ACTION MECHANISM OF SUPERPLASTICIZER IN CONSIDERATION OF EARLY HYDRATION OF CEMENT

セメントの初期水和反応を考慮した分散剤の作用機構

Superplasticizer (S.P.) is used in almost all concrete, made in Japan, to decrease the amount of water. Now the use of hot-weather concrete is increasing. And interstitial phase of cement such as C₃A, C₄AF will be increased for keeping usage amount of by-products. In these cases, early hydration will make great influence on fluidity of cement paste. Therefore, the role of chemical admixture, especially S.P. is getting more important. It is pointed out that the fluidity change of concrete with the lapse of time is influenced by the molecular structure of S.P.. However the mechanism of fluidity change is not clear. And it is necessary to advance the research on the interaction between cement and S.P.. The authors focused on the action mechanism of S.P. especially in the early stage of hydration. In this study, it was pointed out that polycarboxylate based S.P. has better fluidity retaining performance than Naphthalene sulfonate based S.P.. It was thought that this difference was related to the difference of the amount of adsorbed S.P. per specific surface area. It has been shown that the fluidity deterioration of cement paste with Naphthalene sulfonate based S.P. is attributed by the decrease of residual concentration of S.P. in liquid phase.我が国では現在ほとんどすべてのコンクリートに（AE）減水剤（分散剤）や高性能（AE）減水剤が使用されている。暑中コンクリートの利用拡大などにより、流動性に及ぼすセメントの初期水和の影響が大きくなっていくため、経時変化を考慮した分散剤の作用機構の解明が重要である。本研究により、流動性保持性能はβ-NSよりPCの方が良く、それは単位面積当たりの吸着量変化と関係していると考えられた。単位面積当たりの分散剤吸着量の経時変化を吸着等温線と関連させて考えると、吸着量の変化が液相中の分散剤濃度によって大まかに整理できた。したがって流動性の経時変化が分散剤の液相残存濃度と関係しているものと思われた。

• Record URL:
  • https://doi.org/10.14250/cement.68.75
• Summary URL:
  • http://scholar.google.com/scholar_lookup?title=ACTION+MECHANISM+OF+SUPERPLASTICIZER+IN+CONSIDERATION+OF+EARLY+HYDRATION+OF+CEMENT&author=Y.+OHTSUKA&author=D.+ATARASHI&author=M.+MIYAUCHI&author=E.+SAKAI&publication_year=2014
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/09163182
• Authors:
  • OHTSUKA, Yuta
  • ATARASHI, Daiki
  • MIYAUCHI, Masahiro
  • SAKAI, Etsuo
• Publication Date: 2014

Language

• English
• Japanese

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: pp 75-81
• Serial:
  • Cement Science and Concrete Technology
  • Volume: 68
  • 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: Admixtures; Cement paste; Concrete; Fluidity; Hydration; Superplasticizers
• Subject Areas: Construction; Materials; Transportation (General); I32: Concrete; I50: Construction and Supervision of Construction;

Filing Info

• Accession Number: 01564631
• Record Type: Publication
• Source Agency: Japan Science and Technology Agency (JST)
• Files: TRIS, JSTAGE
• Created Date: May 26 2015 4:12PM