Abstract
The dynamic mechanical properties of steel fiber-reinforced concrete (SFRC) under high temperature and high strain rate were studied using a split Hopkinson pressure bar (SHPB) of 74 mm in diameter. As it is difficult to achieve constant strain rate loading in SHPB experiments with high temperature and high strain rate, this paper first presents a method for determining the strain rate under non-constant strain rate loading conditions. This method is proposed to deal with experimental data under non-constant strain rate loading conditions. Then, the influences of temperature on the ultimate compressive strength, peak strain, and failure modes of SFRC under different strain rates were analyzed and the results show that SFRC has a strain rate hardening effect. This paper also points out that there is a strain rate threshold for SFRC. If the strain rate is less than the strain rate threshold, there is a temperature softening effect. Conversely, if the strain rate is greater than the strain rate threshold, there is a temperature hardening effect. Finally, the relationship between the ultimate compressive strength and fiber volume fraction, strain rate, and temperature is presented and the prediction results are consistent with the experimental data.
Highlights
Steel fiber can increase the energy adsorption, crack resistance and impact strength of concrete significantly (Song and Hwang 2004; Yang et al 2017; Holschemacher et al 2010; Li et al 2017a, b; Wang et al 2008; El-Dieb 2009)
Kim et al (2015) studied the factors influencing the mechanical tensile properties of steel fiber-reinforced concrete (SFRC) exposed to high temperatures and the results show that the residual compressive strength, tensile strength and rupture energy of the specimens decreased with increased heating
Brass was used as a shaper to solve the problem of stress uniformity of the SFRC specimens in split Hopkinson pressure bar (SHPB) experiments
Summary
Steel fiber can increase the energy adsorption, crack resistance and impact strength of concrete significantly (Song and Hwang 2004; Yang et al 2017; Holschemacher et al 2010; Li et al 2017a, b; Wang et al 2008; El-Dieb 2009). It has been widely used in military and civilian applications such as pavements, tunnels, bridges and fortifications. The research is mainly focused on the mechanical properties of concrete after exposing it to high temperatures. Tai et al (2011) investigated the stress–strain relationship in reactive powder concrete (RPC) under quasi-static loading after exposure to an elevated temperature, and the experimental results indicate that the residual compressive strength of RPC after heating it at 200–300 °C increases more than that at room temperature, but it significantly decreases when the temperature exceeds 300 °C. Düğenci et al (2015) pointed out that the compressive strength, modulus of elasticity and toughness values of fiber-concrete substantially decreased by the effect of high temperature. Poon et al (2004) showed that the compressive strength and stiffness of concrete will decrease when exposed to
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