Experimental investigation on criterion of three-dimensional mixed-mode fracture for concrete

An investigation was carried out to establish a criterion for three-dimensional (3-D) mixed-mode fracture of concrete. Experiments on 3-D mixed-mode fracture were conducted to obtain the critical load P_cr. The stress intensity factor of the specimens per unit load with different combinations of K_I,, K_II and K_III was calculated by the mixed hybrid finite element method. Based on the stress intensity factor per unit load and the critical load, 25 groups of critical stress intensity factors were calculated, from which a criterion for the 3-D mixed-mode fracture of concrete was derived.