Experimental study on fracture performance of ultra-high toughness cementitious composites with J-integral

Fracture test of three-point flexure was taken on ultra-high toughness cementitious composites (UHTCCs), which is a strain-hardening material, to investigate its ductile fracture performance. On the basis of nonlinear fracture mechanics, a double J -integral criterion was introduced to evaluate its fracture property. Moreover, its J R curve was studied and simplified. The results showed that the J R curve had three stages, with the two separations as the initial cracking point and the crack localizing point. In the stable stage, equal energy was required for equal quantity of crack growth. Moreover, the crack covering area was applicable to describe the crack growth of UHTCC.