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Study on exfoliation of finish mortal of external wall

Research Project

Project/Area Number 06650640
Research Category

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

Allocation TypeSingle-year Grants
Research Field Building structures/materials
Research InstitutionKagoshima University

Principal Investigator

KUNIMOTO Kume  Kagoshima University Fac.of Engineering, Architecture, Associate prof., 工学部, 助教授 (00041525)

Co-Investigator(Kenkyū-buntansha) ARIMA Fuyuki  Kagoshima University Fac.of Engineering, Architecture, Research Assoc., 工学部, 助手 (60232071)
MITANI Isao  Kagoshima University Fac.of Engineering, Architecture, Prof., 工学部, 教授 (70037935)
Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1995: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Keywordsexfoliation of finish mortar / elastic plate theory / thermal stress / shear adhesion strength / thermography / diagnosis for exfoliation / the thicker finish mortar / seasonal condition and orientation / 外壁仕上げ材 / 剥離
Research Abstract

Part I Analytical study on external wall with exfoliating finish mortal including effect fo thermal stress
High temperature gradients due to solar radiation cause thermal stress on the exposed surfaces of structure. On the external wall with exfoliating finish mortar plate and concrete wall, the capability of the buckling of the plate and the propagation of the exfoliation of the plate due to the thermal stress were investigated by using a simple elastic analysis. Based of the Analytical results, the main conclusions are ;
1) High temperature gradients between the exfoliating mortar plate and the concrete wall possibly cause the plte to buckle. Higher gradients in excess of those enough to buckle the plate cause wider gap between them.
2) A theoretical formula for the relation between t and the ratio L/h was proposed, where t=difference in temperature between mortar plate and concrete wall, L=length of shorter side of rectangular plate and h=plate thickness.
3) The existence of the exfolia … More tion of the plate capably causes the nominal stress, which is generating the wider exfoliation, to propagate.
Part II Experimental study on the efficiency of thermographic diagnosis method for external R/C walls
The efficiency of thermographic diagnosis for external R/C walls with the thicker finish mortar depth was investigated. Each test specimen, which is a part of wall, has the artificial defect in the center of wall surface. The test parameters are wall depth of finish mortar (40,50and60mm), the thickness of defects (1and2mm), seasonal condition (summer, fall and winter)and the direction of outer wall (east, west and south).Based on the experimental results, the main conclusions are ;
1) The wall depth limit for thermographic diagnosis on walls with thicker depth is 60 mm.
2) The diagnosis in fall season is the most effective due to sun's altitude and flux of solar radiatio.
3) In case of summer-season diagnosis, the temperature rise more then 5゚C in duration of sunshine is required for the diagnosis. Less

Report

(3 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • Research Products

    (5 results)

All Other

All Publications (5 results)

  • [Publications] 久米 国幹 他: "赤外線映像装置によるRC造外壁の診断法に関する基礎的研究 その4 仕上げモルタルの剥離診断限界厚さ" 日本建築学会研究報告 九州支部. 第35号・1. 201-204 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 久米 国幹 他: "赤外線映像装置によるRC造外壁の診断法に関する基礎的研究 その5 仕上げモルタルの剥離診断限界厚さ(夏季)" 日本建築学会研究報告 四国・九州支部. 第10号. 77-80 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] K.Kume, I.Mitani and f.Arima: "A basic study on thrmographic diagnosis method for outer R/C walls Part 4 diagnostic limit for walls with thicker depth of finish mortar" Kyushu meeting of architectural Institute of Japan. Vol.35. 201-204 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] K.Kume, I.Mitani, F.Arima and T.Kawabata: "A basic study on thermographic diagnosis method for outer R/C walls Part 5 Diagnostic limit for walls with thicker depth of finish mortar (summer)" Chugoku-Kyushu joint meeting of Architectural Institute of Japan. Vol.10. 77-80 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 久米国幹: "赤外線映像装置によるRC造外壁の診断法に関する基礎的研究(その4 仕上げモルタルの剥離診断限界厚さ)" 日本建築学会研究報告 九州支部. 第35号・1. 201-204 (1995)

    • Related Report
      1995 Annual Research Report

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Published: 1994-04-01   Modified: 2016-04-21  

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