Abstract: A method for manufacturing a reinforced cementitious columnar structure including: providing a mold having a cavity which corresponds to a shape and size of the columnar structure; placing at least one nonwoven metal fiber mat around the periphery of the cavity; filling the cavity with a slurry of cementitious material containing aggregate having a particle size greater than the size of the interstitial voids of the fiber mat; curing the slurry of cementitious material; and removing the mold.

Abstract: A method of installing a post in a post hole includes the steps of providing a dry fast setting cementitious composition having a set time and in the form of finely divided particles of at least one cement binder, and pouring an amount of the dry cementitious composition into a volume of water located in a post hole without any type of physical mixing of the cementitious composition and water other than the mixing which occurs merely by applying the cementitious composition into the water. The major portion of the particles of the cementitious composition have approximately the same drop rate through the volume of water. The water contacts the dry cementitious composition when poured into the volume of water to hydrate the particles of the dry cementitious composition, the particles of cementitious composition dropping through the water to displace excess water and form the hydrated cementitious composition into a substantially non-segregated mass.

Abstract: A method of installing a cementitious composition includes providing a dry fast setting cementitious composition having a set time and in the form of finely divided particles of at least one cement binder, pouring an amount of the dry cementitious composition into a volume of water located in a hole without any type of physical mixing of the cementitious composition and water other than the mixing which occurs merely by applying the cementitious composition into the water. The major portion of the particles of the cementitious composition have approximately the same drop rate through the volume of water. The water contacts the dry cementitious composition when poured into the volume of water to hydrate the particles of the dry cementitious composition, the particles of cementitious composition dropping through the water to displace excess water and form the hydrated cementitious composition particles in a substantially non-segregated mass.

Abstract: Residue produced by incineration of commercial, industrial or municipal waste is treated to remove oversize material and ferrous materials. The moisture content of the untreated residue is adjusted, and the residue is mixed with Portland cement to partially aggregate the residue into a free-flowing, granular material containing no more than about five percent by weight fines and having a hydraulic conductivity of at least about 0.001 cm/sec after curing for 24 hours. The treated residue can be used to form a gas-venting layer for a landfill, and retains its good hydraulic conductivity as it cures into a cohesive mass, such that leaching of hazardous materials is reduced.

Abstract: A method and apparatus for the production of a symmetrical oval concrete pipe including an oval male joint member and an oval female joint member formed on opposite ends of an oval pipe body including an outer jacket and an inner core disposed in spaced relationship relative to each other to form the oval pipe body therebetween; an upper pallet and a lower pallet configured to form the oval male joint member and the oval female joint member respectively, and a pallet positioning structure configured to engage the upper pallet and the lower pallet to operatively position the upper pallet and lower pallet relative to the outer jacket and inner core such that corresponding points on the upper pallet and the lower pallet are aligned relative to each other whereby corresponding points of the oval male joint member and the female joint member are aligned relative to each other.

Abstract: A method of environmental cleanup by producing an autoclaved aerated cement building material (termed AAC) by a process that uses the available silica sand and other raw materials in mine tailings, in particular copper mine tailings from porphyry copper mines. The process minimizes the need for processed silica sand and other raw materials, normally used in the production of the AAC building material. The lightweight AAC building material produced from the mine tailings has excellent thermal insulation properties, sound absorption and other desirable construction qualities comparable to AAC building material produced using processed silica sand, i.e. from non-mine tailings raw material sources.

Abstract: The occurrence of efflorescence has been reduced or eliminated in ceramic articles formed from a novel vitreously bonded cement-containing composition. The articles also exhibit improved strength, reduced firing shrinkage and increased frost resistance. The articles are produced by combining hydraulic cement containing calcium silicate and/or calcium aluminate components, vitrifiable inorganic powders forming molten liquid-flowing substances, and reactive or sinterable mineral powders selected from the group consisting of magnesium silicates, aluminum silicates and mixtures thereof; combining the ingredients with water to form a mixture; molding the mixture into an article; hardening the article by hydration; and firing the molded article to a maximum temperature of between about 1000.degree. C. to 1400.degree. C.

