Abstract: Tensioning elements for construction purposes comprising reinforcing rod for prestressing concrete can be fabricated from steel of the following composition:0.7 to 1.0% by weight Mn0.7 to 2.2% by weight Cr0.3 to 0.6% by weight Mo0.5 to 2.2% by weight Niup to 0.45% by weight C (preferably at least 0.1% by weight C.)balance iron and unavoidable steel impuritieswhich is subjected to austenitization, oil quenching and optional tempering to a tensile strength of 1400 to 2000 N/mm.sup.2 and an elongation to break in excess of 7% and preferably about 10% and is welded to a terminal element of the same composition but having a tensile strength substantially 10-20% less than that of the rod, and then incorporated into a concrete structure.

Abstract: A process for making beams of prestressed concrete in an assembly for casting and curing beams of prestressed reinforced concrete, having an individual prestress frame allowing tensioning of longitudinal reinforcements between two fixed end elements maintained in spaced-apart relationship by longitudinal elements; and an individual impression cooperating hermetically with the frame so that the walls of the impression and the walls of the end elements of the frame, connected together, form the sides of a mould receiving the cast concrete, the impression being adapted to be separated from the frame without detensioning of the reinforcements.

Abstract: A concrete tile is disclosed having a preformed substrate member backing comprising a substantially rigid, polymeric material. The lower surface of the substrate member defines the shape of the lower surface of the tile. A concrete layer is disposed on and secured to the upper surface of the substrate member and defines the shape of the upper surface of the tile. In manufacturing the tile, a plurality of through openings in the substrate member are filled with the concrete when the concrete is applied to the substrate member. The concrete is cured on the substrate member and the hardened concrete in the openings of the substrate member forms studs securing the substrate member and concrete layer together. The use of a polymeric substrate member backing provides a tile which uses less concrete and is therefore substantially lighter in weight than other tiles of corresponding strength. The method of manufacturing the tiles utilizes the substrate member as a support for the concrete applied to its upper surface.

Abstract: A method of constructing a reinforced concrete structure (e.g. a cement building or pipeline) wherein an inflatable form is placed on a precast foundation and confined thereto by wrapping the exterior of the inflatable form with a layer of chain link fencing fabric. For large structures, a plurality of adjacent inflatable forms (preferably pneumatically interconnected) is employed wherein either the exterior interstitial spaces between adjacent forms are occupied by lightweight spacer means or structural walls and support means are present to further anchor the chain link fencing fabric. The inflatable form can then be highly pressurized such as to prestress the chain link fence and a uniform layer of fiber reinforced cement is applied to the form. The resulting thin walled structure exhibits excellent structural properties virtually free of form deformation and cement sloughing.

Abstract: The method for forming prestressed centrifugal piles by:disposing a spiral within one of the two constituent half-shells of the mould for the pile to be formed,securing within this spiral a plurality of strands having at least one end emerging from a mould headpiece,pouring the concrete into said half-shell,joining the two half-shells together,inserting axial restraint elements for the strands through suitable apertures provided in the half-shells,tensioning the strands at those ends which emerge from the headpiece and,centrifuging the mould prepared in this manner.

Abstract: An installation for manufacturing reinforced concrete elements, in particular prestressed concrete slabs or pre-slabs, by means of a bench including a manufacturing area of predetermined shape, together with a molding apparatus. Memory means (46) are provided for storing building data relating to the elements to be manufactured and concerning at least the geometry thereof, together with tracing means (48) for marking on the manufacturing area (16) the locations of at least some of the walls placed thereon and constituting portions of the molding apparatus.

Abstract: A method of producing a compressive stress in a mass comprised of plastic material having a tendon therein, at least a portion of the length of the tendon being contained in thermoplastic material within the mass, the method comprising the steps of heating the tendon to a temperature sufficient to soften the thermoplastic material in an annular region surrounding the tendon, applying a tractive force to the heated tendon, thereby placing the heated tendon under tensile stress, and securing the heated tendon to the mass in a manner that causes the tensile force in the tendon to produce a compressive stress in the mass and prestressed plastic bodies produced according to this method.

Abstract: A pressure vessel and a method for distributing the stresses in a thick-walled high-pressure vessel, so that they lie within allowable limits, by constructing the wall in a series of generally concentric layers, at least one intermediate layer of which is to be constructed before the other layers. The intermediate layer is constructed above a base, resting on it through a sliding joint. Then it is placed under an external prestressing pressure. Thereafter, that layer is secured to the base by a rigid concrete connection. The remaining layers of the wall are then constructed and are subjected to an external prestressing pressure. Preferably, stress-relieving slots are applied to the innermost layer, during its construction.

