Analysis of Mixed-Mode Fracture Characteristics of Cracked Concrete Based on the Extended Maximum Tangential Strain Criterion

In this study, two sets of Brazilian discs with a center crack (BDCC) concrete specimens were prepared. The mixed-mode fracture characteristics were investigated under pure Mode I, mixed-Mode I/II, and pure Mode II loading using the extended maximum tangential strain (EMTSN) criterion and digital image correlation (DIC) technique. Results based on the EMTSN criterion showed that the (Formula presented.) -stress in the crack-tip damage zones was negative. This negative (Formula presented.) -stress decreased the crack initiation angle and increased the fracture resistance. From Mode I to Mode II, the fracture resistance increased with critical distance, whereas the crack initiation angle gradually decreased. The DIC results showed that the strain concentration first appeared in the crack-tip region and then propagated toward the loading end, forming a typical wing-shaped crack propagation path.