Feasibility of Magnesium Phosphate Cement (MPC) as a repair material for ballastless track slab

2017 ◽  
Vol 154 ◽  
pp. 270-274 ◽  
Author(s):  
Bing Chen ◽  
Sajjad Yousefi Oderji ◽  
Shakya Chandan ◽  
Shijian Fan
Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2876
Author(s):  
Yingying Zhang ◽  
Lingyu Zhou ◽  
Akim D. Mahunon ◽  
Guangchao Zhang ◽  
Xiusheng Peng ◽  
...  

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.


2021 ◽  
Vol 11 (11) ◽  
pp. 4756
Author(s):  
Gaoran Guo ◽  
Xuhao Cui ◽  
Bowen Du

High-speed railways (HSRs) are established all over the world owing to their advantages of high speed, ride comfort, and low vibration and noise. A ballastless track slab is a crucial part of the HSR, and its working condition directly affects the safe operation of the train. With increasing train operation time, track slabs suffer from various defects such as track slab warping and arching as well as interlayer disengagement defect. These defects will eventually lead to the deformation of track slabs and thus jeopardize safe train operation. Therefore, it is important to monitor the condition of ballastless track slabs and identify their defects. This paper proposes a method for monitoring track slab deformation using fiber optic sensing technology and an intelligent method for identifying track slab deformation using the random-forest model. The results show that track-side monitoring can effectively capture the vibration signals caused by train vibration, track slab deformation, noise, and environmental vibration. The proposed intelligent algorithm can identify track slab deformation effectively, and the recognition rate can reach 96.09%. This paper provides new methods for track slab deformation monitoring and intelligent identification.


Measurement ◽  
2020 ◽  
Vol 160 ◽  
pp. 107866 ◽  
Author(s):  
Liuchong Wang ◽  
Wang Ping ◽  
Caiyou Zhao ◽  
Junyuan Zhen ◽  
Yannan Zhao

2011 ◽  
Vol 84-85 ◽  
pp. 188-193
Author(s):  
Rong Chen ◽  
Wang Ping ◽  
Hao Xu

A high degree of integrity is the most remarkable feature that makes double-block ballastless track different from other ballastless track structure. Based on the beam/plate theory on elastic foundation, influences of several structural parameters (such as size of track slab and support layer, support stiffness of the subgrade, etc) on stress of the ballastless track system under the axle load of 300kN were studied in order to obtain further understanding of the mechanic performance of double-block ballastless track under the train load. Results show that: structure of double-layer combined structure should be adopted to decrease the stress of each layer of ballastless track; the width of support layer should be less than 3.6m; because the ratio of track slab stress to support layer stress is larger than the ratio of their strength, the width of track slab in the double-layer separated structure should be 280mm or less.


2014 ◽  
Vol 906 ◽  
pp. 305-310 ◽  
Author(s):  
Fu Shan Liu ◽  
Zhi Ping Zeng ◽  
Bin Wu ◽  
Zhi Chao Zhang ◽  
Kui Peng

This paper built the three dimension mechanics model of CRTSII slab ballastless track structure on subgrade with ANSYS software. Analysis the influence of deformation and stress characteristics caused by different temperature gradients and the coupling action of temperature gradients and train loads under different work conditions, including no-separated, separated, and multiple-slabs separated with the cement asphalt mortar layer. The results show that, temperature gradients on track slab is one of the main reasons which caused the gap appearing between the bottom of slab track and cement asphalt mortar elastic cushion. And the joint main cause the deterioration of vibration of track slab, accelerating the deterioration of the cement asphalt mortar layer.


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