Abstract: The subject of the invention is a novel plasterboard and its manufacturing processes. The novel board comprises, on one side, two first parallel feathered edges and, on the other side, two other, second, parallel feathered edges that are perpendicular to the first ones; or, on one side, two first parallel feathered edges and, either on the same side or on the other side, two second parallel feathered edges that are perpendicular to the first ones, the said other parallel feathered edges having a width of between 100 and 200 mm; or, on one side, two first parallel feathered edges and, either on the same side or on the other side, two second parallel feathered edges that are perpendicular to the first ones, the said second parallel feathered edges having a width such that the ratio of the width of the said second parallel feathered edges to the width of the said first parallel feathered edges is between 1.5 and 5.

Abstract: A concrete composition includes: a hydraulic binder component which includes cement, particulate materials having a size of less than 200 ?m, and an expansive agent; granular materials having a size (D50) greater than 200 ?m; a shrinkage reducing agent; a superplasticizer; and water; wherein the water to hydraulic binder ratio is from 0.1 to 0.5 by weight, the shrinkage reducing agent is present at 0.1 to 1.0% by weight of binder, and the particulate materials are present in a concentration of from 10 to 80% by total weight of binder.

Abstract: A production process is provided for a board of hydraulic binder with a facing on each of its sides. The process includes on one side first tapered parallel edges and on the same side or the other side, two second tapered parallel edges perpendicular to the first. The process also includes the use of a forming lath having at least two distal parts. The process can be used in a production line that includes a specific lath.

Abstract: The subject of the invention is a novel plasterboard and its manufacturing processes. The novel board comprises, on one side, two first parallel feathered edges and, on the other side, two other, second, parallel feathered edges that are perpendicular to the first ones; or, on one side, two first parallel feathered edges and, either on the same side or on the other side, two second parallel feathered edges that are perpendicular to the first ones, the said other parallel feathered edges having a width of between 100 and 200 mm; or, on one side, two first parallel feathered edges and, either on the same side or on the other side, two second parallel feathered edges that are perpendicular to the first ones, the said second parallel feathered edges having a width such that the ratio of the width of the said second parallel feathered edges to the width of the said first parallel feathered edges is between 1.5 and 5.

Abstract: A method and device allows determination of the flow rate of solids material, under gravity, in an elongate vertical pipe; the device comprises a flow head chamber having an inlet end and an outlet end, an elongate tubular neck extending from the outlet end, the neck having an exit port remote from the outlet end, and the head chamber having an interior wall means converging from the inlet end to the outlet end, and the chamber being in flow communication with the elongate tubular neck such that in a vertically oriented configuration with the inlet end uppermost, the exit port lowermost and the elongate tubular neck disposed downwardly, solids material housed in the device may flow under gravity from the chamber into the elongate tubular neck towards the exit port; in one embodiment the device has plug means adapted to releasably engage the exit port to temporarily close the exit port; in another embodiment the chamber has a volume capacity for the solids material which permits the device to deliver at least

Abstract: An embodiment of the invention provides a production process of sand including the extraction of sand from a quarry; the periodic, on-line and automated withdrawal of a sample of sand; and the automated measurement of the methylene blue value on the sample of sand. Another embodiment of the invention provides a production line of sand including means of extraction of sand from a quarry; periodic and automated means of withdrawal of a sample of sand; and automated means of measuring the methylene blue value for the sample of sand.

Abstract: The present invention relates to a joint compound composition for building elements, particularly paper-faced plasterboards. This composition comprises: a) 50 to 60% of calcium sulphate hemihydrate; b) 5 to 15% of an organic binder in powder form; and c) 0.05 to 0.2% of a water repellent. The invention also relates to a method producing a structure, such as a partition, a wall trim or a ceiling. According to this method: building elements are juxtaposed; the joint compound composition according to the invention is mixed with water so as to obtain a joint compound; the space between the building elements is filled by means of the joint compound obtained above, without using a tape; and the joint compound is left to harden.

Abstract: Producing a structure, in which: building elements are juxtaposed so as to define a space between said building elements; a joint compound composition is mixed with water so as to obtain a joint compound; said space is filled with said joint compound composition, without using a tape; and said joint compound is left to harden, wherein said joint compound composition includes: a) 50 to 60% of calcium sulphate hemihydrate; b) 5 to 15% of an organic binder in powder form; and c) 0.05 to 0.2% of a water repellent selected from the group consisting of oleic acid, stearic acid and their alkali metal or alkaline-earth metal salts.

