Application of hybrid fiber reinforced polymer concrete in railway sleepers: a perspective to rebar-free concrete sleeper

Traditional concrete railway sleepers reinforced with prestressed steel rebar face durability challenges, including corrosion, thermal expansion, and chloride attack. This study explores hybrid fiber-reinforced polymer concrete (HFRPC) as a steel-free alternative, aiming to enhance durability and sustainability. Laboratory tests evaluated four hybrid fibers, i.e., polypropylene, steel, synthetic plastic, and Forta, to determine optimal content and combinations for mechanical performance. The ideal fiber dosages are found to be 0.75 kg/m 3 (polypropylene), 2.5 kg/m 3 (synthetic plastic and Forta), and 25 kg/m 3 (steel), maintaining concrete strength. Compressive and tensile tests revealed that steel, synthetic plastic, and Forta fibers (FFs) enhanced properties, increasing flexural strength by up to 29.37 %. The hybrid combinations of steel-Forta and synthetic plastic-Forta yielded the highest improvements (29.37 % and 27.32 %, respectively). Full-scale sleeper tests confirmed these findings, with rail seat flexural strength increasing by 25.4 % for steel-Forta and 22 % for synthetic plastic-Forta, while center improvements reached 30.9 % and 24 %, respectively. The results demonstrate that HFRPC sleepers, particularly with hybrid fibers, exhibit superior mechanical performance compared with traditional steel-reinforced sleepers. This study highlights HFRPC’s potential as a durable, sustainable alternative for railway applications.