Application of Active Microwave Thermography to delamination detection

Health monitoring of infrastructure is very important in the transportation and infrastructure industries. Many nondestructive testing (NDT) techniques have been applied for structural health monitoring including microwave NDT, ultrasound, thermography, etc. Due to the complex materials (composites, concrete, etc.) commonly used, it may be difficult to thoroughly inspect a structure using one method alone. Thus, hybrid NDT methods have also been developed. Recently, the integration of microwave NDT and thermography, herein referred to as Active Microwave Thermography (AMT), has also been considered as a potential structural health monitoring tool. This hybrid method uses microwave energy to heat a structure of interest, and then the thermal surface profile is measured using a thermal camera. This paper investigates the potential of AMT to inspect rehabilitated cement-based structures. Preliminary simulations and measurements provided herein indicate that AMT has the potential to detect delaminations under carbon fiber patches bonded to concrete.