高掺量粉煤灰自密实混凝土四点弯曲试验离散元模拟分析

Discrete element simulation analysis of high content fly ash self-compacting concrete four point bending test

为了研究不同粉煤灰掺量下自密实混凝土四点弯曲试验的力学性能变化及破坏过程,在PFC2D中建立高掺量粉煤灰自密实混凝土离散元模型,并进行模拟加载,对比离散元模拟结果与试验结果,分析其破坏形态与接触力变化。研究表明:使用离散元可以很好地模拟高掺量粉煤灰自密实混凝土四点弯曲试验,所得结果与实际试验具有较好的一致性,模拟试件破坏裂缝为一条由底部产生向上扩展的竖直裂缝,与试验室所得具有相似性,相较于试验室试验仅能肉眼观测的不足,离散元可以清晰地反映裂纹产生过程及内部应力变化。

In order to investigate the mechanical properties change and damage process of self-compacting concrete four-point bending test with different fly ash content,a discrete element model of high-volume fly ash self-compacting concrete was established in PFC2D to simulated the loading.Compared the results of simulation with experiment to analyzed the failure mode and contact force development.The research shows that discrete element method could simulate the four-point bending test of self-compacting concrete with high content of fly ash,and the results obtained by simulating are consisting with experiment.The failure crack of the simulated specimen is a vertical crack that develops upward from the bottom which is similar to those obtained in the laboratory.Compared with the disadvantages of experiment that can only be observed with the naked eye,discrete element method can clearly reflect the crack generation process and the changes of internal stress.