High cycle tensile fatigue behavior of UHPFRC

In structures, where UHPFRC is subjected to a high number of fatigue stress cycles, the tensile fatigue behavior is critical and must be well understood. This paper studies the high cycle tensile fatigue behavior of UHPFRC utilizing four advanced measurement techniques. Sixteen fatigue specimens from a previous study are re-analyzed and eight specimens are tested. Prior to testing, the local fiber orientation and dosage are determined using a magnetic probe. During testing, specimen behavior is monitored by displacement transducers, digital image correlation and acoustic emission. It is found that fatigue deformation increase shows three stages, and concentrates in the specimen zones with low fiber orientation. Furthermore, fatigue fracture always occurs in the lowest fiber orientation zone. For typical non-structural and structural UHPFRC structures: i) two original fatigue resistance models are developed, describing the relation between average fiber orientation, number of cycles and maximum fatigue stress; ii) the fatigue endurance limit and fatigue strength at 10 million cycles are determined, respectively. Résumé 12 blank lines.