Protection of Steel Hooks Embedded in Glass-Fiber-reinforced Concrete Against Macrocell Corrosion

This study evaluated the corrosion behavior of steel hooks embedded in GFRC, which were protected by a zinc-rich (96% Zn) galvanizing coating. The coating provided the hooks with active cathodic protection and a passive physical shield. Macrocell corrosion may form when the anode is smaller than the total steel surface. Thus, the steel hooks at the embedment juncture were additionally sealed against water ingress and air exchange using a construction sealant. The study was conducted in three phases in a salt-spray chamber. First, the electrogalvanized steel hooks embedded in GFRC were allowed to freely corrode for 7 days. In the second phase, the electrogalvanized steel hooks were painted with the zinc-rich coating and observed over 7 days. In the third phase, the steel hooks were protected by the zinc-rich coating together with a primer and construction sealant, and observed over 7 days. To evaluate the electrogalvanized hooks and the corrosion products formed, the thickness of the material was measured. Corrosion on the metal surface was inferred by studying the surface morphology of the hooks at various points of contact and after different periods of time.