ASTM C61Full Name ASTM C61 – Standard Specification for Gypsum Keene’s CementScope This specification covers various grades of anhydrous calcined gypsum known as gypsum Keene’s cement, designed for use in the base and finish coats of gypsum plaster.Keywords anhydrous gypsum; gypsum; gypsum Keene’s cement; gypsum plaster; Keene’s cement; plasterResourcesASTM International Website: ASTM C61 Need more info?