Performance Evaluation of Iron Slag as a Railway Track Subballast

Abstract

The rising need for railway traffic requires robust and sustainable track structures. Conventional subballast materials, such as granite and basalt, encounter environmental and resource depletion issues, necessitating the exploration of alternative sustainable materials. As a result, a range of alternative strategies has been explored, particularly those involving the use of slags. Hence, this research provides an in-depth evaluation of iron slag as a sustainable alternative for the subballast layer material in railway track systems. Key engineering characteristics, including abrasion resistance, impact strength, particle crushing, permeability, and shear behavior under monotonic and cyclic loading, were thoroughly evaluated. Results showed that iron slag meets standard engineering criteria; exhibits enhanced resistance to crushing, abrasion, and impact; and improves shear performance by 17%–20%. In addition, vertical deformation was reduced by an average of about 26% under various normal stresses compared to conventional materials. The leaching behavior using the Toxicity Characteristic Leaching Procedure (TCLP) test confirmed the environmental compliance of the slag. Overall, iron slag proves to be a technically viable and environmentally friendly substitute for subballast, supporting sustainable development in modern railway infrastructure.