2007 Fiscal Year Final Research Report Summary
Nondestructive Controlled Failure of Concrete based on Elastic-Wave Methods
| Project/Area Number |
16206045
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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 | 一般 |
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| Research Field |
Civil engineering materials/Construction/Construction management
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| Research Institution | Kumamoto University |
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Principal Investigator |
OHTSU Masayasu Kumamoto University, Graduate School of Science & Technology, Professor (80109016)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGEISHI Mitsuhiro Kumamoto Univ, Graduate School of Science & Technology, Assoc. Professor (50253761)
TOMODA Yuichi Kumamoto Univ, Faculty of Engineering, Research Technician (90418830)
KAMADA Toshiro Osaka Univ, Graduate School of Engineering, Professor (10224651)
WATANABE Takeshi Tokushima Univ, Graduate School of Socio-Techno Science, Assistant Prof (50332812)
SUZUKI Tetsuya Nihon Univ, School of Bio-Resource Science, Research Assistant (30434103)
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| Project Period (FY) |
2004 – 2007
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| Keywords | Nondestructive Evaluation / Elastic-Wave Methods / Acoustic Emission / Moment Tensor Analysis / Fracture Mechanics |
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| Research Abstract |
Controlled failure of concrete has been studied by applying the elastic-wave methods, which primarily include acoustic emission, impact echo and ultrasonic. Targeting existing concrete structures, nondestructive monitoring, failure mechanisms and damage evaluation have been clarified. Results achieved are summarized, as follows;
1. Identification of failure mechanisms of concrete by acoustic emission (AE)
AE techniques have been applied to failure process of a variety of cementitious materials. Thus, the failure mechanisms of concrete and concrete structures are clarified.
2. Fracture monitoring of concrete structures by nondestructive evaluation
Monitoring of cracks and defects has been nondestructively investigated. In particular, applications of the impact echo and ultrasonics are extensively studied. Visualization of internal defects by the SIBIE(Stack Imaging of spectral amplitudes Based on Impact Echo)procedure is practically performed
3. Mechanisms of dynamic failure based on elastod
… More
ynamics
Blasting failure of fiber-reinforced concrete has been theoretically studied, and the effect of resonant vibration on failure modes is clarified. Thus, failure process of concrete can be monitored under impact loading, and dynamic fracturing due to pulse-discharge. The latter technique is substantially applied to fabrication of recycled aggregate.
4. Application of fracture mechanics and damage mechanics to controlled failure
With the collaboration of international researchers, fracture mechanics and damage mechanics have been studied in cementitious materials. The SiGMA procedure has been developed for the moment tensor analysis of AE sources(cracks). Visualized presentation of crack location, crack type and crack orientation is now available. Cracking mechanisms at the meso-scale and the macro-scale are clarified by applying the boundary element method(BEM)analysis and AE analysis.
5. Nondestructive monitoring for controlled failure in concrete
Measurement techniques based on the elastic-wave methods have been established for controlled failure. Depending on failure modes of concrete from statics to dynamics, proper measuring and analyzing techniques are developed. Less
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