US3458610A - Method of forming precast concrete structural components - Google Patents

Method of forming precast concrete structural components Download PDF

Info

Publication number
US3458610A
US3458610A US515328A US3458610DA US3458610A US 3458610 A US3458610 A US 3458610A US 515328 A US515328 A US 515328A US 3458610D A US3458610D A US 3458610DA US 3458610 A US3458610 A US 3458610A
Authority
US
United States
Prior art keywords
concrete
mix
mould
beams
aggregate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US515328A
Inventor
Christopher Lawrence Sainty
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Structural Concrete Components Ltd
Original Assignee
Structural Concrete Components Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Structural Concrete Components Ltd filed Critical Structural Concrete Components Ltd
Application granted granted Critical
Publication of US3458610A publication Critical patent/US3458610A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
    • B28B23/0081—Embedding aggregates to obtain particular properties
    • B28B23/0087—Lightweight aggregates for making lightweight articles
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
    • E04C2/04—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres
    • E04C2/049—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres completely or partially of insulating material, e.g. cellular concrete or foamed plaster

Definitions

  • FIG. 2 2 I 0 a j j j 1 l L I l I HGJL H6 4 United States Patent 3,458,610 METHOD OF FORMING PRECAST CONCRETE STRUCTURAL COMPONENTS Christopher Lawrence Sainty, Hassocks, England, assignor to Structural Concrete Components Limited, Hassocks, England, a British company Filed Dec. 21, 1965, Ser. No. 515,328 Claims priority, application Great Britain, Dec. 22, 1964, 51,985/ 64 Int. Cl. B28b 1/08 US. Cl.
  • a stiff mix of appropriate viscosity of spherical aggregate of substantially uniform size and a matrix material consisting of fine gritty material, cement and water is formed.
  • the proportions of the spherical aggregate and the matrix material in the stiff mix are such that the total volume of the matrix material is substantially less than the volume of voids between the spherical aggregate when measured alone.
  • the mix is then placed in a mold and vibrated so as to distribute the matrix to coat all of the spherical aggregate and to fill the voids in the lower portion of the mold thereby forming a structural component having a solid lower portion and a porous upper portion.
  • the component is then removed from the mold and can be used.
  • the invention relates to a method for forming precast concrete structural components, particularly but not exclusively to precast floor beams and slabs, while the object of the invention is to provide a method for forming precast floor beams and slabs which are light in weight in comparison with their strength.
  • Such aggregate can-be natural, but is rarely found sufiiciently spherical and uniform in shape, and it is there fore preferred to use a manufactured spherical aggregate such as pellets of clay, shale or like argillaceous materials which have been rendered spherical and baked, such as known by the name Argilag" R.T.M.
  • a fine gritty material such for example as sand, fiy ash or crushed natural or manufactured mineral material, cement and water, in which the total volume of the matrix is less than that of the voids in the aggregate measured alone, it is possible to vibrate the mix in he mould for the structural component so that the lower part becomes solid while the upper part becomes porous. If the component is a floor beam the solid part is required above the neutral axis and therefore the beam is moulded upsidedown.
  • the invention consists in a method of manufacture of precast concrete structural components such as floor beams and slabs, comprising preparing a stiff mix of appropriate viscosity of spherical aggregate of substantially uniform size, fine gritty material, cement and water in such proportions that the total volume of the matrix is substantially less than the volume of the voids in the aggregate when measured alone, placing the mix in a mould of the shape of the component to be manufactured, vibrating the mix in the mould at a suitable amplitude, frequency and duration as will distribute the matrix in the required location within the interstices in the aggregate under the action of gravity.
