Damage and defect detection through infrared thermography of fiber composites applications for strengthening of structural elements

Fiber Reinforced Polymer (FRP) composites are today widely used for the strengthening and seismic retrofitting of structures. The efficiency of this technology is strongly dependent on the correct positioning and bonding of the fibers on the surface of the structure to be reinforced. The connection between the surface of the substrate (concrete, masonry or steel) and the fibers is assured by the adhesives. The control of the application may be performed with different Non Destructive Evaluation (NDE) techniques but presently there are no standard procedures to assess the quality of the applications in civil engineering structures. Infrared thermography represents a valid tool for the detection and measurement of bonding defects or damage in the composite strips and can be used even for the definition of possible damage progression. The paper presents a series of results obtained using infrared thermography for different types of applications: masonry walls and concrete beams.