| Project/Area Number |
09555134
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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 | 展開研究 |
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| Research Field |
土木材料・力学一般
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| Research Institution | Kanazawa University |
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Principal Investigator |
TORII Kazuyuki Department of Civil Engineering, Kanazawa University Professor, 工学部, 教授 (50115250)
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| Co-Investigator(Kenkyū-buntansha) |
ISHII Kouji PS Corporation Ltd.Senior Researcher, エス・開発技術部, 主任研究員
KAWAMURA Mitsunori Department of Civil Engineering, Kanazawa University Professor, 工学部, 教授 (20019730)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥4,300,000 (Direct Cost: ¥4,300,000)
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| Keywords | Alkali-silica Reaction / Cathodic Protection / Direct Current / Crack / Repair and Strengthening / Electro-chemical Migration Test / アルカリ骨材反応 / 補修 / 屋外暴露試験 / 耐荷力 / ゲルフルオレセンス法 |
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| Research Abstract |
Reinforced concrete beams with different water : cement ratios, 0.2 m by 0.3 m by 2 m, were made from the non-reactive river sand and the reactive andesitic coarse aggregate. After 28 days of the curing time, reinforced concrete beams were exposed outdoors, and the cathodic protection current of 50 mA/m^2 was applied to the steel reinforcement of RC beams. The expansion and cracking were monitored for about 3 years in order to investigate whether or not the cathodic protection may really accelerate the alkali-silica reaction of concrete around the steel cathode. After 3 years of the exposure time, the flexural loading test was carried out for ASR damaged RC beams.
The main results obtained in this study are as follows ;
(1) The concrete cylinders deteriorated due to the occurrence of ASR cracks in spite of the total alkali content of less than 3 kg/m^3 when they were exposed to a natural environment.
(2) The cathodic protection current significantly increased the expansion and cracking of the RC beams containing alkali-reactive aggregates.
(3) The surface treatment by the epoxy-type coating was not effective in controlling the expansion due to ASR especially when the cathodic protection was applied.
(4) The load-bearing capacity in bending of the RC beams did not change independently of the degree of deterioration due to ASR cracks when the cathodic protection was not applied.
(5) The load-bearing capacity in bending of the RC beams was 10 to 20 % lower due to the decrease in the bond strength around the steel cathode when the cathodic protection was applied for a long period.
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