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

Abstract

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.

Biaxial Shear Load Capacity of Anchor System for Quick-Hardening Track on Railway Bridges

“…(4) When the anchor design load was evaluated using the elliptical biaxial shear capacity curve that was determined based on the longitudinal and transverse loading capacities of the anchor system, the proposed design displayed sufficient structural capacity to accommodate the given design loads. (5) When the friction coefficient between the bridge deck and the quick-hardening track was 0.258 or above, the anchor system of Design A was sufficiently robust to ensure the structural safety of the track under the design loading capacity. Likewise, when the friction coefficient was 0.168 or above, Design B was able to ensure the structural safety of the track.…”

“…us, to continue operating while the track is replaced, railways must build a bypass loop around the current railway line. To reduce the cost and complexity of installing a slab track, a quick-hardening track technique based on quickhardening mortar has been developed that drastically shortens the track replacement period [2][3][4][5]. As illustrated in Figure 1, the quick-hardening track technique constructs a slab track by collecting and cleaning existing ballast gravel from old ballast tracks and then recasts and hardens them with quick-hardening mortar.…”

“…Recently, the behavior of quick-hardening track on an earthwork section was analyzed by considering the thermal stress [2], quick-hardening in ll materials for quick-hardening track were developed [3], and a quick-hardening track was installed in a 52 m length of a current railway line to verify the performance of the method [4]. e deformation characteristics of discontinuous sections of quick-hardening track were also examined as part of a fullscale test [5].…”