[EN] Galvanisation of steel reinforcement has been usual practice for the last decades as a protection against certain types of aggressive agents. However, recent results, mostly European, have thrown doubts on the usefulness of galvanisation. The results presented here contribute to explain this controversy. We have identified three factors that may influence the corrosion kinetics of galvanized steel bars embedded in concrete, although they usually go unheeded: type of galvanized coating, type of cement and humidity during curing and hardening. From these factors, this report deals mostly with ambient humidity. Corrosion rate was basically estimated from the Polarisation Resistance in reinforced mortar specimens that were cyclically subjected during curing and hardening to different ambient humidities. The influence on the corrosion kinetics of the structure of the galvanized coating which, in turn, depends on the chemical composition of the steel, is also discussed. Finally, the behaviour of bare and galvanized steel are compared, and criteria are given on the usefulness of galvanized coatings.

[FR] On énonce trois des causes possibles qui, de l’avis des auteurs, ont donné lieu à la discussion actuellement suscitée sur la durabilité de la galvanisation en tant que méthode de protection de l’acier noyé dans le béton: type de structure de la galvanisation, type de ciment, humidité de la cure et durcissement. Dans ce travail, on étudie essentiellement, entre ces trois facteurs, l’effet de l’humidité ambiante sur la cinétique de dissolution de la galvanisation. La vitesse de corrosion a été calculée par la détermination de la résistance de polarisation sur des éprouvettes de mortier, munies d’aciers de précontrainte galvanisés et soumises d’une manière cyclique, pendant leur cure et leur durcissement, à diverses humidités ambiantes.