Development and application of a novel low-cost capacitive sensor for accurate rebar position detection

Abstract A novel effective while low-cost capacitive transducer (CT), which can precisely measure rebar size and reinforcement position in both x-axis and y-axis under concrete cover using capacitance signals, is originally developed. In this paper, numerical simulations and experiments have been carried out to verify the effectiveness of the developed capacitive sensor. In the numerical simulations, electrostatic field distribution has been built and FEM method is adopted to compute the theoretical capacitance outputs during the rebar position testing, in which two kinds of capacitance measuring methods are compared. The same-face electrodes capacitance sensing method is proved to have better performance of rebar position prediction in both x-axis and y-axis directions than the face-to-face electrodes capacitance sensing method. To verify the effectiveness of the developed capacitive sensor in the real onsite scenario, experiments have also been conducted for the rebar position testing in the reinforced concrete. Both simulations and experimental results have shown that the developed CT with innovative capacitance measuring method has great accuracy in predicting the rebar size and position, which is the foundation of the future reinforcement corrosion detection.