Estimation of the main factors influencing potential mapping

Potential mapping is a widely used inspection method for detection of corrosion activity in reinforced concrete structures. The information coming from potential mapping is of vital importance, in particular for condition control and maintenance planning. The potential field, which is caused by an electrochemical macro-cell element, is influenced by a number of different factors. Some factors are influenced by the material resistance itself, some by the environmental condition or by a combination of both (e.g. the concrete resistivity and the oxygen level), others are influenced by the geometry of the tested member (e.g. concrete cover) or by geometric conditions caused by the procedure, e.g. grid size. These factors are well known in practice and literature, but the problem is, to analyze these influences separately. All influencing factors have to be evaluated with regard to the defect size; in the case of potential mapping: the anode area. However, in laboratory or on site the correct determination of the anode area during potential mapping is difficult to perform. The aim of this paper is the estimation of the main factors influencing potential mapping by means of numerical simulation. It is expected that some recommendations concerning the procedure and the interpretation of potential mapping data can be derived.