为研究普通混凝土材料的动态冲击力学性能,利用改进的落锤冲击试验装置,对C30混凝土圆柱体进行低速冲击试验.为降低落锤冲击惯性效应并获得稳定的加载速率,试验采用不同厚度的橡胶或海绵作为波形整形材料;采用20 mm厚橡胶时可消除惯性力影响,延长加载时间,使试件纵向应力趋于均匀分布,并实现恒定速率加载.试验结果表明:冲击荷载下混凝土破坏形态与静载下相同,动态增大系数(DIF)、极限应变与吸收能量随应变率增加而增加,在本文试验参数范围内应变率对混凝土应力-应变曲线形状影响较小.对已有混凝土动态力学性能试验结果进行统计和对比,验证了CEB2010规范公式偏于保守地描述了DIF与应变率的关系,且本文的研究结果填补了应变率10-1/s～100/s范围内试验数据.%In order to investigate the dynamic behavior of ordinary concrete under impact loading, the low-speed impact tests on C30 concrete cylindrical specimens were carried out by using an improved drop hammer test setup. The rubber and sponge with different thickness were used as shaper to reduce the impact inertia effect and obtain steady loading rate. The 20 mm thick rubber pad significantly reduced the inertia effect and prolonged the loading time duration. The longitudinal stress of the specimens tended to uniformly distribute and led to a constant loading rate. The test results show that the concrete failure mode under impact loading is the same as that under static loading. Furthermore, dynamic increase factor (DIF), ultimate strain and energy-absorption increase with the increase of strain rate. However, it is found that within the test parameters of this paper, the strain rate has little effect on the shape of stress-strain curves of concrete. Moreover, the dynamic tests on concrete from the literature were further summarized and compared. The formula recommended by CEB2010 can conservatively describe the relationship between DIF and strain rate. The results in this paper filled in the blank within the strain rate range of 10-1/s～100/s for the existing testing data.
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