| Project/Area Number |
07555133
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
土木材料・力学一般
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| Research Institution | Niigata University (1996)
Tokyo Institute of Technology (1995) |
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Principal Investigator |
NGATAKI Shigeyoshi Niigata University, Dept.of Civil Eng.and Architecture, Professor, 工学部, 教授 (00016320)
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| Co-Investigator(Kenkyū-buntansha) |
HISADA Makoto Tokyo Institute of Technology, Dept.of International Development Eng., Research, 工学部, 助手 (80238295)
OTSUKI Nobuaki Tokyo Institute of Technology, Dept.of International Development Eng., Professor, 工学部, 教授 (40211106)
MIKI Chitoshi Tokyo Institute of Technology, Dept.of Civil Eng., Professor, 工学部, 教授 (20016645)
SAEKI Tatsuhiko Niigata University, Dept.of Civil Eng.and Architecture, Associate Professor, 工学部, 助教授 (90215575)
KAMADA Toshiro Tokyo Institute of Technology, Dept.of Civil Eng., Research Associate, 工学部, 助手 (10224651)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | concrete / composite structure / structural integrity / nondestructive testing / ultrasonic / acoustic emission / infrared thermography / crack / delamination / 健全度評価 / サーモグラフィ法 / X線法 / AE法 / 弾性衝撃波法 |
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| Research Abstract |
Results of this study are summarized as follows :
(A) Study on Evaluation of Concrete Cracks by Nondestructive Testing Methods
A method to estimate the crack height in concrete structures by ultrasonic testing is investigated. This method is based on the relation between the crack height and the maximum echo amplitude obtained from the received wave. In the beginning, a regressive equation for estimating the crack height is developed from the experiments for specimens with slits. Next, the reflection of incident wave at the bottom surface of structures is investigated on the influences on the echo amplitude of received wave. From these results, it is confirmed that the proposed method is applicable to actual cracks in concrete structures.
(B) Study on Evaluation of Delamination in Concrete Members by Nondestructive Testing Methods
Ultrasonic testing and AE measurement are investigated as methods of evaluating the area and the delamination process along the interface between old concrete an
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d the repair material. The results of the investigation showed that : (1) the occurrence of delamination, as shown by the difference between strain in the old concrete and in the repair material, can be detected by ultrasonic echo-amplitude and AE energy. (2) delaminated areas can be identified through contour maps obtained from the echo-amplitude ratio. (3) the delaminated process can be grasped through variations in the contour map obtained from the echo-amplitue ratio. (4) borders of delaminated areas can be obtained from the results of AE source location analysis. (5) the area of delamination can be estimated on the basis of AE energy caluculated from the AE waveform.
(C) Study on Evaluation of Concrete Qualities by Nondestructive Testing Methods
The use of AE for evaluation of the condition of the bond between aggregate and mortar was investigated. The results show that AE hits measured at load levels between 20 and 40 % within cylindrical concrete specimens depend mainly on bond crack occurence, and that the influence of the state of the transition zone on bond crack occurence can be evaluated by the relationship between the AE hit ratio and the load level. Less
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