Rybczynski, SebastianSebastianRybczynskiSchaan, GunnarGunnarSchaanSkorych, VasylVasylSkorychRitter, MartinMartinRitterSchmidt-Döhl, FrankFrankSchmidt-Döhl2025-02-172025-02-172024-1120th fib Symposium on ReConStruct: Resilient Concrete Structures, 2024978-2-9406-4325-7https://hdl.handle.net/11420/54302This paper examines experimental and numerical findings regarding the fatigue characteristics of ultra-high performance concrete (UHPC). To provide detailed characterisation of fatigue-induced damage, UHPC specimens underwent analysis using scanning and transmission electron microscopy (SEM and TEM). Results demonstrated that a densification of the binder matrix occurs accompanied by a transformation of nanoscale ettringite, and the content of unhydrated cement clinker influences the fatigue resistance of UHPC. Numerical investigations of the mechanical behavior of UHPC employed the bonded-particle model (BPM), calibrated with experimental data. The mesoscopic BPM model comprises three phases: matrix, ITZ (interfacial transition zone), and aggregate. A novel rheological fatigue formulation for binder and ITZ bonds was developed to introduce minor scale variations and plastic deformations, accurately replicating fatigue behavior. Additionally, a cyclic-jump technique enabled the analysis of both low-cycle and high-cycle simulations.enCycle-jumps | DEM | Fatigue | ultra-high performance concreteTechnology::600: TechnologyConference PaperConference Paper