| Project/Area Number |
16560623
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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 |
Material processing/treatments
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| Research Institution | Iwate university |
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Principal Investigator |
YASHIRO Hitoshi Iwate University, Faculty of Engineering, professor, 工学部, 教授 (60174497)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2004: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | mortar / reinforcing bar / corrosion / concrete / residual magnetization / SQUID / non-destructive evaluation |
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| Research Abstract |
A new-magnetic corrosion probe has been developed for nondestructive evaluation of concrete against corrosion of reinforcing bar. Two types of probes, a thin iron wire (probe A) and an iron-plated (1 μm thick) copper bar (probe B) were tested whether their changes in residual magnetization with progress of corrosion of iron could be detected using a superconducting interference device (SQUID) magnetometer. The preliminary tests carried out under an atmospheric condition showed that the residual magnetization became less intensive with progress of corrosion for both probes. Then the two types of probes were embedded in mortar for an accelerated corrosion test. The results showed that probe A scarcely corroded in mortar despite that reinforcing bar suffered from corrosion under the identical condition. The probe B corroded as reinforcing bar did, resulting in a sharp decrease in the residual magnetization. The magnetic corrosion probe B was further improved in terms of magnitude and stability of residual magnetization. A thicker (10 μm thick) probe was prepared successfully with a help of saccharin in an electroplating bath. The probe was heat treated before use in order to stabilize the residual magnetization. Then the probe was embedded in mortar for an accelerated corrosion test. The residual magnetization of the 10μm thick probe showed a slower change in comparison with 1 μm thick one. Therefore, the sensitivity of the probe against the corrosiveness can be adjusted by the thickness of plated iron. Thus, the developed probe embedded in mortar can give a magnetic warning against degradation of surroundings regarding the corrosion of reinforcing bar.
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