Fiber-reinforced ultra-high performance concrete under tensile loads

The present paper deals with the material behavior of ultra-high performance concrete (UHPC) at high strain rates up to 160 1/s. Static and dynamic material-parameters and the fracture behavior of a fiber-reinforced ultra-high performance concrete (mixture B4Q) were investigated. The material shows static compression strength up to 180 MPa and static tension strength up to 9 MPa. With the help of Hopkinson Bar experiments, dynamic material-properties like Young's modulus, tensile strength and fracture energy are determined. Furthermore, it was possible to record the failure process in small time-steps by application of a new method of fracture observation. Based on the measured material-parameters, the paper provides "Dynamic Increase Factors" (DIF) of Young's modulus, tensile strength and fracture energy to figure out the differences between UHPC, conventional and high strength concrete and the potential of the new building material.