Background <p>Although repair using cementitious overlays is a cost-effective alternative to reconstruction, inadequate bond development between substrate and overlay could significantly reduce the service life of concrete structures. Moreover, these bonds are prone to dominant shear-type loads, and the inherent flaws in concrete make them more vulnerable to premature failure.</p> Objective <p>In this study, a unique compact butterfly double-wedge Mode II fracture test is proposed to evaluate the cementitious substrate-to-overlay interface bonds prone to dominant shear-type loads.</p> Methods <p>A compact butterfly double-wedge Mode II fracture test fixture is designed for shotcrete-to-concrete interface bond characterization. The cementitious interface bonds using different concrete surface preparation techniques (i.e., chipped, pressure-washed, sandblasted, and as-cast) are prepared and evaluated, from which the Mode II cohesive fracture energy of shotcrete-to-concrete interface bonds are obtained and compared.</p> Results <p>The test results indicate that the test is sensitive to characterize the Mode II cohesive fracture of interface bonds with different concrete surface preparation techniques as well as subjected to cyclic freeze–thaw damage. The proposed test produces the data following the similar trends as observed in other test methods, such as Mode I fracture test and strength-based tests.</p> Conclusions <p>The proposed test is sensitive to the substrate surface preparation technique and can be used as an initial screening test in concrete repairs. The test also captures the variation of substrate surface texture after subjecting the specimens to cyclic freeze–thaw weathering.</p>