Investigation on crack propagation law of ultra-high toughness cementitious composites under fatigue flexure

Based on Paris law and nonlinear fracture mechanics, a fatigue crack propagation equation of ultra-high toughness cementitious composites, which is a strain-hardening material, was proposed in this paper, with the two parameters as crack covering area and fatigue amplitude of J-integral. This law was verified by a three-point bending experiment on the single notched beam. The results showed that, the fatigue crack propagation rate of this material sped up with the increase of the maximum fatigue load, as well as the amplitude; furthermore, the fatigue life of the stable developing stage could be estimated with the monitored crack covering area and the regressed parameters.