WO2025181364A1

WO2025181364A1 - Modular interconnecting structural panel and process for its manufacture

Info

Publication number: WO2025181364A1
Application number: PCT/EP2025/055577
Authority: WO
Inventors: Benjamin Edward SUMMERHILL; Graeme James SMITH; Aleca Jo OTT; John Paul CAREY
Original assignee: Addagrip Terraco Ltd
Current assignee: Addagrip Terraco Ltd
Priority date: 2024-02-28
Filing date: 2025-02-28
Publication date: 2025-09-04
Anticipated expiration: 2026-08-28
Also published as: GB202402829D0

Abstract

The present invention provides a modular interconnecting panel (10) and a method for the manufacture thereof, the panel comprising: a frame (12) having a lower edge (20) for contact with a ground, a substructure or a mounting system in use and an upper edge (18); support means (14) within the frame (12) configured and arranged to support a building material (16) over a ground, substructure or mounting system; and connection formations (34,36) provided on the frame configured to engage with connection formations of one or more adjacent panels in use and to restrict at least lateral movement. The panel (10) may further comprise the building material (16) supported by the support means within the frame and providing an external surface (32) lying in a plane above the plane of the upper edge (18) of the frame (12).

Description

MODULAR INTERCONNECTING STRUCTURAL PANEL AND PROCESS FOR ITS MANUFACTURE

FIELD OF THE INVENTION

The present invention relates to modular interconnecting structural panels and a process for their manufacture. In particular, the present invention relates to interconnecting or interlocking panels for use as a ground surface.

BACKGROUND OF THE INVENTION

Panels for use in the construction of a ground surface such as a path, road, patio, drive or the like may be formed of a binder-bound aggregate.

Typically, a binder-bound surface is prepared by mixing aggregate material with a binder, laying the mixture onto a ground or base material, levelling the mixed aggregate material, and allowing the level material to set. A disadvantage with this method is the requirement to mix multiple components and have on-site mixing equipment as well as a time pressure to lay the mixed material before setting takes place. Further, limited weather conditions allow the material to be applied or to set correctly.

Binder-bound paving panels are known but they suffer from several disadvantages in that they are required to be a certain minimum thickness for a required length and width to prevent brakeage making them heavy and thereby transportation and installation difficult.

In addition, the ground at a site where it is intended to lay a paving panel or other similar ground coverings needs to be suitably prepared to support the panel. An uneven ground or movement over time can adversely affect the paved surface. However, ground preparation requires a significant amount of effort and materials. An area of ground on which a ground covering is to be installed needs to be dug out, removed and backfilled with a depth of hardcore and other sub-base aggregate that is capable of supporting the ground covering, and compaction of the materials in the layers. The construction of drainage surfaces or channels may also be required.

It is an object of the present invention to provide an alternative or improved structural panel.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a modular panel, comprising: a frame having a depth comprising a lower edge for contact with an underlying surface in use and an upper edge; support means within the frame configured to support material above the lower edge; and connection formations provided on the frame configured to engage with connection formations of one or more adjacent panels in use and to restrict lateral movement.

In a second aspect, the present invention provides a modular panel, comprising: a frame having a depth comprising a lower edge for contact with an underlying surface in use and an upper edge; support means within the frame configured to support material above the lower edge; connection formations provided on the frame configured to engage with connection formations of one or more adjacent panels in use and to restrict lateral movement; and material supported by the support means within the frame and providing an external surface lying in a plane above the plane of the upper edge of the frame.

In one embodiment, the support means is formed with one or more apertures or perforations to allow water to permeate therethrough. The frame and/or support means may be provided with structural means, such as channels, to allow water to permeate therethrough. The material preferably comprises interstices to allow water to permeate therethrough. In this way, the panel acording to the second aspect of the present invention is a permeable panel. Preferably, the panel is a permeable binderbound aggregate panel.

