The Influence of Microstructure on the Corrosion Properties of Hot-Dip Galvanized Reinforcement in Concrete^⋆ Available to Purchase

Corrosion properties in concrete of two different types of galvanizing layers were investigated. A bright galvanizing layer with a pure zinc surface was obtained on a silicon-free steel, and a gray galvanizing layer with iron-zinc compounds in the surface was obtained on a silicon-containing steel. Compared to the bright zinc, a higher reactivity of the gray zinc was found with respect to hydrogen evolution as well as the anodic dissolution rate. The high reactivity of the gray galvanizing layer means that it is impossible to prevent bubble formation during concreting by passivation with chromate. The corrosion potential of the gray galvanizing layer can attain the same level as that found for black steel, which promotes the risk of pitting in chloride-containing concrete. Contact with black steel was found to accelerate the corrosion of both bright and gray galvanizing.