Abstract: A low cost steel desulphurating agent includes, compared with the total weight of the agent, at least 10% of SiO2, at least 10% of C2S, and at least 35% of at least one of calcium aluminate or calcium silico-aluminate. The desulphurating agent can include, compared with the total weight of the agent, the following mineralogical phases: 10 to 60% of C2S, 0 to 50% of C3A, 0 to 50% of C2AS, 0to 70% of C12A7, and 0 to 60% of CA.

Abstract: A plaster slurry composition includes plaster, water and starch, the starch having a Brookfield viscosity of less than 60 cps at a temperature below 600 C and a Brookfield viscosity greater than 10,000 cps at a temperature of 700 C.

Abstract: A gypsum dryer/calciner includes a calcining space; a first pipe having an inlet connected to a source of hot gases and an outlet emerging in the calcining space; a second pipe having an inlet connected to a source of gypsum and an outlet emerging in the calcining space, the second pipe being concentric with the first pipe; and a force-feeding screw positioned at least partially in the second pipe, the screw carrying the gypsum along in the calcining space.

Abstract: A drywall joint, suitable for joining dry wall panels of wall and ceiling structures, wherein each drywall panel has an outer surface and an opposite inner surface, the joint including: (a) an outer joint section, extending at least partially the height of and being disposed against the outer surface of the drywall panels; (b) an inner joint section, extending at least partially the height of and being disposed against the inner surface of the drywall panels; and (c) connectors for coupling the outer and inner joint sections together so as to sandwich the drywall panels between the outer and inner joint sections, the connectors including: i. first engagement formations on one of the outer and inner joint sections, and ii.

Abstract: Coating and jointing material systems for wall construction are provided. The coating is applied to drywall elements prior to installation and is compatible with the jointing materials such that a substantially homogeneous surface may be obtained after the drywall elements are assembled with jointing material and the jointing material is dried. Methods for the construction of interior walls and interior construction systems are provided.

Abstract: A process for manufacturing plasterboard and a plasterboard manufacturing unit are provided, the process including feeding hydratable calcium sulphate and water into a first mixer (2) and into a second mixer (3); feeding in a facing (5); preparing a first gypsum slurry in the first mixer (2); preparing a second gypsum slurry in the second mixer (3); applying the first slurry onto the facing and forming a crude surface layer; applying the second slurry onto the crude surface layer and forming a crude core layer with a density lower than that of the crude surface layer; forming a plasterboard; hydrating and drying the board. This process allows the formation of the different layers of gypsum to be controlled independently.

Abstract: A process for manufacturing set cellular cement, including the steps of: (i) mixing cementitious material, water, foaming agent and optionally additives into a free flowing slurry having a slump of at least 100 mm; subsequently (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently (iii) casting the cellular slurry of step (ii); and finally allowing the cellular slurry to set. And, an apparatus for carrying out the process.

Abstract: The invention concerns a fast binder comprising; cement; at least one superplasticizer; calcium nitrite; and at least one formic derivative. The invention also concerns concrete mixtures obtained from said binder and methods for making same.

Abstract: The invention relates to a steel desulphurating agent characterised in that it comprises compared with the total weight of the agent: at least 10% of SiO2, at least 10% of C2S, at least 35% of at least one calcium aluminate and optionally a calcium silico-aluminate.

Abstract: A coating for wall construction is provided whereby a level 5 finish may be obtained without the need for a finishing coat or final skim coat. The coating may be applied to drywall elements prior to installation and is compatible with jointing materials such that a substantially homogeneous surface may be obtained after the drywall elements are assembled with jointing material and the jointing material is dried. The coating formulation includes a noncellulosic thickener, a binder, a mineral filler and water. A method for the construction of interior walls and a construction assembly for interior walls is further provided.

Abstract: A gypsum board which has a gypsum core having a first side and a second side and a facing sheet disposed on the first side, wherein the facing sheet is made of a sheet material and said sheet material has at least one surfactant, filler particles and at least one polymeric binder. Also, a process of making a gypsum board.