Monitoring of concrete structures with respect to rebar corrosion

From security aspects as well as economic reasons it is desirable to localize reinforcement corrosion at an early stage and with non-destructive techniques in order to initiate the necessary rehabilitation measures in time. The potential mapping technique, i.e. measuring half-cell potentials at concrete surfaces with reference electrodes, is a helpful tool to obtain information about the actual state of rebar corrosion. The potential measurement can be modified by additionally applying a short anodic pulse by means of a small counter electrode and a galvanostat. In some cases this technique leads to noticeable improvements with respect to information about the probability of corrosion. The fundamentals of the two kinds of potential measurement techniques are explained and results obtained at different types of structures are described. Copyright (C) 1996 Elsevier Science Ltd.