Study on the Mechanism of the Effects of Coal Particles on the Mechanical Properties of Cement-Based Grouting Materials

This paper systematically investigates the effects of coal particle content and size on the macroscopic mechanical properties and microstructure of cement-based grouting materials, with the goal of improving the sealing performance of gas extraction boreholes. A series of experiments with varying coal particle contents and sizes were conducted to measure the compressive strength at different curing ages. Additionally, Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were employed to analyze the microstructure and hydration products of the materials. The results demonstrate that the incorporation of an optimal amount of coal particles significantly enhances the mechanical properties of cement-based materials, with a content of 40g and a particle size of 1–2mm achieving the highest compressive strength. Microstructural analysis revealed that the appropriate introduction of coal particles promotes the formation of C-S-H gel, thereby improving material compactness and durability. This research provides crucial theoretical insights and practical guidance for the application of cement-based grouting materials in gas extraction operations.