSTAGE
  • Created Date: Apr 23 2015 10:50AM