| Abstract: | Factors influencing the activity of reinforcing steel as cathode on the soil corrosion of steel Factors influencing the corrosion cell established between steel/soil (anode) and reinforcing steel in concrete (cathode) were investigated in field tests extending up to 3 years. In all cases, the differences between the corrosion rates measured in the cell and under free corrosion conditions were higher than the equivalent cell current. This effect means an increase of the cathodic partial reaction by cell action (negative difference effect), and is related to better protecting layers in the case of free corrosion. As to the cathodes, the parameters of the concrete have nearly no effect. But galvanizing of the reinforcing steel has a strong influence on the cell action. Since the cell resistance is mainly controlled by the electrolyte resistance (ground resistance of the anodes) the changes in the polarization resistance of the cathodes can hardly influence the cell action. A decrease of cell currents due to galvanizing the reinforced steel is no doubt present, but the effect is too poor for proper protection against cell activities. Therefore, only conventional electrochemical methods or organic coatings on the reinforcing steel can be applied as protective measures. |
