An experimental study on the characteristics of polyurethane-mixed coarse aggregates by large-scale triaxial test

The two main functions of ballast are train-load distribution and track-water drainage. Repeated train passage subjects ballast aggregates to abrasion and, eventually, breakage. Mixing of bonding materials such as polyurethane into aggregates can effectively mitigate ballast degradation. In the present study, large-scale triaxial tests were carried out to investigate the characteristics of polyurethane-mixed ballast materials. The stiffness and strength of the materials could be predicted in terms of the polyurethane contents, and the linear relationships could be established. According to those relationships, the performance of polyurethane-mixed aggregates as enhanced railway ballast materials can be simply but reasonably estimated.