The determination of the postcrack tensile properties of steel fiber–reinforced concrete (SFRC) after exposure to elevated temperatures is a current methodological challenge. The objective of this research is to evaluate the applicability of the double edge wedge splitting (DEWS) test to characterize the postcrack tensile properties of SFRC after exposure to elevated temperatures. Results show that the DEWS test has reduced scatter and facilitates the interpretation of results with diminished frictional interaction between the apparatus and the specimen. The results in terms of coefficient of mechanical degradation were comparable to those obtained by bending tests in literature, which highlights the suitability of the DEWS test to be adopted in future researches and guidelines. The postcrack tensile properties were not significantly affected up to $\sim 300°\mathrm{C}$ and a linear reduction ratio was verified with the increase in temperature. Additionally, the constitutive model proposed may reproduce the effect of temperature on the tensile stress-strain behavior of the SFRC and is a valuable input for hygro-thermo-mechanical numerical models oriented to simulate the mechanical behavior of structures made with SFRC.

This study aims to evaluate the effect of elevated temperatures on the physical, mechanical and microstructural properties of a hooked-end steel fibre for temperatures of 100, 350, 750 and 1000°C. Results show that an oxidation layer is formed on the surface of the fibres exposed to temperatures of 750°C and above, which leads to an increase in external diameter and mass. Reductions in tensile strength are directly proportional to the temperature increase, while rupture strain values significantly increase for temperatures above the recrystallisation temperature of steel. This study contributes to the understanding of the contribution of steel fibres to the overall behaviour of the composite after temperature exposure and serves as an input for recently developed numerical models.