Effect of Fiber Volume Fraction on Fatigue Crack Propagation Rate of UHTCC

Fatigue flexural fracture test is taken out in this paper, to study the fatigue crack propagation rate of ultra-high toughness cementitious composites (UHTCC), as well as the effect of fiber volume fraction on fatigue crack propagation rate. Three fiber volume fractions are adopted: 1.5%, 2.0% and 2.5%. Similar to Paris law, a fatigue crack propagation equation of UHTCC is introduced, as dA/dN=C(△J)m, with the two parameters A and △J are defined as the covering area of multiple fatigue cracks and the fatigue amplitude of J integral. Through experiment and analysis, the fatigue crack propagation rate slows down with the increase of PVA fiber fraction. Furthermore, the influence of PVA fiber on the propagation rate was found to become obvious with the increase of J integral.