Near-Field Microwave Detection of Disbond in Fiber Reinforced Polymer Composites Used for Strengthening Concrete Structures and Disbond Repair Verification


The use of carbon fiber reinforced polymer (CFRP) composites has been investigated in the past few years as a means to rehabilitate aging concrete structures. The detection of disbonds and delaminations between CFRP laminate and the concrete substrate is a critical issue in this area, as the presence of such defects adversely affects the effectiveness of the reinforcement. Thus, the development of a nondestructive testing (NDT) technique to detect these types of defects is of great interest in this field. Furthermore, any such method should also be capable of verifying the quality of the repair of such defects. Near-field microwave NDT techniques, utilizing open-ended rectangular waveguides, have shown great potential in the past for detecting delaminations and disbonds in complex composite structures. Microwave NDT techniques have the added advantages of providing real-time, noncontact, one-sided, rapid, and robust measurements. This paper presents the experimental results of detecting disbonds in a specially prepared CFRP reinforced mortar sample using near-field microwave NDT techniques, as well as the preliminary results showing the capability of this technique for verifying repair quality.


Civil, Architectural and Environmental Engineering

Second Department

Electrical and Computer Engineering

Keywords and Phrases

Composite Materials; Fiber Reinforced Polymers; Microwaves; Nondestructive Tests; Rehabilitation; Sensors; Composite Testing and Evaluation; Infrastructure Testing and Cement-Based Material Evaluation

Document Type

Article - Journal

Document Version


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© 2004 American Society of Civil Engineers (ASCE), All rights reserved.