Feasibility and Challenges of Ultrafine Stone Powder and Fly Ash Composite Grouting Material

Abstract

Coal mining and coal-fired power generation produce large quantities of coal-based solid wastes such as fly ash and coal gangue, whose accumulation occupies land and poses environmental risks. Meanwhile, ultrafine stone powder, as a byproduct of stone processing, faces similar challenges in resource utilization. The combination of these two types of solid wastes to prepare grouting materials has become an important research direction in fields such as bed-separation grouting for subsidence reduction and goaf filling treatment. This paper systematically analyzes the feasibility basis of ultrafine stone powder and fly ash composite grouting material, including the strong impetus from national policies on solid waste resource utilization, significant reduction in raw material costs, and the complementary performance advantages of the composite system in terms of fluidity regulation, stability improvement, and strength enhancement. At the same time, it deeply discusses the multiple challenges faced by this material, covering the difficulty of matching slurry rheological behavior with bed-separation space, the deterioration of filling quality caused by water separation, the risk of groundwater pollution from heavy metal leaching, and the precise matching between grouting timing and filling effectiveness. The research indicates that this composite material has broad prospects for engineering applications, but its large-scale promotion still requires continuous technical breakthroughs in formulation optimization, environmental risk control, and engineering adaptability.