GB2507631A

GB2507631A - Reinforced lightweight concrete panel

Info

Publication number: GB2507631A
Application number: GB1315432.3A
Authority: GB
Inventors: Albert Kwok Hung Kwan; Dominic Yiu Wah Lai
Original assignee: Archibuild Ltd
Current assignee: Archibuild Ltd
Priority date: 2012-09-03
Filing date: 2013-08-29
Publication date: 2014-05-07
Also published as: HK1180525A2; GB201315432D0; CN203783038U; US20140065349A1

Abstract

An architectural panel comprises a main body 10 cast from lightweight concrete with first and second planar faces 11, 12 parallel to one another. First and second reinforcing mesh sheets are embedded in the body of the panel. Recesses 13 in the first planar face extend through openings 20 in the first mesh sheet 17. Each recess may taper inwardly from a mouth in the first face to a base. The openings in the first mesh and the mouth of the recesses may be square. The concrete may comprise aggregate formed from clay, polystyrene beads, pumice, shale, ash or ceramics. The concrete may be aerated or foamed. The panel may comprise fixtures cast into the body and fixed to the mesh sheets to provide mounting points. A backing layer cast after the main body may extend over the first face whilst a facing layer of lightweight concrete may be bonded to the second face.

Description

I

REINFORCED ARCHITECTURAL PANEL

Technical field

The present invention relates generally to architectural cladding and lining, and particularly to reinforced concrete panels.

Background of the Invention

Modern large buildings generally consist of a basic load bearing structure supporting the exterior cladding and internal linings of the walls. This wall cladding or lining material should be lightweight, durable, of pleasing appearance and compatible with overall environmental objectives for the interior of the building. The interior or exterior S.....

* 10 of some buildings are finished in polished natural stone, such as granite or marble or in a decorative concrete finish. This has a pleasing appearance, but these panels are * generally large, and in order to have sufficient strength to avoid breakage must be hea. Mounting such stone and concrete panels can therefore be difficult, and in *0S some cases there has been a tendency for unevenly distributed weight to cause panel joints to fail over time.

Architectural panels have been made from light weight reinforced concrete to address these difficulties. However, while satisfactory strength-to-weight ratios have been attained by some prior panels, their performance has typically been compromised in other respects, such as simplicity and cost of manufacture and thermal performance. It will be understood that there remains a need for an optimised or improved design which suffers less from such compromises. It is an object of the present invention to address this need or, more generally, to provide an improved architectural panel.

Disclosure of the Invention

According to one aspect of the present invention there is provided an architectural panel comprising: a main body cast from lightweight concrete; first and second major faces on the main body which are substantially planar and parallel to one another; first and second mesh sheets disposed substantially parallel to one another next to the first and second major faces respectively and embedded in the main body such that edges of each mesh sheet are disposed adjacent a respective edge of the main body, the first mesh sheet defining an array of openings, and an an-ay of recesses in the first major face, each recess extending through a 1.qS* * respective one of the openings in the first mesh sheet.

e t* * o S

I

It has been found that a panel according to the invention has a high strength-to-weight ratio, and exceptional thermal performance when correctly installed with the second major face disposed outwardly. In hot climates, when provision is made for air flow over the first major face, the panel is effective in reducing solar gains by dissipating heat to the air. In cool climates, when provision is made to prevent air flow over the first major face, the panel is effective in reducing heat loss from the building envelope.

Preferably the main body has a substantially rectangular prismatic form and the mesh sheets are rectangular.

Preferably no undercut is provided in the recesses.

Preferably each recess tapers inwardly from a mouth at the first major face to a base.

Preferably each recess comprises a plurality of intersecting flat faces. Preferably each recess comprises five flat faces.

Preferably the openings in the first mesh are square and the mouth is square.

Preferably four tapered faces of each recess extend from the square mouth to a square face at the base.

Preferably the four tapered faces have rotational symmetry about a central axis of each recess that extends substantially orthogonal to the first face.

Preferably the lightweight concrete may one of: sintered expanded day as aggregate, * .*.** * 10 expanded polystyrene beads as aggregate, pumice as aggregate, expanded shale as **.* aggregate, bottom ash as aggregate, ceramics as aggregate, aerated concrete and ****.* * . foamed concrete. * . * ** *

Preferably a plurality of fixtures cast into the main body to provide for mounting points, each fixture comprising a plate fixed to a projecting bracket and extending substantially perpendicular to the plate, an aperture in the bracket with an internal screw thread Preferably the fixture has generally the same dimension as the thickness of the panel.

Preferably the fixtures are fixed to the mesh sheets Preferably substantially the full length of the bracket is embedded in the concrete.

Preferably a backing layer extends over the first major face and keyed into the recesses, formed as by casting the backing layer after the body.

Advantageously, a facing layer may be bonded to the second major face so as to be exposed on installation for aesthetic purposes. The facing layer may comprise lightweight concrete with a decorative finish, such as a patterned finish, or exposed aggregate finish. The facing layer may alternatively comprise stone, such as polished marble or granite. Optionally, a decorative finish may instead be applied directly to the second major face.

