Clarification on the Spalling of Concrete Exposed to Fire
| Project/Area Number |
17560406
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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 |
Civil engineering materials/Construction/Construction management
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| Research Institution | Gifu University |
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Principal Investigator |
MORIMOTO Hiroaki Gifu University, Faculty of engineering, Professor, 工学部, 教授 (30021629)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIDA Yuichi Gifu University, Information and Multimedia Center, Professor, 総合情報メディアセンター, 教授 (20213449)
OZAWA Mitsuo Gifu University, Faculty of engineering, Research associate, 工学部, 助手 (80313906)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Concrete / Spalling / Fire / Vapor pressure / Thermal stress / Acoustic emission / 湿度応力 |
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| Research Abstract |
The influences of strength and water content on the spalling of concrete exposed to fire were examined by the experiments, in which vapor pressure, temperature, and AE(Acoustic Emission)arising from cracking were measured. The results obtained by the study are as follows ;
1. Vapor pressures of more than 2.2Mpa were measured in the spalling concrete specimens.
2. Before the spallins arose, the thermal cracking were observed. The thermal cracks is assumed to have a large influence on the scale of subsequent spalling.
3. The spalling with the wet specimens expands from surface toward inside being accompanied by fairly local apalling, meanwhile with the air-dried specimens arises in a region adjacent to the surface at a stretch. This is believed linked to the moisture distribution in the specimens.
4. The spalling is assumed to develop due to chain reaction of cracking, explosion of vapor pressure, spalling, redistribution of vapor pressure, re-explosion, re-spalling.
5. Measuring of AE can be applied for estimating of the development of the cracking and the spalling.
6. AE arose over the whole area of the surface of specimens after 20 to 30 minutes after the beginning of application of heat. More AE counts were measured with the high strength concrete specimens as compared to the normal strength concrete specimens. No meaningful differences in AE counts were observed between the wet specimens and the air-dried specimens.
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Report
(3 results)
Research Products
(21 results)
