GB2037215A

GB2037215A - Casting facings on reinforcing structure

Info

Publication number: GB2037215A
Application number: GB7847682A
Authority: GB
Original assignee: Dow Mac Concrete Ltd
Current assignee: Dow Mac Concrete Ltd
Priority date: 1978-12-08
Filing date: 1978-12-08
Publication date: 1980-07-09

Abstract

A process for producing a precast wall comprises providing an internal reinforcing structure, and casting opposed layers of hardenable material on opposite sides of the reinforcing structure, each said layer being cast face-down in a mould. Fibre-reinforced concrete or resin embedding mesh, steel bars, tiles or exposed aggregate is cast on to opposed faces of a framework of steelwork, or reinforced or prestressed concrete elements of prismatic form including metal ties.

Description

SPECIFICATION The manufacture of precast walls The present invention relates to the manufacture of precast walls.

According to one aspect of the invention, there is provided a process for producing a precast wall comprising, providing an internal reinforcing structure, and casting opposed layers of hardenable material on opposite sides of the reinforcing structure, each said layer being cast face-down in a mould.

According to another aspect of the invention, there is provided a precast wall comprising opposed layers cast individually onto opposite sides of an internal reinforcing structure of the wall, with each layer being cast face-down.

Preferably, the material is a water-hardenable material, although other hardenable materials, such as resin-based materials may alternatively be used.

The novel features of the invention will be apparent from the following description given by way of example only.

The wall is made in two stages. In the first stage an internal framework is constructed and in the second stage opposed outer layers of concrete or other wsste-hardenable material are cast individually onto opposite faces of the framework.

The inner framework may be formed of reinforced or pre-stressed concrete elements of prismatic form.

The concrete elements are joined together to make a grid framework, for example by using galvanised or stainless steel cleats, by dowled and grouted joints using cement grout or an epoxy adhesive or grout, or by casting concrete around interlocking components of the steel reinforcement which project from the concrete elements.

Preferably the prismatic elements are formed with through-holes extending perpendicular to the plane of the grid framework. Metal ties are inserted through these holes when the framework is assembled and are bent at right angles so that their end portions lie within, and anchor, the outer layers when these are cast in the second stage. The metal ties may be of stainless steel or be galvanised.

Alternatively, the ties should be grouted in the holes to protect them from corrosion when the wall is to be located in an environment where corrosion is likely to occur. The tie bars may be cast into the grid framework instead of being grouted into holes therein. Instead of, or in addition to, using metal ties to key the grid framework to the cast outer layers, the prismatic members may be formed with a dovetail cross-section to provide a direct key between the cast outer layers and the prismatic members of the framework.

Instead of using a grid framework composed of concrete as described above, the framework may consist of fabricated steelworkwhich case it should be protected from corrosion by galvanising or other suitable treatment.

A thin layer of concrete, cement, or other waterhardenable material for forming one of the two outer layers of the wall is poured on to a flat, horizontal, surface of a tilting mould and while the layer is still wet, the grid framework is lowered into it in the mould so that the ties (if provided) and/or the prismatic members of the framework are embedded within the layer. If required, the layer poured into the mould may be reinforced by a mesh, steel bars, non-metallic fibres, or any other suitable reinforcement.Instead of incorporating a mesh reinforcement into the layer before the grid framework is lowered into the mould, a reinforcing mesh may first be connected to the appropriate face of the grid framework, and then the grid framework/mesh reinforcement assembly is lowered into the mould, with vibration preferably being applied in order to ensure that the layer penetrates fuliy into the mesh reinforcement.

The cast layer is left to set and when it has reached a satisfactory strength, the mould is tilted and the wall removed. The above process is then repeated for the opposite outer layer of the wall.

If desired, the wall may be preformed with high thermal insulating properties by filling the spaces of the grid framework with blocks of foamed or other insulating material.

