Experimental Research on Coal Gangue Grouting Material for Gob Filling

Grouting fill is one of the main methods of coal gob treatment. The grouting properties directly affect the effect of grouting treatment. Cement-fly ash grout is widely used in the treatment of coal gob. But in many gob grouting fill projects, due to the lack of fly ash, we need to look for other low-cost grouting materials. Study was made through laboratory experiment on the properties of cement-coal gangue materials used for the gob grouting. In this paper, the correlation of water-solid ratio, cement content, admixture, concretion compression strength, setting time, viscosity, water segregation rate and hardening rate is discussed in the case of use of large gangue content cement. The test results show that compared with the grout not go through the activation process, the blended cement grout mixed with coal gangue powder activated by low temperature and mechanical crushing has high concretion compression strength. Water glass has a great effect on the viscosity, initial setting time and final setting time, which can be used to adjust the grout properties to accommodate grouting environment requirements. This grout has the advantage of wide range sources of raw materials, and can be used to solve the lack of fly ash and gangue resource utilization problems.