Experimental Study On Dynamic Behavior Of Concrete After Exposure To High Temperature Under Impact Load

In recent years, frequently happened the building fire accidents and terrorist attacks. The building bearing both of the high temperature and impact load collapsed of whole will take a huge damage to the life and property. Until now, research on the dynamic mechanical properties under high strain rate and static mechanical properties after high temperatures both are relatively mature. However, it is comparatively uncommon for the research on the mechanical properties of concrete under the joint action of high temperature and impact load. Also, the limited studies are mostly conducted by small diameter rod SHPB devices at present. In this paper, ?100mm Split hopkinson pressure bar(SHPB) in Hunan Univertity was used to study impact behavior of concrete after high temperatures. The main jobs as follows:(1) Needs to analyze the effects of the strain rate on material, the static compressive strength tests on concrete after high temperature will be conducted firstly. Then, a statistic of the literature on the static compressive tests of concrete after high temperature domestic and aboard will be conducted to explore the complexity of the change law of residual compressive strength of concrete after high temperature.(2) The SHPB impact mechanical properties of concrete after high temperatures will be tested to analyze the effect of temperature and strain rate on dynamic stress-strain curves of concrete after high temperature with the parameters of temperature and impact volocity.(3) Compare with the tests conducted of small diameter rod SHPB device to expolre change law of the dynamic strength increase factor(DIF) of concrete after high temperature, analyzing the strain rate effect and size effect of concrete after high temperature under impact load of SHPB.(4) Thermogravimetric Analysis(TGA), Scanning Electron Microscope(SEM) and Mercury Intrusion Porosimetry(MIP) tests will be conducted on the concrete after high temperatures to reveal the damage mechanism of high temperature on the dynamic and static mechanical properties of concrete.