Concrete Under Uniaxial Impact Load Failure Criteria Of The Research

Concrete as a building material, with excellent physical and mechanicalproperties, is widely used in housing construction, bridge engineering，nuclearpower and so on. However, there will be exists initial defects inevitably suchas pores, voids and micro cracks during pouring process. Some researchresults show that initial defects will cause a great impact on mechanicalproperties. Meanwhile, concrete have to bear a variety of loads in the work,such as static load and impact loads，and the mechanical properties of concretebetween impact loads and static loads is very far. Therefore, study the failurecriterion of concrete under impact loading and the affect of initial defect tofailure criterion is important. So the main research works are as follows:（1）Uniaxial compression experiments of concrete with prefabricated holewere carried out under strain rate10^-4/s and10^-3/s by using servo pressuretesting machine, meanwhile using acoustic emission technique to obtainenergy information of concrete, and the affect of loading rate, hole diameterand hole location to the mechanical properties of concrete was analyzed, andaccording to the acoustic emission information to analysis the failure law ofconcrete under the low strain rate.（2）Uniaxial impact compression experiments of concrete with prefabricatedhole were carried out under strain rate25/s and50/s by using SHPB （SplitHopkinson Pressure Bar） device, and got the stress-strain curves of concreteunder various conditions. Then the stress uniformity was analyzed. Meanwhile,the affect of loading rate, hole diameter and hole location to mechanicalproperties of concrete under the strain rate of25/s and50/s was analyzd.（3）Based on the test results of concrete dynamic mechanical properties,uniaxial compressive failure criteria of concrete were obtained, where thestrain rate, hole diameter and hole location were considered. Results show thatexperimental data and fitting data agree well.（4）Based on uniaxial SHPB experiment data of concrete at high temperature,uniaxial compressive failure criteria of concrete at high temperature wasobtained, and the experimental results have better tally with fitting results.