基于随机骨料模型的EPS混凝土粒子尺寸效应分析

Analysis of the Particle Size Effect of EPS Concrete Based on Random Aggregate Model

建立基于随机分布的EPS混凝土细观力学模型,对EPS混凝土的受压损伤破坏过程进行数值模拟,分析EPS混凝土的损伤破坏过程。研究表明,EPS混凝土的损伤破坏有两种形态,即延性破坏和脆性破坏。延性破坏与EPS颗粒的面积占有率、断裂过程区长度有关;脆性破坏与EPS颗粒的面积占有率、粒径大小以及颗粒间距有关。在EPS颗粒面积占有率较低的情况下,EPS混凝土的粒子尺寸效应对混凝土力学性能的影响较明显,在较高面积占有率的情况下,粒子尺寸效应对其影响较小。随着EPS颗粒面积占有率的增加,EPS混凝土损伤破坏由脆性破坏向延性破坏转变。建立基于损伤力学与断裂力学的粒子尺寸效应数学模型,用数值模拟进行验证,发现两者吻合较好。

Micro-mechanics model of EPS concrete based on random distribution was built,compression and damage process of EPS concrete was simulated numerically to analyze the compression and damage process of EPS concrete.The results showed that the damage of EPS concrete had two failure forms include ductile failure and brittle failure.Ductile failure was related to area occupancy ratio and the fracture process zone length of EPS concrete.Meanwhile,brittle failure was related to area occupancy ratio,particle size and the spacing between particles of EPS concrete.The size-effect of EPS concrete had obvious effect on stress-strain of concrete when the area occupancy ratio of EPS concrete was low.However,the size-effect of EPS concrete had little effect on stress-strain of concrete when the area occupancy ratio of EPS concrete was high.The damage of EPS concrete turns from brittle failure to ductile failure along with the increase of the area occupancy ratio of EPS concrete.The mathematical model of particle size effect based on damage mechanics and fracture mechanics was built,and then validated by numerical simulation,which indicates that good agreement was obtained.