Underwater non-dispersible grout is a powdered grouting material composed of water-soluble polymers, surfactants, and other compounds. It exhibits strong resistance to dispersion and excellent fluidity, enabling self-leveling and self-compacting of underwater concrete while preventing the dispersion of cement and aggregate during underwater construction. This grout is suitable for various underwater concrete pouring projects, including caisson sealing, cofferdams, caissons, stone pitching grouting, underwater diaphragm wall construction, leveling and filling of underwater foundations, large-scale seamless construction projects such as RC slabs, large-diameter cast-in-place piles, docks, dams, reservoir repairs, waterproof impact-resistant reinforcement for drainage outlets, underwater pile caps, seawall revetments, slope protection, pile sealing and leakage stoppage, as well as other underwater projects where conventional concrete is difficult to apply. CBGM underwater non-dispersible grout is not limited by water depth, construction surface, or concrete volume (it has been successfully used in projects with depths up to 37.8 meters and concrete volumes ranging from a few cubic meters to several thousand cubic meters). It also remains unaffected by tidal fluctuations during concrete construction in intertidal zones.