The practical application of waste materials such as steel furnace slag (SFS) and coal wash (CW) is becoming more prevalent in civil engineering. While the addition of rubber crumbs (RC) derived from waste tyres can influence the geotechnical properties of the mixtures of SFS and CW significantly, especially the energy absorbing property. In this paper, the energy absorbing property of the SFS + CW + RC mixtures under static loading has been evaluated by the strain energy density. As expected, the energy absorbing capacity of the waste mixture increases with the addition of RC. To further illustrate the influence of rubber crumbs on the energy absorbing property of the waste mixtures, particle degradation has also be examined after finishing the triaxial tests. It has been found that the addition of RC can significantly reduce the particle breakage of the waste mixtures. Therefore, with high energy absorbing property, the SFS + CW + RC mixtures can be further extended to dynamic loading projects, such as railway capping layer.