The support means may comprise a platform extending across the width and length dimensions of the frame. In this embodiment, an upper surface of the platform and the side walls of the frame define an upwardly open cavity to receive the material and a lower surface of the platform and the side walls of the frame define a downwardly open cavity within the frame.

In one embodiment, the support means comprises an upwardly facing first major surface formed with a plurality of recesses to receive the material. The recesses are preferably evenly distributed over the first major surface so that the load of the material is evenly distributed over the panel.

In preferred embodiments of the present invention, at least a portion of the material is contained within the confines of the frame.

The panel may be used to provide a ground, wall, ceiling or roof surface of a building or an external ground surface such as a road, driveway or patio. In one embodiment, the frame and the support means form a panel body, wherein the panel body comprises the frame, first and second opposing major surfaces spaced by a depth dimension of the frame, and a plurality of internal walls upstanding in the depth dimension so as to define a plurality of cells within the frame, each cell being open at one of the first and second major surfaces and closed at the other of the first and second major surfaces; optionally wherein the material fills the cells open at the first major surface.

The external or load-bearing surface formed by the material lies in a plane above the plane of the upper edge of the frame. The material may either cover the upper edges of the frame or leave the upper edges of the frame exposed. In this way, a gap may or may not be provided in the external surface of material between adjacent interconnected panels, depending on the required finish.

In one embodiment, the lower edge of the frame is formed with a plurality of cut-outs, for example curved or square cut-outs, providing a discontinuous lower edge for contact with a ground surface in use. The lower edge of the frame may be serrated.

In one embodiment, the panel further comprises a mesh located within the frame to provide additional structural reinforcement to the material. The mesh may be provided below or within the layer of material and may be made of fibre-glass or steel, for example. The open structure of the mesh allows water to permeate therethrough and can therefore be used in combination with a material formed with interstices and a permeable support means to provide a permeable ground panel.

In one embodiment, according the first or second aspect of the present invention, the panel has a thickness within a range of between about 10 mm and about 100 mm, preferably between about 10 mm and about 80 mm, or between about 10 mm and about 60 mm. More preferably, the panel has a thickness within a range of between about 10 mm and about 40 mm. A panel according to the present invention can have a significantly lower thickness relative to known stone, concrete or binder-bound aggregate panels with the same major surface dimensions yet remain durable.

In one embodiment, the connection formations are constructed and arranged so that they can be detachably interengaged in a direction vertical to the plane of the panel.

In one embodiment, the connection formations are configured to engage with connection formations of one or more adjacent panel in use to provide a secure interlocking with the adjacent panel. The connection formations may be arranged to resist displacement of the panel from an adjacent panel in a direction within, and/or out of, a plane of the load bearing surface of the panel. The connection formations may be arranged to resist separation of the panel from an adjacent panel in a direction in he plane ofthe panel but allow separation of the panel from an adjacent panel in a direction orthogonal to the plane of the panel. The connection formations include snap-fit, friction-fit, compression-fit, dovetail, hook-latch or hybrid attachment mechanisms.

In one embodiment, the connection formations comprise one or more female connection formations configured to receive a respective male connection formations on an adjacent panel in use. In one embodiment, the connection formations comprise one or more male connection formations configured to receive a respective female connection formation on an adjacent panel in use.

In one embodiment, the frame comprises two or more sides, one or more of the sides comprising male connection formations, and another of the sides comprising female connection formations.

The permeable or non-permeable material, especially binder-bound aggregate, panel in accordance with the present invention may be used in the construction of, for example, a walkway, recreational surface, patio, terrace, driveway, road surface or balcony. The panel according to the present invention is durable, yet lightweight, is simple and convenient to install by manual handling, and is less prone to movement once installed. Accordingly, a panel according to the present invention comprising binder-bound aggregate, for example, can be used in areas where previously a binderbound aggregate surface was not possible, such as on wooden decking, temporary flooring in marquees, balconies, etc.

