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

Abstract

Railway tracks are conventionally built on compacted ballast and structural fill layers placed above the natural (subgrade) foundation. However, during train operations, track deteriorations occur progressively due to ballast degradation. The associated track deformation is usually accompanied by a reduction in both load bearing capacity and drainage, apart from imposing frequent track maintenance. Suitable ground improvement techniques involving plastic inclusions (e.g., geogrids) and energy absorbing materials (e.g., rubber products) to enhance the stability and longevity of tracks have become increasingly popular. This paper presents the outcomes from innovative research and development measures into the use of plastic and rubber elements in rail tracks undertaken at the University of Wollongong, Australia, over the past twenty years. The results obtained from laboratory tests, mathematical modelling and numerical modelling reveal that track performance can be improved significantly by using geogrid and energy absorbing rubber products (e.g., rubber crumbs, waste tire-cell and rubber mats). Test results show that the addition of rubber materials can efficiently improve the energy absorption of the structural layer and also reduce ballast breakage. Furthermore, by incorporating the work input parameters, the energy absorbing property of the newly developed synthetic capping layer is captured by correct modelling of dilatancy. In addition, the laboratory behavior of tire cells and geogrids has been validated by numerical modelling (i.e., Finite Element Modelling-FEM, Discrete Element—DEM), and a coupled DEM-FEM modelling approach is also introduced to simulate ballast deformation.

Compaction of mixtures of rigid and highly deformable particles: A micromechanical model

“…In an engineering context, recent emerging issues have led to the design of new materials in the form of a mixture of soil particles with rubber pieces (made from discarded tires). Such composite material exhibits new and fascinating mechanical properties, such as better stress relaxation [16][17][18][19], seismic isolation [20][21][22][23], and foundation damping [16,19,24,25], while reducing the weight of the structures or increasing the packing fraction of the granular composites. The range of applications for rigid-deformable composites is potentially broad and opens the door to an extensive field of fundamental topics that are still poorly studied.…”

Pullout Behavior of Different Geosynthetics—Influence of Soil Density and Moisture Content

“…Geosynthetics have been widely used as a reinforcement material in several geotechnical engineering applications, such as roadway and railway layers and embankments Ashmawy and Bourdeau, 1995;Lee and Wu, 2004;Ravi et al, 2014;Ferreira et al, 2016a;Nimbalkar and Indraratna, 2016;Indraratna et al, 2018Indraratna et al, , 2019Ngo et al, 2018;Byun and Tutumluer, 2019;Tatsuoka, 2019). In such applications, the interaction mechanism between the geosynthetic and the surrounding material is of primary importance.…”

Advances in ground improvement using waste materials for transportation infrastructure

“…Furthermore, since good quality natural aggregates are becoming increasingly scarce and associated environmental legislation is becoming more stringent, finding sustainable and innovative ways of recycling various types of industry wastes (used tyre derivatives, CW, plastics, glass etc.) for developing civil infrastructure will become crucial (Arulrajah et al, 2020a(Arulrajah et al, , 2020bIndraratna et al, 2018Indraratna et al, , 2019aNaeini et al, 2020;Suddeepong et al, 2020). The commercial use of these engineered fills (SFS and CW) above the groundwater level has already been approved by the Environment Protection Authority of the state of New South Wales (NSW EPA, 2014a, 2014b), indicating insignificant leachate potential and toxicity.…”