Cementitious compositions and their uses

Abstract

A composition suitable for adding to water to produce a water-resistant hydraulic solid which composition comprises components (a), (b) and (c) as follows: (a) calcium sulphate hemihydrate; (b) portland cement; (c) calcined clay having a pozzolanic activity; wherein the percentages by weight of components (a), (b) and (c) in the said composition are in the respective ranges: (a) from 20% to 98%; (b) from 1% to 50%; (c) from 1% to 30%; the percentages of components (a), (b) and (c) adding to 100% in the three component composition.

Dependencies are inferred from the claim text.