不同温度及加载速率对混凝土冲击变形韧性影响

摘要

Here,the impact deformation and toughness properties of concrete were studied under different temperatures and impact velocities by using a 100mm diameter split Hopkinson pressure bar (SHPB)equipment.The test results indicated that after high temperature the peak strain,flow strain and impact toughness of concrete increase with increase in strain rate,the effect of strain rate on them is significant;simultaneously,increase in loading rate also leads to decreasing of pre-peak toughness ratio and increasing of post-peak toughness ratio and toughness conversion ratio;for the same loading rate,increase in temperature results in increasing of peak strain and flow strain,decreasing of impact toughness and an increasing trend of pre-peak toughness ratio;post-peak toughness ratio and toughness conversion ratio also consistently decrease with increase in temperature;in addition,at 200℃,the impact toughness of concrete firstly decreases,then increases with increase in strain rate compared with that at room temperature.%利用Φ100 mm SHPB分离式霍普金森压杆装置研究不同温度及加载速率下混凝土冲击变形韧性。结果表明，高温后混凝土峰值、流动应变及冲击韧性均随加载速率增加而增加，应变率效应显著；试件峰前韧性比不断降低，峰后韧性比及韧性转化比逐渐升高；同一加载速率下温度升高总体上使混凝土峰值应变及流动应变增大、冲击韧性降低，试件峰前韧性比呈上升趋势，峰后韧性比及韧性转化比逐渐下降；200℃时其冲击韧性在低应变率下相对较小，在高应变率下超过常温水平。