聚苯乙烯混凝土动态劈裂实验

利用直径为74mm 的分离式Hopkinson压杆径向冲击巴西圆盘试样,测试了不同聚苯乙烯(expandedpolystyrene,EPS)颗粒粒径、不同体积含量的EPS混凝土的动态拉伸性能。为了保证实验的可靠性,在试样和入射杆、透射杆之间加上精确设计的垫块,防止试样两端因应力集中而被压碎破坏;通过选择合适的整形器,保证试样有足够的时间达到应力均匀。并分析了EPS混凝土劈裂破坏形态。实验结果表明:EPS混凝土的劈裂强度随应力率的增大而增大;在EPS体积含量较低的EPS混凝土中,EPS混凝土的劈裂强度表现出一定的粒子尺寸效应,随EPS颗粒体积含量的增加,这一现象逐渐消失。

Dynamic splitting test of expanded polystyrene (EPS) concrete

To explore the splitting strength of expanded polystyrene(EPS) concrete with the different volume concentrations of EPS,Brazilian disc specimens were diametrally impacted by using a 74-mm-diameter split Hopkinson pressure bar(SHPB) at different impact velocities.For each volume concentration of EPS,the Brazilian disc specimens were tested in the cases of two different particle sizes of EPS,respectively.And accurately designed cushions were placed in the interspaces between the input and output bars and the specimens to prevent the specimens from being crushed due to the stress concentration at the two ends of the specimens.At the same time,an appropriate pulse shaper was used to ensure enough time for the specimens to reach an equilibrium stress state during the experiment.And the splitting failure patterns of EPS concrete were analyzed.The results display that the splitting strength of EPS concrete increases with the increase of stress rate;and that in the EPS concrete with the low volume concentration of EPS,the splitting strength of EPS concrete takes on a certain particle size effect,and this effect disappears gradually with the increase of the EPS volume concentration.