Early Debonding Detection of Rebar-Concrete Interface due to External Loading Utilizing AC Impedance Spectroscopy

Abstract

A novel method for detecting early damage at the steel-concrete interface due to external loading based on AC impedance spectroscopy technology was proposed. Firstly, alkali pretreatment was introduced to ensure the accuracy and repeatability of the AC impedance test. Secondly, the AC impedance spectroscopy between the steel bar and concrete surface of different bonding positions was tested, and then the physical quantities reflecting the bonding damage condition were obtained by equivalent circuit fitting. Theoretical debonding position calculation and AC conductive structure analysis indicate that the change of interface resistance and interface capacitance can seize the development of bonding damage during the loading process. As the interface damage develops, obvious changes in interface resistance and interface capacitance are observed, and they cannot be recovered after unloading.

Keywords

concrete / bond / AC impedance spectroscopy / equivalent circuit model / damage

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