Infrared Thermography Testing of FRP Bridge Decks

Abstract

This paper presents the results from an experimental study that investigated the use of infrared thermography for subsurface defect detection in Fiber Reinforced Polymer (FRP) bridge decks. FRP bridge deck specimens were cast with embedded subsurface defects (air‐ and water‐filled) of varying planar sizes and thicknesses. These decks were tested using infrared thermography under the influence of several heating sources including a quartz heater, heating blanket and solar radiation. The solar radiation test was conducted for a full 24 hour cycle in order to observe both daytime and nighttime surface temperature profiles. While the daytime surface temperature differences between defective and defect‐free areas were significant (up to 4 °C), it was found that the nighttime temperature differences were less than 0.5 °C. The study also compared the results between hot sunny weather and relatively cold weather.