This invention provides an architectural panel which is effective and efficient in operational use, which may be economically constructed and has an overall simple design which minimizes manufacturing costs and improves structural and thermal performance. * .

Brief Description of the Drawings S.. * S *5e

*:" Preferred forms of the present invention will now be described by way of example :::: with reference to the accompanying drawings, wherein:

S S..

Figure 1 is an isometric view of a panel according to an embodiment of the invention; Figure 2 is a fragmentary section indicated byAAon Fig. 1; Figure 3 is a fragmentary section indicated by BB on Fig. 1; Figure 4 is a fragmentary section corresponding to Fig. 2 but showing an additional facing layer bonded to the panel of Fig. 1; Figure 5 is a longitudinal section through a fixture of the invention; Figure 6 is a fragmentary section through of a panel according to a second embodiment of the invention; Figures 7 and 8 are fragmentary views of a major face of the panel of Fig. 6, and Figure 9 is a fragmentary section through of a panel according to a third embodiment of the invention.

Description of the Preferred Embodiments

Referring to Figs. I to 3 of the drawings, an architectural panel according to a first embodiment of the invention may have a generally rectangular prismatic main body cast from lightweight concrete, and having a first major face 11 and an opposing second major face 12. The major faces 11, 12 are substantially planar and parallel * * to one another. * * * S...

* *..: A rectangular array of recesses 13 are disposed in the first major face 11. and may :::: be of like form and regularly spaced, with an uninterrupted margin 14 extending about the perimeter of the array of recesses 13 adjacent to a peripheral edge 15 of the main body 10.

The main body 10 is reinforced with first and second substantially rectangular reinforcing mesh sheets 17, 18 disposed substantially parallel to one another next to the first and second major faces 11, 12 respectively. A corner section of the mesh sheet 17 is illustrated by the dashed lines in Fig. 1, while both sheets 17, 18 are illustrated by the circular section wires in Figs 2-4. The mesh sheets 17, 18 may be made of stainless steel wire and are embedded in the main body 10 such that edges 19 of each mesh sheet 17, 18 are disposed inside and adjacent to the peripheral edge 15. Each mesh sheet 17, 18 defines an array of square openings 20, the two sheets being aligned such that the openings 20 that are in registration with one another, and with the recesses 13.

Each recess 13 has a mouth 16 at the first major face 11 and tapers inwardly from the mouth 16 to a base 21. The base 21 is below the level of the mesh sheet 17 such that each recess 13 extends through a respective one of the openings 20 in the first mesh sheet 17, but stops short of the second mesh sheet 18.

Each recess 13 has a concave form without undercut, allowing the recesses to be cast readily. Each recess may have four intersecting planar faces 22a-22d that taper inward as they extend toward the base 16. A face of the base 21 forms a fifth face bounding the recess. In the preferred embodiment the mesh openings 20 and recesses 13 are centred on a transverse axis 24 that extends substantially *..... * .

orthogonal to the first and second major faces 11, 12, the recesses 13 having a **.* symmetrical shape such that the four tapered faces have rotational symmetry about ***s** * * a central axis. * .** * . * ** .

Fig. 4 illustrates a composite panel comprising a facing layer 26 bonded to the second major face 12 of the main body 10. The facing layer 26 may be formed with an exposed face 27 with a decorative finish, such as a patterned finish, or exposed aggregate finish.

The main body 10 and facing layer 26 may be cast from lightweight concrete, such as concrete including lightweight aggregates, especially expanded polystyrene beads, pumice, expanded shale, bottom ash and ceramics. Alternatively, the lightweight concrete may be foamed or aerated concrete. The panels are self-supporting but may be non-structural and suitable lightweight concretes may have a density of about 1400-1500 kg/m3 and compressive strength of 25-30 MPa.

Providing recesses 13 allows a further weight saving to be achieved and it is believed that the recessed inner major face 11 contributes to the improved thermal performance in reducing solar gains in hot climates (when provision is made for air flow over the first major face) by improving heat dissipation to the air. In cool climates, when made substantially airtight the recess provide a still air gap effective in reducing heat loss from the building envelope. The recesses 13 also provide suitable locations for fasteners for fixing the panels.

Referring to Figs 5-8, a plurality of fixtures 30 are cast into the main body 10, to provide mounting points on the panel for connection to the frame of a building. Each fixture 30 may comprise a plate 31 fixed to a projecting bracket 32, as by a screw **" fastener 33. The bracket 32 may extend perpendicular to the plate 31, and include a *::* longitudinally through-extending aperture 34 with an internal screw thread 35. An opening in the plate 31 for receiving the screw 33 may be disposed generally centrally. The fixture 30 may have generally the same dimension as the thickness of the panel, such that the outer face 37 of the bracket 32 and outer face 36 of the plate 31 are generally coplanar with the first and second major faces 11, 12 respectively. Edges 39 of the recesses 13 may be radiused.

