THE EFFECTS OF BLEEDING ON THE MICROSTRUCTURE OF HARDENED CEMENT PASTE

ブリーディングがセメントペースト硬化体の微細構造に及ぼす影響評価

Bleeding is defined as the upward movement of water after a concrete has been placed, but it has set. It affects on the physical properties of the cured concrete. However the effect of bleeding on the microstructure has not yet been understood quantitatively. In this study, the pore structure of hardened cement paste (HCP) which was deformed by bleeding was discussed quantitatively using electron microscopy method and thermoporometry by low temperature differential scanning calorimeter (DSC). Connectivity of pore structure was also examined by the LCR meter. It is clear that bleeding increases capillary pore in the upper part of cement paste than the lower part, and has few influence on the pore which is smaller than capillary pore. In addition, a correlation was seen between the porosity and electrical conductivity of HCP regardless of bleeding. That suggests that the connectivity of the pore structure of hardened cement paste is strongly dependent on its porosity.コンクリートの材料分離現象であるブリーディングは、硬化後のコンクリートの物性に影響を与えるが、その微細構造に関して定量的な解明は進んでいない。本研究ではブリーディングが発生した硬化セメントペースト（HCP）の空隙構造について、電子顕微鏡と低温DSCを用いて定量的に評価し、空隙構造の特性を電気伝導度から検討した。その結果、ブリーディングによって打設方向上部にかけて増加する空隙は毛細管空隙であり、それ以下の径の空隙形成にはほとんど影響を及ぼさないことが明らかとなった。また、HCP中の空隙量と電気伝導性にはブリーディングや水セメント比及び材齢に依らず相関が見られ、空隙の連続性は空隙量のみに依存することが示された。

• Record URL:
  • https://doi.org/10.14250/cement.66.111
• Summary URL:
  • http://scholar.google.com/scholar_lookup?title=THE+EFFECTS+OF+BLEEDING+ON+THE+MICROSTRUCTURE+OF+HARDENED+CEMENT+PASTE&author=K.+ISHIGAKI&author=K.+KURUMISAWA&author=T.+NAWA&publication_year=2012
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/09163182
• Authors:
  • ISHIGAKI, Kunihiko
  • KURUMISAWA, Kiyofumi
  • NAWA, Toyoharu
• Publication Date: 2012

Language

• English
• Japanese

Media Info

• Media Type: Web
• Pagination: pp 111-118
• 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: Bleeding (Pavements); Cement paste; Deformation; Electrical conductivity; Electron microscopy; Microstructure
• Subject Areas: Highways; Materials; Pavements; I32: Concrete; I52: Construction of Pavements and Surfacings;

Filing Info

• Accession Number: 01515562
• Record Type: Publication
• Source Agency: Japan Science and Technology Agency (JST)
• Files: TRIS, JSTAGE
• Created Date: Feb 24 2014 8:43AM