(1. 中南大学 资源与安全工程学院，长沙 410083；
2. 中南大学 深部金属矿产开发与灾害控制湖南省重点试验室，长沙 410083)
摘 要: 利用大杆径分离式霍金森压杆(SHPB)试验装置，对1、3、7、14、28 d这5组龄期下的混凝土进行冲击压缩试验，研究早龄期混凝土(C20)在不同冲击条件下的力学特性。结果表明：龄期7 d以前，各龄期50%临界入射能的冲击有助于提高混凝土的强度和弹性模量；龄期7 d以后，无论是75%还是50%临界入射能的冲击，都会使混凝土的强度和弹性模量降低；在单次冲击条件下，混凝土的变形能力和单位体积吸收能与龄期呈对数关系增长；在多个龄期冲击条件下，混凝土的变形能力和单位体积吸收能都受到不同程度的影响，其中单位体积吸收能下降了50%。
关键字: 混凝土；力学特性；早龄期；分离式霍普金森杆
（1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China;
2. Hunan Key Laboratory of Resources Exploitation and Hazard Control for Deep Metal Mines,
Central South University, Changsha 410083, China）
Abstract:In order to understand the mechanical properties of early age concrete(C20) under different loading conditions systematically, the impact compression tests of five early age concrete were conducted with a large diameter split Hopkinson pressure bar. The results show that, the dynamic strength and elastic modulus of concrete are improved under the impact level of 50% or 75% corresponding critical incident energy before age of 7 d, while they would decrease if concrete suffered any impact after age of 7 d. The growth trend of deformation capacity and unit volume absorption energy of concrete with age can be presented with a logarithmic function under single impact. While the deformation capacity and unit volume absorption energy of concrete are affected when the concrete suffers impact at multiple ages, and the later is even declined by 50%.
Key words: concrete; mechanical property; early age; Split Hopkinson pressure bar