Abstract: A light weight formed body used for building materials, heat-insulating materials, furnitures, backing materials and the like, and a method for producing the same. In the light weight formed body and in the manufacturing method thereof, the principal material is a surface-reformed slag of which the reforming involves reforming through the dissolution reaction and the hydration reaction of glass and the reforming through dehydration of the surface-reformed slag above mentioned under heating, and one or more of a polymer dispersion, a reinforcing fiber, a coagulant, a light weight aggregate, a thickener, a dispersing agent, a pigment, a synthetic pulp, a needle- to fiber-shaped calcium silicate hydrate and a hydraulic gypsum are further used together with the above principal material.

Abstract: Cast stone for architectural use is made by subjecting a mixture of aggregate and Portland cement in a mold to repeated dropping against an anvil, and thereafter applying a vertical pressure to the contents of the mold while applying repeated mechanical blows to a table on which the mold is situated. The process makes it possible to produce a high quality cast stone in 3-4 minutes as compared with the 20 minutes required using prior processes.

Abstract: An improved method for lining a section of pipe with a cement mortar. After a wet cement mortar has been applied to a cleaned interior surface of a pipe, carbon dioxide is introduced into the freshly lined section of the pipe in such quantity that a crust of calcium carbonate will be formed on the surface of the wet cement mortar lining as the carbon dioxide reacts with calcium compounds of the wet cement mortar in a relatively short period of time. This crust is provided to tolerate a low-velocity flow of water to protect the underlying mortar from scouring until the normal hardening of the underlying mortar through hydration can take place so as to substantially reduce the out-of-service time of the section of pipe which is being lined.

Abstract: A roller vacuum apparatus removes cement slurry from a freshly laid exposed aggregate surface. In one embodiment, the exposed aggregate surface is applied to a cement substrate which is worked to compact the aggregate and draw the portland cement in the mixture to the surface of the coating. Subsequently, the surface coating is washed to remove excess portland cement. The roller vacuum removes the cement slurry without disturbing the freshly laid exposed aggregate surface by wicking the slurry into a transfer medium of the vacuum roller. A vacuum is applied to the transfer medium to remove the cement slurry from the roller.

Abstract: A hydrated calcium silicate slurry composition is made up of 100 parts by weight of hydrated calcium silicate, 5 to 40 parts by weight of a powdered resin and water and molded articles are produced therefrom. In addition to the above components, 1 to 30 parts by weight of a reinforcing fiber and/or 20 to 35 parts by weight (as solids) of a latex or emulsion may be used. When the latex or emulsion is used, the powdered resin is reduced to an amount of 5 to 20 parts by weight. Since the molded calcium silicate articles have a superior workability and a good thermal dimensional stability, they are very useful especially in the preparation of molds or models where high levels of processing precision and thermal stability are required.

Abstract: A switch cross tie is made in a mold having a base plate formed with a plurality of holes in a predetermined pattern corresponding to a particular type of concrete switch cross tie by first overlying the entire base plate of a mold with a covering sheet provided with markings in a pattern corresponding to that of the holes needed for another particular type of concrete cross ties. This covering sheet overlies and blocks all the holes formed in the base plate and it is fixed in place atop the base plate. Then the operator or a computer-guided drill press cuts through the covering sheet and into the base plate at each of the markings to form thereat a respective new hole. Each such new hole is fitted with an anchor, and the mold is filled with concrete over and around the anchors with the covering sheet blocking all the holes other than the new holes. It is important that the covering sheet be sufficiently strong to inhibit entry of concrete through it into any of the holes other than the new holes.

