Abstract: A process and apparatus are disclosed for production casting of railroad ties and the like to obtain maximum mold utility. The casting is accomplished by arranging tendons within a mold and subjecting them to an appropriate tensile stress. Uncured concrete is then introduced at a temperature of around 80.degree. C.-90.degree. C. The mold is vibrated and subsequently closed. It is then maintained at 60.degree. C.-80.degree. C. for a time sufficient to cure the concrete such that the prestressing mechanism can be released. The mold may then be immediately re-used. One mechanism by which the molds may be closed during the curing process in most efficient manner is to employ succeeding molds in a stacked arrangement to cover each preceding mold cavity. A single piece conical locking member is also employed to anchor the tendon in the mold.

Abstract: Masonry units are cured in a kiln having a gaseous atmosphere including water vapor. A portion of this atmosphere is withdrawn and mixed with a flowing stream of heated water. This mixture is injected into a body of water disposed within the kiln at a plurality of spaced apart locations and beneath the surface of the body of water whereupon the gaseous atmosphere is heated and rises to and escapes from the surface of the body of water in the form of bubbles. In a preferred embodiment, the apparatus for withdrawal of atmosphere from the kiln includes an aspirator incorporated in a conduit which also circulates heated water to the body of water within the kiln.

Abstract: Reinforced facings, including reinforcing webs entrained in hydraulic cement via a slurry bath, adhere to a nailable lightweight aggregate cementitious core to form a panel web. The reinforced web is formed on abutting conveyed carrier sheets, and the web is transversely cut, between the sheets, while moving or when stopped, in response to sensing of the sheets. The cut panels, on respective sheets are stacked for curing without damaging the panel edges and in a manner to minimize panel flex. Slurry bath, facing applicators, and cutter and stacking apparatus are included.

Abstract: An article is cast from a composition comprising a binding agent containing, by weight, from 90% to 10% calcined gypsum and from 10% to 90% Portland cement mixed with water to produce a fluid mixture which is caused to flow into a mould or other supporting device and is there allowed to set. To increase the durability of the cast article in the presence of moisture, sodium carbonate in an amount up to 5% by weight of the dry weight of the cement is added to the composition. The sodium carbonate is preferably present in an amount between 0.1% and 0.5% of the dry weight of the cement and the composition preferably also contains an acrylic resin emulsion in an amount from 0.25% to 4% of the dry weight of the gypsum and cement in the composition and a pigment such as iron oxide, titanium oxide or cobalt oxide in an amount from 0.25% to 4% by weight of the dry weight of the gypsum and cement in the composition.

Abstract: A method of improving the surface characteristics of a formed article of magnesium oxychloride or magnesium oxysulfate cement is shown in which molded articles of magnesium oxychloride or magnesium oxysulfate are treated with water at temperatures of 90.degree. F. to 212.degree. F. (32.2.degree. C. to 100.degree. C.) for periods of 1 to 30 minutes or longer to prevent the formed article from efflorescing.

Abstract: The invention provides a process of producing lightweight concrete units, which may or may not be reinforced, which comprises making a mix including cementitious material, fine and, optionally, coarse aggregate, water and material for aerating the mix, preferably aluminium powder and alkali; inserting the mix into a mould and allowing the mix to set into a block in the mould; stripping the mould, and autoclaving the block. In this process, in accordance with the invention, the mix is inserted into the mould before the aeration of the mix is completed and without completely filling the mould, the mould is provided with a closure which allows gas but not solids to escape, and the mix is allowed to expand to fill the mould and set under pressure produced by its own aeration.

Abstract: A method and apparatus is provided for the manufacture of concrete products in which a mixture comprised of cement, aggregate, a vinyl acetate-dibutyl maleate copolymer and an amount of water sufficient to make a relatively dry mixture is initially compressed into the desired configuration. This compressed-shaped article is then cured in a chamber charged with carbon dioxide gas to provide a fully cured concrete product having excellent physical properties. The method and apparatus of this invention is especially useful in the manufacture of terrazzo panels and the like.

Abstract: A method and apparatus is provided for the manufacture of products of concrete or like construction, in which a mixture of calcareous cementitious binder substance, such as cement, an aggregate, a vinyl acetate-dibutyl maleate copolymer, and an amount of water sufficient to make a relatively dry mix is compressed into the desired configuration in a mold, and with the mixture being exposed to carbon dioxide gas in the mold, prior to the compression taking place, such that the carbon dioxide gas reacts with the ingredients to provide a hardened product in an accelerated state of cure having excellent physical properties.

Abstract: A cement panel reinforced with fibers comprising a base plate composed predominantly of inorganic fibers and a cement, an inner waterproof layer of a synthetic resin formed on a surface of the base plate, a coloring material layer composed predominantly of a cement and a pigment and formed on the inner waterproof layer, and a surface waterproof layer of a synthetic resin formed on the coloring material layer. The synthetic resin of the inner waterproof layer, having penetrated into both the base plate and the coloring material layer and solidified, gives a fastener effect, bonding them together.

Abstract: A process for manufacturing concrete articles of improved initial strength and long-term strength from a hydraulic cement composition capable of forming predominantly tobermorite group crystalline calcium silicate hydrate is provided. The hydraulic cement composition, having incorporated therein specified amounts of alumina cement and calcium hydroxide and/or oxide, is initially set in a mold and after the concrete so formed is allowed to stand at a temperature of not higher than approximately 40.degree. C for a period of 2 hours to 5 days, the concrete is finally cured at an elevated temperature and pressure.