  • the invention further consists in a method of manufacture of precast concrete structural components as set forth in the preceding paragraph in which the vibration of the mix is carried out for such duration that the concrete at the bottom of the mould is dense and without voids while the concrete at the top of the mould is porous.
  • FIGURE 1 is a cross section through a mould filled with the mix before it is vibrated
  • FIGURE 2 is a cross section of the same mould after the mix has been vibrated
  • FIGURE 3 is an enlarged part-section showing the relationship between the aggregate, and the cement before it is vibrated, while,
  • FIGURE 4 is an enlarged part section showing the relationship between the aggregate of the cement after the mix has been vibrated.
  • FIGURES 1 and 2 The mould shown in FIGURES 1 and 2 has side wall portions 1 and 2 which stand upon a flat bottom plate 3, while the main reinforcement parts 4 are secured in position as shown, by any known convenient method. At the same time that the mix is placed in the mould, the solid matter and the voids will be distributed in random manner throughout the mould as represented by the cross hatching of average density,
  • the mix After the mix has been vibrated at a suitable. amplitude and frequency, and for a suitable duration, the mix will sink in the mould and all voids in the lower part of the mould will be filled and only that part towards the upper part of the mould will contain voids, as shown in FIG- URE 2 and represented by the dense and light cross hatching respectively.
  • the main function of the porous part of the beam is to support and locate the main reinforcement.
  • the beam has to perform the solid part might generally constitute one fifth or less of the total depth of the beam.
  • One advantage of manufacturing beams in the proposed manner is that they can be supplied to the building site and be laid to form a floor with a smooth and fiat upper surface and thus avoid the necessity of laying a screeding thereon.
  • Floor beams may be about twelve inches wide and little difiiculty is experienced in laying them side by side to provide a level, smooth surface over any required area and where the joints between the beams are filled with a suitable cement and sand mix.
  • the edges of the beams in the porous area may be so shaped that, when forced together, a concentrated load on one beam may be transferred to the adjacent beam.
  • the beams may be made of such sections that channels are left in the upper surface of the fioor between adjacent beams for the accommodation of electric conduits and the like, and since the concrete forming the lower layers of the floor is comparatively soft, holes may be punched through where necessary for electrical outlets.
  • the tensile strength of the porous part of the component may be increased by the addition of fibrous material of a mineral character to the mix or a binding emulsion may be added to the cement if desired to increase its tensile strength.
  • manuiacture panels which may be used as wall panels having an external solid face which is impermeable while the inner porous face provides insulation against heat loss.
  • Such panels can be substituted with advantage for cavity walls and the external face can be provided with any desired finish.
  • precast concrete components of other forms may be constructed in accordance with the present invention.
  • a method of manufacturing lightweight precast concrete structural components such as beams and slabs comprising the steps of introducing spherical aggregate of substantially uniform size and matrix material consisting of fine gritty material, cement and water to form a stiff mix, said mix having proportions of said spherical aggregate and said matrix material such that the total volume of said matrix material is substantially less than the volume of voids between said spherical aggregate when measured alone; placing said stilf mix in a mold defining the particular structural component being cast; vibrating said stiff mix in said mold at a predetermined amplitude, frequency and duration as will distribute said matrix to coat all of said spherical aggregate, uniformly distribute said spherical aggregate in said mold, and fill in the voids between said distributed spherical aggregate in the lower portion of said mold thereby forming a solid lower portion and a porous upper portion; and removing the so formed structural component from said mold.

