This open access book focuses on the synergistic utilization of multi-source industrial solid waste in manganese slag-based grouting materials. It presents key methods like high-temperature activation of electrolytic manganese slag (EMR), alkali excitation, and multi-scale characterization (XRD, SEM, MIP), along with optimized performance and environmental safety data of three grouting materials (EFGM, ESGM, ECGM). Featuring over 200 illustrations, 11 tables, and a COMSOL-based performance prediction model, it offers an engineering-oriented approach. Readers gain insights into solid waste recycling and grouting material R&D. It benefits researchers, engineers in environmental engineering, materials science, and geotechnical engineering.