Corrosion mechanism of hot-dip galvanised reinforcement bar in cracked concrete

In this paper, probable corrosion mechanisms of hot-dip galvanised reinforcement bar in cracked concrete based on long-term durability tests and other studies are determined. The fist mechanism consists of a local dissolution of eta (η) and zeta (ζ) phase. In the second mechanism due to non-uniform zinc coating local dissolution of eta (η) and zeta (ζ) phase together with longitudinal and perpendicular cracking in zinc layer may lead to separation of zinc layer. In the third mechanism due to non-uniform zinc coating full dissolution of eta (η) and partial dissolution of zeta (ζ) phase together with longitudinal and perpendicular cracking in ferrite may lead to separation of zinc layer and ferrite. Corrosion rate with used cement type was decreasing. That is not dependent on concrete quality. However, concrete type has an effect on corrosion rate and moisture conditions.