Description

1 O6 9 7 CROSS REFERENCE EXAMINER July 9, 1969 c. 1.. SAINTY 3,458,510
METHOD OF FORMING PRBCAST CONCRETE STRUCTURAL COMPONENTS FiledDec. 21. 1965 FIG FIG 2 2 I 0 a j j j 1 l L I l I HGJL H6 4 United States Patent 3,458,610 METHOD OF FORMING PRECAST CONCRETE STRUCTURAL COMPONENTS Christopher Lawrence Sainty, Hassocks, England, assignor to Structural Concrete Components Limited, Hassocks, England, a British company Filed Dec. 21, 1965, Ser. No. 515,328 Claims priority, application Great Britain, Dec. 22, 1964, 51,985/ 64 Int. Cl. B28b 1/08 US. Cl. 264-69 2 Claims ABSTRACT OF THE DISCLOSURE In manufacturing lightweight precast concrete structural components having two predominant densities, a stiff mix of appropriate viscosity of spherical aggregate of substantially uniform size and a matrix material consisting of fine gritty material, cement and water is formed. The proportions of the spherical aggregate and the matrix material in the stiff mix are such that the total volume of the matrix material is substantially less than the volume of voids between the spherical aggregate when measured alone. The mix is then placed in a mold and vibrated so as to distribute the matrix to coat all of the spherical aggregate and to fill the voids in the lower portion of the mold thereby forming a structural component having a solid lower portion and a porous upper portion. The component is then removed from the mold and can be used.
The invention relates to a method for forming precast concrete structural components, particularly but not exclusively to precast floor beams and slabs, while the object of the invention is to provide a method for forming precast floor beams and slabs which are light in weight in comparison with their strength.
It is common knowledge that in a simple reinforced concrete beam designed to be subjected to loads acting vertically downwards, the concrete above the neutral axis is subjected to compressive forces, which forces the concrete is suitable to resist, and that below the neutral axis the beam is subjected to tensional forces which concrete alone is not suitable to resist and that steel reinforcement is provided to resist the tensional forces.
It is known to provide reinforced concrete beams in which the cross section area of the concrete below the neutral axis is substantially less than the area of concrete above the neutral axis, the concrete being of the same consistency throughout, thereby to economize in the vol ume of concrete used and to reduce the weight of the beams without substantially affecting the strength of the beams.
It is now proposed in accordance with the present invention to produce precast concrete beams, slabs and other structural components in which the density of the concrete is different in different parts of the components, that par of the component being subjected under load to compressive forces being of dense concrete while the parts not so subjected are of a less dense nature.
It is proposed in accordance with the invention to make use of a particular property of uniform spherical aggregate. Such aggregate can-be natural, but is rarely found sufiiciently spherical and uniform in shape, and it is there fore preferred to use a manufactured spherical aggregate such as pellets of clay, shale or like argillaceous materials which have been rendered spherical and baked, such as known by the name Argilag" R.T.M.
If a stiff mix of appropriate viscosity is made with a uniform spherical aggregate of substantially uniform size,
"ice
a fine gritty material, such for example as sand, fiy ash or crushed natural or manufactured mineral material, cement and water, in which the total volume of the matrix is less than that of the voids in the aggregate measured alone, it is possible to vibrate the mix in he mould for the structural component so that the lower part becomes solid while the upper part becomes porous. If the component is a floor beam the solid part is required above the neutral axis and therefore the beam is moulded upsidedown.
With aggregates of the type mentioned, and with vibration of suitable amplitude, frequency and duration, it is possible to produce concrete components with the desired proportion of solid and porous parts, depending upon the ratio of the quantity of matrix used to the quantity required to completely fill all the voids in the aggregate. Concrete of this sort can be made with very high com-pressive strength in the solid part and very much lower strength, modulus of elasticity and weight in the porous part.
The technique proposed above presents no difficulties in the manufacture of'concrete components on a large scale.
The invention consists in a method of manufacture of precast concrete structural components such as floor beams and slabs, comprising preparing a stiff mix of appropriate viscosity of spherical aggregate of substantially uniform size, fine gritty material, cement and water in such proportions that the total volume of the matrix is substantially less than the volume of the voids in the aggregate when measured alone, placing the mix in a mould of the shape of the component to be manufactured, vibrating the mix in the mould at a suitable amplitude, frequency and duration as will distribute the matrix in the required location within the interstices in the aggregate under the action of gravity.
The invention further consists in a method of manufacture of precast concrete structural components as set forth in the preceding paragraph in which the vibration of the mix is carried out for such duration that the concrete at the bottom of the mould is dense and without voids while the concrete at the top of the mould is porous.
