Modifying the One-Dimensional Response of Ballast Box System Using Resiliently Bound Ballast

The transition zones especially railroad bridge transitions are one the weakest track sections that need more maintenance in order to keep a good track performance. These locations are also commonly create noise and vibration pollution which is unpleasant specifically in urban parts of the city. A new product known as Resiliently Bound Ballast (RBB) is a new engineered material composed of Ballast, tire derived aggregate (TDA) and proprietary elastomeric epoxy binder which can be manufactured with different mixtures to meet various engineering properties. In order to study the workability of this material in railroad bridges, in this research a one dimensional (1D) two degree of freedom (2DOF) composite RBB-Ballast track on concrete deck bridge has been modeled with different RBB thicknesses from 0.01 in. (0.025 cm) to 23.99 in. (60.94 cm) and material damping of 2.5, 5 and 10 %. The range of properties for RBB are based upon values obtained from static and dynamic testing. The results show that the most peak amplitude reduction occurs between 2.5% to 5% damping, RBB has the ability to dissipate energy over a broader range of frequencies and as the damping increases, the RBB thickness becomes more effective in track dynamic performance.