Mortars and floor plaster binder - based on Portland cement, with lump gypsum as a sulphate source, and also containing conventional additives

摘要

Binder contains C3A-free Portland cement, a sulphate source and additions, e.g. retarder, accelerator, defoamer, pore-former, thickener and/or fluidiser. The sulphate source is lump gypsum (beta calcium sulphate hemihydrate). Preferably, the ratio of cement to gypsum is 1-3.5:1 and the total additive content is 0.1-3.0 wt.%. The binder is preferably mixed with 1-4 wt. parts aggregate per wt. part binder and, when used in a plaster mortar, contains up to 10 wt.% hydrated lime and optionally up to 300 l/tonne light aggregate such as expanded perlite.