Behavior of railway bridge slab without ballast using GFRP reinforced lightweight concrete

Purpose This study investigates the structural performance of lightweight concrete (LWC) slabs reinforced with glass fiber-reinforced polymer (GFRP) bars as an alternative to conventional deck slab systems with timber sleepers on existing steel girder railway bridges. Design/methodology/approach LWC specimens using keramzit lightweight aggregates were fabricated and tested for their mechanical properties. Besides, three LWC slabs using GFRP reinforcement were also casted for evaluation of their load-bearing behavior. A static four-point bending test simulating train loading was conducted on three GFRP reinforced LWC slabs. Finally, finite element analyses were conducted to analyze the behavior of LWC slabs. Findings The results showed that the strength of LWC increased rapidly between 7 and 21 days. The greater the age of the sample, the greater the density. The pull-out test results showed that the larger the GFRP diameter, the larger the GFRP bar pullout force or the bond stress between the concrete and the GFRP. The four-point bending test showed that slabs reinforced with GFRP bars of larger diameters demonstrated higher load-carrying capacities. In addition, the simulation results showed good agreement with the test results in terms of estimated load-bearing capacity and enabled evaluation of the stress distribution within the GFRP reinforcement. Originality/value This study investigates LWC slabs reinforced with GFRP as a durable and high-performance alternative to traditional reinforced concrete in railway bridge decks. The corrosion resistance of GFRP and the superior load-bearing capacity of LWC offer a practical solution for rehabilitating and strengthening railway bridge decks on steel girders.