Environmental suitability, carbon footprint and cost savings of recycled plastic for railway applications

Abstract

ABSTRACT With the aim of achieving a zero-waste society, this paper presents the environmental suitability of reusing recycled plastic instead of using virgin aggregate materials for railway sub-ballast. Recycled plastic collected from a local recycling company in the state of Victoria, Australia were tested to evaluate any potential contaminant leaching from such material to the surrounding environment. Leaching tests were conducted for 238 potential contaminants following Australian Standard Leaching Procedure (ASLP) using pH-neutral water. From the series of leaching test results, it is clear that concentrations of all the assessed contaminants, except Lead in the tested samples, are either below their individual detection limits or below the Environmental Protection Authority (EPA) Victoria defined limits to label these materials as hazardous. Apart from one pollutant, the material is safe to be reused for different engineering applications. In addition, a carbon footprint analysis was conducted considering a sustainable approach of using such recycled plastic with recycled concrete and recycled glass. It is found that through using such recycled materials total carbon footprint savings for 1 km railway track ballast material would be up to 52,211 kg CO2e. Finally, a cost analysis is presented to demonstrate economic benefit of using recycled plastic.