Behaviour of Steel Slag Ballast for Railway under Cyclic Loading

Steel industry produces substantial amount of steel slag as a by-product generated during manufacturing of pig iron and steel. The steel slag has huge potential to be used in Indian Railways as a ballast material. Steel slag ballast provides high drainage because of its high percentage of void space and exhibits high resistance to degradation. The rapid development of semi-high-speed railway or upgrading the existing one to a higher speed limit and its maintenance under demanding operational conditions have brought new challenges to the Indian Railways. The study on the behaviour of steel slag as railway ballast under cyclic loading is limited and one of the prerequisites for predicting the performance of railway on account of increasing speed and demanding operational condition. This study investigates the cyclic response of steel slag ballast using the parallel gradation modelling technique. The tests were performed on the ballast compacted at two different initial relative density (60 and 90%) and under two different confining pressures (40 and 60 kPa). Resilient modulus, permanent axial strain, shear modulus and damping ratio are determined for two different loading frequency (1 and 3 Hz) and number of load cycles. The impact of various controlling parameters on the degradation behaviour of the ballast is studied.