Effect of high temperature on the mechanical properties of concrete reinforced with different fiber contents

Abstract

This study evaluates the effect of fiber content on the thermo-mechanical properties of steel fiber reinforced concretes (SFRC) and contributes to the definition of design-oriented parameters for SFRC after temperature exposure, which are limited in literature and current guidelines. The mechanical behavior of samples subjected to high temperatures (25 °C ≤ T ≤ 750 °C) and produced varying the fiber contents were analyzed. The tensile properties were determined using the Double Edge Wedge Splitting (DEWS) test, which proved to be a viable methodology to evaluate the post-crack behavior of SFRC exposed to high temperatures. The rate of degradation in compressive and tensile strength was reduced for higher contents of steel fibers after exposure to elevated temperatures. The reductions in compressive strength and the elastic modulus were more severe than those prescribed by European guidelines. Additionally, the tensile properties reduced significantly for T ≥ 450 °C. Also, a temperature-related reduction rate in the post-crack tensile properties was parameterized for all the fiber content samples, in which only 20% of fFts and 30% of fFtu room temperature values were retained after exposure to 600 °C, which are higher values comparing the European guidelines.