Bridge decks in Canada are deteriorating rapidly due to exposure to various degradation mechanisms. Exposure to freezing and thawing cycles coupled with the ingress of chloride ions from de-icing salts used during winter seasons typically damage bridge decks at a higher rate than other bridge components. Recently, there has been an increase in the use of non-destructive testing (NDT) methods to augment visual inspection of bridge decks for better informed decisions related to deck rehabilitation and replacement. Detecting subsurface delamination defects using remote sensing and data collection, without physical contact, is a paramount advantage of infrared thermography (IRT). Moreover, detecting corrosion defects with minimal human data interpretation is a key advantage of ground penetrating radar (GPR). In the present study, IRT and GPR are combined to inspect a full-scale reinforced concrete bridge deck in order to detect anomalies such as subsurface delamination, cracking, and corrosion defects. The IRT data are presented as temperature contrast on the concrete surface and analyzed to create a delamination map of the bridge deck, while the GPR data are presented as reflected amplitude profiles of the top rebar layer and analyzed to create a corrosion map of the bridge deck. While the two techniques rely on different mechanisms, their results show good agreement. The findings from this case study demonstrate that the combination of IRT and GPR is a practical option for consistent and rapid in-situ evaluation of reinforced concrete bridge decks, representing a strong contender for incorporation in bridge deck inspection manuals.
