title: Hydrothermal formation of tobermorite studied by in situ X-ray diffraction under autoclave condition.
abstract: Hydrothermal formation of tobermorite from a pre-cured cake has been investigated by transmission X-ray diffraction (XRD) using high-energy X-rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide-angle X-ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non-crystalline C-S-H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures.
authors.affiliation: Analysis and Simulation Center, Asahi-KASEI Corporation, Japan. kikuma.jb@om.asahi-kasei.co.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Kikuma
authors.forename: Masamichi
authors.initials: M
authors.lastname: Tsunashima
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Matsuno
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ogawa
authors.forename: Kunio
authors.initials: K
authors.lastname: Matsui
authors.forename: Masugu
authors.initials: M
authors.lastname: Sato