In accordance with a third aspect, the present invention provides a covering system, comprising a plurality of panels according to the present invention arranged to be laid side-by-side in a common plane or layer such that each panel is interlocked with two or more adjacent panels in the system. In the covering system, the upper edge of the frame of one or more panels may be exposed so that the load-bearing or external material surface layers of adjacent panels are separated by a gap, and the system may further comprise a filler, such an adhesive or particulate material, for use in filling the gaps. In one embodiument of the third aspect, the covering system is a ground covering system and the panels are arranged to be laid side-by-side on the ground.

In accordance with a fourth aspect, the present invention provides a method for the manufacture of a modular interlocking binder-bound aggregate panel, the method comprising the steps of:

(a) providing a panel body comprising a frame having a lower edge for contact with an underlying surface in use and an upper edge, and connection formations provided on the frame configured to engage with connection formations of one or more adjacent panels in use and to restrict lateral movement; and support means within the frame configured to support material above or over the underlying surface; and

(b) applying the material to the panel body over the support means so that it is contained within the frame supported by the support means and provides an external or load-bearing surface that extends above the plane of the upper edge of the frame.

In one embodiment of the fourth aspect, the material of the panel is binder-bound aggregate and step (b) of the method comprises either mixing aggregate material and binder together before applying the material to the panel body, or first applying aggregate material to the panel body over the support, followed by applying binder over the aggregate material. The method further comprises curing to harden the binder-bound aggregate.

The binder-bound aggregate may be cured by allowing the panel to cure and harden at room temperature and/or by applying suitable heat/infrared to cure and harden the panel.

The panel body serves as a mould for the binder-bound aggregate which simplifies production relative to known methods in which a step of removing the boundaggregate from a mould is required. In one embodiment of the fourth aspect of the present invention, the method further comprises levelling the binder-bound aggregate material prior to curing. The binderbound aggregate may be levelled by applying downward pressure, for example with a hand tool, weighted roller, or compactor, and/or by placing the panel on a vibrator machine.

The binder-bound aggregate may, as a first step, be made level with the upper edge of the frame and cured. As a second step, a further layer of binder-bound aggregate may be applied over the cured or uncured binder-bound aggregate to provide the external surface layer of the panel.

In one embodiment of the fourth aspect of the present invention, binder is applied to or mixed with the aggregate material such that it adheres the individual aggregate particles together whilst maintaining interstitial spaces, thereby permitting water to permeate through the binder-bound aggregate. The viscosity of the binder is such that on application to the aggregate material, it adheres to the aggregate particles and remains within the panel body prior to curing. One advantage of the presence of the panel body is that it keeps the aggregate bound and allows use of less binder and less aggregate material. In addition, by being permeable as described, water can percolate down through the panel to the ground underneath. By use of the panel according to the present invention, other than levelling and possibly some compaction of the ground underneath, there is no need for the construction of a sub-base.

The material supported by the support means is a structural or building material for internal or outdoor use. The material may be a composite material where a binder, such as cement, resin or a polymer, is combined with aggregates. The aggregate material may be any material suitable for carrying out the desired function in the panel. It can be stone, gravel, rubber, glass, marble, granite, basalt, quartz or recycled granular graded material, for example.

It is preferable to limit the upper size of particles so that the passageways within the material are optimized. Preferably, therefore, the aggregate material comprises particles having a size less than 20mm, preferably less than 10mm. Ideally, three size requirements are combined so that the aggregate material preferably comprises particles in the size range of 0.1-20mm. A more preferred size range is about 5-15mm or about l-10mm, and a size range of about 0.1-6mm has been shown to work well in practice. Two particularly preferred types of aggregate are 10mm pea shingle or drive gravel, and 10mm road stone chippings. The depth of the aggregate applied to the panel body/panel base will depend on the specific site requirements (e.g., likely loads to be encountered) and the properties of the aggregate and binder. For example, a depth of between about 10mm to about 50mm above the upper edge of the frame may be suitable to create a finished modular surface.

