The deterioration of concrete due to corrosion of reinforcing steel bars is a widespread problem in civil infrastructure systems. Corrosion of the reinforcing steel creates tensile stresses in the concrete that lead to subsurface cracking delaminations) and eventually spalling of the concrete. Once spalling of the concrete is observed through visual inspection, deterioration is typically widespread such that significant remediation is required. This presents a significant challenge for inspection and maintenance engineers. The typical method for detecting delaminations in the concrete is hammer sounding, which requires hands-on access to the material under inspection. The application of infrared imaging to detect the subsurface features in concrete has the potential to image these types of defects from a distance, such that direct access to the surface of the concrete is not required. However, the method relies on environmental conditions to create thermal gradients in the concrete such that these subsurface features can be detected. The study reported here examines environmental conditions that effect the detectability of subsurface deterioration in concrete. The effects of solar loading from direct sunlight and wind speed have been examined. The optimum time of day for the detection of subsurface defects and the effect of their depth is discussed.

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