Temperature-Insensitive Corrosion Monitoring in Reinforced Concrete Structures Using Ground-Penetrating Radar

Ground-penetrating radar (GPR) has shown its potential for corrosion detection in reinforced concrete (RC) structures. However, conventional GPR systems exhibit limited sensitivity to early-stage corrosion and fluctuations in corrosion rates, primarily due to their weak responsiveness to minor material changes and susceptibility to environmental temperature fluctuations. To overcome these limitations, this study proposes a novel monitoring approach that uses second reflections captured by a GPR system with the antenna oriented perpendicular to the rebar. This polarization enhances corrosion detection accuracy by maximizing the electromagnetic interaction with the rebar’s cross-sectional geometry. Moreover, second reflections amplify corrosion-induced signal changes through multiple interactions, thereby improving sensitivity to corrosion progression. To address the influence of temperature variations in GPR signals, this study introduces the intersection point of second reflections across different temperatures as a stable and temperature-insensitive monitoring parameter. This intersection point is highly responsive to corrosion damage while remaining unaffected by temperature fluctuations, ensuring reliable corrosion assessment. Experimental validation confirms that this parameter exhibits strong sensitivity to early-stage corrosion and variations in corrosion rates. This technique offers significant potential for accurately estimating rebar mass loss due to corrosion, representing a promising advancement in the nondestructive monitoring of RC structures.