In one method of manufacture in accordance with the invention it is proposed to cast beams in moulds with a smooth fiat bottom plate, with the main reinforcement secured in the upper part of the mould. There may be provided in the lower part of the mould light reinforcement solely for the purpose of making the beams safe against breakage in handling. When the beams are finished the lower part in the mould is the dense part and the beams are therefore installed with this part uppermost, so that it forms the compressive zone above the neutral axis.
The accompanying drawing shows diagrammatically, by way of example only, the precast aggregate component in the course of manufacture in which,
FIGURE 1 is a cross section through a mould filled with the mix before it is vibrated,
FIGURE 2 is a cross section of the same mould after the mix has been vibrated,
FIGURE 3 is an enlarged part-section showing the relationship between the aggregate, and the cement before it is vibrated, while,
FIGURE 4 is an enlarged part section showing the relationship between the aggregate of the cement after the mix has been vibrated.
The mould shown in FIGURES 1 and 2 has side wall portions 1 and 2 which stand upon a flat bottom plate 3, while the main reinforcement parts 4 are secured in position as shown, by any known convenient method. At the same time that the mix is placed in the mould, the solid matter and the voids will be distributed in random manner throughout the mould as represented by the cross hatching of average density,
After the mix has been vibrated at a suitable. amplitude and frequency, and for a suitable duration, the mix will sink in the mould and all voids in the lower part of the mould will be filled and only that part towards the upper part of the mould will contain voids, as shown in FIG- URE 2 and represented by the dense and light cross hatching respectively.
During the process of mixing the concrete all the spherical aggregate is wetted by the cement and when first placed in the mould a superfluity of the cement and sand is positioned in places such as indicated at 5 in FIGURE 3 while the spherical aggregate in other places such as at 6 is in contact and has a thin coating all over with additional cement around the points of contact, held there by surface tension.
When the mould has been fully vibrated the excess cement falls to the bottom of the mould and fills the voids as at 7 up to a predetermined level, while above this level the whole of the concrete is provided with voids.
The main function of the porous part of the beam is to support and locate the main reinforcement. Depending upon the duty the beam has to perform the solid part might generally constitute one fifth or less of the total depth of the beam.
One advantage of manufacturing beams in the proposed manner is that they can be supplied to the building site and be laid to form a floor with a smooth and fiat upper surface and thus avoid the necessity of laying a screeding thereon. Floor beams may be about twelve inches wide and little difiiculty is experienced in laying them side by side to provide a level, smooth surface over any required area and where the joints between the beams are filled with a suitable cement and sand mix.
The edges of the beams in the porous area may be so shaped that, when forced together, a concentrated load on one beam may be transferred to the adjacent beam.
If desired the beams may be made of such sections that channels are left in the upper surface of the fioor between adjacent beams for the accommodation of electric conduits and the like, and since the concrete forming the lower layers of the floor is comparatively soft, holes may be punched through where necessary for electrical outlets.
The tensile strength of the porous part of the component may be increased by the addition of fibrous material of a mineral character to the mix or a binding emulsion may be added to the cement if desired to increase its tensile strength.
It is also within the scope of the invention to manuiacture panels which may be used as wall panels having an external solid face which is impermeable while the inner porous face provides insulation against heat loss. Such panels can be substituted with advantage for cavity walls and the external face can be provided with any desired finish.
Only beams, slabs and panels have been referred to hereinbefore, but it is to be understood that precast concrete components of other forms may be constructed in accordance with the present invention.
I claim:
1. A method of manufacturing lightweight precast concrete structural components such as beams and slabs comprising the steps of introducing spherical aggregate of substantially uniform size and matrix material consisting of fine gritty material, cement and water to form a stiff mix, said mix having proportions of said spherical aggregate and said matrix material such that the total volume of said matrix material is substantially less than the volume of voids between said spherical aggregate when measured alone; placing said stilf mix in a mold defining the particular structural component being cast; vibrating said stiff mix in said mold at a predetermined amplitude, frequency and duration as will distribute said matrix to coat all of said spherical aggregate, uniformly distribute said spherical aggregate in said mold, and fill in the voids between said distributed spherical aggregate in the lower portion of said mold thereby forming a solid lower portion and a porous upper portion; and removing the so formed structural component from said mold.
2. A method of manufacture as claimed in claim 1 in which said spherical aggregate is of the manufactured kind.
References Cited Troxell and Davis, Concrete, 1956, page 97. Orchard, D. F., Concrete Technology, volume 2, 1962, pp. 230-231.
ROBERT F. WHITE, Primary Examiner I. H. SILBAUGH, Assistant Examiner US. Cl. X.R. 106-97; 26471
US515328A 1964-12-22 1965-12-21 Method of forming precast concrete structural components Expired - Lifetime US3458610A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB51985/64A GB1090880A (en) 1964-12-22 1964-12-22 Improvements in or relating to precast concrete structural components

