The asphalt core type embankment dam (ACED) with its many advantages has been applied worldwide since 1960s. Among the completed asphalt core dams, the Storglomvatn Dam in Norway and the Yele Dam in China were the highest until 2017, both with a dam height of 125 m [1,2]. In recent years, many investigations and applications for asphalt cores in embankment dams have been done. Wang and Höeg [3] proposed a simplified material model for analyzing asphalt cores in embankment dams based on extensive long-term creep triaxial test results. Wang and Höeg [4] as well as Akhtarpour and Khodaii [5] studied the cyclic behavior of asphalt concrete used as impervious cores in embankment dams for dam sites located in seismic regions. Zhang et al. [6] investigated the conditions that hydraulic fracturing would take place for asphalt cores in very high embankment dams and concluded that hydraulic fracturing would be of no concern. Asphalt concrete used as water barrier in dams provide watertightness, cracking resistance, and self-healing properties [7]. With the experience gained from research and field experience, the dam height of ACEDs has reached a level of more than 150 m. The 174 m high Quxue Dam was completed in February 2017 in China and other high ACEDs are under construction or under final design [8,9]. The 153 m high Zarema Dam is about to be completed in Ethiopia and the Moglicë Dam in Albania is in the early stages of construction and will be about 170 m high [9]. Asphalt core is placed and compacted layer by layer with transition zone on either side of the core with a compacted thickness of 20–۲۵ cm to form a no-joint impervious wall protected by the transition zones in the embankment dam. The interface between asphalt core and transition zones play an important role to transfer stresses and deformations during the dam construction and reservoir impounding. The behavior of the interface of asphalt core-transition zone has not been investigated very much in the published literature. Tajdini et al. [10,11] studied the interface behavior between asphalt concrete and granular materials using direct shear tests. However, they used a small size 10 × ۱۰ × ۲٫۵ cm direct shear box with a cut smooth face of asphalt specimens for testing. The results and conclusions could have some limitations due the small sizes of the test box and the smooth face of asphalt specimens while the interface of the asphalt core-transition zone in a dam is rather rough and interlocked [12,13]. The authors have studied the interface behavior of asphalt core-transition zone in embankment dams using a large shear box with overlapping rectangular steel plates for an interlocking interface, and the results will be published in another paper [14]. In most of the ACEDs constructed so far, the asphalt core rests on a concrete plinth (sill), and the plinth is anchored to the rock foundation to serve as a cap for contact and curtain grouting. In cases where there is deep soil overburden, the plinth may rest on a concrete cut-off wall or jet-grouted wall. The asphalt core width is conventionally in the range of 0.5–۱٫۲ m, and the core width is doubled toward the contact with the plinth on the foundation and against the abutments. The asphalt core-plinth connection (joint) is crucial and must remain watertight when the core and plinth undergo deformations (displacements) during construction and dam operation. For situations with gentle abutment slopes the connection is subjected to compressive and moderate shear strains that are unlikely to cause any leakage [2,12,13]. Kruntcheva et al.