Recycled Glass Blends with Recycled Concrete Aggregates in Sustainable Railway Geotechnics

Mahdi Naeini,Suksun Horpibulsuk,Arul Arulrajah,Alireza Mohammadinia

doi:10.3390/su13052463

Abstract

This research investigates the static and cyclic characteristics of recycled glass (RG) as a supplementary material with recycled concrete aggregate (RCA) in the rail track capping layer. RG was blended by-weight with RCA in 10% increments up to 50% RG content. A performance-based laboratory testing scheme was designed according to the field loading conditions of capping layers in rail tracks. Basic geotechnical properties of RG + RCA blends were evaluated through their particle size distribution, compaction properties, and California bearing ratio. Effect of flooding was assessed with one-dimensional static and cyclic compression tests. Multistage triaxial compression tests were performed to determine the effect of RG content on shear strength parameters. A new repeated loading triaxial testing protocol was introduced for railway capping layer materials to assess the stiffness of RG blends to cyclic loading. Long term performance of samples also was evaluated through multistage cyclic permanent deformation tests. The shakedown concept was used to assess the permanent deformation results of RG + RCA samples. Results indicated that RG can be used effectively as a supplementary geomaterial in construction of rail track substructure.

Highlights

recycled glass (RG) and recycled concrete aggregate (RCA) were sourced from a recycling facility in Australia
The Australian Rail Track Corporation [19] specifies a California bearing ratio (CBR) value of more than 50% as the singular strength requirement for the granular materials to be acceptable for capping layer construction
Blends with up to 30% RG content had a CBR value similar to the conventional capping materials reported in the literature [4]

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The non-biodegradable nature of waste glass has become an environmental concern worldwide. More than 10 million tonnes of waste glass are landfilled each year [1]. Most of the developed and developing countries have a recycling rate of less than 60% and face challenges in efficiently increasing their recycling rate [1]. Australia in particular has a relatively constant recycling rate of below 60% with a landfilling amount of approximately

Methods

Results

Conclusion