GB2169327A - Paving assembly - Google Patents

Abstract

A paving assembly incorporates slab-like elements 10 connected together by flexible elongate connection means 11, 12 The assembly may be made by moulding the slab-like elements 10 in individual closely packed moulds with slotted walls to take the elongate connection elements 11 or moulding in a single mould to produce an array in which the slab-like elements 10 are integrally connected by thin frangible webs 16 of the moulded material which are cracked apart after manufacture and before use. <IMAGE>

Description

SPECIFICATION Paving This invention relates to paving.

It was specifically designed for "do it yourself" use for relatively small scale paving jobs, for example garden paths, patios and drive ways. However the principles of the invention could be applied to commercial paving.

At present, there is no satisfactory "do it yourself" paving kit available. It is a relatively skilled job to lay commecial paving which comes in either of two basic forms.

Firstly, there are the large paving slabs, typically between 0.3 and 1 metre in length and breadth and 30 to 70 mm thick, made of concrete and laid on a base of compacted and levelled sand. These large slabs are very heavy to lift and it is a skilful operation to provide the necessary levelled compacted base on which the slabs can be laid. Inadequate support of the slabs will lead to their rocking and the paving will rapidly become more and more uneven. The slabs also have an intrinsic disadvantage in that, if not extremely well supported, they are prone to crack under heavy weights for example if a slabbed area is used for parking cars. This is because the shear strength of concrete is relatively low.

A second form of commercial paving is even more difficult to lay since it consists of small blocks or "setts" the upper surfaces of which have to be maintained level. This type of paving includes traditional cobblestones, brick paving and custom made small concrete setts which may be shaped to interlock in for example a herringbone pattern.

Because of the small size of these setts, it is difficult to achieve a level upper surface.

However, cracking of the setts under load is less of a problem than with the large area paving slabs previously referred to.

It is an object of the present invention to provide a paving which can be laid by a householder with minimum skill and which has good durability under loading.

According to the invention there is provided a paving comprising a unitary assembly of a plurality of small rigid slab-like elements secured together in a closepacked array as hereinafter defined by flexible elongate connection means.

The unitary assembly may be manufactured integrally in one piece with the slab-like elements connected by frangible webs in addition to said flexible elongate connection means, whereby breaking of the frangible webs leaves the assembly secured together solely by said flexible elongate connection means.

A close-packed array is one in which a plurality of elements (which may be of the same or of different shapes) are arranged edge to edge without substantial spaces between the elements. In the present context however, the elements may not abut against each other but may have small intervening gaps to permit some relative movement of the elements to take up unevenness or sinkage of the substrate on which they are laid. These gaps are small in relation to the thickness of the slablike elements. The expression "close packed array" should therefore be taken in this context in the present description. The slab-like elements may have ribs or lugs projecting at spaced positions on their edges to abut each other and act as spacers for the elements, leaving small intervening gaps.

The slab-like elements may be secured together in a close packed array in which the gaps between adjacent edges of the elements define a plurality of straight flexure lines extending throughout the assembly.

The slab-like elements may be generally rectangular or triangular. They may be of a length and breadth lying in the range 50 to 300 mm and may have a thickness lying in the range between 10 and 120 mm.

The slab-like elements may be made of a cementitious material such as cement mortar, concrete, fibre reinforced cement for example grc (glass fibre reinforced cement) and the material may include additives for example polymers, pozzolanic materials, colouring or surface modifying materials such as terrazzo.

A preferred material is a dense compacted concrete including sand, cement and small aggregate.

The slab-like elements could be of naturally occurring materials such as slate or stone or alternatively fired brick or ceramic materials could be used.

The elongate connection means may comprise monofilaments or tapes, metal wire, natural or synthetic fibre yarns, or flexible netting or fabric of metal, plastics or other material.

The invention also provides a method of making a paving comprising taking a mould having a plurality of close-packed mould cavities, introducing flexible elongate connection means into the mould and pouring settable material into the mould so that, on curing, a plurality of slab-like elements are formed, connected by said flexible elongate connection means.

The method may include a further step of breaking frangible webs of moulded material between said slab-like elements.

An alternative method of making a paving is provided, comprising taking a mould having one or more mould cavities, introducing at least one anchor means into the or each cavity, pouring a settable material into the mould so as to form, on curing, one or more slablike elements each having at least one anchor means moulded therein, the method including a further step of securing flexible elongate connection means to said anchor means to form a close packed array of slab-like elements.

The settable material may be compacted after pouring or being placed in the mould, and before curing.

The connection means need not be permanently durable in use since they are primarily an aid to laying the pavement but they should not be harmful to the material of the slab-like elements if the connection means deteriorate in use, for example they should not cause splitting or cracking.

