Anaerobic Corrosion of Reinforcement in Concrete – Inspection Techniques, Risk Factors and Mechanisms 

Anaerobic corrosion of steel in concrete can be a highly-localised form of corrosion where the corrosion products typically do not cause the concrete to fracture, even when the reinforcement section loss is substantial. Iron ions can migrate through defects within the concrete, meaning that the locations where corrosion products are observed are not always the locations with maximum section loss. However — because anaerobic corrosion can carve through reinforcement — detecting it can be crucial. Here we review the literature on anaerobic corrosion of reinforcement. We then provide examples that we have found in a seawater conduit,  stormwater infrastructure, and a water tank, and discuss the observations made in each case. In some instances, the corrosion was identified by visual inspection of corrosion products, while other cases required breakouts or ground-penetrating radar.