For the recovery of aggregates from construction wastes, the principle process is separation of aggregates by breakage from the cement paste. In this study, a model based on DGB (Discrete Grain Breakage) and DEM (Discrete Element Method) was used to simulate the breakage behavior of a block of concrete waste in a drop test. Typical DEM model is capable of describing the motion of particles and calculating the impact forces between particle and particle, and particle and wall contact under various operating conditions. DGB model includes the particle-particle bonding mechanism to simulate the breakage of particle assembly. The developed DGB model was used to investigate the number of drops and impact energy required for clean liberation of aggregates from the concrete waste.