Kelvin Probe electrode for contactless potential measurement on concrete – Properties and corrosion profiling application

The practical feasibility of Kelvin Probe measurement of potential of the concrete surface was demonstrated. The measurements require no contact between the reference element and the concrete. Potential readings when placing the probe on dry concrete were nearly instantaneous and highly stable, in contrast with considerable potential drift with a conventional wet-tip electrode. The probe output was only modestly sensitive to the reference element working distance. The shape and range of potential profiles measured with the probe on concrete with locally corroding reinforcement were consistent with those using a conventional wet-tip reference electrode, both identifying the anode location.

► Demonstrated Kelvin Probe for contactless concrete surface potential measurements.
► Potential readings were nearly instantaneous and highly stable.
► In contrast, conventional electrodes showed considerable drift.
► The probe successfully produced potential profiles to identify corroding spots.
► Applications not possible with conventional electrodes are proposed.