Abstract: A process for producing lightweight, panel or block-shaped gypsum building materials with a pore structure, in particular wall panels, wherein calcium sulphate alpha-hemihydrate, water in a slightly more than stoichiometric quantity, setting retarders and/or accelerators and additives are mixed to form a pourable suspension and subjected to suitable forming. The ground calcium sulphate alpha-hemihydrate, having a Blaine specific surface area greater than 2000 cm.sup.2 /g, is combined if appropriate, with calcium sulphate beta-hemihydrate in a quantity of up to about 30% by weight relative to the calcium sulphate alpha-hemihydrate, and mixed before forming with a surfactant foam of a defined apparent density in the range from 40 to 80 kg/m.sup.3 and a uniform defined pore size, in a quantity for adjusting the apparent density of the gypsum building material to a defined value in the range from 300 to 1200 kg/m.sup.3.

Abstract: A reconstruction of a heating wall of a coking oven. The reconstruction includes utilization of a novel large size cast refractory repair module which may be utilized to replace existing silica bricks within a coke oven heating wall. The novel large size cast refractory module are monolithic structures formed from a castable refractory material having very high dimensional stability over a wide range of temperatures. Each repair module is a rectangular parallelepiped having one or more vertically extending flues formed therein, one end of a module being adapted to conform to the end shape of the damaged heating wall, the other end of the module being adapted to interfit with existing brickwork. The modules are assembled by initially removing damaged brickwork from the heating wall and then placing in the new modules which are mortared in place.

Abstract: Calcium aluminum magnesium phosphate ceramic hard tiles and processes for them are described. The tiles have a density in excess of about 110 pounds per cubic foot, a curl value less than about 20 mils and a flexural strength of at least about 2500 pounds per square inch. To prepare the hard tiles 100 parts (by wt.) of an aluminum phosphate-phosphoric acid solution is mixed with at least 5 parts magnesium oxide and 50-110 parts wollastonite. If the acid has more than 15% by weight water, then mica or vermiculite is added.

Abstract: A method for making concrete roof tiles includes the steps of forming a continuous elongated ribbon or layer of concrete; cutting the continuous layer into a row of spaced end to end ribbon sections having a front edge and a rear edge; precompacting the front edge of one of two adjacent ribbon sections and compacting the precompacted front edge of the other ribbon section.

Abstract: A process for preparing cast articles includes preparing a primary mold of a flexible resilient bag-shaped membrane, disposing casting material in a flowable state into the primary mold and allowing the casting material to harden. Optionally, a relatively fixed secondary mold or a combination of relatively fixed secondary molds can be used adjacent the outside of the primary mold to impart a predetermined shape to portions of the cast object. A continuous ultra-smooth surface is created on the cast objects duplicating the surface of smooth naturally weathered stone.

Abstract: A molded and cured concrete paving member for paving driveways, walkways, patios, plazas and the like, comprising portland cement, a coal slag aggregate, water and an acrylic additive. The blend is poured into a non-porous, high gloss polyvinylchloride (PVC) mold in a relative dry mix and is vibrated to drive the portland cement to the bottom of the mold and to suspend the aggregate into chemical suspension. This also drives the lighter weight water to the top of the molding configuration, which top, due to the configuration or orientation of the mold, ultimately becomes the bottom of the paving member. The molding is accomplished while hanging from a frame in a so-called bag mold so that when the concrete expands and contracts in the relatively flexible mold during the hydration curing process a bond of the concrete to the PVC mold is maintained. The non-porosity of the high gloss mold surface and induced vibration pull the portland cement to the bottom of the mold cavity and suspend the aggregate.

Abstract: A process is disclosed for fast and uniform hydration of uncured concrete products. Pressurized and superheated water is supplied to a manifold supporting a plurality of small diameter orifice nozzles housed inside a curing room which also houses the products during curing. Water is ejected by the nozzles in very fine particulate form, creating a mist or suspension of superheated water particles that surrounds the products and creates the desired high humidity, moderately high temperature environment for promoting hydration. The water preferably is softened before it is pressurized and supplied to the nozzles. Under favorable conditions, the hydration reaction supplies sufficient heat to maintain a desired temperature within the curing room, eliminating the need to heat the water before it is supplied to the nozzles.

