Screen-printed electrode as a cost-effective and miniaturized analytical tool for corrosion monitoring of reinforced concrete

Herein, we report the first electrochemical sensor based on a screen-printed electrode designed to evaluate the corrosion level in iron-reinforced concrete specimens. The combination of an Ag pseudoreference electrode with a gel polymeric electrolyte allows for fast, stable and cost-effective potentiometric measurements, suitable for evaluating the corrosion of iron bars embedded in concrete samples. The sensor was found to be capable of discriminating between a standard non-corroded sample and samples subject to corrosion due to the presence of chloride or carbonate in the concrete matrix. The potential in concrete-based specimens containing carbonate (pH 9, −0.35 ± 0.03 V) or chloride (4% w/w, −0.52 ± 0.01 V) was found to be more negative than in a standard concrete-based sample (−0.251 ± 0.003 V), in agreement with the ASTM standard C876 method which uses a classical Cu/CuSO4 solid reference electrode. Our results demonstrate that a printed Ag pseudoreference electrode combined with KCl agar provides an efficient and reliable electrochemical system for evaluating the corrosion of iron bars embedded in concrete-based structures.