粉煤灰高性能混凝土动态压缩性能试验研究

Experimental study on dynamic compressive properties of fly ash high performance concrete

为研究冲击荷载下高性能混凝土抗压性能,利用分离式霍普金森压杆对C30、C40、C50强度等级的普通混凝土(NC)和高性能混凝土(HPC)进行了5种应变率下的动态压缩性能试验,并与各类试件的静态抗压强度、弹性模量进行对比分析,还采用LS-DYNA有限元软件对冲击压缩试验进行了模拟。结果表明HPC的静态抗压强度和弹性模量均明显优于NC,HPC更加密实,抵抗变形能力更强。随应变率增加,混凝土动态抗压强度提高,提高幅度越大其破坏程度更严重。NC和HPC的动态抗压强度、动态弹性模量均有明显的应变率效应。受粉煤灰和硅灰的影响,HPC的弹性模量增长因子随应变率的变化不大。模拟结果反映了HPC-50抵抗动态冲击压缩的能力优于NC-50,模拟的破坏规律与实际试验中的破坏规律具有一致性。

In order to study the compressive performance of high-performance concrete under impact load,the dynamic compressive performance tests of C30,C40,C50 strength grade normal concrete(NC)and high performance concrete(HPC)under five strain rates were carried out by using split Hopkinson compression bar,and the static compressive strength and elastic modulus of various specimens is compared and analyzed.The impact compression tests is simulated by LS-DYNA finite element software.The results show that the static compressive strength and elastic modulus of HPC are significantly better than those of NC.HPC is more dense and has stronger resistance to deformation.With the increase of strain rate,the dynamic compressive strength of concrete increases,and the greater the increase,the more serious the damage is.The dynamic compressive strength and dynamic elastic modulus of NC and HPC have obvious strain rate effect.Under the influence of fly ash and silica fume,the elastic modulus growth factor of HPC changes little with strain rate.The simulation results show that HPC-50 has better resistance to dynamic impact compression than NC-50,and the simulated failure law is consistent with the failure law in the actual experiment.