According to a comprehensive study conducted in 1998 by CC Technologies, corrosion to the US economy was $276 billion or 3 % of the 1998 GDP (FHWA-RD-01-156). From that amount, $121 billion was spent on corrosion control and $107 billion was spent on protective coatings alone. CC Technologies reported that better corrosion protection could save up 40% of that cost. Improved practices for corrosion protections are: coating quality control and effective inspection at time of coating application; routine/periodic coating inspection during the service life of the structure; an appropriate repair action when coating degradation or delaminate or substrate corrosion is detected. Currently Federal guidelines hold contractors responsible for coating quality. However there is no federal guideline or other practical methodology for evaluating a protective coating quality and subsurface condition.

The objective of this research project is evaluation of infrared thermography as a method for detecting hidden corrosion on steel structures. A previously conducted research validated an infrared thermography as a method for detection of early corrosion onset in gas pipelines beneath the protective coating. The studies indicated that it is possible to detect corrosion at earlier than with current ultrasonic thickness gauges. Also it is possible to detect poor quality coating, such as the presence of air blisters, even in the absence of corrosion. Furthermore thermal imaging is a two dimensional technique and lends itself for improved inspection and documentation of surfaces.