Methods for plasticizing cementitious mixtures having relatively high water/cement ratio (at least 0.40 or higher) are surprisingly improved in terms of dosage efficiency, compared to conventional superplasticizer polycarboxylate polymers, when the comb-type carboxylate copolymer is formed from two different polyether side chains having specifically selected monomer constituents.

The invention concerns a process for the preparation of a calcium silicate hydrate and ettringite containing hardening accelerator composition by reaction of a water-soluble calcium compound, silicate compound, aluminum compound and a sulfate compound, wherein the molar ratio of silicon to sulfate is from 2/1 to 30/1 and the reaction of the four compounds being carried out in the presence of an aqueous solution which contains a comb polymer suitable as a plasticizer for hydraulic binders. Also concerned are the use of said accelerators in building material mixtures, the building material mixtures containing said accelerators and a process for the preparation of a sprayable binder composition in which said accelerators are used.

The invention concerns a process for the for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound, the reaction being carried out in the presence of an aqueous solution which contains a plasticizer suitable for hydraulic binders, characterized in that said reaction is being carried out in the presence of apatite and that the molar ratio of calcium to phosphor in the hardening accelerator is from 25/1 to 400/1.

The present invention relates to a polycarbonic acid-based cement dispersant, a method for preparing the same, and a mortar-concrete admixture using the polycarbonic acid-based cement dispersant.

The cement dispersant of the present invention and the mortar-concrete admixture using the cement dispersant are applied to a cement composition such as a cement paste, mortar, concrete, etc., enhance a dispersion and retention force between cement molecules, have excellent fluidity due to the suppression of slump loss, and have an effect of improving workability, such as shortening a concrete mixing time by 20% or more. Further, the mortar-concrete admixture using the cement dispersant of the present invention has an effect of providing a very good concrete condition and an appropriate compressive strength over time.

The invention concerns a method for producing pulverulent hardening accelerators by reactive spray drying, where an aqueous phase I comprising calcium ions, and an aqueous phase II comprising sulphate ions, the molar ratio of the calcium ions to the sulphate ions being from 1/5 to 5/1, are contacted at a spray nozzle, and the phases I and II contacted with one another at the spray nozzle are sprayed in a streaming environment of drying gas. Likewise concerned are the pulverulent hardening accelerators producible by the method of the invention, and their use for accelerating the hardening of bassanite and/or anhydrite with formation of gypsum.

The presently disclosed and/or claimed inventive process concept(s) relates generally to a water soluble or water dispersible composition comprising a copolymer and use in oil field. More particularly, the presently disclosed and/or claimed inventive concept(s) relates to the copolymers comprising allyloxy linkage and its function derivatives and its use in oil field such as a high temperature cement retarder composition.

Disclosed is an aqueous additive or sealing composition for cementitious compositions comprises a water-soluble salt of carbonate or hydrogen carbonate, a silica-based material, a specifically selected dispersant, at least one specifically selected thickening agent, and water. Furthermore, a method of manufacturing the aqueous additive or sealing composition, a cementitious composition comprising a hydraulic cementitious binder, a mineral aggregate, the aqueous additive composition, and optionally water and its preparation method is described. Moreover, a method of treating a surface of a cementitious structure by applying the aqueous additive or sealing composition on a surface of a cementitious structure as surface treatment agent or coating material is disclosed. The disclosed additive and sealing composition can be used as liquid crystalline waterproofing admixture composition in several applications.

A combination of retarders and regulators for hydration reaction of cementitious binders including clinkers based on Ye'elimite. Set retarders are calcium complexing agents, consisting of sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, phosphates, phosphonates, borates and amines. Regulator general formula (I) is ##STR00001##
where M is H, NH.sub.4 or chosen from monovalent or divalent metal of groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of periodic table of elements, where M is a divalent metal, a second equivalent of RSO.sub.3 is present, and M is chosen from group consisting of H, NH.sub.4, Li, Na, K, MgX, CaX, or NiX with XRSO.sub.3, and R is chosen from H, NH.sub.2, OH or from hydrocarbon chain with 1-18 C atoms which may be substituted by N and/or O and/or which may be linear or branched and/or which contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic moieties.

A process for preparing a wet concrete composition, including mixing with water: aggregate(s), a binder system, which is 400 Kg per m.sup.3 or less of the wet concrete composition, and an admixture formulation. The binder system is prepared before or during the mixing, from at least some of the different components of the binder system, taken separately and/or in premix form(s). The binder system has between 1% and 34% dry weight of lime source(s), between 5% and 75% dry weight of ground granulated blast furnace slag, between 21% and 90% dry weight of filler(s), and between 0.1% and 5% SO.sub.3 dry weight, relative to the lime source(s), slag and filler(s). The admixture formulation includes at least one water reducing polymer, optionally with a wetting agent and/or surfactant. The mixing is carried out at a water to binder system weight ratio between 0.2 and 0.4.

A process for preparing a wet concrete composition, including mixing with water: aggregate(s), a binder system, which is 400 Kg per m.sup.3 or less of the wet concrete composition, and an admixture formulation. The binder system is prepared before or during the mixing, from at least some of the different components of the binder system, taken separately and/or in premix form(s). The binder system has between 1% and 34% dry weight of lime source(s), between 5% and 75% dry weight of ground granulated blast furnace slag, between 21% and 90% dry weight of filler(s), and between 0.1% and 5% SO.sub.3 dry weight, relative to the lime source(s), slag and filler(s). The admixture formulation includes at least one water reducing polymer, optionally with a wetting agent and/or surfactant. The mixing is carried out at a water to binder system weight ratio between 0.2 and 0.4.