Abstract: This study adopts an accelerated corrosion method to achieve corrosion of stainless steel bars embedded in concrete with different target corrosion degrees for an accurate description of steel bar corrosion morphology and a better understanding of corrosion effect. We conduct steel bar tensile tests, use a 3D scanning technology to examine the corrosion factors and deteriorated mechanical properties of the corroded steel bars, and extract accurate corrosion information from the measurements of 3D profiles. Corrosion degree and corrosion non-uniformity are represented using the areas loss of the largest cross section and a uniformity parameter. We find that the corrosion of stainless steel is prone to pit corrosion, its unevenness of corrosion is more prominent in comparison to ordinary carbon steel, and the degree of its corrosion non-uniformity increases linearly with corrosion rate. Fracture surface analysis illustrates the necking and fracturing originate from the location of a critical corrosion pit. Through tensile tests, we can examine the degradation of mechanical properties of corroded steel bars with different corrosion degrees, and then develop a model to describe the degradation of their bearing capacity and elongation rate. Comparison to ordinary carbon steel bars reveals stainless steel is much better in ductility and can maintain a certain elongation ratio even in the case of severe corrosion, manifesting a great advantage in preventing structural brittle failure.

Key words: stainless steel bar, pit corrosion, 3D scanning, mechanical properties, corrosion factors