Detecting Interfacial Debonding of FRP-Concrete Joints using Active Microwave Thermography


Civil engineering structures that have been strengthened with externally bonded fiber reinforced polymer (FRP) composites can be challenging to inspect. This study explores the use of a new nondestructive testing (NDT) technique referred to as active microwave thermography (AMT) to detect interfacial debonding of FRP-strengthened concrete structures. An experimental campaign was carried out in which FRP-concrete joint specimens were tested in a single-lap direct shear setup and subjected to monotonic loading. Microwave energy was used to heat the specimens, and subsequently the surface thermal profile within the composite bonded area was measured using a thermal camera. The premise is that as the microwave energy heats the FRP-concrete interface, interfacial debonding and cracking disrupts the thermal diffusion and results in a local concentration of heating. The thermal profiles were used in an attempt to detect the initiation and propagation of interfacial debonding. Overall, the preliminary results presented here indicate the strong potential of AMT as an NDT tool for health monitoring of FRP-rehabilitated concrete structures.

Meeting Name

9th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII-9 (2019: Aug. 4-7, St. Louis, MO)


Electrical and Computer Engineering


National Science Foundation, Grant 1609470

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2019 International Society for Structural Health Monitoring of Intelligent Infrastructure (ISHMII), All rights reserved

Publication Date

07 Aug 2019

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