Publications (1)

Publication Number Publication Date
US3458610A true US3458610A (en) 1969-07-29

Family

ID=10462196

Family Applications (1)

Application Number Title Priority Date Filing Date
US515328A Expired - Lifetime US3458610A (en) 1964-12-22 1965-12-21 Method of forming precast concrete structural components

Country Status (4)

Country Link
US (1) US3458610A (en)
DE (1) DE1584757A1 (en)
FR (1) FR1460483A (en)
GB (1) GB1090880A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2474939A1 (en) * 1980-01-31 1981-08-07 Ytong International Ab PROCESS FOR MANUFACTURING LIGHTWEIGHT CONCRETE CONSTRUCTION ELEMENTS
WO1986000386A1 (en) * 1984-06-20 1986-01-16 Vapor Corporation Refractory choke for a high intensity combustor
US5662846A (en) * 1995-03-29 1997-09-02 E. I. Du Pont De Nemours And Company One-step process for producing solid surface material with foam backing
US5702651A (en) * 1996-03-01 1997-12-30 The United States Of America As Respresented By The Secretary Of The Army Use of oriented tabular aggregate in manufacture of high-flexural-strength concrete

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2176818B (en) * 1985-06-07 1988-09-28 Quikspan Construction Limited Structural member
DE3809383A1 (en) * 1988-03-19 1989-09-28 Bernd Lechner Process for producing a precast wall panel from lightweight concrete

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3192060A (en) * 1961-05-24 1965-06-29 Benjamin L Tilsen Lightweight aggregate and method of producing same
US3202522A (en) * 1961-12-28 1965-08-24 Johns Manville Cementitious product

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3192060A (en) * 1961-05-24 1965-06-29 Benjamin L Tilsen Lightweight aggregate and method of producing same
US3202522A (en) * 1961-12-28 1965-08-24 Johns Manville Cementitious product

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2474939A1 (en) * 1980-01-31 1981-08-07 Ytong International Ab PROCESS FOR MANUFACTURING LIGHTWEIGHT CONCRETE CONSTRUCTION ELEMENTS
WO1986000386A1 (en) * 1984-06-20 1986-01-16 Vapor Corporation Refractory choke for a high intensity combustor
US5662846A (en) * 1995-03-29 1997-09-02 E. I. Du Pont De Nemours And Company One-step process for producing solid surface material with foam backing
US5702651A (en) * 1996-03-01 1997-12-30 The United States Of America As Respresented By The Secretary Of The Army Use of oriented tabular aggregate in manufacture of high-flexural-strength concrete

Also Published As

Publication number Publication date
DE1584757A1 (en) 1970-04-16
FR1460483A (en) 1966-11-25
GB1090880A (en) 1967-11-15

Similar Documents

Publication Publication Date Title
US5806264A (en) Multi-cellular wall structure
US20210395971A1 (en) Method of making molded concrete blocks having simulated brick or stone outer surfaces
US9849607B2 (en) Methods and systems for the formation and use of reduced weight building blocks forms
US4935186A (en) Method of manufacturing concrete beams
US4357289A (en) Method for the production of building elements of the lightweight concrete type
EP3568273B1 (en) Plant and method for producing pumice blocks having cavities filled with insulation material
US3458610A (en) Method of forming precast concrete structural components
US5397516A (en) Process for making building panels
US3286418A (en) Prestressed composite load-bearing slab
US2839812A (en) Method of manufacturing a structural panel
EP0000837A1 (en) Load bearing wall panels and method of manufacture thereof
US4141946A (en) Hollow-core concrete slabs and the method of making the same
RU2643055C1 (en) Three-layer bearing panel manufacturing method
US4056910A (en) Structural building element
RU2747282C1 (en) Method for manufacture of assembled concrete products
GB2085502A (en) Building units for forming permanent formwork
US3497580A (en) Method and apparatus for making faced concrete blocks
US2526174A (en) Method of casting concrete pipes and the like
US2315732A (en) Porous concrete construction and method of making the same
EP0056220B1 (en) A method of producing lightweight multi-layer building elements
US1389404A (en) Reinforced concrete construction
US2948947A (en) Method for manufacturing reinforced lightweight concrete
RU2422269C1 (en) Method of producing road cover plate
GB1592363A (en) Manufacture of constructional elements
JPS6325144B2 (en)