The detection of subsurface damage using Infrared Thermography (IRT) typically relies on a subjective assessment of a color-coded image representing the surface temperature of the concrete. The accuracy of the technique may be analyzed by comparison with cores extracted from the test object in areas where subsurface damage is detected in the IR image. Assessing the accuracy in this way may be of limited utility if it is not accompanied with an assessment of the false positive rate (FPR) and the false negative rate (FNR). This paper presents an analysis method to quantitatively interpret IRT data and objectively assess its reliability for the detection of subsurface delamination, considering all correct and incorrect output. Receiver operating characteristics (ROC) in conjunction with a simplified image processing method were used to accomplish the objective of the research. Results of the study have demonstrated the capability of IRT technology to discern delaminated and sound concrete based on testing of simulated delamination. This conclusion was reached since the nonparametric estimate of the area under the ROC curve (AUC) and its 95% confidence limits were 0.867 and 0.842∼0.884, respectively.
1. Nenad Gucunski, A.I., Francisco Romero, Soheil Nazarian, Deren Yuan, Herbert Wiggenhauser, Parisa Shokouhi, alexander Taffe, Doria Kutrubes, Nondestructive Testing to Identify Concrete Bridge Deck Deterioration. 2013.
2. Metz, C.E., Receiver operating characteristic analysis: a tool for the quantitative evaluation of observer performance and imaging systems. J Am Coll Radiol, 2006. 3 (6): p. 413-22.
3. Martino, N., et al., Determining Ground Penetrating Radar Amplitude Thresholds for the Corrosion State of Reinforced Concrete Bridge Decks. Journal of Environmental and Engineering Geophysics, 2014. 19 (3): p. 175-181.
4. Shin, H. and D. Grivas, How Accurate Is Ground-Penetrating Radar for Bridge Deck Condition Assessment? Transportation Research Record: Journal of the Transportation Research Board, 2003. 1845 (- 1): p. 139-147.
5. Rumbayan, R. and G.A. Washer, Modeling of environmental effects on thermal detection of subsurface damage for concrete bridges. 2013.
6. Davis, A., et al., Nondestructive test methods for evaluation of concrete in structures. American Concrete Institute, ACI, 1998. 228 .
7. Zweig, M.H. and G. Campbell, Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine. Clinical chemistry, 1993. 39 (4): p. 561-577.
8. ASTM, Standard ASTM D4788 - 03(2007) Standard Test Method for Detecting Delaminations in Bridge Decks Using Infrared Thermography. Standard Test Method for Detecting Delaminations in Bridge Decks Using Infrared Thermography", ASTM International, West Conshohocken, PA, 2007.
9. Brown, C.D. and H.T. Davis, Receiver operating characteristics curves and related decision measures: A tutorial. Chemometrics and Intelligent Laboratory Systems, 2006. 80 (1): p. 24-38.
10. Washer G., B.N., Fenwick R., and Harper J., Effects of Environmental Variables on the Infrared Imaging of Subsurface Features in Concrete Bridges. Transportation of Research Board, 2009. No. 2108 : p. 107-114.
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