Slags are the byproducts of iron and steel factories usually stored and stashed in large depots around these factories. Extensive investigations have been conducted around the world to find suitable applications for this material. Ballasted track are a possible use case through which large volumes of this materials can be consumed. Studies suggest that employing slags as ballast tracks brings about many advantages such as increasing the lateral resistance of railway tracks. However, as one of its major drawbacks, this material can also increase the track stiffness, which is of great importance in cases where dissipation of energy (damping) is necessary. This drawback, if not resolved, can lead to faster destruction of the railway tracks due to the increased dynamic impacts, specifically at the rail track joints, which can consequently affect the destruction of the ballast and reduce its Service life. This thesis attempted to incorporate tire delivered aggregate (TDA) into the ballast layer to mitigate the aforementioned problem and increase its Service life. To this end, TDA was used at two gradations, namely 10 to 20 mm and 20 to 60 mm (the same gradation as the ballast materials). The ballast box test was used to examine the effect of TDA on this layer by measuring parameters such as settlement, stiffness, damping ratio, and ballast breakage index of materials. The TDA was used at 0, 5, 10, and 15 wt%. Finally, based on the obtained optimal weight percentage and gradation type, modifications were applied to the morphology of the employed TDA, and the aforementioned parameters were again examined. Ultimately, the Abaqus software was used to model the ballast box test, and the settlement results obtained from the numerical and experimental models were compared. In addition, the stress contours for the models were also extracted. The results suggest that TDA increases the track damping ratio and settlement while reducing the stiffness and ballast breakage index. Moreover, compared to finer gradations, the gradation of 20 to 60 mm resulted in a greater increase in the track settlement and damping ratio. Addition of 10 wt% TDA with a gradation of 20-60 mm increased the settlement and damping ratio by 4.5 and 2.72 compared to the simple sample. However, this mixture also caused a greater reduction in the stiffness and ballast breakage. According to the results, a higher mechanical performance was achieved using the ballast layer containing TDA with a gradation of 20 to 60 mm compared to the 10 to 20 mm gradation.