| Project/Area Number |
59420035
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Building structures/materials
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
1984 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥14,000,000 (Direct Cost: ¥14,000,000)
Fiscal Year 1985: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1984: ¥11,000,000 (Direct Cost: ¥11,000,000)
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| Keywords | Concrete / Concrete Member / Submerged Condition / Low-Cycle Fatigue / Acoustic Emission / 生存確率 |
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| Research Abstract |
Low cycle fatigue loading tests were performed on the concrete cylinders and the reinforced on prestressed concrete beams under submerged condition to verify the evil influences of water upon the fatigue life. From the tests, the following conclusions can be obtained.
1. In the plain concrete having relatively larger water-cement ratio, low-cycle fatigue strength becomes much smaller under submerged condition. Similar deterioration in fatigue life can be obtained from the water absorbed concrete even when tested in air. These fact indicate that the wedge action of water trapped in the micro-cracks or void and the reduction of surface energy lead to the deterioration of fatigue life. This conclusion was assured from the source location of local fracture by acoustic emission measurements. And the statistical treatment of the test data resulted in larger reduction in fatigue life as a mean value under submerged condition than in air.
2. Significant reduction in flexural fatigue life was observed in RC or PC beams under submerged condition. In the beams cast by relatively larger water cement ratio of concrete the reduction in fatigue strength under submerged condition is mainly caused by the rapid deterioration of compressed concrete due to water. On the contrary, that in beam made of ultra-high strength concrete is induced by the pumping action of water trapped into the flexural cracks.
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