Integration of active thermography and ground penetrating radar for the detection and evaluation of delamination in concrete slabs

Subsurface delamination is one of the main damage mechanisms that affect the integrity of structural components. Its detection effectively and reliably is a crucial step for in-service assurance and avoiding further accidents. In that scenario, it is necessary to explore alternatives to current inspection practices so that effective non-destructive methods can be implemented in the field. This paper investigates the application of infrared thermography and ground penetrating radar to detect and evaluate subsurface delamination in concrete components. To this aim, laboratory specimens made of reinforced concrete with Teflon inserts to simulate internal delamination are inspected with the step-heating approach. The IR data collected during the heating and cooling process is then evaluated and processed with pulsed-phase thermography and principal component regression. The extension or severity of the delamination is then evaluated with ground penetrating radar. The results will be evaluated to determine the applicability of the methods at larger scales.