Abstract: A method and apparatus is provided for the manufacture of products of concrete or like construction, in which a mixture of calcareous cementitious binder substance, such as cement, an aggregate, a vinyl acetate-dibutyl maleate copolymer, and an amount of water sufficient to make a relatively dry mixture is initially compressed into the desired configuration. This compressed shaped article is then subjected to an accelerated curing process in a chamber that is charged with carbon dioxide gas to provide a hardened product in an accelerated cure state having excellent physical properties, although the apparatus may be used, if desired, to provide only a desired amount of curing, as the circumstances may dictate.

Abstract: This invention relates to a method and apparatus for manufacturing pavement blocks and the product resulting therefrom in which said blocks have rubber tips projecting from the surfaces thereof, and includes inserting a perforated plate and introducing projection elements into the perforation and against the base plate, thereafter introducing filler material, compressing the ingredients, removing the compressed unit from, including the base, the frame and thereafter removing the base plate and perforated plate.

Abstract: In a process for making large-size building elements called "plate bricks" of ceramic material, which comprises preparing the ceramic material, forming it to large-size plate-shaped bricks, drying and burning the same, the improvement which consists of drying the element evenly over the cross section after forming. The invention also relates to the brick made by the process.

Abstract: A method of efficiently curing and protecting a structural concrete column, beam or the like and which includes the steps of filling the form with concrete, removing the form upon the concrete becoming sufficiently rigid to be self-supporting but prior to the full curing thereof, and then disposing a tubular length of polymeric sheet material coaxially about the column and maintaining the same thereabout until the concrete is fully cured.

Abstract: A method of making a cast article from a composition which contains a hydraulic binding agent comprising by weight from 90% to 10% calcined gypsum and from 10% to 90% Portland cement comprises mixing the composition with water to produce a fluid mixture, either the water or some at least of the components of the composition or both being heated so that the mixture has a temperature of from 70.degree. to 130.degree. F, and pouring the fluid mixture into a mould or other supporting device where the reaction of the calcined gypsum with the water causes the mixture to set and the heat of this reaction causes the temperature of the mixture to begin to rise. As soon as the mixture has set sufficiently to be self supporting, the set mixture, which forms the cast article, is removed from the mould or other supporting device and then the dissipation of both heat and moisture from the cast article is controlled so that the temperature of the article continues to rise to from 90.degree. to 180.degree. F.

Abstract: A process for the production of shaped articles from wood particles, especially chipboards, wherein the basic cellulosic material comprised of wooden articles is admixed with at least one mineralizing agent, water, and a hydraulic binder such as cement, the mixture is shaped and then pressed at a constant temperature above the freezing point; the process being characterized in that the water required for activating the hydraulic binder is added and admixed with the basic cellulosic material before the addition of the mineralizing agent and the hydraulic binder.

Abstract: Production of high strength structural building components by steam curing a compressed mixture of laterite, lime and water at a temperature preferably between 70.degree. and 100.degree. C.

Abstract: A method of making stressed concrete articles made from a cement containing as an additive to portland cement a mixture of alumina cement, calcium sulfate and ground caustic lime, the method including hydrothermal treatment at 50.degree. C or above followed by curing in cold water for several days.

Abstract: The invention pertains to a process for agglomerating compressible powders, particles or fibres of mineral substances, said process comprising the steps of placing at least one layer of a steam and gas pervious product on a layer of said compressible substances in which the water content is such that, after vaporization, a sufficient amount of water is still present to ensure the desired chemical reaction, then subjecting the layers to the simultaneous action of pressure and heating.

Abstract: Cement-resin composite articles are manufactured by preparing cement articles from Portland cement having a high silicic modulus, or a mixture of 50 to 90% by weight of Portland cement and 50 to 10% by weight of siliceous reactive material, presetting the cement articles at ambient temperature, steam curing the articles under pressure at a temperature from 150.degree. to 250.degree. C. for 1 to 6 hours, subjecting the steam cured articles to a thermal treatment in an anhydrous environment at a temperature of 120.degree.-350.degree.C. for 1 to 12 hours, impregnating the resulting articles with a monomeric polymerizable substance, and polymerizing the monomeric substance. The monomeric substance may be styrene, methylmethacrylate, vinyl ester, or a mixture of copolymerizable monomers. The articles may be placed under vacuum before impregnation and impregnation may be conducted under elevated pressure.

Abstract: A concrete mixture is provided which is homogeneous and free of lumps and comprises 5-15 parts by weight of sand, 2-3 parts by weight of cement and 1 part by weight of water. Said mixture is charged into a mold in a molding machine in a charging operation having a duration of about 30-120 seconds. Said mold is vibrated in said molding machine in a vibrating operation from the beginning of said charging operation until after said charging operation, whereby said mixture is compacted and air is expelled from said mold and a molding is formed therein. At least part of said mold is removed from said molding when said vibrating operation has been completed and before said molding has completely set. Said molding is stored outside said molding machine until said molding has completely set.

Abstract: This invention relates to a method for curing concrete products.The method comprises the steps of subjecting the products to be cured to a steam of a given temperature to produce partial hydration of the products, then subjecting the products to steam of a different temperature, and finally subjecting the products to cooled air, all for predetermined periods of time.

Abstract: A wire reinforced hollow core concrete fence post is made by injecting concrete into a form in which is centrally supported a longitudinally extending mandrel having a plurality of radially extending spacers extending longitudinally along its surface, the spacers being adapted to support a cylindrical tube of wire mesh reinforcing remote from the surface of the mandrel. A pallet board is disposed in the bottom of the form for supporting the concrete injected therein. Means are provided to rotate the manadrel and the tube of wire mesh reinforcing while the concrete is being injected into the form. Means are also provided to withdraw the mandrel from the form after the concrete has been injected, while retaining the concrete and the reinforcing within the form.