GB569596A - Improvements in or relating to the production of floorings or other strong set masses from water-setting cementitious materials - Google Patents

Abstract

Compositions for floorings, eaves, skirtings, shelves, table tops, &c. are obtained by mixing from 60 to 30 per cent by volume of finely-ground anhydrous calcium sulphate, from 40 to 70 per cent by volume of an aggregate consisting of crushed rock anhydrite or gypsum so graded that none passes B.S. sieve 52 and not less than 75 per cent by weight is retained on B.S. sieve 25, water and a catalyst for accelerating the set of anhydrous calcium sulphate. The ground anhydrous calcium sulphate is of plaster fineness, a suitable grading being 80 per cent passing B.S. sieve 172. Compositions suitable for floors contain 60 to 40 per cent by volume of anhydrous calcium sulphate and 40 to 60 per cent by volume of the aggregate, of grading between B.S. sieves 52 and 3/16 in. or, if the surface of the set product is to be subsequently finished by abrading, between B.S. sieves 36 and 10. Metal or other reinforcement may be employed. Anhydrous calcium sulphate catalysed as described in Specifications 236,695, 317,672, [both in Class 22], 459,134 or 554,952 is preferred. In laying a floor, the composition may be applied to a layer of open mesh hessian attached to a foundation by means of an adhesive of the kind described in Specification 524,928. The set or setting composition may be wetted with water or with a solution of a salt which catalyses the set of anhydrous calcium sulphate. The surface of the dried set composition may be treated with a drying oil or with a tung oil modified phenol-formaldehyde resin. Fillers, such as wood, sawdust, cork or asbestos fibre may be incorporated in the compositions in amounts up to 10 per cent of the sum of the volumes of the aggregate and the catalysed anhydrous calcium sulphate. Specifications 451,113 and 521,997 also are referred to.