Abstract: A composite, pre-stressed structural member comprised of concrete and a lower metal support member, and method for forming and pre-stressing the same. The metal support member and a concrete mold are connected for parallel deflection with the support member uppermost and shear-connectors extending into the mold. The connected mold and support member are supported for deflection and concrete is poured into the mold and allowed to harden. During hardening of the concrete the mold and support member are deflected by the weight of the concrete, mold and support member, pre-stressing the support member. Upon hardening of the concrete and inverting to a concrete-uppermost position, a composite, pre-stressed structural member is provided.

Abstract: Concrete; structural elements having a high permissible working load typically in the range of at least 50-100 MPa. The element includes a block of compressed concrete surrounded by a tubular hoop made of intercrossed wires. Such elements are useful for making beams, posts, cables and the like.

Abstract: A method for producing a constructional element comprising a steel casing filled with concrete, for instance, a machine body having good load carrying and vibration-absorbing properties. The main steel parts of the element are arranged to form a hollow casing filled with a fluid concrete mass. Internal pressure is supplied in the casing to act on the concrete mass during its hardening phase, the pressure being selected so as to provide in the steel casing an elastic deformation and expansion which substantially exceeds the shrinkage of the concrete mass during its hardening phase. The internal pressure must be sufficient to cause such a deformation of the steel casing that there is a remaining compression between the steel casing against the dry shrunk concrete in the finished element under all the loading and deforming conditions for which the constructional element has been designed.

Abstract: An improved composite, pre-stressed structural member and method of forming such a member of the type provided by upside down forming which includes connecting the steel beams of the composite member to the upper side of a mold so that a parallel deflection of the mold and beams occurs as the mold is filled with concrete. The improvement comprises utilizing a steel beam having a flange at or near the neutral axis with respect to a vertical deflection of the support member. After the composite structure is formed, the flange is away from the neutral axis with respect to a vertical deflection of the composite structure. This flange, therefore, significantly increases the section modulus of the composite structure while not adding significantly to the resistance to bending of the beam during pre-stressing. Stacked and welded I-beams are an example of a support in accordance wth this invention.

Abstract: A plain concrete pipe having an evenly distributed steel wire reinforcement is disclosed, said pipe being suitable for water piping and the like; this pipe being reinforced with a reinforcement constituted by thin wires evenly distributed and arranged in a circumferential pattern and a longitudinal pattern; a method is also disclosed for the manufacture of the pipe on an industrial scale in an efficient and economical manner.

Abstract: A portable system for making harped, reinforced concrete beams includes a series of inverted T-shaped concrete bed sections, with aligned longitudinally extending holes for receiving tensioning cables to hold the sections together, to provide two beds, one on either side of the center wall of the sections, to make the concrete beams. At points near the center of each beam to be formed, arrangements for "harping" or depressing the longitudinally extending tensioning steel strands or cables are provided.

Abstract: Disclosed is a method and apparatus for forming continuous slabs having parallel longitudinally extending post-tensioned tendons therein.

Abstract: Manufacturing lined concrete pipe in a reduced time, and provision of such pipe with reduced tendencies to rusting and liner separation, are achieved by a cartridge assembly (22) movable to and away from the pipe machine, a work stand assembly (23) for positioning the cartridge to receive a liner, liner tensioning structures (68) and liner to cartridge clamps (87) for moving the liner to the cartridge, tightening the liner, and holding the liner during transport by the cartridge, and tension bars (96) controlling wire tension during pipe formation. Concurrently with operation of the standard pipe machine, the work stand operates to place a liner on the cartridge. During the stripping cycle of the pipe machine, the cartridge delivers the liner to the core. During the pipe machine vibration under pressure cycle, the tension on the liner tension wires is relieved.

Abstract: A method for installing a new steel tendon and for repairing a damaged or deteriorated steel tendon in a prestressed concrete slab is disclosed. The repair method includes the steps of relieving substantially all stress in the defective original tendon, removing the original tendon, installing a new tendon in the space vacated by the original tendon, installing new concrete around the new tendon to replace any original concrete removed while removing the original tendon, and stressing the new tendon thereby again prestressing the previously structurally defective slab. Installation of a tendon where none has previously existed is similar except an original tendon need not be removed.