For a typical path construction, a ground panel (body panel and binder-bound aggregate) may have a depth of between about 20mm and about 70mm or about 60mm or about 50mm. For an aggregate-bound surface layer above the panel body, a depth of between about 10mm and about 30mm would be suitable. The depth of the body panel may be between about 10mm and about 50mm, such as 45mm. Binder-bound aggregate may fill the body panel, for example, cavities or recesses provided therein to a depth of between about 10mm or about 15mm and about 20mm or about 30mm.

In one embodiment of the present invention, the panel body comprises a rigid plastics material. The panel body can be made from recycled or virgin plastic, typically from ABS, or polypropylene, HDPE, LDPE or blends of the same combined with fillers and pigments. The panel body preferably is formed with perforations to allow drainage. In one embodiment, the panel has a dimension of about 400mm by about 600mm (L x W), such as about 500mm by about 500mm, and may have a weight of about 0.5 to about 3 kg, or about 1 to about 2 kg, or about 1.3 to about 1.9 kg

The binder is such that it adheres the aggregate material together to form a cohesive aggregate material which also adheres to the panel body. It is preferred that the binder is inherently flexible and resilient. Further, it is preferable that the binder does not fill the interstitial voids in the aggregate, but only partially fills them so that the cohesive aggregate layer remains permeable. Therefore, the binder will only contact the aggregate particles at certain points, binding the aggregate into a cohesive layer without making the layer rigid and inflexible.

Preferably, the binder is a polymeric binder. The binder is preferably applied to the aggregate material in liquid form, which then cures or otherwise solidifies into an inherently flexible binding material within the aggregate layer. Preferably therefore, the binder is a cured polymeric binder, such as a moisture-cured polymeric, e.g., polyurethane, binder. For example, the binder may be a IK or 2K binder (polyurethane system incorporating HDI, MDI, TDI, natural polyols, epoxy 2k, water-based epoxy, synthetic polyols, acrylic, PUD, AUD, polyaspartic, STPE, MMA, etc.) which adheres the individual or blended aggregate materials together to provide a wearing surface.

The binder should preferably have a viscosity in the range of about 400 to about 6000 centipoise (cps). The viscosity needs to be controlled such that, on application of the binder to the surface, the viscosity is high enough to coat the aggregate and remain in position there, but low enough so that sufficient binder flows down and reaches the support means, at least in some places. As discussed above, it is not critical in the invention that the aggregate is fully bound, it is simply a requirement that the aggregate is sufficiently bound and that the bound aggregate adheres to the panel body such that a cohesive structure results.

The binder can be applied by means of a pump, with a nozzle or wand attached, or poured.

If the binder is a moisture-cured MDI binder, curing generally starts well after the liquid has stopped flowing, at around 30 minutes for example, and fully cures over 24 hours typically. Chemicals could be added to the binder to speed up the start of the process, if required. The amount of binder used is dependent on the depth of aggregate required for a particular application, as well as the intended use of the base and its required strength. A typical application such as a path or light vehicle drive may have a 3 to 4cm deep aggregate. In order to provide a base with greater depth and increased strength (such as may be required in the construction of a road, for example), multiple bases of the present invention may be layered vertically.

Once the panel in accordance with the invention has been constructed, a top layer or surface dressing layer may be added, which will vary depending on the particular use of the finished surface. The surface dressing layer may comprise one or more of the following materials: turf, artificial turf, sand, gravel, aggregate, tarmac, geotextile, composites (e.g. materials including plastics or rubber).

To provide a non-permeable finish, a surface pore filler may be used or a fine grade aggregate blend may be used to reduce interstices.

The panel in accordance with the present invention can be preformed or constructed on site. For construction on site, a panel body is laid on the surface to be tiled and interconnected with one or more adjacent panel body. In the case of a ground panel, an aggregate and binder may then be applied, optionally premixed, to the interconnected or interlocked panel bodies.

