高温后混凝土动态力学性能时间效应试验

Time effect experimental research of the concrete dynamic Mechanical property after high temperature

采用ANSYS软件模拟C60混凝土试件加热过程中的温度场,确定不同温度组试件的加热时间.利用高温SHPB试验装置进行不同加热长的高温后混凝土冲击压缩试验,分析了高温和加热时间对混凝土动态压缩力学性能的影响.结果表明:经历高温后且不同加热时间的混凝土材料,在自然冷却后表现出明显的温度软化效应和时间效应;在不同高温后,随着加热温度的升高混凝土动态抗压强度逐渐减小,峰值应变先增大而后略微降低且始终大于室温条件下的峰值应变;在相同温度且不同加热时间的条件下,混凝土随着加热时间的增加,其动态抗压强度不断降低,峰值应变总体上先增大后减小,弹性模量减小.

In this paper the temperature field during the heating process is simulated to determine the C60 concrete specimen heating times in different temperature groups by using the ANSYS software.Impact loading experiments were carried out on concrete at high temperature and different heating time by using the high temperature split Hopkinson pressure bar apparatus. The results show that C60 concrete has obvious softening effect and time effect after high temperature and different heating time and then natural cooling. The dynamic compressive strength decreases gradually with increasing temperature, the peak strain rises first and then falls slightly with temperature increasing but always being higher than the peak strain under room temperature; Under the same temperature and different heating time condition, with increasing temperature, the dynamic compressive strength decreases and the peak strain increases first and then decreases generally and the elastic modulus decreases.