The mechanical behavior of mortar-aggregate interface transition zone is critical to the macro mechanical properties of concrete. A series of dynamic axial tensile tests on 40 mortar-granite interfaces specimens are carried out on MTS. Effects of different strain rates (10-6～10-2 s-1)

different initial static loads (30%、50%、70%) and the cyclic load (frequency of 1、5 Hz) on the dynamic axial tensile mechanical properties are analyzed . The fracture mechanism is explored based on the experiment results. The results indicate that: ① the dynamic tensile strength of the interface is increased obviously with the increasing of the strain rate; ② the initial static load about less than 50 percent of the strength will not influence the dynamic tensile strength but maybe beneficial for it; more initial static load will be harmful to the dynamic strength because of the damage effect; ③ the fatigue damage by cyclic variable amplitude load leads to the descending of strength because of the cumulative damage. Residual strain decreases with the increasing of cycle frequency; ④ the ascending branch of the stress-strain curve before 50% tensile strength can be looked as straight line and then it goes into nonlinear stage which will trend toward linear with the increasing of strain rate. In addition

the complete stress-strain curve of interface is achieved on the condition of stable fracture.