Deformation characteristics of discontinuous section of quick-hardening concrete tracks under full-scale test

A quick-hardening concrete track has been developed to convert old ballast tracks into concrete tracks on operating lines. This method has been utilized to convert urban railways since 1997. With recent increases in train traffic and speed, maintaining track irregularities within design criteria has become essential to ensuring safety. On quick-hardening tracks, track irregularities are predominantly caused by irregular settlement around construction joints. These construction joints are inevitable in quick-hardening concrete; however, they create discontinuous sections that can affect the stable running of trains and structural durability. In this study, full-scale tests were performed with quasi-static and repeated loading on both continuous and discontinuous sections in which the earth pressure acting on the trackbed, accumulated settlement, and elastic displacement were measured. The results obtained indicate that construction joints are disadvantageous in terms of load transfer, settlement, and displacement. Additional field observations conducted on the Seoul Metro Line corroborated the results of the full-scale tests. The overall findings strongly suggest that construction joints on quick-hardening concrete tracks would need to be reinforced.