Prestressed GFRP-reinforced concrete sleepers: An experimental study on reinforcement ratio optimization

Prestressed concrete sleepers are conventionally reinforced with steel strands to achieve the required flexural capacity. However, the susceptibility of steel to corrosion and its electrical conductivity can compromise the long-term durability of the sleepers and interfere with track circuit reliability in electrified railways. This study investigates the use of Glass Fiber-Reinforced Polymer (GFRP) bars as an alternative prestressing reinforcement to enhance durability, improve dynamic performance, and provide full electrical insulation. Three groups of sleepers with different GFRP reinforcement ratios were fabricated and evaluated through three-point bending tests, experimental modal analysis, and insulation tests. The results indicate that prestressed GFRP-reinforced sleepers achieved load-bearing capacity and natural frequencies comparable to conventional steel-reinforced sleepers, while exhibiting higher damping ratios and eliminating measurable current flow through the reinforcement, thereby mitigating track circuit short-circuit risks. Increasing the GFRP reinforcement ratio significantly improved mechanical performance, although the performance gains exhibited diminishing returns beyond an optimal ratio. Both GB 50608–2020 and the ACI 440 series provided reasonably accurate predictions for cracking load, deflection, and crack width, supporting their applicability for design. The findings demonstrate that prestressed GFRP reinforcement offers a viable and durable alternative for concrete railway sleepers, particularly for applications requiring electrical insulation and enhanced vibration attenuation.