Recently, polymer concrete has been widely used as an alternative material of cement concrete because of its outstanding mechanical and dynamic properties [1][2][3]. Polymer concrete is a composite material combining various types of aggregates and the polymer matrices. Polymerizing the monomer and the aggregate mixture enables dense packing which can enhance the mechanical strength, adhesion properties, resistance to corrosion and vibration damping characteristics. In addition, the hardener, mixed with an epoxy monomer in a polymer concrete accelerates its curing time than conventional cement concrete and easy to fabrication enough to use in various environments. Therefore, polymer concrete has been applied in many areas including pump base, machine tool bed and repairing damaged airstrip, road and bridge [4][5][6]. Also, the waste/recycled plastic (e.g. PET, PP, PEI, CFRP, GFRP) has been widely investigated with polymer concrete because it has low price, light weight, durability and reduces energy consumption and solid waste. However, in previous studies, application of the recycled plastic was focused only on the improvement for durability of construction material. Moreover, it is not clear how the recycled plastic affects the damping capability for noise reduction [7][8][9][10].In this work, polymer concrete was investigated for railway application with outstanding mechanical/ dynamic properties. In particular, a significant noise problem occurred due to low vibration/noise absorption characteristics of sleeper. The sleeper is clamped in the transverse direction with the rail on the ballast. In addition, in order to apply to railway sleeper of high-speed train, high strength and stiffness to prevent cracks are also important. Therefore, we used recycled polyetherimide (PEI) thermoplastic with the polymer concrete to enhance the mechanical/dynamic properties of the railway sleeper application. PEI is an excellent amorphous engineering thermoplastic which belongs to polyimide family. A functional group of condensed polyimide on the PEI backbones has been characterized as mechanical properties, high-temperature stability, and good chemical and environmental stability [11,12]. Moreover, PEI was considered as an excellent composition material of airplanes and ground transportation requiring sufficiently high damping capability of noise/vibration absorp-