Abstract: Compound concrete composition for the manufacture of moulds, comprising: (1) a binder which comprises an alkaline-earth mineral substance, a constituent made up of fine particles of a compound other than an oxide, 90% of which have a particle size of between 1 and 150 .mu.m with a median diameter of between 3 and 20 .mu.m, these fine particles comprising particles of a substance which has a thermal conductivity higher than approximately 30 W/mK, chosen from silicon carbides, silicon carbonitrides, silicon nitrides, boron carbides, titanium carbides and tungsten carbides and a constituent made up of ultrafine particles at least 70% of which have a particle size smaller than 1 .mu.m with a median diameter of between 0.3 and 0.8 .mu.m, (2) water optionally with the addition of a dispersant, and (3) fillers comprising metal granulates and metal fibres, wherein the water/binder ratio is lower than 0.20 and the concrete composition has a thermal conductivity at 200.degree. C.

Abstract: A method for forming hollow concrete structures or shells in which the top, bottom and sides are formed into an integral unitary structure by rotating an assembly of reinforcing members to enable the concrete forming the top, bottom and side to each be finished in a substantially horizontal position with a minimum of forms. Openings for doors and windows may be formed by using suitable blanks that are prepositioned prior to pouring the concrete. Also, suitable end closure members can also be formed in a flat or horizontal position inside the unitary structure for subsequent erection in a vertical position.

Abstract: An insulated concrete building block 10, a method of making block 10 by pouring concrete around a block of insulation 53 in a form box 50, and a construction system employing various alternate configurations of block 10 in a method of construction wherein scaled miniatures of the various blocks are employed to build a model of the structure to be realized, followed by realization of the structure with full scale blocks. Alternate block molding and block keying embodiments are disclosed.

Abstract: Two lifting units (1, 2) have lifting grabs (3) for lifting individual concrete slabs (29) off a prestressing bed on which they have been cast and then stacking them on a pair of support beams (6) to form a pile (28). Once the pile (28) has been formed, the lifting units (1, 2) use lifting hooks (16) contained within an upper frame (14, 15) to lock into the beams (6). A jacking mechanism (13) then raises the upper frames (14, 15) relative to lower frames (11, 12) to lift up the entire pile of slabs (28). The lifting units (1, 2) are mounted on rails (9) which run along the sides of the prestressing bed and lead off to a stockyard where the pile of slabs (28) is taken by the lifting units (1, 2) for storage. During transfer of the individual slabs (29) to the pile (28), drilling units (4) are swung under each slab ( 29) to drill drainage holes. One of the lifting units (1) has a container (21) for dispensing and collecting the beams (6).

Abstract: The method of treating a waste liquid or solid hydrocarbon to reduce risk of environmental contamination by the waste hydrocarbon, that includes forming a flowable cementitious paste of Portland cement and additives; introducing the hydrocarbon into the mix and distributing the hydrocarbon therein; forming the mix into a shape for curing, and allowing the formed mix to cure so as to encapsulate the hydrocarbon in the cured concrete mix.

Abstract: An improved molding powder which comprises alkali metal alginate, calcium salt, tetrasodium pyrophosphate and filler, the alginate being from Laminaria hyperborea. The mixture sets to form a rubbery object.

Abstract: A method for making concrete cored bricks and capping bricks includes providing a mold having a row of mold cavities separated by cross members having core-bar holes formed therein, inserting a core bar through each cavity and into and filling a core-bar hole associated with rear cavity. Next, a rear core-bar hole is plugged and the cavities are filled with a concrete to form plural uncured bricks. The bricks are then compacted and an elongate, interconnecting pattern is pressed into a first surface of each brick. Next, the core bar is removed from the cavities and the bricks are ejected from the mold. Finally, plural wet layers of colored coatings are applied to the first surface of each brick after which the bricks are cured. Antiqued concrete capping brick including a top surface, four side surfaces, and a bottom surface having formed therein at least one recess are also formed. Additionally, a first side surface of the brick includes elongate, interconnected indentations that extend to the edges thereof.