The present invention provides a lightweight, simple interlocking modular system; easy to transport and ideal for areas with restricted access. The panel according to the present invention has excellent drainage properties, if required, and allows drainage in two directions. Under normal conditions, water will flow vertically down through the aggregate layer and synthetic panel body/base into the ground underneath. In periods of heavy rain, or if the ground underneath the area of the base becomes saturated water will then move sideways through the aggregate layer and synthetic base until it can percolate down into the ground.

Because of the unified nature of the panel system according to the present invention, in the case of a ground panel, other than levelling and possibly some compaction of the ground underneath, there is no requirement for the construction of a sub-base. For a typical two-dimensional structure such as a path or patio area therefore, the invention provides a significant cost saving in materials, transport and labour costs. Further enhancements possible with the various structures made in accordance with the present invention include filling the binder-bound surface with a pore-filler to reduce porosity, the addition of colour to the surface or to mark out specific areas such as a path, edges, etc. The addition of a photoluminescent material to the surface may be useful to increase the surface visibility in low light or after dark, for example in the case of a golf buggy track. Different grades or colours of surface aggregate may be used to create patterns, company logos within the modular surface as an individual modular surface or group of modular surfaces as required. The mineral aggregate of the panel may comprise recycled rubber and EPDM (ethylene propylene diene monomer) to produce a safety tile.

Additional features and advantages of the present invention are described in, and will be apparent from, the description of the presently preferred embodiments which are set out below with reference to the drawings in which:

BRIEF DESCRIPTION OF THE FIGURES

In the accompanying drawings:

Figure 1 shows a perspective view from above of an embodiment of a panel body component of a panel according to the present invention;

Figure 2 shows a perspective view from below of the panel body of Figure 1;

Figure 3 shows a view of a side view of the panel body of Figure 1 filled with binderbound aggregate material; and

Figure 4 shows an underside view of a section of a panel body according to the present invention with alternative connection formations. DEFINITIONS

The following definitions shall apply throughout the specification and the appended claims.

Within the present specification, the term "binder" is used herein to refer to any resin and/or adhesive system capable of adhering together particulate material, such as stone granules and powder, to form a cohesive slab or panel. Examples of suitable binders include resins, such as epoxy, urethane, acrylic, vinyl ester, and silicone. When the binder is a polymeric material, it may include various additives that affect the cure rate, and the adhesion of the resin to the particulate material. The resin should remain inert once cured.

Unless otherwise stated or indicated, terms such as "front", "rear", "upper", "lower", "upwardly", "downwardly", "side", "horizontal", "vertical", and the like, are used as words of convenience to provide reference points and are not to be construed as limiting terms.

Within the present specification, the term "about" means plus or minus 20%; more preferably plus or minus 10%; even more preferably plus or minus 5%; most preferably plus or minus 2%. In terms of percentage weight, the term means plus or minus 1% ; in terms of size, in mm, plus or minus 1 or 2 mm; and in terms of temperature, plus or minus 10°C.

The singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise.

Within the context of the present specification, the term "comprises" is taken to mean "includes" or "contains", i.e., other integers or features may be present, whereas the term "consists of" is taken to mean "consists exclusively of".

Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Within this specification embodiments are described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described with reference to the drawings. In Figures 1 to 3, a base unit generally in the form of a panel body 10 comprises a frame 12 and a support platform 14 extending the width of the frame 12. The frame has an upper edge 18, and a lower edge 20 for contact with an underlying ground in use. The panel body 10 is generally rectangular, such as square, in plan having a central region in which the support for the binder-bound aggregate is located surrounded by the frame. In alternative embodiments the panel body could be a different shape, for example hexagonal. The panel body 10 is configured to lie flat on the ground in use and support a binder-bound aggregate 16 contained therein.

