| Project/Area Number |
13650986
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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 |
資源開発工学
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| Research Institution | Yamaguchi University |
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Principal Investigator |
ISHIDA Tsuyoshi Yamaguchi University, Faculty of Engineering, Professor, 工学部, 教授 (10232307)
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| Co-Investigator(Kenkyū-buntansha) |
水田 義明 山口大学, 工学部, 教授 (20107733)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | expansive cement agent / acoustic emission / thermal stress / rock mechanics / 静的破砕剤 |
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| Research Abstract |
Calcium oxide (CaO)-based expansive cement, also known as "non-explosive demolition agents", has been widely used to fracture massive rocks and concrete structures. To clarify its fracture mechanism, we made an experiment to fracture a mortar specimen of 200 mm and 300 mm cubic by setting calcium oxide-based expansive cement in a 50 mm diameter hole bored in the center of the specimen. AE (acoustic emission) sources clustered in outside of the specimen rather than vicinity of the hole just before macroscopic cracks generated, suggesting that macroscopic cracks originated at the outside of the specimen and then extended inward. Although the expansive pressure causes tensile stress in tangential direction of the hole, the stress is the maximum in the hole wall and decrease in proportion to square of the distance from the hole. On the other hand, thermal stress due to heating of the hole is tensile in the outside of the specimen but it is compressive in the vicinity of the hole. Thus, it could be concluded that thermal stress has large effects in the fracture caused by calcium oxide-based expansive cement, at least, in a rock or concrete block without preexisting crack
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