This invention provides low density gypsum products. This invention also provides a method of making the low density gypsum products.

This invention provides low density gypsum products. This invention also provides a method of making the low density gypsum products.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

Process for the preparation of cement/mortar/concrete compositions or systems, (for simplicity hereafter “cement” compositions or systems or even “cements”), of a generally known type containing low or medium (standard) “filler(s)”, and/or optionally HP filler(s), as carbonate-based filler(s), namely coarse low or medium calcium carbonate(s), namely coarse marble(s); Product comprising, or consisting of, the pre-blend (A) of coarse, low or medium (or optionally HP) “calcium carbonate-based filler” pre-blended with at least an UF; Aqueous compositions (B) obtained by mixing the above pre-blend (A) of coarse filler(s) with UF(s) with an aqueous system such as mix water, aqueous mix fluid; Product (C) consisting of, or comprising, the pre-blend (A) or the compositions (B), treated or pretreated with at least one superplastifier or aqueous system containing superplastifier(s); Cement and Use of cement.

Process for the preparation of cement/mortar/concrete compositions or systems, (for simplicity hereafter “cement” compositions or systems or even “cements”), of a generally known type containing low or medium (standard) “filler(s)”, and/or optionally HP filler(s), as carbonate-based filler(s), namely coarse low or medium calcium carbonate(s), namely coarse marble(s); Product comprising, or consisting of, the pre-blend (A) of coarse, low or medium (or optionally HP) “calcium carbonate-based filler” pre-blended with at least an UF; Aqueous compositions (B) obtained by mixing the above pre-blend (A) of coarse filler(s) with UF(s) with an aqueous system such as mix water, aqueous mix fluid; Product (C) consisting of, or comprising, the pre-blend (A) or the compositions (B), treated or pretreated with at least one superplastifier or aqueous system containing superplastifier(s); Cement and Use of cement.

Methods of using extended-life cement compositions are disclosed. A method comprises providing an extended-life cement composition comprising calcium-aluminate cement, water, and a cement set retarder. The method additionally comprises mixing the extended-life cement composition with a cement set activator to activate the extended-life cement composition. The method further comprises Introducing the activated extended-life cement composition into a subterranean formation and allowing the activated extended-life cement composition to set in the subterranean formation; wherein the activated extended-life cement composition has a thickening time of greater than about two hours.

Methods of using extended-life cement compositions are disclosed. A method comprises providing an extended-life cement composition comprising calcium-aluminate cement, water, and a cement set retarder. The method additionally comprises mixing the extended-life cement composition with a cement set activator to activate the extended-life cement composition. The method further comprises Introducing the activated extended-life cement composition into a subterranean formation and allowing the activated extended-life cement composition to set in the subterranean formation; wherein the activated extended-life cement composition has a thickening time of greater than about two hours.

The present invention provides compositions useful as a replacement for cellulose ether in cement, plaster or mortar compositions comprising i) nonionic or substantially nonionic vinyl or acrylic brush polymers having pendant or side chain polyether groups, and having a relative weight average molecular weight of from 140,000 to 50,000,000 g/mole, and ii) aromatic cofactors containing one or more phenolic groups, such as catechol tannins, phenolic resins, polyphenolics, and napthhols or, in combination, one or more aromatic groups with at least one sulfur acid group, such as naphthalene sulfonate aldehyde condensate polymers, poly(styrene-co-styrene sulfonate) copolymers, and lignin sulfonates, preferably branched cofactors, including phenolic resins, aldehyde condensate polymers and lignin sulfonates. The compositions may comprise a dry powder blend of i) and ii), one dry powder of both i) and ii), or an aqueous mixture.

The present invention provides compositions useful as a replacement for cellulose ether in cement, plaster or mortar compositions comprising i) nonionic or substantially nonionic vinyl or acrylic brush polymers having pendant or side chain polyether groups, and having a relative weight average molecular weight of from 140,000 to 50,000,000 g/mole, and ii) aromatic cofactors containing one or more phenolic groups, such as catechol tannins, phenolic resins, polyphenolics, and napthhols or, in combination, one or more aromatic groups with at least one sulfur acid group, such as naphthalene sulfonate aldehyde condensate polymers, poly(styrene-co-styrene sulfonate) copolymers, and lignin sulfonates, preferably branched cofactors, including phenolic resins, aldehyde condensate polymers and lignin sulfonates. The compositions may comprise a dry powder blend of i) and ii), one dry powder of both i) and ii), or an aqueous mixture.