The support platform 14 is positioned within the frame 12 between the upper 18 and lower 20 edges thereof. It has an upwardly facing surface 22 configured to support binder-bound aggregate material 16. Figure 1 shows the upwardly facing surface 22 of the support platform 14 to be substantially flat but in alternative embodiments the surface may be provided with formations/internal walls projecting/upstanding in a depth dimension of the frame, for example.

The support platform 14 has a downwardly facing surface 24 that forms a downwardly facing cavity with the sides of the frame 12. One or more internal walls 26 (a cutaway part of an internal wall is shown in Figure 2) may be provided that depend from the downwardly facing surface 24 of the platform 14 and have a lower edge 28 arranged to be in contact with the ground. The internal wall(s) 26 further support the platform 14 and binder-bound aggregate 16 load from below. The platform 14 is formed with performations or apertures 30 to allow water to permeate therethrough.

Binder-bound aggregate 16 fills the frame 12 section above the support 14 and forms a layer of binder-bound aggregate 16 above the upper edge 18 of the frame 12 providing an external surface 32 (shown in Figure 3).

The frame 12 is arranged with connection formations 34, 36, to allow connection to one or more adjacent panel of the same type. The connection formations 34, 36, are provided at a plurality of sides/edges of the frame 12 to allow for the joining of a plurality of panels to create a substantially continuous panel system made up of adjoining panels. The connection formations 34, 36, are selectively engageable to allow connection and disconection of adjacent panels.

The connection formations comprise a male connector formation 34 and a female connector formation 36. In the example shown in Figures 1 and 2, a plurality of male connector formations 34 are provided on a first side and a second side of the frame 12. A plurality of female connector formations 36 are provided on a third side and a fourth side of the frame. In alternative embodiments, for example, the frame 12 may only comprise male connector formations and the panel connects to another panel comprising only female connector formations.

The connection formations may be configured to interlock with an adjacent panel. An example of such interlocking formations 38, 40, are shown Figure 4. The connection formations comprise a shaped member 38 configured to engage a correspondingly shaped recess 40 in an adjacent panel to provide an interlocking connection therebetween.

In forming a panel in accordance with the present invention, suitable aggregate granules are mixed with a specific predetermined amount of a suitable resin until the aggregate granules are suitably coated. The mix is then poured into the panel body 10 over the upwardly facing surface 22 of the support platform 14 so that it fills the frame 12. A mould in the form of a rim (not shown) may be provided at the upper edge 18 of the frame 12 to allow for the binder-bound aggregate 16 to form a layer above the upper edge 18 of the frame 12 (Figure 3). The exposed upper surface 32 of the resin-coated aggregate mix within the mould/panel body 10 is then spread and compacted to provide a level upper surface for the finished panel. Alternatively, the panel body 10 may be vibrated to ensure a compact and uniform distribution of the aggregate granules throughout the panel. The resin and aggregate mix is then finally levelled and hand-floated, power-floated or automated machine finished to a specific desired finish, and left to cure and set.

The spacing (mm) of connection formations on the frame of a panel (tile) is determined according to the formula below.

The formula allows tiles of different width and length dimensions to be connected together.

In use for the construction of a ground surface such as a driveway, panels are located onto a firm and level ground surface and adjacent panels are manually interconnected. Building material for the panel may be applied after the frame is in position or a prefabricated panel may be used. The cavity in the underside of the panel allows base material on the ground surface to enter the cavity or series of cavities, to securely fix the panel and prevent slippage. An especially secure fixing is provided where the lower edges of the frame and any internal downwardly depending walls are formed with cut-outs. Panels of the present invention are hardwearing and durable, yet relatively lightweight, and have a desirable overall appearance. The structure of the panel body adds strength to the panel and to the installation as a whole, and facilitates a more secure foundation and fixing of the aggregate panel to the ground and further improves the drainage of surface water. The connection formations provide a secure connection between adjacent panels and restrict lateral movement. Further, the connection formations allows a simple disconnection of panels by merely lifting the side of the panel or the adacent panel rather than the disassembly of the entire panel system. For use as a wall or ceiling covering, the panel may be mounted to a substructure or mounting system, for example, rail and clip systems, bracket systems, adhesive systems, and grid systems.

