CRUDE MIXTURE FOR PROTECTIVE COATING Russian patent published in 2020 - IPC C04B41/50 C04B28/04 

FIELD: construction.

SUBSTANCE: invention relates to construction materials and can be used for protection of spent mines. Raw mixture for protective coating contains, wt%: portland cement 37.0–40.0; sand 0.125 mm fraction 27.0–27.5; microcalcite of 100 mcm fraction 11.2–11.8; finely ground magnesia limestone with specific surface area of 320 m²/kg 7.5–9.0; complex additive 0.9–1.0; water 13.4–13.7. Complex additive contains, wt%: potassium nitrite KNO₂ 2.8–3.3; polymer-containing component Sika Viscocrete 225 based on allyl ether and maleic acid anhydrite 96.7–97.2.

EFFECT: high adhesion strength of the protective coating to the surface of the rock and low vapor permeability of the hardened protective coating.

1 cl, 2 tbl, 1 ex