GB2484385A

GB2484385A - Tyre bale and concrete block

Info

Publication number: GB2484385A
Application number: GB201116996A
Authority: GB
Inventors: Patrick Doherty
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-10-04
Filing date: 2011-10-03
Publication date: 2012-04-11
Also published as: GB201116996D0; GB201016588D0

Abstract

There is described a method of making constructional units from tires. The method uses a number of tyres which are severed into a tread portion and sidewall portions. The sidewall portions are formed into an annular stack having a central aperture into which the tread portions are placed to form a substantially solid cylindrical block of tyre parts. The block is then encased in concrete to form a constructional unit. Also described is a constructional unit made using the method, and a constructional unit comprising at least one block of tyre material encased in concrete, the block (or each block) comprising an annular stack of severed side wall portions filled with severed tread portions. The tyre block may be placed in a bag before encasing in concrete and haggles of the bag may provide lifting loops for the cast block. Waste tyre rubber can be recycled in this way and the concrete prevents leaching.

Description

Constructional Units including Used Tyres, and Method of Making This invention relates to recycling used tyres into constructional units.

The term "constructional unit" is used herein in two senses. Firstly, a discrete unit capable of being lifted into a desired position (e.g., by crane or excavator), typically to be placed in proximity to other similar units.

Secondly, a monolithic unit constructed in situ and not intended to be lifted.

Modern society produces vast numbers of used tyres, which present a serious disposal problem. A number of routes have been used or proposed, but each of these presents problems.

Tyres can be chipped or shredded to recover steel reinforcement and provide a rubber material for re-use. However, the equipment required to do this is expensive, and there is a limited market for the recovered rubber.

Tyres can be burnt as a fuel substitute in energy-intensive industries, for example in plants producing gypsum plasterboard (drywall). Again, the necessary plant is expensive and it is necessary to use sophisticated control and flue gas treatment equipment to meet environmental standards.

It has also been proposed to de-vulcanise tyre rubber to provide a feedstuff for rubber manufacture, but this also requires shredding and is not economically attractive.

A number of proposals have been made to use old tyres as the basis for constructional items, for example by stacking tyres in various formations and filling them with concrete, or linking tyres with chains or the like to form a mat for stabilising soil. Although there has been limited use of such concepts, the number of tyres used in a given construction is limited.

It is also known to compress tyres into a bale which is then bound with galvanised wire or the like. The British Standards Institution has published PAS 108 "Specification for the production of tyre bales for use in construction" which defines a reference bale which is enclosed within a rectangular shape having nominal dimensions 1.33 m x 1.55 m x 0.83 m and mass of 810 kg. Such bales have been used for example in bottoming material for roads, especially on soft ground.

However, PAS 108 bales present a number of problems. The bales are significantly non-uniform in shape, size and mass. They cannot be stacked one on the other in a reliably stable manner. Site operatives tend to lift the bales by engaging the binding wires with crane hooks or lifting forks, which frequently causes the wires to break, leading to disintegration of the bale.

Moreover PAS 108 bales, and other uses in which uncovered tyres are buried or immersed, are not acceptable to some environmental regulators (for example the Scottish Environmental Protection Agency) because of fears that leaching may lead to contamination.

There is therefore a need for a process and product which make use of used tyres in a way which is economical, simple, environmentally friendly, and disposes of the maximum number of tyres per product. The present invention seeks to address this need.

According to one aspect of the present invention there is provided a method of making constructional units from tyres, comprising the steps of: -providing a number of tyres; -severing each tyre into a tread portion and a pair of sidewall portions; -forming at least one annular stack of side wall portions defining a central aperture; -placing tread portions within the central aperture to form a substantially solid cylindrical block of tyre parts; and -encasing one or more of said blocks in concrete to form a constructional unit.

A single block may be encased to form a substantially cubic unit, which may for example be approximately 1.4 m3 containing 65 tyres.

Alternatively, two or more blocks may be arranged in a line and encased to form a rectangular unit; or four blocks may be arranged in a square formation and encased to form a rectangular unit which may for example be approximately 1400 mm x 1400 mm x 1 meter height containing 160 tyres.

Preferably the tyre material is bounded on all sides by at least 30 mm concrete, preferably at least 70 mm.

Where multiple blocks are used, the blocks may be placed in contact with each other before the concrete is cast, or the blocks may be spaced apart to leave spaces in which concrete is cast to form ribs.

Preferably, each tread portion is cut transversely at least once to form one or more strips before being placed in said central aperture.

The block (or each block) may be formed by stacking sidewall portions within a bag and filling the central aperture with tread portions, the bag then being placed within a form into which concrete is cast.

