水泥砂浆应变率效应研究

为分析试件长径比和应变率对水泥砂浆动态力学性能的影响规律，采用准静态实验测量了砂浆的单轴压缩强度、弹性模量以及泊松比.利用分离式SHPB压杆进行1维应力压缩实验，对水泥砂浆试件进行了回收和比较，获得了不同长径比水泥砂浆试样在不同加载速率下的动态损伤破坏过程和应力应变曲线，研究了动态强度增强因子随应变率的变化规律.结果表明:动态压缩强度随应变率的增加而显著增大；试件直径相同时，厚度小的获得的动态强度增强因子要小于厚度大的；随着应变率提高，试件损伤增加，碎块尺寸越小，表明破坏能量随应变率的增加而提高. 

Study on the Strain Rate Effect of Cement Mortar

To investigate the influence of strain rate on stress-strain relation and dynamic strength, uniaxial compression strength, elastic modulus and poisson''s ratio of mortar were measured by quasi-static experiments.The one-dimensional stress experiment was carried out by using split Hopkinson pressure bar(SHPB), dynamic damage and stress-strain relation of the cement mortar with various length-diameter ratios at different loading rates were obtained,and the relation of DIF(dynamic strength increase factor) and strain rate was studied.The results show that dynamic compressive strength increases significantly with increasing strain rate.The DIF with thin specimens are smaller than those with thick specimens when diameters are the same, but length-diameter ratios are different.By comparing the recovered specimens, as the strain rate increases, the damage of the specimen increases, and the fragment size decreases.It is found that the failure energy increases with the growing of the strain rate.