Mechanical properties of steel fiber-reinforced rubber concrete after elevated temperature

The frequency of engineering fires is increasing, and the study of the residual mechanical properties of steel fiber-reinforced rubber concrete (SFRRC) after high temperatures is essential for evaluating its load-bearing capacity after fire. This study examines the mechanical properties of SFRRC after being subjected to elevated temperatures, considering the impacts of varying steel fiber amounts (V_sf =0.6, 1.2%) and different rubber substitution ratio (r_g=0, 5, 10, 15%) on the specimens after different temperatures (20, 200, 400, 600, 800 °C). All specimens were tested in cubic and axial compression, split tensile and four-point flexure tests. The findings indicated that steel fibers and rubber enhance the durability and safety of concrete by reducing the risk of cracking at high temperatures and inhibiting crack extension. When 1.2% steel fibers and 5% rubber particles were added, the mechanical properties of specimens after exposure to high temperatures were improved compared to normal concrete, with cube compressive strength, uniaxial compressive strength, splitting tensile strength, and flexural strength increased by 0.23-8.48%, 1.13-4.16%, 22.92-44.23%, and 3.03-19.81%, respectively. In this study, the mechanism of temperature action on SFRRC was analyzed. On the basis of experimental data, prediction models for SFRRC after high temperatures were proposed. The models were compared with experimental data and previous research results. The results of the study will help to promote the formulation of specifications in related fields and promote the practical application of SFRRC as a novel material.