Abstract: The present invention aims to evenly and surely knead a concrete material comprising less water amount. Concrete material layer entered into a kneading tank is cut in an up-and-down direction and divided into a plurality of layer sections arrayed side by side along a right-and-left direction, and one of the divided layer sections is piled up another one of the divided layer sections in the up-and-down direction, then piled up concrete layer sections are compacted, in other words are pressed in the up-and-down direction and extended in a horizontal direction, and further these steps are repeated.

Abstract: This invention provides a hydraulic composition which contains a cementitious material in powder form, .beta.-1,3-glucan, and a superplasticizer. The composition makes it possible to prepare concrete with high resistance to segregation, high fluidity, and excellent filling ability. Because of this, vibration of the concrete is not necessary during casting; it can simply be poured.

Abstract: A process for forming a poured slab, preferably of concrete, which has different colored portions. The process includes (a) pouring a wet concrete mixture of cement particles, sand particles and gravel particles into a horizontal mold cavity having a stepped mold bottom surface, (b) curing the mixture to produce a slab with a roughly horizontal rear surface and a stepped front surface corresponding to the mould bottom surface, and (c) mechanically removing the cured mixture between a cut plane generally parallel the rear surface through the slab and the front surface. The resultant slab has different portions with different coloration and appearance due to the cut plane passing through portions of the concrete having different proportions of cement, sand and gravel particles.

Abstract: The method of forming a three-dimensional pattern, wherein a pattern forming mold formed from an expanded polyethylene is attached to the work surface where a desired pattern is to be formed, a surfacing material of a specific acrylic resin concrete is cast onto the work surface, the surfacing material is allowed to harden, and the mold is detached and removed from the work surface.

Abstract: A method and device for fabricating posts made of concrete having a polygonal cross-section includes the steps of providing and opening an integral liner, applying backing panels to the liner, holding the panels together with a hooping means, and pouring and hardening concrete in the integral liner. The liner is collapsible and preformed to open in the shape of a right prism with an internal section identical to that of the post to be manufactured. Backing panels made of cardboard or plastic material support the external faces of the liner and entirely cover the external faces of the liner. At least one of the backing panels is adhered to an external face of the liner. A hooping means holds the liner and the backing panels assembled in mutual contact during the use of the device.

Abstract: A steel reinforced cement product having substantially increased strength made by: positioning prestressed reinforcing steel in a mold cavity; providing a cementitious mixture in the mold cavity about the reinforcing steel in an amount sufficient to fill the mold cavity to a predetermined extent; curing the reinforced cementitious-steel composite article in the mold; drying the article; applying a glaze to the surface of the dried article; burning the glaze; cooling the burned, glazed article, whereby reducing the strength of the composite article; hydrating the reduced strength composite article; and then recurring the thus produced article.

Abstract: A device for temporary retention of a lifting element on a metal surface of a form during the concrete pouring and setting phases of a prefabricated concrete member includes a part which is designed to form a depression in a concrete section and is equipped with magnets for attachment to a metal surface of a form. The device includes a part having a flat face, a recess terminating at a face opposite the flat face and orthogonal thereto desinged to permit passage with sealing action of a lifting element, and a slot terminating in the flat face. A locking element is mounted in the slot and pivots around an axis transverse to the slot. The locking element has a hook which forms a bolt designed to ensure retention of a free end of the lifting element when the locking element is in an unlocked position in the slot.

Abstract: A depositing method of wall concrete, in which unset concrete is deposited in a form, includes the step of disposing a non-hygroscopic soft sheet which has a large number of hollow projections or ridges on an inner surface of the form being deformable when lateral pressure is applied thereto by the hardening of the concrete.

Abstract: Gypsum/fiber board, especially for use as floor board, is fabricated by paring a binder consisting of at least 60% by weight of calcium sulfate alpha hemihydrate, and at most 35% by weight calcium sulfate beta hemihydrate, the balance, if any, inert material such as grinding residues from finished plaster board, in an amount of 100 parts by weight of the binder to 20 parts by weight of fiber, especially cellulose fiber or a mixture of cellulose fiber from scrap paper with reinforcing fiber. This dry mixture combined is with water in an amount such that no water can be expressed from the prepared mix by the subsequent pressing step and the prepared mix is then pressed in a peripherally-closed form such that the finished gypsum/fiber board will have a raw density of at least 1.5 g/cm.sup.2.

