Coal Gangue Applied to Low-Volume Roads in China

Coal gangue is a solid waste produced from the production, washing, and selection of coal processes. Coal gangue is a mixture of minerals containing carbonaceous shale, sandstone, shale, and conglomerate. Stabilizing coal gangue with different inorganic binders, such as lime, cement, and a combination of lime and fly ash, was studied. The mix design of inorganic binder–stabilized coal gangue was determined on the basis of compaction tests and unconfined compressive strength tests. The performance of inorganic binder–stabilized coal gangue was evaluated by testing for compressive strength, flexural tensile strength, freeze–thaw stability, and thermal shrinkage. It was found that inorganic binder–stabilized coal gangue has high compressive strength and flexural tensile strength, good freeze–thaw stability, and a low thermal shrinkage property. These properties satisfy the requirement of third-class roads in China. Therefore, coal gangue can be used as a base or subbase material in low-volume rural roads when it is properly stabilized by lime and fly ash or cement.