Abstract: The invention relates to an apparatus and method for manufacturing concrete structural elements. In order to manufacture the elements, setting of the concrete takes place in a casing (1), while the concrete is compressed with an axial pressure of at least 50 MPa and the casing is surrounded with a hoop (2,3) so as to create transverse planes of pressure.

Abstract: The apparatus and method for processing steel strand wire cable and the like for use in prestressed concrete is disclosed in which the outer surface of the cable produced has a substantial pure rust or hydrated oxide coating thereon enabling the cable to be utilized immediately in concrete configurations to thereby produce substantially higher flexural strengths in prestressed concrete than heretofore in the prior art. The apparatus and method specifically encompasses the use of ultrasonic cleaning equipment which causes cavitation cleaning effects in the liquid medium through which the cable passes during its cleaning process. In effect, the ultrasonic cleaning "catalyzes" the chemical redox reactions by removing all surface inhibitors and reducing reactant diffusion barriers thus accelerating surface wetting of the strand cable with H.sub.2 O and O.sub.2, such that the rusting chemical reactions can occur spontaneously. The dominant bond developed between the steel and concrete is chemical.

Abstract: Workpieces of prestressed concrete, specifically railroad ties, are molded in a form having its bottom covered with several transversely separated templates whose outline corresponds to that of respective ties to be produced; the form is longitudinally traversed by reinforcing rods or cables attached to its ends under tension. Each template is provided with several countersunk nuts to be engaged by retaining bolts which pass through upright screw anchors with downwardly opening throats loosely occupied by internally threaded centering sleeves that come to rest on the associated template. With the form compartmented by removable spacers separating the templates, concrete is poured into each compartment and allowed to harden about the screw anchors rising therein; the retaining bolts are then withdrawn along with the spacers to provide the resulting concrete blocks with a certain mobility whereupon the tensioned reinforcing armatures are released to prestress these blocks and are subsequently cut between them.

Abstract: A method of manufacturing railway switch-point concrete sleeper blocks of varying lengths and having different number of attachment means located in mutually different positions for the attachment of rails. A plurality of steel matrix plates 102 whose respective lengths correspond to the desired lengths of the various sleeper blocks and which exhibit detachably mounted dowels 109 are placed end to end in an elongate mould bed with the dowels facing upwardly, whereafter reinforcing lines rods 5 are tensioned and concrete is poured into the mould bed and permitted to harden. The thus formed coherent concrete body is then removed from the mould and the matrix plates removed with the dowels remaining cast in the concrete block. The concrete body is then cut into sleeper blocks of desired length. The dowels are accurately mounted in predetermined positions in frame members affixed to the matrix plates.

Abstract: Prefabricated concrete wall panel and method of forming same having a continuous peripheral metallic skeletal panel frame with its opposite sides being adjustably disposed/constrained during fabrication to provide a substantially parallelogram shaped wall panel. A plurality of spaced transversely extending, for example, nut and bolt type clamping means are disposed between opposite sides of the panel frame at least during the fabrication process to maintain the sides generally straight and parallel until the concrete has attained sufficient set strength. A plurality of hook means are affixed to opposite sides of the panel frame and extend inwardly into the concrete for holding the parallelism of the opposite sides following removal of the clamping means.

Abstract: A method of manufacturing railway switchpoint concrete sleeper blocks of varying lengths and having different number of attachment means located in mutually different positions for the attachment of rails. A plurality of steel matrix plates 102 whose respective lengths correspond to the desired lengths of the various sleeper blocks and which exhibit detachably mounted dowels 109 are placed end to end in an elongate mould bed with the dowels facing upwardly, whereafter reinforcing rods 5 are tensioned and concrete is poured into the mould bed and permitted to harden. The thus formed coherent concrete body is then removed from the mould and the matrix plates removed, with the dowels remaining cast in the concrete block. The concrete body is then cut into sleeper blocks of desired length. The dowels are accurately mounted in predetermined positions in frame members 111 affixed to the matrix plates.

Abstract: A composite, pre-stressed structural member comprised of concrete and a lower metal support member, and method for forming and pre-stressing the same. The metal support member and a concrete mold are connected for parallel deflection with the support member uppermost and shear-connectors extending into the mold. The connected mold and support member are supported for deflection and concrete is poured into the mold and allowed to harden. During hardening of the concrete the mold and support member are deflected by the weight of the concrete, mold and support member, pre-stressing the support member. Upon hardening of the concrete and inverting to a concrete-uppermost position, a composite, pre-stressed structural member is provided.

