Current State of Knowledge on Bare High-Nickel Type Weathering Steel Towards the Application as Concrete Reinforcement

Abstract

The principal issue facing reinforced concrete (RC) structures is the cost of failure due to corrosion and aging of steel reinforcements. High-Ni weathering steel (WS) is presently one of the most viable materials seen to address this issue. It is considered a cheap alternative to heavily alloyed stainless steels and also offers significantly better corrosion resistance than carbon steels (CS). This paper reviews the history and development of high-Ni WS around the world. The authors traced in detail how its protective rust layer forms under aggressive marine atmosphere in comparison to conventional Cr-type WS and CS. Synthesis of multiple studies reveals their differences in terms of rusting mechanism, corrosion products, and microstructural characteristics. It became apparent, however, that there exists a vast gap in our understanding of high-Ni WS in the context of RC structures. Some of the unresolved issues identified from literature are: (1) compositional difference of rusts that form in atmosphere and concrete; (2) long-term behavior; (3) lack of parameters necessary for service-life prediction; and (4) required concrete conditions for rust development. Information derived from these research gaps will provide important insights for future development of high-Ni WS towards the end-goal of integrating it in concrete structures.