Gypsum concrete
Gypsum concrete is a building material used as a floor underlayment used in wood-frame and concrete construction for fire ratings, sound reduction, radiant heating, and floor leveling. It is a mixture of gypsum plaster, Portland cement, and sand. The brand name Gyp-Crete, a Maxxon Corporation trademark, has come into general use as a term for gypsum concrete by construction professionals and architects.