Early-age mechanical properties and constitutive model of polystyrene concrete under impact load

Abstract

The dynamic mechanical tests of polystyrene concrete with ages of 12 h, 24 h and 36 h and 28 d were carried out by Φ 100 mm SHPB equipment. The effects of strain rate and age on dynamic mechanical properties of polystyrene concrete were analyzed in terms of the relationship between strain rate and impact velocity, strength characteristics, deformation characteristics and energy absorption characteristics. And based on Saenz model, the early-age dynamic constitutive model of polystyrene concrete was constructed. The results show that the strain rate of polystyrene concrete is positively correlated with the impact velocity. At the same impact velocity, the strain rate of polystyrene concrete decreases with age. The strength characteristic indicators, deformation characteristic indicators and energy absorption characteristic indicator of polystyrene concrete all have strain rate strengthening effect, and all these indicators and the strain rate sensitivity of these indicators increase with age. Polystyrene concrete has good deformation and energy absorption characteristics at early age. At the age of 36 h, the peak strain, ultimate strain and specific energy absorption of polystyrene concrete can reach 77∼80%, 95∼106% and 86∼92% of that at the age of 28 d, respectively. The constructed dynamic constitutive model is reasonable and reliable, and it can be used to describe the mechanical behavior of polystyrene concrete at early age under impact load.