| Project/Area Number |
12450178
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
MIYAGAWA Toyoaki Dept. of Civil Eng., Kyoto University, Prof., 工学研究科, 教授 (80093318)
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| Co-Investigator(Kenkyū-buntansha) |
UEDA Takao Tokushima Univ., Associate Prof., 工学部, 助教授 (20284309)
KOBAYASHI Koichi Chubu Univ., Instructor, 工学部, 講師 (20283624)
HATTORI Atsushi Dept. of Civil Eng., Kyoto University, Associate Prof., 工学研究科, 助教授 (30243067)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥10,700,000 (Direct Cost: ¥10,700,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2000: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Keywords | Desalination / Effect of Repair / Micro Vickers Hardness / Bond Strength / Reinforced Concrete / Prestressing Steel / Prestressed Concrete / Hydrogen Embrittlement / 水素脆化 / 耐荷性能 / アルカリ骨材反応 / 供用性判定 / 片引試験 / 曲げ試験 / ひび割れ分散性 |
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| Research Abstract |
Desalination is an electrochemical method aimed at removing chlorides from reinforced concrete structures. In this study, influences of applying desalination on durability and load-carrying capacity of RC structures were investigated.
The results obtained in this study can be summarized as follows.
(1) As results of the pull-out test, maximum bond stress of treated specimens was found to be smaller than that of non-treated specimens. The decrease due to desalination became larger with an increase in the amount of premixed chlorides or an increase in the total current density, because soft layers were formed around the steel bars due to passing of electric current.
(2) According to the results of flexural test of beams containing 8.0 kg/m3 of C1, the change in the ultimate load was slight and the capacity of deflection increased at 8 weeks treatment.
(3) In the case of flexural failure type beams, maximum crack width at the reinforcing steel level of specimens receiving 4 weeks treatment was less than that of non-treated ones. However, in some specimens treated for 8 weeks, maximum crack width at the reinforcing steel level was greater than the permissible crack width. Moreover, by applying desalination, the number of cracks was decreased and crack distribution became deteriorated.
(4) Slow strain rate tensile tests on prestressing steel removed from treated PC prism specimens indicated no change in elastic behavior nor strength-related properties but the fracture behavior was altered by the absorbed hydrogen. For example, the falling branch in stress-strain curves was shortened and the contraction rate of fractured steel section decreased as compared with non-treated specimens.
(5) As results of flexural loading tests on treated PC beams, the rupture of prestressing steel due to hydrogen embrittlement were not observed, and both load-displacement performance was not reduced by desalination, compared with the non-treated specimens.
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