The process described in which both outer layers are cast face down in a mould enables a high quality finish to be obtained. This process can be used with particular advantage to produce a precast wall which constitutes the entire playing surface of any one of the four walls of a squash court. In such a case, the outer layer which is to form the playing surface of the wall may be cast in ordinary cement, white cement, or pigmented cement to provide a high quality smooth surface which is free from joints. If the wall is to act as a partition wall between two squash courts located side-by-side, each of the two outer layers of the wall will be cast so as to form a playing surface, the other layer may be formed with any appropriate surface finish, for example as will be described below.

The process may also be used to form walls having exposed aggregate, tiled, or specially moulded external finishes. The surface finish is determined by the material used to form the cast layer of the wall or by incorporating tiles or moulded inserts on the bottom of the mould before the layer of hardenable material is poured.

1. A process for producing a precast wall comprising, providing an internal reinforcing structure, and casting opposed layers of hardenable material on opposite sides of the reinforcing structure, each said layer being cast face-down in a mould.

2. A process according to claim 1, wherein the material is a water-hardenable material.

3. A precast wall comprising opposed layers cast individually onto opposite sides of an internal reinforcing structure of the wall, with each layer being cast face-down.

4. A process substantially as hereinbefore described.

5. A precast wall substantially as hereinbefore described.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION The manufacture of precast walls The present invention relates to the manufacture of precast walls. According to one aspect of the invention, there is provided a process for producing a precast wall comprising, providing an internal reinforcing structure, and casting opposed layers of hardenable material on opposite sides of the reinforcing structure, each said layer being cast face-down in a mould. According to another aspect of the invention, there is provided a precast wall comprising opposed layers cast individually onto opposite sides of an internal reinforcing structure of the wall, with each layer being cast face-down. Preferably, the material is a water-hardenable material, although other hardenable materials, such as resin-based materials may alternatively be used. The novel features of the invention will be apparent from the following description given by way of example only. The wall is made in two stages. In the first stage an internal framework is constructed and in the second stage opposed outer layers of concrete or other wsste-hardenable material are cast individually onto opposite faces of the framework. The inner framework may be formed of reinforced or pre-stressed concrete elements of prismatic form. The concrete elements are joined together to make a grid framework, for example by using galvanised or stainless steel cleats, by dowled and grouted joints using cement grout or an epoxy adhesive or grout, or by casting concrete around interlocking components of the steel reinforcement which project from the concrete elements. Preferably the prismatic elements are formed with through-holes extending perpendicular to the plane of the grid framework. Metal ties are inserted through these holes when the framework is assembled and are bent at right angles so that their end portions lie within, and anchor, the outer layers when these are cast in the second stage. The metal ties may be of stainless steel or be galvanised. Alternatively, the ties should be grouted in the holes to protect them from corrosion when the wall is to be located in an environment where corrosion is likely to occur. The tie bars may be cast into the grid framework instead of being grouted into holes therein. Instead of, or in addition to, using metal ties to key the grid framework to the cast outer layers, the prismatic members may be formed with a dovetail cross-section to provide a direct key between the cast outer layers and the prismatic members of the framework. Instead of using a grid framework composed of concrete as described above, the framework may consist of fabricated steelworkwhich case it should be protected from corrosion by galvanising or other suitable treatment. A thin layer of concrete, cement, or other waterhardenable material for forming one of the two outer layers of the wall is poured on to a flat, horizontal, surface of a tilting mould and while the layer is still wet, the grid framework is lowered into it in the mould so that the ties (if provided) and/or the prismatic members of the framework are embedded within the layer. If required, the layer poured into the mould may be reinforced by a mesh, steel bars, non-metallic fibres, or any other suitable reinforcement.Instead of incorporating a mesh reinforcement into the layer before the grid framework is lowered into the mould, a reinforcing mesh may first be connected to the appropriate face of the grid framework, and then the grid framework/mesh reinforcement assembly is lowered into the mould, with vibration preferably being applied in order to ensure that the layer penetrates fuliy into the mesh reinforcement. The cast layer is left to set and when it has reached a satisfactory strength, the mould is tilted and the wall removed. The above process is then repeated for the opposite outer layer of the wall. If desired, the wall may be preformed with high thermal insulating properties by filling the spaces of the grid framework with blocks of foamed or other insulating material. The process described in which both outer layers are cast face down in a mould enables a high quality finish to be obtained. This process can be used with particular advantage to produce a precast wall which constitutes the entire playing surface of any one of the four walls of a squash court. In such a case, the outer layer which is to form the playing surface of the wall may be cast in ordinary cement, white cement, or pigmented cement to provide a high quality smooth surface which is free from joints. If the wall is to act as a partition wall between two squash courts located side-by-side, each of the two outer layers of the wall will be cast so as to form a playing surface, the other layer may be formed with any appropriate surface finish, for example as will be described below. The process may also be used to form walls having exposed aggregate, tiled, or specially moulded external finishes. The surface finish is determined by the material used to form the cast layer of the wall or by incorporating tiles or moulded inserts on the bottom of the mould before the layer of hardenable material is poured. CLAIMS 1. A process for producing a precast wall comprising, providing an internal reinforcing structure, and casting opposed layers of hardenable material on opposite sides of the reinforcing structure, each said layer being cast face-down in a mould. 2. A process according to claim 1, wherein the material is a water-hardenable material. 3. A precast wall comprising opposed layers cast individually onto opposite sides of an internal reinforcing structure of the wall, with each layer being cast face-down. 4. A process substantially as hereinbefore described. 5. A precast wall substantially as hereinbefore described. New claims or amendments to claims filed on 25 Jan.1980 Superseded claims 1 - 5 New or amended claims:- 1 - 15

