This invention relates to improved high temperature resistant calcium sulphate-based products e.g. gypsum wallboard products and, in particular, to products having reduced shrinkage at high temperatures. The invention provides calcium sulphate-based product comprising gypsum and a shrinkage resistance additive. The shrinkage resistance additive is melamine polyphosphate or melamine pyrophosphate.

A set control composition for cementitious systems comprises (a) an amine-glyoxylic acid condensate, and (b) at least one of (i) a borate source and (ii) a carbonate source. The carbonate source is selected from inorganic carbonates having an aqueous solubility of 0.1 gL.sup.−1 or more, and organic carbonates. The set control composition improves workability of cementitious systems for prolonged periods of time without compromising early compressive strength. Due to the retarding action of the set control composition, the dosage of dispersant(s) necessary to obtain a desired flowability of the cementitious system can be reduced.

A composition contains at least one microorganism which can form a phosphate or carbonate precipitate in an alkaline medium, and at least one calcium source. The composition has at least one silicon compound having at least one Si-atom, at least one C-atom, and at least one H-atom. The composition can be used in a method for producing a construction product.

A composition contains at least one microorganism which can form a phosphate or carbonate precipitate in an alkaline medium, and at least one calcium source. The composition has at least one silicon compound having at least one Si-atom, at least one C-atom, and at least one H-atom. The composition can be used in a method for producing a construction product.

The present invention relates to a composite cement obtainable by grinding Portland cement clinker and latent hydraulic material together, preferably in the presence of at least one amine grinding aid, to provide a ground mixture and combining the ground mixture with a mineral filler. It further relates to a method of manufacturing the composite cement comprising the steps of grinding a latent hydraulic material and a portland cement clinker together, preferably in the presence of at least one amine, to provide a ground mixture and combining the ground mixture with one or more mineral fillers as well as to binders and to using the cement or binders as building material.

The present invention relates to a composite cement obtainable by grinding Portland cement clinker and latent hydraulic material together, preferably in the presence of at least one amine grinding aid, to provide a ground mixture and combining the ground mixture with a mineral filler. It further relates to a method of manufacturing the composite cement comprising the steps of grinding a latent hydraulic material and a portland cement clinker together, preferably in the presence of at least one amine, to provide a ground mixture and combining the ground mixture with one or more mineral fillers as well as to binders and to using the cement or binders as building material.

A method including introducing a well cementing composition into a wellbore, the cementing composition including a pumpable slurry of cement comprising a liquid anti-shrinkage additive including: an aqueous base fluid; a calcined magnesium oxide; and an anti-hydration agent; and allowing at least a portion of the cementing composition to harden. A liquid anti-shrinkage additive for cement including an aqueous base fluid, a calcined magnesium oxide, and an anti-hydration agent.

A method including introducing a well cementing composition into a wellbore, the cementing composition including a pumpable slurry of cement comprising a liquid anti-shrinkage additive including: an aqueous base fluid; a calcined magnesium oxide; and an anti-hydration agent; and allowing at least a portion of the cementing composition to harden. A liquid anti-shrinkage additive for cement including an aqueous base fluid, a calcined magnesium oxide, and an anti-hydration agent.

Ceiling tiles and wallboards can be produced with vesicle dedusting agent. For example, a ceiling tile can comprise: a dried base mat that includes: (a) mineral wool; (b) binder; (c) a vesicle dedusting agent at about 0.01 to about 10 wt %, wherein the vesicle dedusting agent comprises vesicles; (d) optionally cellulosic fiber; (e) optionally perlite; (f) optionally glass fiber; and (g) optionally calcium sulfate dihydrate. For example, a wallboard produced from a slurry comprising: (a) calcium sulfate hemihydrate at 70 to 95 wt %; (b) a vesicle dedusting agent at about 0.01 to about 10 wt %, wherein the vesicle dedusting agent comprises vesicles; (c) optionally cellulose fibers at about 0.5 to about 3 wt %; (d) optionally at least one dispersant at about 0.01 to about 2 wt %; and (e) water at a ratio of water to dry components of about 1:6 to about 20:1.

Ceiling tiles and wallboards can be produced with vesicle dedusting agent. For example, a ceiling tile can comprise: a dried base mat that includes: (a) mineral wool; (b) binder; (c) a vesicle dedusting agent at about 0.01 to about 10 wt %, wherein the vesicle dedusting agent comprises vesicles; (d) optionally cellulosic fiber; (e) optionally perlite; (f) optionally glass fiber; and (g) optionally calcium sulfate dihydrate. For example, a wallboard produced from a slurry comprising: (a) calcium sulfate hemihydrate at 70 to 95 wt %; (b) a vesicle dedusting agent at about 0.01 to about 10 wt %, wherein the vesicle dedusting agent comprises vesicles; (c) optionally cellulose fibers at about 0.5 to about 3 wt %; (d) optionally at least one dispersant at about 0.01 to about 2 wt %; and (e) water at a ratio of water to dry components of about 1:6 to about 20:1.