Study of stress-strain dependence of polystyrene-modified concrete under axial compression

Concrete modified with polystyrene particles is a new type of energy-conserving construction material that can be used as wall material characterized by light weight, heat preservation and insulation, and energy saving. Taking polystyrene-modified concrete as the research object, five prismatic specimens and cube specimens with different densities were prepared. The experiments were conducted to study the effect of specific gravity on the failure mode, mechanical properties and stress-strain curve of polystyrene-modified concrete. The experimental results show that the specific weight of polystyrene-modified concrete affects significantly on the mechanical properties of prismatic specimens. When the specific gravity of concrete increases from 495 kg/m(3) to 1269 kg/m(3), the peak stress, elastic modulus and brittleness index increase by 473.4 %, 199.35 % and 58.93 % respectively, while the ultimate strain and toughness index decrease by 23.72 % and 30.21 % respectively. In addition, the higher the content of polystyrene particles in concrete, the more slowly the stress-strain curve declines in the softening stage, and the larger the residual stress and residual strain. The stress-strain full curve equation was established by using the Guo model equation and the power function for polystyrene-modified concrete with medium and high specific gravity. The equation is in good agreement with the experiment results, which can provide a theoretical basis for engineering applications.