Experimental Study of the Post-Fire Mechanical and Material Response of Cold-Worked Austenitic Stainless Steel Reinforcing Bar

• Published in: Materials Vol. 15; no. 4; p. 1564
• Main Authors: Rehman, Fazal-Ur, Cashell, Katherine A, Anguilano, Lorna
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 19.02.2022; MDPI
• Subjects: Alloys; austenitic; Austenitic stainless steels; Carbon steel; Carbon steels; Cold; Cold working; cold-worked; Concrete; Concrete structures; Cooling; Cooling rate; Corrosion resistance; Ductility; fire; High temperature; Hot rolling; Life cycle costs; Maintenance; Mechanical properties; Metallurgy; Molybdenum; Phase transitions; post-fire; Rehabilitation; Reinforced concrete; Reinforcement; Reinforcing steels; residual properties; Stainless steel; Strain hardening; Structural integrity; Temperature; residual properties; cold-worked; tensile test; stainless steel; post-fire; fire; material characterization; austenitic; metallurgical assessment
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15041564

This paper is concerned with the behaviour of stainless steel reinforcing bar following exposure to elevated temperatures from a fire, followed by subsequent cooling. Stainless steel-reinforced concrete is an increasingly popular solution for structural applications which require corrosion resistance, excellent mechanical properties, and long life cycles with little maintenance. In addition, although stainless steel reinforcement has a higher initial cost compared with traditional carbon steel bars, the overall life cycle costs are likely to be quite similar, owing to the lack of maintenance required for stainless steel materials. There is no information available in the literature on the post-fire properties of austenitic stainless steel reinforcement, although these data are essential for any engineer who wishes to study the structural integrity of a reinforced concrete component or system following a fire. Accordingly, this paper presents a detailed discussion and analysis from the results of a series of laboratory experiments on three grades of austenitic stainless steel reinforcement following various levels of temperature exposure and also different cooling rates. Both the mechanical and metallurgical properties are examined, and the behaviour is compared to that of B500B carbon steel reinforcement. It is shown that the stainless steel bars retained their mechanical properties under the majority of the scenarios examined and to a greater degree than traditional materials. This is important for the rehabilitation and salvage of existing reinforced concrete structures following a fire and also to avoid unnecessary demolition and replacement.