Identifying NDT methods for damage detection in concrete elements reinforced or strengthened with FRP

Abstract

The application of Fiber Reinforced Polymer (FRP) materials in concrete structures has been rising due to their several advantages, including lightweight, high tensile strength, ease of installation, and corrosion resistance. They have been mostly implemented for strengthening and repairing existing structures in the form of an externally bonded system, i.e., sheet, jacket, near surface mounted. Furthermore, they have been recently utilized as internal reinforcement of concrete elements in the form of bars, meshes and tendons. Although higher durability and performance are associated with the FRP as compared to steel, this fact does not exclude the possibility of damages and defects, many of which are related to their unique features. For example, debonding of FRP materials from a concrete surface or within a concrete element has occurred and needs to be corrected to avoid the premature failure of a structure. To this end, concrete elements reinforced or strengthened with FRP materials (FRP-RSC) should be inspected periodically to detect potential problems and hence prevent premature failures. This study first determines possible or potential damages and anomalies attributed to FRP-RSC elements. It then investigates Non-Destructive Testing (NDT) methods that can be applicable to the inspection of FRP reinforced/strengthened concrete elements from a literature survey of past studies, applications, and research projects. Finally, it proposes the most promising methods for detecting FRP and their damage/defects in FRP-RSC elements. By providing the inspection community with more clarity in the application of NDT to FRP, the results of this study offer means for verifying the performance and, therefore, help the proliferation of FRP materials in concrete structures.