Abstract: An uncured cementitious dough or paste, which is substantially free of particulate components having a diameter greater than 100 microns, said paste comprising in admixture;(a) At least one hydraulic cement;(b) at least one polymer latex, the polymer being present in an amount of 1 to 20 parts by weight per 100 parts of the cement;(c) total water in an amount from 8 to 20 parts by weight of water per 100 parts by weight of cement.A cured cementitious composition may be produced by heating said dough or paste at a temperature of above 100.degree. C. and may be used for products such as roofing elements, for cladding the exterior walls of buildings and other building products.

Abstract: An uncured cementitious composition comprising in admixture:(a) at least one hydraulic cement;(b) at least one reactive water-soluble polymer which is capable of providing a viscous solution in water at low addition levels;(c) water in an amount of from 10 to 25 parts by weight of water per 100 parts by weight of the cement; and(d) a water soluble cross-linking agent capable of effecting chemical cross-links between molecules of the said polymer in the presence of the cement and water.

Abstract: A board of sandwich construction which comprises two outer preformed support membranes consisting of or comprising fibrous material, the said membranes having interposed therebetween an aerated intermediate layer comprising at least 70% by weight based on the dry board of an unfired clay which contains less than 20% by weight of expandable minerals and the intermediate layer also including fibres therein.The boards of the present invention are intended mainly for use as plasterboard substitute.

Abstract: A vortex combustion furnace (1) for the production of glass beads or the like is generally cylindrical and has an outlet flue (24) at its upper end. A burner (13) at the lower end burns a gas/air mixture. Secondary air is introduced into the chamber through tangential air inlets (16) and creates a vortex (71) within the chamber. Tertiary air is introduced through a ring of angled nozzles (71) surrounding the burner further to swirl the flame. The vortex has a top-hat temperature profile with a central heating region with a temperature in excess of 1000.degree. C. and a surrounding cooling region with a temperature not much above ambient. Glass cullet is supplied to a fluidized bed (53) and then entrained in a pipe (44) to be injected into the chamber. The cullet follows a spiral path in the vortex, is heated, melts to form glass beads, is then cooled and finally is collected after striking the wall of the chamber.

Abstract: A vortex combustion furnace (1) for the production of glass beads is generally cylindrical and has an outlet flue (24) at its upper end. A burner (13) at the lower end burns a gas/air mixture. Secondary air is introduced to the chamber through tangential air inlets (16) and creates a vortex within the chamber. The vortex has a top-hat temperature profile with a central heating region with a temperature in excess of 1000.degree. C. and a surrounding cooling region with a temperature not much above ambient. Glass cullet injected into the chamber follows a spiral path in the vortex, is heated, melts to form glass beads, is then cooled and finally is collected after striking the wall of the chamber.