One embodiment of the invention will now be described in more detail by way of example only with reference to the accompanying drawings in which; FIGURE 1 is a plan view of a paving assembly, FIGURE 2 is a side elevational view of the assembly, FIGURE 3 is an end elevational view of the assembly.

FIGURE 4 illustrates an alternative form of paving in side elevation, partly sectioned.

FIGURE 5 shows a further alternative form of paving in side elevation.

FIGURE 6 illustrates a packaging method.

Referring to Figures 1 to 3 of the drawings, a paving assembly comprises a plurality, in this case nine, generally rectangular slab-like elements 10, each of rectangular form in plan view and having sides of 100 mm and 200 mm in length. The nine slab-like elements 10 are disposed in three rows of three elements each and are connected by connection means 11 in the form of strands of metal wire.

Each siab-like element 10 has an upper face 12, a lower face 13 and side edges 14 which taper slightly towards the upper face 12. To manufacture the elements, a suitably shaped mould is used with the upper face 12 being cast against the base of the mould and the tapering side edges providing a suitable "draw angle" for removing the cast block from the mould.

To produce the assembly shown in Figures 1 to 3 of the drawings, a set of nine single cavity moulds is provided with small intervening gaps between adjacent moulds. The walls of the moulds are provided with slots in their upper edges, so that the connection means 11 in the form of loops of metal wire can be positioned in the moulds within the bulk of the material to be cast.

Although not shown in the drawings, small ribs or lugs may be formed projecting from the slab-like elements at their edges to define spacers which will pre-determine the separation of the slab-like elements. These ribs or lugs will not co-incide in position with the connection elements.

The elements can be cast in two stages forming firstly the upper face 12 and part of the side walls, and then adding the connection elements before casting the second layer forming the lower surface 13 of the elements as considered in use. However, if the concrete material is of a very suitable consistency, the casting can take place in a single stage with the wire loops being pressed into the material which will then close over the top to embed the connection means in the concrete.

It is preferred that, if an aggregate is used, this should be of relatively small size so as not to hinder the embedding of the connection means.

Since the slab-like elements are intended to support substantial weight, it is preferred that the mouldable material of which they are formed is compacted for maximum strength.

This can either be done by exerting pressure on the material while it is in the moulds before setting or by the use of vibration to compact the material while it is still in a flowable state. Any generally known form of additive can be used in the cementitious mouldable material, for example plasticizers, setting agents, fibres of cement compatible types such as zirconium glass fibre, surface modifying materials such as terrazzo, pozzolanic materials, colouring or polymers.

It is preferred that the connection elements are in the form of galvanised steel wire. However plastics mono-filaments or tape, natural or synthetic yarns and other materials of some flexibility are also suitable.

The slab-like elements 10 need not be moulded in single cavity moulds as described above. A large mould having a number of mould cavities disposed in a close packed array can be used to make a whole paving assembly simultaneously. The mould cavities may be partially filled to produce individual slab-like elements but, in the products shown in Figure 4 of the drawings, the moulded material has been allowed to completely cover the mould so that the slab-like elements 10 are linked in an array 15 by frangible webs 16 of the moulded material. The elongate connection means 11 are in the form of woven plastics tapes which are embedded in the moulding material above the level of the individual mould cavities and hence extend through the frangible webs 16.

After the assembly 15 has been cured, the individual slab-like elements 10 are cracked apart by breaking the frangible webs 16, leaving the only connection through the flexible connection element 11.

In use, the array of slab-like elements can be picked up and handled as a single unit but, because of the slightly flexible connection between the adjacent slab-like elements, it is not necessary accurately to level the substrate. A paving can be laid by clearing an area of ground, adding a layer of roughly compacted sand and then laying the assemblies as shown in the drawings side by side with or without intervening gaps. The paving is then bedded down into the sand and, because each ele ment is of relatively small size and is flexibly connected to the adjacent elements, any small irregularities in the substrate are taken care of by relative tilting of the elements.

This is in contrast to the laying of a single slab where the substrate must be accurately levelled and strongly compacted otherwise rocking and subsequent cracking of the slab is to be expected, particularly under loading from for example a car parked on the paving.

It will be appreciated that, in contrast to laying traditional commercially available setts by hand, a much larger area of ground can be covered more rapidly using the assembly of the present invention and the skill required to do so is greatly reduced since only the assemblies, rather than the individual slab-like elements, have to be positioned correctly.

It is also possible to lay the paving without using a sand substrate provided that a fairly flat and stable substrate is available. So for example in some circumstances, it may be possible to lay the array directly onto a cleared area of soil or an existing cinder path.

Using a sand substrate the invention can also readily be used to improve the appearance and durability of an existing cracked or damaged concrete or tarmacadam area.

Naturally, the assemblies shown in the drawings may need to be cut down by the removal of one or more slab-like elements to fit into the proposed limits of a paved area.

