Executive Summary : | India's steel sector produces 12 million tonnes of steel slag and 24 million tonnes of iron slag annually, with iron slag production predicted to reach 45-50 million tonnes by 2030. This study aims to investigate the use of iron and steel-making slags as sub-ballast in railway track beds. Existing studies on replacing granular materials with iron and steel slag in concrete manufacturing, asphalt concrete, and pavement are limited, and there is no detailed research specific to iron and steel slags as a sub-ballast layer in railway track beds. The objectives of this study include investigating the strength and abrasive resistance of iron and steel slags as railway sub-ballast, comparing the shear performance of iron and steel slags and traditional sub-ballast material, assessing the interface shear behavior of iron and steel slags with geogrids, and understanding their performance through numerical investigations. Single Particle Crushing Tests will be conducted using Universal Testing Machine, and Los Angeles abrasion tests will be used to determine the abrasive resistance of iron and steel slags. Large-scale direct shear tests will be conducted on iron and steel slags to understand their shear behavior, and design charts of interface friction angle and dilation angle between slags and geogrids will be presented. A detailed numerical investigation using the finite element method will be conducted to understand the performance of iron and steel slags as a sub-ballast layer. The project's output will be used to develop design guidelines for wider applications of iron and steel slag as sub-ballast layers in railway track beds. |