Abstract: A hydraulic inorganic compositions which comprises a hydraulic inorganic powder at least one of polysaccharides selected from the group consisting of .beta.-1,3-glucans, pullulan and XCD-Polymer in an amount of 0.1-10 parts by weight in relation to 100 parts by weight of the hydraulic inorganic powder, and water in an effective amount.The composition preferably further contains a reinforcing fiber, a filler, in particular mountain leather, a coagulant and/or a second molding aid, in particular, methyl cellulose.The composition is hardened by hydration under normal pressure to provide a hardened molded article such as a cement board.

Abstract: A mold for the manufacture of non-round glass shapes and method for making such molds. In molds for glass blowing and pressing, especially for producing non-round shapes where molten glass must be in contact with the mold for an extended time, an economical, heat resistant mold adaptable to any shape is produced by mixing defined ratios of water, hydraulic compound and amorphous fused silica to form a pourable composite mixture which is shaped into a mold by placing the mixture on or in a master pattern and curing the mixture at room temperature and then at elevated temperature.

Abstract: A thin-walled ferrocement product is formed from mortar supplied in a liquid or semi-liquid state, and a thin foraminous layer of reinforcement positioned centrally between the opposite wall surfaces of the product. The liquid or semi-liquid mortar is deposited in a uniform layer on a conveyor and the reinforcing material is positioned parallel to the lower surface of the conveyor. In a preferred embodiment, the material is maintained under tension at the desired position above the conveyor surface as the mortar is deposited onto the conveyor and flows through the foraminous reinforcing layer. The mortar is developed to a coherent plastic state before removal from the conveyor, preferably with the application of heat. The developed plastic material may be formed into various configurations, or may be maintained flat, while subjected to curing to a solid state. The developed plastic ferrocement material may be separated into convenient lengths for handling.

Abstract: In pressing wet concrete between a ram and a mold to compact the concrete and express water from it so as to produce a molded slab, a layer of filter material is provided between the ram or the base of the mold and the concrete and the filter material is secured by a discontinuous coat of adhesive applied as a transfer to the ram and/or to the base of the mold. The adhesive is applied over a sufficient area of the filter material to secure adhesion of the filter material to the ram or base of the mold. The discontinuous adhesive coating is provided as a pattern of particles which covers substantially the entire area of the face of the filter and is present over between 2% and 15% of the total surface area of the filter material.

Abstract: A method and apparatus for forming a curb section of a predetermined length sub-divided into modules by transverse grooves which give the appearance of shorter blocks and provide for fracturing the curb section at those locations. Each module of the curb section includes a rearward fastening projection having a vertical bore for passing a nail to engage the curb section to pavement or other base. Such linear mold sections are all that are required when a curve is dictated. The mold sections are sub-divided into the modules to form the curve. The apparatus includes an open frame moving vertically against a platform and mold shoes for pressing down on the concrete when poured in the mold frame, including plugs for forming the tops of the fastening projections. According to the method, the plugs are removed after the mold frame is lifted, and then the shoes are removed to leave the formed curb sections on the bottom wall.

Abstract: A process for the production and treatment of concrete blocks, which are produced in molds filled with concrete and are imprinted on their surface by means of dies that exhibit recesses or protrusions. Subsequently thereto, the surface of the concrete blocks is roughened or formed or textured and freed of loose particles by brushes, in particular strip brushes and roller brushes.

Abstract: A method and apparatus for constructing an above ground concrete encased storage tank. The apparatus has a support assembly that extends from the baseplate of a concrete form, that supports, elevates, and secures an inner storage tank from the form baseplate, so that the tank may be completely surrounded by concrete. The form has removable walls that may be pivotally attached to the baseplate and initially in a horizontal position. The support assembly has anchor bolts that extend through holes in the baseplate. The anchor bolts are screwed into anchor nuts that are attached to a pair of brackets. The anchor nuts and brackets are spaced from the baseplate by sleeves that fit over the threaded portions of the anchor bolts. The brackets are constructed to support the storage tank, which is placed in the form on top of the support assembly. The tank is then fastened to the support assembly.