Abstract: A combination long lower mold and pretension bench for the formation of prestressed concrete materials is constructed by serially connecting plurality of unit lower molds of concrete, attaching prestressing steel wire tension benches one each to the foremost and rearmost unit lower molds, and fastening the unit lower molds and the tension benches collectively with steel wires. Prestressed concrete materials are obtained by stretching prestressing steel wires along the upper surface of the long lower mold, continuously pouring and placing stiff-consistency concrete on the long lower mold, causing a slide upper mold to run on the concrete thereby shaping the concrete in a required cross section, curing the shaped concrete strip, and cutting the cured concrete strip into pieces of a desired size.

Abstract: Prefabricated prestressed concrete members are formed on a stressing bed with a number of working stations arranged next to one another along the length of the bed. A frame froms the working stations and the frame is movable over the stressing bed. With a previously poured concrete member in one of the working stations, part of a form is placed in another working station and is filled with concrete. After the form part is completely filled and consolidated, a second form part is placed downwardly on the filled part completing the form. A lifting member on the frame which placed the second form part on the filled part is then moved to the station containing the previously poured member which is still within the form. The form is stripped from the concrete member and the frame is then moved along with the lifting member returning the stripped form to the working station where it is to be filled with concrete.

Abstract: The invention describes a method of constructing a building involving the assembly of a rigid skeletal framework of struts defining the contours of the desired building which is for example domed, or part-barrel shaped. A membrane or envelope of plastics material is inflated within the framework to lift the struts from a state of compression under their own weight into a state of tension. The membrane is then coated on at least one side with settable material such as concrete or other glass fibre reinforced material and the membrane deflated when the material has set. In an example of the invention, support zones at the junctions of the struts support the set material.

Abstract: Some self-supporting screens for closing the mold head, some self-supporting separating screens, group positioning devices and group tensioning devices, are used. A series of novel installations for the shock heat treatment, stripping and removal of the products enables by combination with the foregoing means, improvement with respect to known processes, on the one hand of the manufacturing process and on the other hand enables stripping to be brought forward.

Abstract: Equipment for the production of pre-stressed concrete beams or railway sleepers includes two, spaced, reinforcement-tensioning, abutment assemblies with a casting bed lying between the assemblies. Mobile moulds can be moved into and out of the casting bed through one of the abutment assemblies and the latter includes a plurality of displaceable arms carrying reinforcement clamping means. Each arm is displaceable to allow passage of the moulds when the latter are filled with at least partially cured pre-stressed concrete articles. A mould train can be removed as a whole with cured articles therein and individual articles formed by severing the tensioning reinforcing bars or wires and the finished articles subsequently demoulded at a site remote from the casting bed.

Abstract: A method of filling a sleeve 4 of cable stay anchorage with a filling material comprising aggregate particles and a curable liquid mixture of an epoxy resin and a powder, comprising the steps of first filling the sleeve 4 with the curable liquid mixture (via pipe 10), secondly adding the aggregate particles (via pipe 11) and then allowing the liquid mixture to cure to form a solid mass containing the aggregate particles. The method of filling the anchorage is considerably easier than prior art methods, does not require the use of injection pumps and provides a filling material with low shrinkage and good corrosion and friction preventing properties. The anchorage also has plastics locating members 7, 8 to hold the wires 1 out of contact with the sleeve wall, to prevent friction under cyclic loads.

Abstract: A concrete mould employs resilient side shuttering, made of rubber for example, which is prevented from deflecting, when concrete is poured, by tensioning wires extending along the length of the shuttering. Pieces of the shuttering, forming the sides of a casting box, extend between fixed end plates having a series of holes to receive the tensioning wires for adjusting the modular width of panels cast in the box. A series of apertures is provided in each piece of side shuttering so that pneumatic core formers can be inserted through aligned apertures so as to extend across the casting box. Different types of joint formers, either fully or partly resilient, can be located about the core formers, each joint former having a series of grooves to receive reinforcement or tensioning wires or rods. When inflated the pneumatic core former locks the joint formers in place. Opening formers can be made from the shuttering and the joint formers.

