2013 Fiscal Year Final Research Report
VERIFICATION OF COMBINATION USE OF EXPANSIVE AGENT AND LIGHTWEIGHT AGGREGATE ON FATIGUE RESISTANCE OF RC SLAB AND THERMAL STRESS RESTRANT AND ITS UTILIZATION
| Project/Area Number |
24656267
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Civil engineering materials/Construction/Construction management
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Yuya 東京大学, 生産技術研究所, 助教 (40624531)
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| Project Period (FY) |
2012-04-01 – 2013-03-31
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| Keywords | コンクリート / 床版 / 疲労 / 温度応力 / 膨張材 / 軽量骨材 |
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| Research Abstract |
It was reported that simultaneous use between expansive agent and artificial lightweight aggregate in cement concrete could restrain thermal stress induced under elevated temperature, and it could also prolong fatigue life of RC slab. In this study measurements of thermal expansion coefficient of specimens and microscopic visual observation around lightweight aggregate were conducted to understand its complicated mechanism. By the experimental investigations two tendencies were suggested as important factors. One is time dependent change of thermal expansion coefficient of this concrete. It is higher than normal concrete at the early age but it becomes small in the longer time. The other is that thermal expansion coefficient of lightweight aggregate is almost half of normal aggregate. Precipitation of additional hydration product at the gap space created around lightweight aggregate due to expansive action was not observed though it was suggested as a possible cause of that mechanism.
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