Post-fire Behaviour of Stainless Steel Rebars
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Stainless steel rebars (SSR) are a highly advantageous option for use in reinforced concrete structures where corrosion is a major concern. Stainless steel is not only known for its outstanding corrosion resistance but also for its excellent mechanical strength and high ductility. Despite this, the utilization of SSR is less common than carbon steel rebars (CSR) due to their higher cost. This is probably the main reason of the lack of research on the mechanical properties of rebars after its exposure to elevated temperatures compared to CSR. In the present study, an experimental campaign was conducted on SSR of different grades (austenitic, duplex and ferritic) and production routes (hot-rolled and cold-formed) to determine their response after fire. Specimens were heated to an elevated temperature (up to 800ºC), maintained at this temperature for a soaking time and then cooled down in air to room temperature. Afterwards, the specimens were submitted to tensile testing to compute their key mechanical properties, including yield stress, ultimate tensile strength, Young’s modulus, ultimate strain and strain at fracture, as well as the complete stress-strain curve. The measured properties were compared to those obtained at room temperature to quantify the residual properties of each stainless-steel grade after fire. The results highlight the influence of chemical composition and production route on the post-fire behaviour of stainless steel rebars.