Assessment of the Bond Quality Degradation in FRP-strengthened Masonry using IR Thermography Technique

The FRP-to-masonry bond behavior in externally bonded reinforced masonry structures is the main mechanism in controlling the effectiveness of this technique. Therefore, monitoring the quality of bond during the service life of the structure is of crucial importance for structural health evaluation. The bond quality may be affected due to environmental conditions which results in local detachments at the FRP/substrate interface. These detachments can propagate along the interfacial region and affect the bond performance to a large extend. Therefore, the use of feasible non-destructive techniques for assessment of the bond quality and monitoring the debonded areas are of great interest. This paper investigates the applicability of infrared thermography technique in the assessment of the bond detachments in environmentally degraded FRP-strengthened masonry elements. FRP-strengthened specimens have been exposed to accelerated environmental conditions in a climatic chamber and the changes in the bond quality are monitored with infrared thermography technique. Infrared thermal videos were taken from the specimens after different periods of exposure to accelerated environmental conditions and the delaminated areas have been quantitatively evaluated. The obtained results are presented and critically discussed. It is observed that this technique can provide acceptable results for the system investigated in this study