Modelling of the steel–concrete interface to obtain information on reinforcement bar corrosion

The selection of an equivalent circuit that faithfully models the steel–concrete interface response to the application of electrical signals is a fundamental aspect of the electrochemical determination of reinforcement corrosion rate. Experimental evidence is provided in favour of using a modified Randles circuit in which the corroding interface is characterised by a parallel combination of a constant phase element and a charge transfer resistance in series with a Warburg element. An advantage of having an appropriate model of the steel–concrete system is the possibility of carrying out studies of quality of the information that is extracted from the experimental data. A sensitivity-algorithm is applied with the object of identification of the conditions in which the system’s response is dominated by certain parameters or combinations of them.