Research on shotcrete in mine using non-activated waste coal gangue aggregate

Concrete is a building material that has been widely used in many industries, including coal mines. Because of environmental influences related to traditional aggregates in the concrete industry, a more eco-friendly method of making concrete is needed. Gangue is waste rock produced by coal mine excavation that has led to many environmental and social problems. An eco-friendly way to make concrete is proposed in this paper that replaces traditional aggregates with crushed non-activated coal gangue (NACG). This concrete offers a sustainable alternative to mitigating the environmental problems related to the extraction and depletion of concrete raw materials and the disposal of coal gangue. This experimental research is conducted to study the slump, setting time, air content, compressive strength and splitting tensile strength of different mixture proportions of coal gangue concrete (CGC). The slump, setting time and air content were measured according to the regulations provided by the China National Standard (MOHURD, 2016) using the slump flow test. Hardened properties include compressive and splitting tensile strengths. Optimal mixes design of NACG aggregates were conducted to optimize the fresh and hardened properties of coal gangue concrete. As the percentage of fine NACG aggregates replacement increased, the workability and tensile strength of the coal gangue concrete decreased. Additionally, as the maximum size of coarse NACG aggregates increased, an increase was observed in the compressive strength of coal gangue concrete. (C) 2020 Elsevier Ltd. All rights reserved.