Impact of fiber distribution on fatigue life variability in high-performance fiber-reinforced concrete

This study analyzes the influence of fiber orientation on the scatter of fatigue life in fiberreinforced concrete (FRC).For this purpose, prismatic specimens with three fiber contents were manufactured and subsequently subjected to bending fatigue under identical relative stress levels.Fiber orientation and distribution were characterized using micro-computed tomography prior to testing.The results show that fiber orientation parameters (mean angle relative to the longitudinal axis and orientation factor along this axis) clearly correlate with fatigue life.Specimens with betteraligned fibers endured a greater number of cycles, and this relationship was observed both in the combined analysis of all series and in separate studies.Furthermore, fiber orientation affects the rate of fatigue damage propagation.These findings contribute to reducing uncertainty in fatigue tests, optimizing fatigue design criteria.