Anti-Corrosion Methods and Materials

Purpose – This work seeks to present a systematic study that aimed to provide quantitative understanding of the fundamental factors that influence the chloride threshold of pitting corrosion of steel in concrete, by conducting a set of laboratory tests to assess the corrosion potential (Ecorr) and pitting potential (Epit) of steel coupons in simulated concrete pore solutions.

Design/methodology/approach – With the aid of artificial neural network, the laboratory data were used to establish a phenomenological model correlating the influential factors (total chloride concentration, chloride binding, solution pH, and dissolved oxygen (DO) concentration) with the pitting risk (characterized by Ecorr-Epit). Three-dimensional response surfaces were then constructed to illustrate such predicted correlations and to shed light on the complex interactions between various influential factors.

Findings – The results indicate that the threshold [Cl^-]/[OH^-] of steel rebar in simulated concrete pore solutions is a function of DO concentration, pH and chloride binding, instead of a unique value.

Research limitations/implications – The limitations and implications of the research findings were also discussed.

Practical implications – This research could have significant practical implications in predicting the service life of new or existing reinforced concrete in chloride-laden environments.

Originality/value – This study further advances the knowledge base relevant to the chloride-induced corrosion of steel rebar in concrete.