Ultra high performance concrete (UHPC), a type of concrete which is produced since the 1970s with compressive strengths >150 N/mm with a water-binder ratio of 0.22 excells in strength criterias but is also characterized by a highly brittle failure and post-failure behaviour. Therefore, scientists and engineers tried to get rid of this problem by finding solutions to make this material more ductile to reach a safer state of failure behaviour, if failure occurs. In the course of creating a material with a higher ductility, composite fibre materials are used. These fibres with high tensile strengths and a highly ductile behaviour are mixed with UHPC in dosages of 1-5 Vol.% to create UHPFRC (=ultra high performance fibre reinforced concrete). These fibre materials lead to a reinforcement of the microand macrostructure of the given concrete, which is now able to develop higher tensile strengths. These fibres also stop the abrupt failure of the material. The usage of fibres and fibre compositions, which are so called “cocktails” of different fibre lengths, forms and materials, may lead to higher ductility of the given UHPFRC, with high residual strengths at big deformations. Some fibre compositions may lead to a “Strain Hardening Effect” of the given UHPC, which leads to an increase of material strengths even after the first cracks appear. These cracks would lead to an abrupt, brittle failure of an unreinforced UHPC. In course of this thesis, a UHPC mixture with a compressive strength around 190 N/mm with a water-binder ratio of 0.22, was mixed with different fibre types, to examine the material behaviour in terms of strength and fracture mechanics of these compositions. Different types of steel fibres were used, one type of these fibres was recycled from used truck tires. Additionally, these steel fibres were mixed with synthetic fibres (polyvinylalcohol). Using these fibre types, seven fibre compositions, always added to the same UHPC mixture, were examined in terms of their failure and post-failure behaviour. The produced samples were tested in different experiments, for example in uniaxial compressive tests, three-point bending tests and wedge splitting tests. With these results it was possible to assess the pros and contras of each of the fibre types, regarding their length, form and fibre material.