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Mechanism of Developing Cold Joint in Concrete, Its Pore Structure and Repair Technique

Research Project

Project/Area Number 13650619
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Building structures/materials
Research InstitutionTokyo Institute of Technology

Principal Investigator

TANAKA Kyoji  Tokyo Institute of Technology, Materials and Structure Laboratory, Professor, 応用セラミックス研究所, 教授 (40016829)

Co-Investigator(Kenkyū-buntansha) MIYAUCHI Hiroyuki  Tokyo Institute of Technology, Materials and Structure Laboratory, Research Associate, 応用セラミックス研究所, 助手 (40313374)
Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥2,600,000 (Direct Cost: ¥2,600,000)
KeywordsConcrete / Mortar / Placing Joint / Cold joint / Permeability / Environmental Condition / Pore structure / Repair / 水密性 / 打ち足し時間
Research Abstract

A time gap in placing between two concrete layers and environmental condition at concrete placing is found out to be the main cause for producing a cold joint in a concrete member. It is because that the first concrete layer started hydration at long interval time before placing of the second concrete layer and at higher temperature. To discuss quantitatively effect of the two parameters, liquid permeability of mortar specimens that were produced at several placing intervals and at various temperatures were measured. The equation for calculating permeability composed of interval time and temperature was proposed on the basis of the experimental results.
As for the effect of outdoor environment on permeability, specimens with cold joints were made at several interval times of placing in summer and winter and the difference in influence of the seasons on formation of a cold joint was discussed. Furthermore permeability of each specimen was estimated by calculation using temperatures of the specimens. The usefulness of the above method to estimate to permeability of a cold joint is also confirmed in an actual field.
A new technique, in which gallium is intruded m pores of a specimen at high pressure and then the distribution of it is mapped by an EPMA measurement, was developed for studying the structure of a cold joint. It was made clear that a discontinuous plane was formed along the cold joint in concrete and it became more noticeable at longer interval time and at higher temperature.
To make a cold joint watertight three kinds of repair agents, mainly composed of magnesium silicofluoride and calcium silicate, were injected in cold joints at low pressure, and their permeability were measured. It was found out that they produced some crystals in cold joints and decreased their permeability. It was also confirmed by the observation of pore structures at the cold joints that the structures became dense.

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] Young-Joo SHIN, Kyoji TANAKA: "Permeability and Pore Structure of Placing Joint of Cement Mortar Produced in Casting"Proceedings of 9^<th> International Conference on Durability of Building Materials and Components. 1-7 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 申英珠, 田中享二: "コンクリート壁のセパレータ部の透水性に影響を及ぼすブリーディングについての研究"日本建築学会関東支部研究報告集. 61-64 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 申英珠, 田中享二: "コンクリート壁体の打ち足し部の水密性改善材料に関する研究"日本建築学会大会学術講演梗概集. A. 11-12 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 申英珠, 田中享二, 宮内博之: "施工時の温度・湿度環境がモルタルの打足し接続部の水密性に及ぼす影響"日本建築学会構造系論文報告集. 567. 13-19 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] 申英珠, 田中享二: "コンクリート壁体のセパレーター部の透水性と細孔構造"日本建築学会関東支部研究報告集. 53-56 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Young-Joo SHIN, Kyoji TANAKA: "Permeability and pore structure of placing joint of cement mortar produced in casting"Proceedings of 9^<th> International Conference on Durability of Building Materials and Components. 1-7 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Young-Joo SHIN, Kyoji TANAKA: "A study on the bleeding which effects the permeability in separator of concrete wall"Proceeding of the 72th Architectural Research Meetings, Kanto Chapter, Architectural Institute of Japan. 61-64 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Young-Joo SHIN, Kyoji TANAKA: "A study on materials which improve water tightness in placing joint"Summaries of Technical Papers of Annual Meeting of AIJ. A-1. 11-12 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Young-Joo SHIN, Kyoji TANAKA and Hiroyuki MIAYUCHI: "Effect of ambient temperature and humidity on permeability of placing joint of mortar in casting"Journal of Structural and Construction Engineering, AIJ. No.567. 13-19 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Young-Joo SHIN, Kyoji TANAKA: "Permeability and pore structure in separator of concrete wall"Proceeding of the 73th Architectural Research Meetings, Kanto Chapter, Architectural Institute of Japan. 61-64 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] Young-Joo SHIN, Kyoji TANAKA: "Permeability and Pore Structure of Placing Joint of Cement Mortar Produced in Casting"Proceedings of 9^<th> International Conference on Durability of Building Materials and Components. 9. 331-337 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] 申英珠, 田中享二: "コンクリート壁体の打ち足し部の水密性改善材料に関する研究"日本建築学会大会学術講演梗概集. A. 11-12 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] 申英珠, 田中享二: "コンクリート壁体のセパレータ部の透水性と細孔構造"日本建築学会関東支部研究報告集. 73. 53-56 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] 申英珠, 田中享二, 宮内博之: "施工時の温度・湿度環境がモルタルの打ち足し接続部の水密性に及ぼす影響"日本建築学会構造系論文報告集. 567. (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] 申英珠, 田中享二: "モルタルの打ち足し部の透過性と細孔分布に及ぼす施工環境の影響"日本建築学会構造系論文集. A. 793-794 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] 申英珠, 田中享二: "コンクリート壁体のセパレーター部分の透過性"日本建築学会関東支部研究報告集. 17-20 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] 申英珠, 田中享二: "コンクリート壁のセパレータ部の透過性に影響を及ぼすブリーディングについての研究"日本建築学会関東支部研究報告集. 61-64 (2002)

    • Related Report
      2001 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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