1. A process for producing a precast wall, comprising providing an internal reinforcing structure in the form of a frame composed of preformed elements of water-hardenable material, and casting opposed layers of hardenable material on opposite faces of the frame, each said layer being cast face-down in a mould.

2. A process according to claim 1, wherein the frame includes ties projecting transversely from said opposed faces of the frame to key the layers to the frame.

3. A process according to claim 1 or claim 2, wherein the frame elements are shaped to provide a direct key between the layers and the frame.

4. A process according to any one of claims 1 to 3, wherein blocks of thermal insulating material are placed within the frame.

5. A process according to any one of claims 1 to 4, wherein material for forming the exposed surface of at least one of said layers is laid in the mould prior to casting of the layer.

6. A process for producing a precast wall, comprising providing an internal reinforcing structure composed of preformed concrete elements joined together to form a grid framework, said framework having metal ties projecting transversely from its opposed faces, and casting opposed layers of waterhardenable material onto the opposite faces of the frame, each said layer being cast face-down in a mould and being keyed to the framework by means of the ties projecting from the adjacent face of the framework.

7. A process according to claim 6, wherein the ties are inserted into preformed holes provided in the frame elements.

8. A process according to claim 6, wherein the ties are cast into the frame elements.

9. A process according to any one of claims 6 to 8, wherein blocks of thermal insulating material are located in voids within the framework.

10. A process according to any one of claims 6 to 9, wherein material for forming the exposed surface of at least one of said layers is laid in the mould prior to casting of the layer.

11. A method for producing a precast wall according to claim 1, substantially as herein before described.

12. A precast wall produced by a method according to any one of the preceding claims.

13. A precast wall comprising an internal reinforcing structure in the form of a grid framework composed of reinforced prismatic elements of water-hardenable material, and opposed layers of water-hardenable material, each cast face down onto a respective one of the two opposed faces of the framework, said layers being keyed to the framework by means of the ties.

14. A wall according to claim 12 or claim 13, said wall being a wall for a squash court, wherein one of said layers of the wall forms the entire playing surface for one side of the squash court.

15. A precast wall substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.