Experimental investigation of the mechanical properties and large-volume laboratory test of a novel filling material in mining engineering

Abstract

In this paper, a novel filling material was developed that consisted of a coal gangue and fly ash mixture as the main material and a ground slag, quicklime and plaster mixture as the cementing material. Moreover, an auxiliary agent was added as an activator. The test results showed that the optimum composition of the filling material included coal gangue and fly ash at a 2:1 ratio, accounting for 85% of the total mass, ground slag (G), quicklime (Q) and plaster (P) at a 5:3:2 ratio, accounting for 15% of the total mass, an expansive agent content of 0.01%, and a modifier additive content of 1.0%. A large-volume sample (1 m × 1 m × 1 m) was evaulated with this optimized material composition. The experimental temperature, mechanical performance, regeneration strength, and failure characteristics were determined. The results showed that the temperature of the middle part of the filling body was the highest and peaked at 40.2 °C. The filling material had a high compressive strength and exhibited ideal plastic deformation characteristics. The strength could be restored after damage had occurred and the fracture surface was destroyed along a certain angle.