Abstract: An anchor for use in the post-tensioning of prestressed concrete, including an anchor case having a longitudinally tapering outer wall surface and a tapered longitudinal bore for receiving a chuck comprising wedge segments which are in gripping engagement with a tendon passing therebetween. The anchor case and chuck are approximately the same length, and the anchor case is cold forged with the top end thereof folded inwardly to effect greater thickness at that point, which structure, in combination with a dome-shape thrust plate extending outwardly from the outer periphery of the anchor case proximate the folded portion thereof, contains the hoop forces exerted on the anchor case by the chuck.

Abstract: Concrete pipe including a hollow tube of concrete with a grid of reinforcing bars embedded therein. A plurality of inserts are embedded in the concrete pipe in between the bars of the grid and have passageways therethrough to form slots between the interior of the concrete pipe and the exterior thereof at predetermined locations to form slotted concrete pipe. The inserts are attached to the grid of reinforcing bars during formation of the pipe and the concrete is introduced to surround the grid and inserts and is permitted to set. Thereafter, the formed concrete pipe contains embedded reinforcing bars and inserts in predetermined locations resulting in a slotted reinforced concrete pipe.

Abstract: A device for removing from their moulds elements made of pre-stressed concrete employing stretched adherent reinforcements on a "long bed" and passing through at least one row of moulds of said elements, wherein, prior to the release of the tension of the reinforcements, each of the elements is detached from its mould by an upward thrust exerted on at least one movable portion of the bottom of this mould, then maintained in lifted position until the tension is released and these reinforcements are cut.

Abstract: A process and system for recovery and recycling of hard rock core forming aggregate used in the slip forming of elongated hollow-cored concrete planks using wash water to remove slurry and a rotating screen to remove the water from the aggregate with collection and conveying means for the aggregate.

Abstract: A self-propelled slip form, closed at its top, front, and sides, but open at its rear and bottom, provides a pressure chamber having the cross-sectional shape of a wall or similar structure to be cast. Such slip form may be advanced continuously at a slow rate or in stages, but whichever it is, the advance is due solely to pressure exerted against the closed front of the slip form through the intermediacy of the deposited, unset concrete or the like. Such pressure can be utilized to pre-stress reinforcing material on a continuous basis as it is fed into the pressure chamber simultaneously with deposit of the concrete or the like.

Abstract: A concrete post molding device is disclosed for simultaneously forming a plurality of uniform, reinforced concrete posts. The device includes a housing containing an annular chamber defined by a fixed horizontal first plate having a central cylindrical pipe and a spaced concentrically arranged sleeve vertically supported thereon. A plurality of circumferentially spaced radial fin members are connected with the pipe for dividing the chamber into a plurality of circumferentially arranged vertical compartments, and the first plate contains a plurality of openings arranged opposite the compartments. The concrete post molding device is characterized by novel reinforcing rod suspension and tensioning apparatus. An annular ring is connected with the upper portion of the pipe and includes a plurality of first chucks for gripping the upper portions of the reinforcing rods. The lower portions of the rods are suspended in spaced relation in the compartments and extend vertically through the first plate openings.

Abstract: A prestressed concrete pressure-containment vessel having one or more cavities within its external shell. The cavities, whether cylindrical or other shape, are totally contained by prestressing tendons, which apply forces to contain various pressures within the structure. By permitting and actually inducing controlled cracking of the vessel in the outer portions of the thick shell wall, one embodiment of a pressure-containment vessel relieves stresses and enhances resistance to very high internal pressures and to stresses due to high internal temperatures and steep temperature gradients.

Abstract: An improved lightweight cementitious product consisting essentially of an aqueous cementitious mixture and reclaimed polystyrene beads in which the reclaimed polystyrene beads are bonded to the cementitious material. The cementitious product is prepared by dispensing reclaimed polystyrene beads in an aqueous cementitious mixture, such as hydraulic cement and water, to form a resulting mixture, placing the resulting mixture in a mold, and compressing the resulting mixture in the mold until setting of the resulting composition occurs. The volume of the resulting mixture in the mold is reduced during compression by approximately fifteen percent of the original volume and substantially no water is exuded from the resulting mixture during compression. The reclaimed polystyrene beads are substantially spherical in configuration and have a particle size substantially larger than "virgin" polystyrene beads.

