Considerations and Issues in the Utilization of Infrared Thermography for Concrete Bridge Inspection at Normal Driving Speeds

The main objective of this study is to comprehensively evaluate the utilization of infrared thermography (IRT) considering different technologies, critical environmental parameters, and uncertainties for bridge deck evaluation. For this purpose, a real bridge was scanned and the results were compared with other nondestructive evaluation (NDE) technologies that were implemented on the same bridge. There are a number of considerations and factors that affect the utilization of IRT, such as thermal contrasts, camera specifications, distance, and utilization speed, and these are evaluated by using three different infrared (IR) cameras with different specifications. These considerations are discussed and results are presented. When compared at fully documented locations with eight concrete cores, a high-end IR camera with cooled detector distinguished sound and delaminated areas accurately. Furthermore, indicated location and shape of delaminations by three IR cameras were compared with other NDE methods from past research, and the results revealed that the cooled camera showed shapes almost identical to other NDE methods including chain drag. It should be noted that these data were collected at a normal driving speed without any lane closures, making it a more practical and faster method than other NDE technologies. It is also presented that the factor most likely to affect high-speed application is integration time of the IR camera.