The storage of mining waste not only consumes a vast tract of land, but it also poses environmental problems due to the leaching of heavy metals, dusting, and occasional slope failure. A coal mine overburden (hereafter referred to as black shale) is one of the mining wastes produced during the coal mining activity, dumping of which causes an environmental problem. By considering the issue associated with waste storage and the requirement for alternate civil engineering material, an attempt has been made to develop cementless controlled low strength material (CLSM) from black shale. For this purpose, black shale is mixed with a varying percentage of alkali activated ground granulated blast furnace slag (GGBS) and fly ash. The fresh CLSM is investigated for flowability, bleeding, and density, whereas the hardened CLSM is examined for unconfined compressive strength (UCS), hardened density, water absorption, ultrasonic pulse velocity, and durability. The CLSM developed in the present research is found to have self-flowing and self-leveling consistency, with flowability higher than 200 mm and a relative flow area between 2.06 and 7.70. The CLSM is found easily excavatable with a removability modulus less than 1. The 28-day UCS of CLSM is found between 0.48 MPa and 2.1 MPa, whereas it is found low to medium durable with a durability index between 84.44 % and 87.39 %. Further, the shear modulus of the hardened CLSM is evaluated using ultrasonic pule velocity. Finally, the CLSM is found non-toxic based on the result of the leaching analysis.

来源平台：CONSTRUCTION AND BUILDING MATERIALS