ABSTRACT
The onset of corrosion consists in the passage of the steel state from a passive or negligible corrosion rate to an active corrosion state identified visually by the appearance of rust (Page et al 1982) with the corresponding loss of bar cross section. The corrosion rate is not commonly measured in spite of its importance to predict the evolution of the loss in structural load bearing capacity. One of the difficulties in the interpretation is linked to the evolution of the values of the corrosion rate with the climate due to its dependence on the degree of concrete water saturation and on the temperature (Vennesland 1997) (Andrade et al. 2002). In present paper are presented examples of variations of the corrosion rate Icorr in specimens exposed to natural atmospheres and of the accumulated corrosion penetration, Pcorr, which has much less variation than the instantaneous corrosion rate.
