高温下混凝土动态力学特性试验

Experiment for dynamic mechanical properties of concrete at high temperatures

基于自行研制的适用于100 mm分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)装置的高温试验设备,采用相应高温试验技术在100 mm SHPB装置上对混凝土分别在常温、200、400、600、800和1000℃下的动态力学特性进行了试验研究。结果表明:高温下混凝土的动态应力应变曲线体现出温度效应和应变率效应,随温度和应变率增大,曲线逐渐表现出塑性特性;高温下混凝土的动态抗压强度随温度升高或平均应变率增长先提高后降低;高温下混凝土的动态峰值应变随温度升高或平均应变率增大而不断提高,动态峰值应变与平均应变率之间存在近似线性增长关系;高温下的动态峰值应变大于常温下,相对增幅随温度升高或应变率增大而不断提高。

In order to study dynamic mechanical properties of concrete subjected to high temperatures,on basis of high temperature test equipment developed by ourselves for 100 mm split hopkinson pressure bar（SHPB）device,impact tests of concrete at room temperature,200,400,600,800 and 1000 ℃ were carried out using relevant test techniques.The results show that dynamic stress-strain curves of concrete reveal temperature and strain rate effect,and exhibit plasticity properties with increasing temperature and strain rate gradually;dynamic compressive strength rises at first,and then falls with temperature and average strain rate increasing;dynamic peak strain rises with temperature or average strain rate increasing,there are approximate linear relations between dynamic peak strain and average strain rate,dynamic peak strains at high temperature are greater than those at room temperature,the relative increaments increase with temperature or average strain rate increasing.