Laboratory Investigation into the Flexural Behavior of Embedded Concrete Sleepers in Two-Stage Concrete with Preplaced Ballast Aggregate

The conversion of ballasted railway tracks into slab tracks using the preplaced aggregate concrete (PAC) technology over the bridges and in the tunnels has been introduced by many researchers but the flexural behavior of this composite system has not yet been studied. Therefore, in the first stage, a series of mortar and concrete mixture designs were proposed and evaluated. Subsequently, a concrete beam mold with dimensions of 3 * 0.6 * 0.5 m, which represented the track conditions, was developed and the bending behavior of the constructed beams in both conditions of the presence and absence of the concert B70 sleeper were investigated. The maximum bending force in the middle of the concrete beam without a sleeper (SE) equaled 177.5 kN. In addition, the average values of bending tolerance by the sleeper including a PAC beam for three specimens in the four modes of the positive moment of midspan (SPM), negative moment of midspan (SNM), positive moment of rail seat (SPR), and negative moment of rail seat (SNR) were 55.25 kN m, 32.5 kN m, 91.84 kN m, and 38.21 kN m, respectively, which met the requirements of the AREMA regulations.