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利用杆径为75mm的SHPB试验装置对5种不同龄期下的混凝土分别进行了冲击压缩试验,系统了解了冲击载荷对不同龄期支护混凝土力学特性的影响。为了进行对比,利用INSTRON系统也进行了相应龄期下的静载压缩试验。试验研究表明:静载下混凝土强度、割线弹性模量随龄期增长而增长,其中强度增长主要集中在龄期7d以前,割线弹性模量增长则集中在龄期14d以后,而峰值应变随龄期增长整体上呈减小的趋势;动载下混凝土强度、峰值应变以及单位体积吸收能随着龄期增长而增长,在各个龄期都表现出对应变率具有一定的敏感性,其中不同龄期混凝土的动态强度随应变率增加呈现指数函数增长趋势。不同龄期的混凝土在动载下以拉伸破坏为主,静载下基本呈现剪切破坏形式。
The impact compression tests were carried out on concrete under five different ages using the SHPB test device with a diameter of 75 mm. The influence of impact load on the mechanical properties of concrete with different ages was systematically studied. For comparison, INSTRON system was also carried out under the age of static load compression test. The experimental results show that the strength of concrete and the secant elastic modulus increase with age, of which the strength increases mainly before 7 days and the secant elastic modulus increases after 14 days, while the peak strain With age, the overall trend is decreasing. The strength, peak strain and energy absorption per unit volume of concrete under dynamic load increase with age, and show a certain sensitivity to strain rate at all ages The dynamic strength of concrete at different ages increases exponentially with the increase of strain rate. Different ages of concrete under dynamic load to the main tensile damage, static load basically showed the form of shear failure.