Corrosion development of low-chromium alloy steel bars in concrete

Abstract

Low-chromium alloy steel bars (LASBs) are a new type of corrosion-resistant steel bar, which are not only simple in preparation and processing, but also low in price. They have a good application prospect in improving the durability of concrete structures. This paper systematically reviews the research progress of the corrosion development of LASBs in concrete. Firstly, the development and application of LASBs and the influence of alloying elements on the microstructure of steel bars are briefly introduced. Secondly, the corrosion development of LASBs influenced by chloride attack and carbonation, and the role of alloying elements in enhancing steel reinforcement corrosion resistance are increasingly clarified from three aspects: corrosion rate and electrochemical characteristics, rust layer, and corrosion products. Chloride attack and carbonation reducing the protection of the rust layer to the steel matrix by destroying corrosion products and promoting the formation of non-protective corrosion products, thereby promoting the corrosion development of LASBs. When the two corrosion effects coexist, the corrosion development of LASBs is further enhanced. Cr, Mo, Ni and Cu slow down the corrosion development of LASBs by promoting the formation of a compact, stable and cationic selective inner rust layer on the steel bar matrix. Finally, the existing problems and future research prospects on the corrosion development of LASBs are discussed.