As best seen in Figs 6 and 7, the fixtures 30 may also be fixed to the mesh sheets 17, 16. By securing the mesh sheets 17, 18, as by welding, to the bracket 32 the fixtures 30 can also be used for supporting the mesh sheets 17, 18 in position during casting, as with the outer faces 36, 37 abutting opposite walls of a form (not shown) in which the panel is cast. The bracket 32 may be connected to both wires 40a, 40b of the mesh panels 17, 18 as by locating the bracket 32 acjacent the intersection between the wires 40a, 40b. Substantially the full length of the bracket 32 is preferably embedded in the concrete, and this is achieved by locating the fixtures 30 outside the recesses 13. For instance, as shown in Fig. 8, the regular, rectangular array of recesses 13 may be interrupted by areas adjacent the fixtures 30 without recesses 13.

Fig. 6 also illustrates a second embodiment of the architectural panel comprising the body 10 with a facing layer 42 bonded to the second major face 12 and formed, for instance, from stone. Strips 43 of the same stone as the facing layer 42 may be fixed along the edges of the panel. The outer face 36 may be bonded to the inner side 44 of the facing layer 42 as by a layer 45 of adhesive, such as epoxy. A cementitous bond is achieved between the rest of the inner side 44 and the body 10 by casting the body against the facing layer 42, and the edge strips 43.

*fl... * *

A third embodiment of the architectural panel is illustrated in Fig. 9, having generally *** *-: like construction to the second embodiment of Fig. 6, but further including a backing * layer 50 extending over the first major face 11 and keyed into the recesses 13, being * **.

* formed as by casting the backing layer 50 after casting the body 10 to provide a * ** cementitous bond between the two. The backing layer 50 may be formed from a lightweight concrete of lower density than that of the body 10, and which provides increased thermal insulation. The backing layer 50 may be fibre reinforced, as by glass fibre or synthetic fibre, providing a high strength-to-weight ratio. The fixture 130 used with this panel is of like construction to the fixture 30, but includes a longer bracket 132 that extends to the rear face 51 of the backing layer 50.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

Claims

CLAIMS: 1. An architectural panel comprising: a main body cast from lightweight concrete; first and second major faces on the main body which are substantially planar and parallel to one another; first and second mesh sheets disposed substantially parallel to one another next to the first and second major faces respectively and embedded in the main body such that edges of each mesh sheet are disposed adjacent a respective edge of the main body, the first mesh sheet defining an array of openings, and *..... * *an array of recesses in the first major face, each recess extending through a **.respective one of the openings in the first mesh sheet. -S..

*
2. The architectural panel of claim I wherein the main body has a substantially rectangular prismatic form and the mesh sheets are rectangular.
3. The architectural panel of claim I or claim 2 wherein no undercut is provided in the recesses.
4. The architectural panel of any one of claims I to 3 wherein each recess tapers inwardly from a mouth at the first major face to a base.
5. The architectural panel of any one of claims 1 to 4 wherein each recess comprises a plurality of intersecting flat faces.
6. The architectural panel of any one of claims 1 to 5 wherein each recess comprises five flat faces.
7. The architectural panel of any one of claims 1 to 6 wherein the openings in the first mesh are square and the mouth is square.
6. The architectural panel of any one of claims I to 6 wherein four tapered faces of each recess extend from the square mouth to a square face at the base.
9. The architectural panel of claim 8 wherein the four tapered faces have rotational symmetry about a central axis of each recess that extends substantially orthogonal to the first face.
10. The architectural panel of any one of claims 1 to 9 wherein the lightweight concrete comprises one of: sintered expanded clay as aggregate, expanded * 10 polystyrene beads as aggregate, pumice as aggregate, expanded shale as S.. aggregate, bottom ash as aggregate, ceramics as aggregate, aerated concrete So.and foamed concrete *.*
11. The architectural panel of any one of the preceding claims, further comprising a 0** plurality of fixtures cast into the main body to provide for mounting points, each fixture comprising a plate fixed to a projecting bracket and extending substantially perpendicular to the plate, an aperture in the bracket with an internal screw thread
12. The architectural panel of claim 11 wherein the fixture has generally the same dimension as the thickness of the panel.
13. The architectural panel of claim 11 or claim 12 wherein the fixtures are fixed to the mesh sheets
14. The architectural panel of any one of claims 11 to 13 wherein substantially the full length of the bracket is embedded in the concrete.
15. The architectural panel of any one of the preceding claims, further comprising a backing layer extending over the first major face and keyed into the recesses, formed as by casting the backing layer after the body.
16. The architectural panel of any one of the preceding claims wherein the mesh is formed of steel wire.
17. The architectural panel of any one of the preceding claims further comprising a facing layer of lightweight concrete bonded to the second major face.* *
18. An architectural panel substantially as hereinbefore described with reference to * * the accompanying drawings. S.. * S S... *e.*e * SS SS