Although the present invention has been described with respect to preferred embodiments, the present invention should not be limited to these embodiments, and it will be appreciated by those skilled in the art that various modifications may be made without departing from the spirit and scope of the present invention. It is therefore intended that such changes and modifications are covered by the appended claims.

Claims

1. A modular panel, comprising: a frame having a depth comprising a lower edge for contact with an underlying surface in use and an upper edge; support means within the frame configured to support material above the lower edge; and connection formations provided on the frame configured to engage with connection formations of one or more adjacent panels in use and to restrict lateral movement.

2. The panel according to claim 1, further comprising: material supported by the support means within the frame and providing an external or load bearing surface lying in a plane above the plane of the upper edge of the frame.

3. The panel according to claim 1 or claim 2, wherein the support means is provided with one or more apertures or perforations to allow water to permeate therethrough.

4. The panel according to any one of the preceding claims, wherein the support means comprises an upwardly facing first major surface formed with a plurality of recesses to receive material for an external or load bearing surface.

5. The panel according to any one of the preceding claims, wherein the frame and the support means form a panel body for the panel, the panel body comprising a frame having a peripheral edge, first and second opposing major surfaces spaced by a depth dimension of the frame, and the support means is in the form of a plurality of upstanding internal walls upstanding in the depth dimension so as to define a plurality of cells within the frame, each cell being open at one of the first and second major surfaces and closed at the other of the first and second major surfaces; and wherein the connection formations are provided at the peripheral edge.

6. The panel according to claim 5, wherein material, such as a binder bound aggregate, fills the cells open at the first major surface and forms an external or load bearing surface layer above the support means.

7. The panel according to any one of the preceding claims, wherein the lower edge of the frame is formed with a plurality of cut-outs providing a discontinuous lower edge for contact with a ground surface in use.

8. The panel according to any one of the preceding claims, wherein the material is formed with interstices to allow water to permeate therethrough.

9. The panel according to any one of the preceding claims, wherein the panel has a thickness within a range of between about 10mm and about 40mm.

10. The panel according to any one of the preceding claims, where the connection formations comprise one or more female connection formations configured to receive a respective male connection formation on an adjacent panel in use.

11. The panel according to any one of the preceding claims, configured to engage with connection formations of one or more adjacent panel in use to resist separation of the panel from an adjacent panel in a direction within a plane of the upper or lower edges of the panel.

12. The panel according to any one of the preceding claims, for use in the construction of a walkway, recreational surface, patio, terrace, driveway, road surface or balcony.

13. A covering system, comprising a plurality of panels according to any one of the preceding claims, arranged to be laid side-by-side in a common plane such that each panel is interlocked with two or more adjacent panels in the system.

14. A covering system according to claim 13, wherein the covering is a walkway, recreational surface, patio, terrace, driveway, road surface or balcony.

15. A method for the manufacture of a modular binder-bound aggregate panel, the method comprising the steps of:

(a) providing a panel body comprising a frame having a lower edge for contact with an underlying surface in use and an upper edge, and connection formations provided on the frame configured to engage with connection formations of one or more adjacent panels in use and to restrict lateral movement; and support means within the frame configured to support material above the underlying surface; and either

(bl) mixing aggregate material and binder together, and applying the binder-bound aggregate material to the panel body over the support means so that it is contained within the frame supported by the support means and provides an external or load-bearing surface that lies in a plane above the plane of the upper edge of the frame; or

(b2) first applying aggregate material to the panel body over the support means so that it is contained within the frame supported by the support means and provides an external or load-bearing surface that lies in a plane above the plane of the upper edge of the frame, followed by applying binder over the aggregate material; and

(c) curing to harden the binder-bound aggregate.