Abstract: In a method of manufacturing for a railway switch-point concrete sleeper blocks (15') of varying lengths and having different number of attachment means (15'b) located in mutually different positions for the attachment of rails to said blocks there is used a plurality of steel matrices (2) whose respective lengths correspond to the desired lengths of the various sleeper blocks and which exhibit detachably mounted dowels (3). The matrices are placed end to end in an elongate mould bed with the dowels facing upwardly, whereafter reinforcing lines (5) are tensioned and concrete is cast into the mould bed and permitted to harden. The thus formed coherent concrete body (15), whose length may exceed 30 meters, is then removed from the mould and the matrices (2) removed and the dowels (3) remaining cast in the concrete block. The concrete body (15) is then cut into sleeper blocks (15') of desired length.

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: The invention relates to building.The invention relates to a building device characterised in that it comprises a layer of at least one knitted fabric elastically deformable in all directions on an at least temporarily supporting skeleton, and a binder capable of setting on the knitted fabric.

Abstract: A method of manufacturing reinforced elements includes the steps of providing a lattice-like mesh of threads lying in a first plane, applying a plurality of reinforcing fibers so that they extend in planes located at angles to the first plane in which the mesh of threads lies, and embedding the lattice-like mesh with the thus-applied fibers into a bulk of cement. A reinforced concrete element includes a bulk of cement and a reinforcing structure comprising a lattice-like mesh of threads and a plurality of fibers located in planes which are inclined to the plane of the mesh. The reinforcing fibers may extend normal or be inclined to the plane of the mesh of threads. They may be prefixed to the same before the embedding step.

Abstract: Concrete railroad crossties are mass-produced by slip-forming concrete using a specially adapted continuous casting machine to deposit concrete over a plurality of forms arranged side by side and end to end above an elongated casting bed. Each group of side-by-side casting forms is supported above the bed on a carriage longitudinally moveable on rollers, thereby permitting relative movement of adjacent end-to-end carriages to compensate for concrete contraction when pretensioned wire strands in the concrete are detensioned and for a slight recoil action when adjacent end-to-end crossties are separated by sawing. An apparatus for lifting side-by-side crossties in groups is equipped with hydraulic jacks for forcibly ejecting the concrete crossties from their forms.

Abstract: A hold-down anchor device for securing reinforcing strands in a mold while the strands are tensioned, the mold filled with concrete, and the concrete allowed to set, is held in place by an anchor means traversing the mold wall. The hold-down anchor device includes a pair of side frame elements which are disposed parallel to each other and positioned generally vertically in the mold. A number of strand hold-down means extend transversely between the side frame elements. A swivel means is pivotally secured to the lower ends of the side frame elements and includes means for engaging the anchor means. The swivel means further includes means for retaining one or more reinforcing strands near the lower ends of the side frame elements in corresponding closely spaced relation with the mold. The swivel means may include either grooves or rollers for retaining the reinforcing strands near the lower ends of the side frame elements.

Abstract: Apparatus for forming prestressed concrete beams comprising groups of molds, each group forming a module, with the modules arranged consecutively and tracks are placed alongside the modules. Plates seal off the ends of each mold and the beams are lifted off the molds by the plates after the prestressing wires have been cut.

Abstract: A characteristic feature of the present invention is the fact that the pipe producing plant has a horizontal platform rotatable round a vertical axis, on which a mould with conduit formers for pipe making is located. The base of the plant mounts a mechanism for feeding, tensioning of the reinforcement wire and wounding it onto a moulded pipe, and bench carrying a mechanism for filling the mould with concrete mix, a mechanism for smoothing the pipe end face and a mechanism for placing a protective cement mortar cover upon the reinforcing wire wound onto the moulded pipe. The plant incorporates also a mechanical actuator for alternatively raising and lowering the conduit formers, said actuator being mounted on a rigid base outside the rotary platform.

Abstract: A method of making a prestressed concrete pole, including placing a heat softenable plastic pipe in a metal tube or pipe and filling the space between the pipes with concrete, rotating the metal pipe-concrete assembly rapidly to center the plastic pipe therein, applying hot fluid pressure to the interior of the plastic pipe, longitudinally prestressing the concrete pipe assembly for several hours while the concrete sets, and gradually releasing the fluid pressure and prestressing pressure to obtain a prestressed concrete pole.

Abstract: A pipe joint of a reinforced resin having a structure in which the wall of at least a socket portion consists of an inside surface layer composed of a cured product of a reinforced resin molding material, an outside surface layer composed of a cured product of a reinforced resin molding material, and an interlayer between these layers composed of a cured product of a resin mortar.

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.