Concrete-to-concrete interface are widely used in composite construction in practical engineering, such as between precast concrete elements and cast-in-situ concrete, or between new and old concrete elements. In modern high-speed railway, ballastless track made of concrete composite structure are utilized due to its better performance such as lower maintenance requirements and higher track stability. The structure usually consists of prefabricated elements, cast-in-situ concrete elements as well as filing layers. Ballastless track works well when these composite elements are integrated. The Bond strength between different concrete layers is generally assumed to be high enough to avoid cracking under usual monotonically increasing short-term loading. However, cracking or even delamination at the interface occurs due to repeated actions caused by different sources. This phenomenon causes durability problems and higher maintenance costs. In severe cases, cracks at interface could also lead to safety risks. In order to study the debonding mechanism that occurs at the interface between concrete layers, interface resistances regarding shear and tensile directions has been studied. Experimental investigation has been conducted to study the damage mechanism of interface. Concrete and cement-asphalt mortar have been used to obtain the stress-slip correlation of the interface.