Use of Rubber Mats to Improve the Deformation and Degradation Behavior of Rail Ballast under Cyclic Loading

Abstract

The deterioration of a rail track due to large dynamic wheel loads is inevitable over the years, and one that leads to frequent and high maintenance costs. This problem is more critical in isolated rail track locations such as bridges and tunnels where the substructure is much stiffer than the surface track assembly. One measure used to minimize track deterioration is to place geosynthetic inclusions such as rubber mats under the layer of ballast. In this study, cyclic loads from fast and heavy haul trains were simulated on stiffer track foundation conditions using a large-scale process simulation triaxial (prismoidal) apparatus (PSPTA) to investigate the 2 performance of ballast improved by rubber mats locally manufactured from recycled tires. The laboratory results indicate that the energy absorbing (damping) characteristics of rubber mats reduce the amount of deformation and degradation of ballast under stiffer track conditions. The study shows that rubber mats distribute the stress applied from moving trains more uniformly by increasing the effective contact area, which then reduces the dynamic amplification of applied vertical stress and contributes to much less ballast degradation.

Experimental Research on Deformation Characteristics of Using Silty Clay Modified by Oil Shale Ash and Fly Ash as the Subgrade Material after Freeze-Thaw Cycles

“…In previous studies [33,46,49], almost all of the cycle load number, used to study permanent deformation characteristics or cumulative plastic strain of soil medium, are lower than one million times. In this manuscript, in order to present the residual deformation in more rigorous cases than previous studies, we assume 10 million times of cycle loads to predict the cumulative plastic strain of MSC used as subgrade material.…”

Use of Geogrids and Recycled Rubber in Railroad Infrastructure for Enhanced Performance

“…These impact forces can likewise be generated at transition zones involving abrupt variations of vertical track stiffness, such as at the approaches to tunnels, bridge or viaduct and level crossings, or where there is a sudden change from conventional ballast to slab track intensifying ballast breakage and adversely affecting track stability [11][12][13][14][15]. One potential method of enhancing the substructure capacity to withstand the large cyclic and impact loads induced by fast-moving heavy-haul trains is to improve the performance of the ballast layer using plastic (e.g., geogrids) and rubber inclusions (e.g., rubber mat, tire cell, and rubber crumbs) [2,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Application of geoinclusions for sustainable rail infrastructure under increased axle loads and higher speeds

“…placed at the interfaces between rails and sleepers); (ii) under sleeper pads (i.e. placed at the sleeper/ballast interfaces); (iii) rubber mats installed beneath the ballast (shock mats); and (iv) ballast mixed with rubber crumbs or shreds [17,41,60]. The inclusion of rubber shock mats decreases the hard interface between the ballast aggregates and other track components, such as the sleepers or underlying formations, and allows the particles bedding into softer pads, thus enhancing the area of contact of the aggregates and minimising the inter-particle contact forces [42,47,51].…”