IMPACT TESTS ON DYNAMIC BEHAVIOR OF CONCRETE AT ELEVATED TEMPERATURES

A Split Hopkinson pressure bar (SHPB) and a purpose-developed electrical furnace were used to experimentally study the dynamic behaviors of normal concrete at elevated temperatures. The dynamic strength and stress-strain relation curves of concrete at elevated temperatures were measured to discover the effects of high temperature and the strain rate on the dynamic behavior of concrete at elevated temperature. Test results show that concrete at elevated temperature except the temperature range from 200℃ to 300℃ experienced a remarkable strain rate effect, the higher the temperature was and the greater the strain rate effect was. There are no obvious effects of temperature and the strain rate on the shape of ascending branch of normalized stress-strain relation curves of concrete at elevated temperatures. Thus a uniform formula can be used to express the ascending branch of normalized stress-strain relation curves. Much attention should be paid not only to the mechanical property of no significant strain-rate effect of concrete at the lower temperature range from 200℃ to 300℃, but also to the strength degradation under static loading at such a temperature range. Additionally, further research on the dynamic behavior of concrete at elevated temperature is necessary.