Investigation of interface between asphalt core and gravel transition zone in embankment dams

The asphalt core is located between the upstream and downstream transition zones that are simultaneously placed and compacted in the central part of the embankment dam to form a strong interlocking asphalt core-gravel transition zone (AC-GTZ) interface. The asphalt core usually settles a little more than the transition zones during dam construction, and AC-GTZ interface shear displacements develop. Shear tests were conducted in the laboratory to investigate the interface behavior. Test results show that the AC-GTZ interface was gradually deformed up to a shear displacement of 60 mm, but the properties of the asphalt surface layer did not deteriorate. The integrity of the asphalt core would be better maintained if a sliding layer is placed between the core and the transition zone.