Bond behavior of micro steel fibers embedded in ultra‐high performance concrete subjected to monotonic and cyclic loading

Ultra‐high performance fiber‐reinforced concrete (UHPFRC) is usually applied for thin‐walled and lean constructions because of its excellent mechanical properties. However, these lightweight constructions such as bridge girders, masts, towers, and railway tracks, for example, are susceptible to oscillations due to cyclic loading. A model describing the fatigue behavior of UHPFRC is required. Therefore, the material behavior of all mixture components and the composite itself, each subjected to cyclic tensile loading, is studied experimentally and numerically on the mesoscale at iBMB, Division of Concrete Construction and Institute of Structural Analysis both at TU Braunschweig. In this paper, first findings concerning bond processes of single and multiple micro steel fibers embedded in ultra‐high performance concrete as well as a new geometrically and physically nonlinear bond model are presented.