Geo-environmental analysis and mechanical properties of geosynthetics in railway components industry (Sub and Superstructures)

Abstract

The sustainability Development Goals (SDGs), particularly SDG 13, emphasize the objective of the 2015 Paris Agreement to limit global warming to a maximum of 1.5 °C. Additionally, SDG 12 promotes sustainable production and construction practices. The primary goal of improving railway transportation for both freight and passenger services is to increase the speed and capacity of trains. While ballasted tracks have been commonly used, recent developments involve the use of geosynthetic materials within the track substructures. These geosynthetics, particularly those made from recycled materials, enhance the reinforcement and stability of substructures. This improvement in performance is expected to lead to a reduction in environmental impacts, such as CO2Eq emissions, due to longer lifespans, fewer repairs, and a decrease in the need for raw material extraction. This study presents a new substructure design that incorporates a geosynthetic layer made of recycled polypropylene (PP) and compares it with alternative scenarios using virgin PP and conventional ballast. Initially, Finite Element (FE) simulation is used to assess the mechanical performance of the PP as a reinforced layer in the substructure components. Subsequently, the Life Cycle Assessment (LCA) methodology is applied to evaluate the environmental impacts of the design. The FE simulation results show that incorporating a geogrid layer in the substructure reduces stress and deformation, contributing to an extended rail lifespan and a reduced environmental burden. Moreover, according to the LCA, the recycled geogrid scenario has the least environmental impact over a service life. However, the valuable environmental Impacts achieved in this study can be quite useful for decision-makers and engineers to choose the most suitable railway track substructure for decoupling the increase of technical properties from environmental impacts.