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