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2005 Fiscal Year Final Research Report Summary

Development of a technology to control thermal cracking in concrete by means of a smart material

Research Project

Project/Area Number 15206061
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field Building structures/materials
Research InstitutionTohoku University

Principal Investigator

MIHASHI Hirozo  Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (90091751)

Co-Investigator(Kenkyū-buntansha) KANEKO Yoshio  Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (60312617)
KIRIKOSHI Kazuki  Tohoku University, Graduate School of Engineering, Research Engineer, 大学院・工学研究科, 技術職員 (60240660)
SAKAI Etsuo  Tokyo Institute of Technology, Graduate School of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助教授 (90126277)
Project Period (FY) 2003 – 2005
Keywordsmicrocapsule / hydration-rate / thermal cracking / smart material / retardation effect
Research Abstract

Hydration heat of cement in massive concrete causes significant thermal stress leading to cracking at early ages. In order to avoid such a stress, a smart material for controlling the hydration heat is developed in this study. As the first step, the influence of curing temperature history on mechanical properties of concrete is quantitatively discussed as a function of equivalent age. It was confirmed that high temperature curing of concrete at the early ages prevents the increase of strength in the matured condition. On the basis of these results, the melting temperature of paraffin microcapsule was chosen to be less than 60 degree C. Smart materials developed in this study are composed of paraffin microcapsule containing very fine particles of a hydration-retarder agent. Hence the rising rate of temperature of concrete and thermal stress are controlled under the specified value. Performance and applicability for practical purpose of the developed smart materials are verified by a ser … More ies of experimental studies. Conclusively the following results are obtained :
1. Timing and technique of mixing the microcapsules with fresh concrete was one of the most difficult subjects in this study. While microcapsule are easily damaged during concrete mixing, adding the microcapsules to fresh concrete in agitator at the construction site just before placing the concrete is most acceptable for the practical purpose.
2. Amount of microcapsules necessary for controlling the hydration rate of concrete is strongly dependent on the type of used fine aggregates. Therefore it is essential to examine the necessary amount of the microcapsules in advance.
3. Reduction of hydration heating rate does reduce the thermal stress in concrete, though the maximum temperature is the same as that of plain concrete in case of a very thick and massive concrete. For the practical application, the necessary amount of microcapsule needs to be determined by analyzing the thermal diffusion process in the thickness of the member given in the design documents since the maximum temperature is much lower than that of the adiabatic condition as obtained in the experimental study especially when the hydration heating rate is reduced. Less

  • Research Products

    (10 results)

All 2006 2004 2003

All Journal Article (10 results)

  • [Journal Article] インテリジェント材料を用いたコンクリートの温度応力制御技術の開発に関する研究,(その1)ワックスコーティング型マイクロカプセルの性能と各種影響因子2006

    • Author(s)
      竹内 徹
    • Journal Title

      日本建築学会東北支部研究報告集 69号(構造系)(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] インテリジェント材料を用いたコンクリートの温度応力制御技術の開発に関する研究,(その2)実機施工実験による施工性の検討2006

    • Author(s)
      西山 直洋
    • Journal Title

      日本建築学会東北支部研究報告集 69号(構造系)(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Concrete of Thermal stress in Early Age Concrete with Smart Material (Part I) Performance of Microcapsule Made with Wax Coating Technique and Influencing Factors2006

    • Author(s)
      Tohru Takeuchi
    • Journal Title

      Proceedings of AIJ Tohoku Chapter Architectural Research Meeting No.69(in print)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Concrete of Thermal stress in Early Age Concrete with Smart Material (Part II) Experimental Study on Application of Smart Concrete to In-situ Execution2006

    • Author(s)
      Naohiro Nishiyama
    • Journal Title

      Proceedings of AIJ Tohoku Chapter Architectural Research Meeting No.69(in print)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] 養生過程で温度履歴を受けたコンクリートの活性化エネルギーと有効材齢2004

    • Author(s)
      伊藤 憲雄
    • Journal Title

      コンクリート工学論文集 第15巻・1号

      Pages: 100-109

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] 養生過程で温度履歴を受けたセメント硬化体の力学的性質に対する推定法とその適合性2004

    • Author(s)
      伊藤 憲雄
    • Journal Title

      日本建築学会構造系論文集 No.577

      Pages: 9-14

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Apparent Activation Energy and Equivalent Age of Concrete Influenced by Curing Temperature History2004

    • Author(s)
      Norio Ito
    • Journal Title

      Concrete Research and Technology Vol.15, No.1

      Pages: 100-109

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Prediction Method of Mechanical Properties of Concrete Cured in Different Temperatures and its Applicability2004

    • Author(s)
      Norio Ito
    • Journal Title

      Journal of Structural and Construction Engineering (Transactions of AIJ) No.577

      Pages: 9-14

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] セメント硬化体の力学的特性増進の温度依存性2003

    • Author(s)
      伊藤 憲雄
    • Journal Title

      セメント・コンクリート研究討論会論文報告集 30

      Pages: 1-6

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Temperature Dependency of Development Process of Mechanical Properties of Cementitious Composites2003

    • Author(s)
      Norio Ito
    • Journal Title

      Proceedings of Cement and Concrete Science & Engineering Vol.30

      Pages: 1-6

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 2007-12-13  

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