This can readily be done by cutting through the connection elements using conventional wire cutters or snips. For an irregularly shaped path, the edges can be made good using cement mortar or part elements. It is envisaged that the generally rectangular shape of the elements 10 shown in the drawings is likely to prove the most suitable in use and that most shapes of paved area can be covered using the assembly as shown or cut down by removal of some elements, possibly with the addition of some triangular loose slab-like elements equivalent to one of the elements 10 divided corner to corner.

However, it is not necessary to form the slab-like elements as rectangles. They could be triangular or of other shapes provided that they can be disposed in a close packed array as defined. It is preferred that the gaps between the adjacent elements should form straight lines of flexure across the assembly but this is not essential. It is also not essen tial that all the slab-like elements in an assembly should be of the same size and shape.

Although the method of making the paving has been described in relation to the use of settable cement base materials, natural stone or slate could be used with suitable flexible connection means. These connection means need not penetrate into the individual slab-like elements but could be secured to them for example by adhesive. Similarly, an assembly could be made using fired materials such as bricks or ceramic tiles.

Figure 5 of the drawings shows a paving assembly in which the flexible connection element 11 is in the form of a woven mesh backing or of a suitable tape or wire, secured externally to individual slab-like elements 10 to attach them together into a close packed array.

Since the connection between adjacent slablike elements is flexible, it will be appreciated that this might pose handling problems between the stage of manufacture and the point of sale, although it becomes an advantage when the product is in use. In order to permit of mechanical handling and safe stacking of the products, it is envisaged that each paving assembly would be held in a rigid condition until required for use by the packaging means shown in Figure 6. Plastics or metal banding tapes 17 is secured round the edges of the array to hold the otherwise flexible assembly together. Additionally or as an alternative, or in addition the paving assembly can be encapsulated in plastics wrapping.

Claims (23)

1. A paving comprising a unitary assembly of a plurality of small rigid slab-like elements secured together in a close packed array (as defined) by flexible elongate connection means.

2. A paving according to Claim 1 wherein the unitary assembly is manufactured integrally in one piece with the slab-like elements connected by frangible webs in addition to said flexible elongate connection means, whereby breaking of the frangible webs leaves the assembly secured together solely by said flexible elongate connection means.

3. A paving according to Claim 1 or Claim 2 whereinthe slab-like elements are secured together in a close packed array in which the gaps between adjacent edges of the elements define a plurality of straight flexure lines extending throughout the assembly.

4. A paving according to Claim 3 wherein the slab-like elements are generally rectangular.

5. A paving according to Claim 3 wherein the slab-like elements are generally triangular.

6. A paving according to any preceding claim wherein the slab-like elements have a length and breadth lying in the range 50 to 300 mm.

7. A paving according to any preceding claim wherein the slab-like elements have a thickness lying in the range between 10 and 120 mm.

8. A paving according to any preceding claim wherein the slab-like elements are made of a cementitious material such as cement mortar, concrete or glass fibre reinforced cement.

9. A paving according to Claim 8 wherein the cementitious material includes additives selected from the following; polymers, pozzolanic materials, colouring, surface modifying materials such as terrrazzo

10. A paving according to Claim 8 or Claim 9 made of dense compacted cement concrete including sand, cement and small aggregate.

11. A paving according to any one of Claims 1 to 7 wherein the slab-like elements are of natural material such as slate or stone.

12. A paving according to any one of Claims 1 to 7 wherein the slab-like elements are of fired brick or ceramic material.

13. A paving according to any preceding claim wherein the elongate connection means comprises mono-filaments or tapes.

14. A paving according to any one of Claims 1 to 12 wherein the elongate connection means comprises metal wire.

15. A paving according to any one of Claims 1 to 12 wherein the elongate connection means comprises a natural or synthetic fibre yarn.

16. A paving according to any one of Claims 1 to 12 wherein the elongate connection means comprises a flexible netting or fabric.

17. A method of making a paving according to Claim 1 comprising the steps of taking a mould having a plurality of close packed mould cavities, introducing flexible elongate connection means into the mould and pouring or placing settable material into the mould so that, on curing, a plurality of slab-like elements are formed connected by said flexible elongate connection means.

18. A method according to Claim 17 including a further step of breaking frangible webs of moulded material between said slab-like elements.

19. A method of making a paving according to Claim 1 comprising taking a mould having one or more mould cavities, introducing at least one anchor means into the or each cavity, pouring a settable material into the mould so as to form, on curing, one or more slablike elements each having at least one anchor means moulded therein, the method including a further step of securing flexible elongate connection means to said anchor means to form a close packed array of slab-like elements.

20. A method according to any one of Claims 17 to 19 wherein the settable material is compacted after pouring or placing in the mould and before curing.

21. A paving substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.

22. A paving substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings.

23. A paving substantially as hereinbefore described with reference to and as illustrated in Figure 5 of the accompanying drawings.