Mixed Mode Fracture of Concrete: An Experimental Investigation

In this paper, the mixed mode experimental results of 24 notched beams of concrete with various notch depths and locations are reported. The test results for conventional critical stress intensity factors and crack trajectories are demonstrated. It is noted that with the larger thickness, which results in conditions closer to plane strain, the crack path can be better predicted by linear elastic fracture mechanics criteria. The effects of applied load and specimen weight on the fracture are considered with the use of separate stress intensity factors. It is observed that the final failure angles, based on the crack path's intersection point with the beam's top side, are better predicted than the crack initiation angles, from the maximum principal stress criterion. Conventional mixed mode fracture toughness increases with an increase in the mode II to mode~I stress intensity factors ratio.