ANALYSIS OF C₃A HYDRATION IN CONSIDERATION OF FORMATION OF AMORPHOUS COMPOUNDS

非晶質物質の生成を考慮したアルミネート相の水和反応解析

System in C₃A-Gypsum, hydration analysis was carried out by ²⁷Al MAS-NMR (nuclear magnetic resonance) analysis and X-ray diffraction Rietveld analysis. As a result, in the presence of Gypsum, C₃A hydration divided into three stages. First stage, degree of C₃A hydration remains at constant value. Second stage, C₃A hydration rapidly proceeds. Third stage, C₃A hydration calms down. In first stage, amorphous phase remains at constant amount and AFt is formed until second stage. In second stage, amorphous phase rapidly increase at the same time of converting AFt into AFm. In third stage, AFt increase and amorphous phase slowly decrease. It has been shown that the amorphous phase which is generated in the early period of C₃A hydration should be a low crystallinity AFm, the amount of amorphous material remained at nearly constant amount until the disappearance of Ettringite, and rapidly increase at the same time as the disappearance of Ettringite. Composition of amorphous minerals is determined from the results which are obtained from X-ray diffraction Rietveld analysis. In addition, the amount of minerals in amorphous phase was calculated by measurements of ²⁷Al MAS-NMR and separation each materials of chemical shifts which are include Al. As a result, it was implied that there was the possibility of existence of aluminum hydroxide gel in the amorphous phase. At an early period, it was implied that the amorphous materials was C-A-H including sulfate ion. At a latter period, it was implied that crystal AFm is produced from AFt-like gel through AFm-like gel. C₃A-Gypsum系において、XRD・リートベルト解析および²⁷Al MAS-NMR測定により水和解析を行った。その結果、非晶質量はAFtが消失するまでほぼ一定量で推移し、AFtの消失と同時に急激に増加することが示された。XRDより得られた結果から非晶質物質の組成を決定した。また、NMRスペクトルをAlの化学シフト値で分離することで、非晶質物質中の鉱物量を算出した。その結果、非晶質物質中にアルミナゲルが存在する可能性が示唆された。材齢初期における非晶質物質は硫酸イオンを含むC-A-Hであることが示唆された。材齢後期では、AFt様のゲル状水和物からAFm様のゲル状水和物を経てAFmを生成する可能性が示唆された。

• Record URL:
  • https://doi.org/10.14250/cement.66.230
• Summary URL:
  • http://scholar.google.com/scholar_lookup?title=ANALYSIS+OF+C%e2%1a%92A+HYDRATION+IN+CONSIDERATION+OF+FORMATION+OF+AMORPHOUS+COMPOUNDS&author=A.+HATAKEYAMA&author=J.+YAMAMOTO&author=T.+NAWA&author=K.+KANEHASHI&publication_year=2012
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/09163182
• Authors:
  • HATAKEYAMA, Aoi
  • YAMAMOTO, Junki
  • NAWA, Toyoharu
  • KANEHASHI, Koji
• Publication Date: 2012

Language

• English
• Japanese

Media Info

• Media Type: Web
• Pagination: pp 230-236
• Serial:
  • Cement Science and Concrete Technology
  • Volume: 66
  • Issue Number: 1
  • Publisher: Japan Cement Association
  • ISSN: 0916-3182
  • EISSN: 2187-3313
  • Serial URL: https://www.jstage.jst.go.jp/browse/cement/-char/en
• Publication flags:

  Open Access (libre)

Subject/Index Terms

• TRT Terms: Aluminates; Diffraction; Ettringite; Hydration; Nuclear magnetic resonance; X rays
• Subject Areas: Highways; Materials; I30: Materials;

Filing Info

• Accession Number: 01506027
• Record Type: Publication
• Source Agency: Japan Science and Technology Agency (JST)
• Files: TRIS, JSTAGE
• Created Date: Jan 29 2014 7:32AM