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The ageing of reinforced concrete (RC) structures in the industrialized countries increases the probability of durability issues. The mechanism of chloride-induced corrosion, the most common deterioration process in RC structures, is still not well understood. Improvement in the understanding of localized corrosion initiation is crucially required to allow for cost efficient and durable maintenance of the existing infrastructures and for service life design of new structures. This study reports results from localized electrochemical characterization of reinforcing steel surfaces taken with a local sensor positioned at different locations on the rebars. This permitted “mapping” the local Open Circuit Potentials for different rebars with different surface conditions. Moreover, local cyclic voltammetries on selected spots were also carried out. Subsequently, the samples were exposed to a chloride solution to provoke corrosion initiation. The corrosion initiation sites from visual inspection were correlated with the local electrochemical characterization. Results show a clear difference depending on the surface condition. Furthermore, for non-rusted surfaces, a spatial distribution of the local electrochemical behaviors seems to follow a pattern depending on the geometry of the steel bar and influencing the location of corrosion initiation.

Robot‐assisted point‐by‐point wire and arc additive manufacturing is considered a promising technology for optimising the production of metallic connections used in complex nodes, space trusses or grid shells. While mechanical properties of such elements were proved suitable for structural applications, a lack of knowledge exists concerning their durability. We investigate the corrosion performance of low carbon steel bars produced by point‐by‐point wire and arc additive manufacturing. Metallurgical analyses show uniform microstructure along the length of the steel bars. Corrosion initiation tests in simulated atmospheric exposure reveal the influence of geometry on corrosion, in particular, the presence of concave areas. The surface state and postprinting cleaning processes were investigated with microscopy and electrochemical techniques. These experiments indicate a detrimental effect of oxide scales due to the wire and arc additive manufacturing process on the corrosion behaviour of the steel. The results of the study show that special care must be given to the geometry and surface state of wire and arc additively produced low carbon steel components in case of long‐term use.

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