Research Progress and Discussion on Modified Cement-Based Borehole Sealing Materials for Mining

[Image: see text] As the concept of green mining develops, organic sealing materials are losing popularity in mining, yet the development of inorganic sealing materials for mining has become a research focus. The most common inorganic sealing materials are Portland cement (PC) and sulfate aluminate cement (SAC), but they fail to meet the performance requirements for sealing gas boreholes in complex coal seams due to their limitations. Thus, their performance needs to be modified. This study aims to explore and grasp the current development of inorganic modified cement-based materials from the perspective of improving the performance of cement-based materials of PC and SAC. First, the characteristics of the main hydration products of PC and SAC as well as the effects of these characteristics on their properties were analyzed. Next, the effects of additives such as admixtures, coagulant regulators, and nanomaterials on their properties including hydration properties, coagulation time, and strength were analyzed. Finally, the modification methods and mechanisms were discussed. It is proposed that the optimization of modification effects by various additives is of great practical significance for the development and application of modified PC and SAC in sealing gas boreholes in engineering practice.