Preparation of sustainable high-performance grouting material developed with high volume solid waste

The implementation of deep underground engineering (such as deep mining, geothermal exploitation, and oil/gas exploration) faces considerable obstacles, including high in-situ stress, elevated temperatures, and severe excavation disturbances. These conditions necessitate the use of grouting for effective rock mass reinforcement. Solid waste-based grouting materials (SWG) have emerged as a viable alternative to P·O 42.5 cement-based grouting materials (PCG), while their practical application is limited by inadequate workability and strength. This study created a novel SWG consisting of almost 99 wt% solid waste, providing considerable environmental and economic benefits. The results revealed that the formulated SWG consisted of 48.31% ground granulated blast-furnace slag, 30% fly ash, 0.38% carbide slag, 7.2% flue-gas desulfurization gypsum, 0.04% polycarboxylate, and 0.3% calcium formate. The produced SWG substantially surpassed PCG, exhibiting a compressive strength increase of 17.9-88.6% within 28 days, a flowability enhancement of 101.3%, an extension of the diffusion range in three-dimensional fracture networks by 17.21%, and a 44.1% decrease in final bleeding. The solidification mechanism of SWG was examined by investigations of its hydration process and microstructure. A comparative sustainability evaluation further revealed that the developed SWG reduced carbon emissions and cost by 87.79% and 58.44%, respectively, relative to PCG. This study offers a feasible approach for the valuable utilization of solid waste in deep underground engineering.