2022 Volume 76 Issue 1 Pages 245-251
In recent years, hot-dip galvanized and weathering steels have been considered applicable for reinforcing bars in concrete. The galvanized coatings and protective rust on the surface of these steels are expected to provide high corrosion resistance in the air. However, the effect of the steel surface layers on the electrochemical behavior of steel in concrete is still unknown.In this paper, corrosion rate and corrosion form were evaluated based on electrochemical noise measurements and statistical and wavelet analysis to grasp each steel’s corrosion protection mechanism and corrosion process in concrete based on charge behavior.
Statistical analysis of electrochemical noise showed that hot-dip galvanized steel tended to corrode uniformly, while weathering steel had the lowest corrosion rate among the steels examined in the experiment. Wavelet analysis of electrochemical noise indicated that the current noise energy of hot-dip galvanized steel and weathering steel was lower than that of rolled carbon steel under the same conditions, inferring a lower charge response. This implies that both steels exhibit slow corrosion propagation, and zinc-origin passive film and weathering steel-derived protective rust is possible to contribute to this corrosion resistance.
From the corrosion state and EN analysis results, hot-dip galvanized steel and weathering steel have slower corrosion propagation than rolled carbon steel under the same conditions. They are expected to have corrosion resistance in concrete.
