Abstract: A cementitious panel having a basalt fiber-containing reinforcing web embedded in at least one major surface, preferably both major surfaces, of the panel. The basalt fibers-containing reinforcing webs preferably are in the form of a mesh or scrim comprising spaced basalt fiber strands in both the warp and fill directions, each strand made from a plurality of aligned, continuous basalt fibers. The basalt fiber reinforcing webs also can be in the form of woven or non-woven fabrics of basalt fibers, having aligned or randomly oriented staple and/or micro fibers, so long as the fabrics have sufficient void area to permit a cementitious core material to penetrate the fabric when the fabric is embedded in one or both major surfaces of the cementitious panel before the cementitious core material hardens.

Abstract: A composition for accelerating the setting reaction of an aqueous calcined gypsum slurry, and a method of making the same are disclosed. The composition includes a vibratory ball milled mixture of calcium sulfate dihydrate and a surfactant. The composition is prepared by subjecting the mixture to the high-frequency, low-impact grinding action of a vibratory ball mill. The resultant composition has a potency superior to that of conventional gypsum set accelerators.

Abstract: Cementitious binders include calcium sulfate beta-hemihydrate, a cement component comprising Portland cement, and either silica fume or rice-husk ash. The silica fume or rice-husk ash component is at least about 92 wt % amorphous silica and has an alumina content of about 0.6 wt % or less.

Abstract: A cementitious composition useful for water-resistant construction materials, including floor underlayments, backing boards, self-leveling floor materials, road patching materials, fiberboard, fire-proofing sprays, and fire-stopping materials includes about 20 wt. % to about 75 wt. % calcium sulfate beta-hemihydrate, about 10 wt. % to about 50 wt. % Portland cement, about 4 wt. % to about 20 wt. % silica fume and about 1 wt. % to about 50 wt. % pozzolanic aggregate. The Portland cement component may also be a blend of Portland cement with fly ash and/or ground blast slag.

Abstract: A cementitious composition useful for water-resistant construction materials, including floor underlayments, backing boards, self-leveling floor materials, road patching materials, fiberboard, fire-proofing sprays, and fire-stopping materials includes about 20 wt. % to about 75 wt. % calcium sulfate beta-hemihydrate, about 10 wt. % to about 50 wt. % Portland cement, about 4 wt. % to about 20 wt. % silica fume and about 1 wt. % to about 50 wt. % pozzolanic aggregate. The Portland cement component may also be a blend of Portland cement with fly ash and/or ground blast slag.

Abstract: A backer board for use as a base to which ceramic tile is bonded for a bathtub or shower area, in which the board is made by forming a gypsum core board with fiber glass laminated composite facings, which include an inner fiber glass scrim, an outer fiber glass nonwoven matte and an acrylic film, which film is formed of an acrylic latex of a class commonly employed as an ingredient in Portland cement mortar for applying ceramic tile.

Abstract: A fire-retardant gypsum wallboard having, in the gypsum core, about 2% by weight of a feldspar-free muscovite, in combination with other minor additives including 1/2 inch long glass fibers.

Abstract: By-product gypsum, which is formed during a flue gas desulfurization process, (FGD gypsum) is carefully formed as an aqueous slurry of crystals having a mean particle diameter of between about 35 microns and 80 microns and filtered, which filter cake is substantially completely dried before calcination, without any substantial grinding action, the crystals are then flash calcined to a hemihydrate, then ground, to reduce consistency, and then formed into an aqueous slurry from which a paper-covered gypsum board is formed of superior core quality.

Abstract: Lightweight gypsum wallboard produced by continuously combining a small amount of surface active agent with a liquid stream which stream is made up of substantially all of the liquids to be used in the manufacture of a continuous web of gypsum wallboard, subjecting this mixture to an intense agitation with vaned saw tooth-like rotary blades in a foam generator while adding a controlled quantity of air thereto, forming a uniformly dispersed foam of very small bubbles from the liquid by completely generating all of the surface active agent therein to form this foam, and mixing this foamed liquid with finely ground dry calcined gypsum in a suitable mixing device to form a foamed settable gypsum slurry, disposing the slurry between paper cover sheets, and forming a continuous web of gypsum wallboard.

Abstract: A gypsum set accelerator, produced by compression milling a mixture of ground gypsum rock and starch, and the addition thereof to an aqueous slurry of settable calcined gypsum such as in the forming of paper-covered gypsum wallboard.