Railway sleepers are one of the essential parts of the ballasted railway tracks that provide support to the rails, retain the track gauge, and transfer the rail-seat loads uniformly to the underlying ballast layer. Prestressed concrete (PSC) sleepers are currently the most well-known railway sleepers used by the railway industry. It is estimated that there are around 400 billion prestressed concrete sleepers used in railway tracks worldwide and this number is increasing rapidly. The manufacturing process of the PSC sleeper requires relatively spacious indoor area with expensive machinery. Additionally, this manufacturing process needs heat curing and, therefore, is energy-consuming and pollutes the atmosphere due to the emission of greenhouse gases. This research proposes the application of non-prestressed concrete sleepers as an alternative to the currently used PSC railway sleepers. For manufacturing non-prestressed concrete sleepers, ultra-high tensile strength concrete is needed to
In this paper, an optimal ultra-high performance fibre-reinforced concrete (UHP-FRC), which is also known as reactive powder concrete (RPC), with high flexural strength was developed to satisfy the demands for manufacturing non-prestressed concrete sleepers. First, a preliminary analysis is performed to estimate the maximum flexural stresses developed within sleepers with typical dimensions under typical train axle loads of 25 and 40 tonnes. After determining the required flexural strength, the optimum mix proportions of the RPC is obtained using the Taguchi method. The effects of four important parameters, i.e., silica fume to cement ratio (SF/C), sand to cement ratio (Sand/C), superplasticizer to cement ratio (SP/C), and water to binder ratio (W/Binder) are investigated. It is found that an optimum RPC mix with maximum flexural strength can be developed using the SF/C ratio of 0.3, Sand/C ratio of 1.2, SP/C ratio of 0.4, and W/B of 0.2. Subsequently, it is proved that the UHP-FRC wit