Patent ID: 6923857

Claim:
A non-efflorescing cementitious body being formed upon curing of an aqueous paste formed by the addition of water to a pre-mixed dry binder comprising from 10% to 49% by weight of a first ingredient comprising a source of active silica, and a remainder including: (i) from 40% to 90% by weight of a second ingredient comprising a source of calcium aluminate selected from calcium alumiate cement or clinker and calcium sulpho aluminate cement or clinker, said source of calcium aluminate having at least 25% alumina or a C/A ratio of less than 3; (ii) from 5% to 55% by weight of a third ingredient comprising Portland cement or clinker as a source of calcium silicate; and (iii) from 3% to 50% by weight of a fourth ingredient comprising a source of sulphate at least 25% being SO 3 ; said ingredients being present in such relative proportions that, upon hydration, both mono-sulphate (C 3 A.Cŝ.12H) and hydrated alumina (AH 3 ) are formed.