Abstract. 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 fracturebehavior of a fiber-reinforced ultra-high performance concrete (mixture B4Q) were investigated. Thematerial 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 fail-ure process in small time-steps by application of a new method of fracture observation. Based onthe measured material-parameters, the paper provides “Dynamic Increase Factors” (DIF) ofYoung’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. 1. INTRODUCTIONToday’s constructions tend to be higher, more filigree and more flexible in use. As well, they wereseen to be loaded by new load cases, like dynamic loads from explosions or impacts.Ultra-high performance concrete is one of the youngest materials within concrete research. Itsinvestigation offers new applications in the construction of, e.g., high-rise buildings and widelyspanned bridges. For an efficient use of UHPC, the material behavior has to be known. Especiallyin the constructions mentioned above, the consideration of dynamic loads has an increasinginfluence to the calculation of these structures.Thepresentpaper isfocusedondynamicloadsonanexistingultra-high performanceconcrete.The experiments may be seen as one part of an investigation to determine material-parameters fora material model used in numerical simulations.As a new construction material, UHPC is still under investigation concerning static, dynamicand long-time investigation. First results are reported in [4]. However, dynamic behavior of ultra-high performance concrete and investigations efforts on it are very rarely published.2. TESTING PROCEDURE2.1 Test configuration and specimensTo investigate the material-properties at high strain rates, Hopkinson Bar experiments offer agood possibility to receive exact parameters. With the spallation configuration, which wasestablished by Schuler at EMI [1] and [6], it is possible to measure dynamic Young’s modulus,tensile strength and fracture energy for brittle materials.The specimens require a diameter of 75 mm and a length of 250 mm. The experiments werecarried out in two geometrical configurations. Notched specimens were tested to measure fractureenergy in a predetermined fracture plane. Across this plane, failure process is monitored with anDYMAT 2009 (2009) 671–677 EDP Sciences, 2009DOI: 10.1051/dymat/2009095