Reliable Corrosion Monitoring in RC Structures Using a Temperature-Insensitive GPR Approach

Corrosion of reinforcing bars is a primary cause of deterioration in reinforced concrete structures. Early detection of corrosion is critical for timely maintenance and ensuring structural safety. Ground penetrating radar (GPR) has shown strong potential for corrosion monitoring due to its sensitivity to changes in material properties induced by corrosion. However, conventional GPR systems face challenges in detecting early-stage corrosion and tracking variations in corrosion rate, primarily due to their limited responsiveness to subtle material changes and susceptibility to signal dispersion caused by temperature fluctuations. To address these limitations, we propose a monitoring method based on a perpendicular-polarized antenna system, which enhances electromagnetic interaction with the cross-section of rebars. This configuration enhances sensitivity to subtle corrosion-induced material changes surrounding the rebars. In addition, a temperature-insensitive intersection point, derived from second-order rebar reflections, is introduced as a reliable indicator for tracking corrosion progression. This point amplifies the detection of subtle corrosion-induced changes through multiple signal interactions while maintaining robustness against temperature-induced signal dispersion. Experimental results validate the effectiveness of the proposed method, demonstrating enhanced sensitivity to early-stage corrosion and improved tracking of corrosion rate variations. The approach offers a reliable and robust solution for long-term, non-destructive corrosion monitoring in reinforced concrete structures.