A low-cost electrical impedance analyser for interrogating self-sensing cement repairs

In this paper, we showcase initial results from a bespoke, low-cost interrogator for complex impedance measurements of our robotically deployed self-sensing cement (geopolymer) technology for concrete monitoring and maintenance. Our low-cost (£30, $40 USD) interrogation system is benchmarked against the performance of a £12k ($16k USD) commercially available lab-spec electrical impedance analyser. Results show the low-cost interrogator is able to match the commercial interrogation system well-enough for the field measurement of impedance, with an impedance root mean square error (RMSE) of ±5.4 % for an ideal cell. For pure geopolymer samples, similar results are found, with an RMSE of ±5.2 %. During patch measurements, although non-linearity was witnessed, the low-cost interrogator showcased the ability to measure the impedance and impedance-frequency variations. Therefore, the first iteration of low-cost interrogator design shows promise for monitoring geopolymer self-sensing repair complex impedances in the field.