| Project/Area Number |
14550459
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
土木材料・力学一般
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| Research Institution | Kitami Institute of Technology |
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Principal Investigator |
AYUTA Koichi Kitami Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (90003186)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Mechanism of frost damage / Scaling / Freezing-thawing action / Cooling rate / Minimum temperature / Water cement ratio / Offshore concrete / 最低温度保持時間 / 海水 / 凍結速度 |
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| Research Abstract |
The results of this study indicates the following :
It is well known that concrete undergoes significant deterioration when exposed to sea water and frost in cold regions. In order to clarify the effects of freezing-thawing action on the scaling of concrete exposed to sea water, we performed freezing and thawing tests on specimens immersed in either sea water or fresh water. The tests were performed at various cooling rates and the minimum temperatures. We also used specimens of different water to cement ratios.
Scaling occurred when we used specimens soaked in sea water. Scaling occurred more on specimens that had high water to cement ratio, slowly cooling rate and more at low minimum temperature. The experiment of the results showed that sea water entered into cement paste matrix that had high water to cement ratio. At low minimum temperatures. sea water entered into cement paste matrix. Cement paste matrix was filled with sea water, which caused scaling. The specimens showed more scaling when the water was slowly cooled to the freezing point. Experiment results of these specimens showed that the sea water had entered the cement paste matrix. Therefore, scaling occurs when the water cools slowly and then remains for a long time.
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