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Effects of Curing of Winter Concreting on the Freeze-Thaw Resistance of Concrete

Research Project

Project/Area Number 04650417
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field コンクリート工学・土木材料・施工
Research InstitutionUniversity of Tsukuba

Principal Investigator

YAMAMOTO Yasuhiko  University of Tsukuba, Inst.of Eng.Mechanics, Professor, 構造工学系, 教授 (40061220)

Project Period (FY) 1992 – 1993
Project Status Completed (Fiscal Year 1993)
Budget Amount *help
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywordscold weather concreting / frost damage / water content / slow freeze-thaw test / freeze-thaw durability / curing / compressive strength / water-cement ratio / 若材令コンクリート / 強度低下 / 回復養生 / セメントの水和
Research Abstract

The followings are main findings in this research.
(1) The procedure of allowing moderate water-evaporation from concrete for 1 or 2 days immediately after placing of concrete, and, then, providing sufficient moist curing is an effective and practical way of remakably increasing the freeze-thaw durability of concrete without impairing its strength development.
(2) The required compressive strength of concrete at the end of curing may be decreased as the water-cement ratio is decreased.
(3) Even within the range of usual water-cement ratio, say, 45 to 65 %, the required periods of curing in cold weather concreting can be greatly shortened by lowering the ratio.
(4) The inner deteriorations caused by an action of slow freezethaw cycles such as that under the natural weather conditions are considered to be isolated and minute ones, which can be remedied easily by the hydaration products of cement if a sufficient amount of unhydrated cement remains in the concrete.
(5) Lowering water-cement ratio enhances the benefit of improving the freeze-thaw durability of concrete through such effects as the increased capability of remedying inner frost damge, increased resistance against deteriorating actions due to atrength increse after curing, decreased degree of water-saturation due to the continued cement hydration after curing.
(6) The freeze-thaw resistance of fully saturated concrete with water is dependent entirely on its compressive strength, and satisfactory freeze-thaw durability can be obtainted only when its compressive exceeds about 230 kgf/cm^2.

Report

(3 results)
  • 1993 Annual Research Report   Final Research Report Summary
  • 1992 Annual Research Report
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] 山本、武田、長合: "若材齢コンクリートの耐凍害性" 土木学会論文集. (平成6年度に発表予定).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] 山本、武田、山元: "緩速凍結融解の繰返しを受ける若材齢コンクリートの耐凍害性" 土木学会論文集. (平成6年度に発表予定).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Y.Yamamoto, A.Takeda and T.Chouai: ""Freeze-Thaw Resistance of Concrete at Early Ages"" To be contributed to Proc.of JSCE in 1994.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] Y.Yamamoto, A.Takeda and H.Yamamoto: ""Freeze-Thaw Resistance of Early-Age Concrete Subjected to Slow Freeze-Thaw Cycles"" To be contributed to Proc.of JSCE in 1994.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1993 Final Research Report Summary
  • [Publications] 山本、武田、長合: "若材齢コンクリートの耐凍害性" 土木学会論文集. (平成6年度に発表予定).

    • Related Report
      1993 Annual Research Report
  • [Publications] 山本、武田、山元: "緩速凍結融解の繰り返しを受ける若材齢コンクリートの耐凍害性" 土木学会論文集. (平成6年度に発表予定).

    • Related Report
      1993 Annual Research Report

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Published: 1992-04-01   Modified: 2016-04-21  

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