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Smart Structures and Systems
  Volume 22, Number 1, July 2018 , pages 1-11
DOI: https://doi.org/10.12989/sss.2018.22.1.001
 


Electrical impedance-based crack detection of SFRC under varying environmental conditions
Man-Sung Kang, Yun-Kyu An and Dong-Joo Kim

 
Abstract
    This study presents early crack detection of steel fiber-reinforced concrete (SFRC) under varying temperature and humidity conditions using an instantaneous electrical impedance acquisition system. SFRC has the self-sensing capability of electrical impedance without sensor installation thanks to the conductivity of embedded steel fibers, making it possible to effectively monitor cracks initiated in SFRC. However, the electrical impedance is often sensitively changed by environmental effects such as temperature and humidity variations. Thus, the extraction of only crack-induced feature from the measured impedance responses is a crucial issue for the purpose of structural health monitoring. In this study, the instantaneous electrical impedance acquisition system incorporated with SFRC is developed. Then, temperature, humidity and crack initiation effects on the impedance responses are experimentally investigated. Based on the impedance signal pattern observation, it is turned out that the temperature effect is more predominant than the crack initiation and humidity effects. Various crack steps are generated through bending tests, and the corresponding impedance damage indices are extracted by compensating the dominant temperature effect. The test results reveal that propagated cracks as well as early cracks are successfully detected under temperature and humidity variations.
 
Key Words
    self-sensing concrete; electrical impedance; crack detection; steel fiber-reinforced concrete; structural health monitoring; temperature and humidity variation
 
Address
Man-Sung Kang and Yun-Kyu An:Department of Architectural Engineering, Sejong University, 209, Neungdong-ro, Gwangjin-gu, Seoul, 05006, Republic of Korea
Dong-Joo Kim: Department of Civil and Environmental Engineering, Sejong University, 209, Neungdong-ro, Gwangjin-gu, Seoul, 05006, Republic of Korea

 

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