Corrosion resistance of low-alloy steel in concrete subjected to long-term chloride attack: Characterization of surface conditions and rust layers

Abstract

Long-term corrosion behavior of a Cr-bearing low-alloy (LA) steel with different surface conditions (as-received, pickled and pre-rusted) in concrete when partially exposed to 3.5 wt% NaCl solution was measured using electrochemical impedance spectroscopy during the 8-year exposure period. According to the results of BSE/EDS elemental mapping, FT-IR and XPS measurements, the morphology and composition of different rust layers were identified for LA steel. The improved corrosion resistance of LA steel was primarily attributed to the formation of a compact and protective inner rust layer enriched with Cr and Si, which can be further protected by the mill scale.