Abstract: In casings for switch cross ties, the bottom plate 3 serves at the same time as a pattern for the position of the construction components. As a rule, a new casing is prepared for each series of cross-ties type. In small series with various positions of the construction components it is economical to use the bottom plate repeatedly. This is done by providing the bottom plate, prior to its insertion in the casing, with holes (A,B,C) for several types of finished parts, by provisionally closing the unnecessary holes by suitable means and by finding the combination of holes required for the production of a certain type of finished part through a certain searching procedure and freeing them of their provisional closing means.

Abstract: A method of sealing a concrete joint formed between a pair of concrete castings by creating an injection hole wherein a removable frame member can be attached to the bottom surface of the first concrete casting so as to form obtuse angles with the concrete casting surface. The other concrete casting is then cast around the frame member. The frame member is then removed to form the injection hole of the desired configuration, and sealing material can then be inserted into the injection hole for feeding into, and sealing of, the joint.

Abstract: A method for controlling the manufacturing process in the continuous prodion of gypsum-cemented workpieces utilizing a belt-type press or similar equipment including a number of press segments joined in tandem relationship. Utilizing this press, the gypsum undergoing hydration is compacted until the end of the hydration is reached. The swelling pressure created in the course of the hydration is measured and utilized to control the manufacturing process.

Abstract: Methods of forming cast prestressed concrete elements and structures include a non-corrosive reinforcing element being formed of a plurality of substantially parallel continuous filaments embedded in a matrix of thermosetting resin. These reinforcing elements are tensioned, then concrete cast about the elements is permitted to harden and the tension transferred to the now-hardened concrete in order to prestress the same. The resulting concrete elements and structures have high resistance to alkali induced corrosion of the prestressing elements.

Abstract: Magnesium oxychloride cement compositions, products, and uses thereof, are provided by mixing magnesium oxide, a magnesium chloride solution, and aggregate particles. The cement compositions are adapted for use in repairing damaged concrete surfaces, casting both functional and decorative forms, and coating surfaces with stucco. The addition of a small amount of acid to the cement composition promotes a more complete cementing reaction. The resulting cement product exhibits substantially increased strength and water resistance. Brine from the Great Salt Lake is a preferable source of the magnesium chloride solution. Brine from the Great Salt Lake results in a cement composition substantially stronger than cement produced from a pure magnesium chloride solution. Use of the Great Salt Lake brine as the gauging solution in lieu of a gauging solution made from magnesium chloride flakes (hexahydrate) reduces manufacturing costs of magnesium oxychloride cement products.

Abstract: A form device for cellular concrete, including a number of piled-up form units having a heat-insulating bottom and shell, a heat-insulating top board, and a bottom-to-shell joint. A cellular concrete manufacture is produced by mixing cement with warm water at a temperature of 40.degree. to 75.degree. C. to form a warm cement mortar, mixing the mortar with a bubbled warm frother solution to form a warm cellular concrete paste, and hardening the paste using such heat-insulating form device.

Abstract: A process for the production of concrete roofing products of reduced weight loading having a thickness in section of not greater than 15 mm. The process involves forming an asbestos-free cementitious composition comprising (i) lightweight aggregate, (ii) hydraulic cement, (iii) water and (iv) reinforcing fibers in an amount of not more than 4% by weight of the total weight of the composition but the fibers being present in an amount sufficient to provide a reinforcing effect and impact strength in the roofing product, the cementitious composition being capable of being shaped by a roller and slipper method, and thereafter shaping the cementitious composition by the method to provide a shaped extrudate, dividing the extrudate to form sections and curing the sections to provide roofing products, wherein the reinforcing fibers have lengths of 0.5 mm to 20 mm. The impact resistant roofing products are useful as roofing tiles, or a replacement for shingles, shakes and slates.