ABSTRACT
However, to numerically investigate properties of concrete reinforced with steel fibres, a better way is to model the two materials separately. Thereby researchers only need to know parameters of the two materials but not the composite material since data for the separate materials are much easier to access than their composite. Fang & Zhang (2013) employed meso-scale approach to model HSCs reinforced with steel fibres and validated it by single fibre pull-out tests, uniaxial compression and tension tests, and successfully applied this approach to Split Hopkinson Pressure Bar (SHPB) test simulations. In their modelling, interaction between concrete and fibres was achieved by establishing slide line contact in the hydrocode LS-DYNA. Delaunay triangulation was used to mesh the model, which posed the most complexity
1 INTRODUCTION
Steel fibre concrete is an ideal fire-resistant material. Not only does presence of steel fibre benefit mechanical properties of concrete, but also improve its thermal behaviors when exposed to elevated temperatures. When concrete is subjected to high temperatures, a major concern is spalling. Kodur & Sultan (2003), Kodur & Khaliq (2011), Khaliq & Kodur (2011) carried out a series of tests to investigate thermal properties of high performance concrete reinforced with fibres including steel, polypropylene, and hybrid fibres. They found inclusion of steel fibres in High Strength Concrete (HSC) can decrease occurrence of spalling. Also the authors suggested steel fibres exhibit little effect on specific heat, though have marginal improvement in conductivity of HSC under different temperatures. Mei et al. (2007) conducted tests to study thermal properties and temperature responses of concrete with steel fibres and they concluded temperature gradient in concrete with steel fibres is lower than that in normal concrete without steel fibres, which helps reduce thermal stress and cracks in concrete. However, researches on how addition of steel fibres affects thermal properties of concrete are still very limited. Nevertheless, it is essential to know thermal properties of HSCs or Ultra High Performance Concrete (UHPCs) to thoroughly investigate their behaviors when subjected to elevated temperatures.
