Reinforcement corrosion of concrete structures is investigated by the non-destructive techniques. Investigated electrochemical parameters, i.e. half-cell potential, polarization resistance and concrete resistance are used to amount the corrosion rate. Above parameters are combined by theoretically developed methods to calculate the macro-cell corrosion rate. The results show that the calculated currents by theoretical methods represent the behaviour of macro-cell corrosion compared to half-cell potentials only. However, they are not matching when the polarization resistance is taken into account. None of the method show a similarity with the macro-cell current measured using a segmented steel bar. [This abstract is not included in the PDF)