In another embodiment a number of said blocks are placed in a layer at a point of use and concrete is poured around them in situ. In this case, each block may suitably comprise a single tyre containing a number of severed tread portions and severed side wall portions.

From another aspect the invention provides a constructional unit comprising at least one block of tyre material encased in concrete, the block (or each block) comprising an annular stack of severed side wall portions filled with severed tread portions.

The constructional unit may comprise a single block of tyre material forming a rectangular, preferably cubic, unit.

Alternatively, the constructional unit may comprise two or more blocks of tyre material and form a rectangular unit, in which case the blocks of tyre material may be spaced apart to provide concrete ribs between them.

The constructional unit may include formations to facilitate interfitting with other constructional units.

The constructional unit preferably includes means for engagement by lifting apparatus, such as apertures in the concrete of the unit, or lifting loops cast into the concrete of the unit. Where such lifting loops are used, they preferably form part of a big bag within which the block of tyre material is located.

In a further aspect the invention provides an article for use in making a constructional unit, comprising a block of tyre material comprising an annular stack of severed side wall portions filled with severed tread portions.

The side wall portions are preferably located within a complete tyre, and means (such as metal strapping) may be provided for binding the article together for ease of handling and transport.

Embodiments of the invention will now be described, by way of example only, with reference to the drawings, in which: Fig. I is a perspective view of a tyre; Fig. 2 is a similar view showing the tyre severed into three parts; Figs. 3a and 3b are side and plan views of a stack of tyre parts; Figs. 4, 5 and 6 are schematic perspective views illustrating various forms of constructional units incorporating stacks of tyre parts; Figs. 7a and 7b are plan views illustrating alternative arrangements of the unit shown in Fig. 5; Figs. 8a and 8b are side and plan views illustrating one method of making a constructional unit of the type shown in Fig. 4; Fig. 9a is a side view illustrating one method of making a constructional unit of the type shown in Fig. 5; Fig. 9b is a plan view of the resulting constructional unit; Fig. 10 is a plan view of a further embodiment; Fig. 11 is a sectional side view corresponding to Fig. 10; and Fig. 12 illustrates a tyre stack used in Figs. 10 and 11 in more detail.

Referring to Fig. 1, a tyre has a tread 10 and side walls 12. The first step of the present process consists of severing the tyre along the junctions of the tread 10 and side walls 12 to form two side wall portions 14 and a tread portion 16. The tread portion 16 is also cut across at 18 to form a flexible strip. Alternatively, the tread portion 16 could be cut across in several places to form shorter strips, or could be left in the form of a loop although this is less convenient for subsequent use.

The severing of the tyres can be carried out in any suitable way. This can be done manually, for example by using a knife to cut near the junction of each side wall and the tread, and a knife or saw to cut across the tread.

Alternatively, mechanical sidewall removal and tread cutter machines suitable for these operations are commercially available and are currently used as a preliminary to shredding or baling.

The resulting portions from a number of tyres are then formed into stacks, one of which is seen in Fig. 3 and generally designated 20. The stack 20 consists of a number of side wall portions 14 stacked one on the other in an annular shape with a central aperture which is filled as closely as possible with tread portions 16. The latter can be rolled into a bundle and inserted into the central aperture, if necessary two or more bundles high.

In this way a relatively dense monolithic block of recycled tyre material is obtained. This allows the eventual constructional unit to consist of a high proportion of recycled tyre material and a relatively low quantity of concrete, thus maximising the number of tyres disposed of and minimising cost.

The next stage in the process is to place one or more stacks 20 in a form into which is poured concrete to obtain a constructional unit. The form can be a simple open-topped box. A bottom layer of concrete can be poured first, followed by placing the stack(s) 20, followed by filling the rest of the form. The relative densities of the concrete and the stack 20 are such that the stack 20 can simply rest on the bottom layer.

Since the stack 20 is essentially a solid body, the concrete largely forms a skin around the stack(s). It is believed that a concrete skin providing a minimum thickness of about 75 mm is particularly suitable for general constructional use.

Figs. 3, 4 and 5 show some possible arrangements.

In Fig. 4, a single stack 20 is encased in concrete 22 to form a cube block.

This arrangement is particularly suitable for disposing of truck tyres which can conveniently be used to produce a cube of 1.2 m per side weighing about 2.5 tonne.

Fig. 5 shows a block with four stacks 20 in a 2x2 arrangement. This is particularly suitable for disposing of smaller tyres to produce a block 1.4 m x 1.4 m; if a height of 1 meter is used, the resulting block weighs about 3 ton ne.

Other arrangements are possible depending on the desired end use. For example, Fig. 6 shows four stacks 20 in a linear array.

Where a number of stacks are used in a single constructional unit, the stacks 20 may be arranged to touch tangentially, as seen in Fig. 7a. It is preferred, however, to leave spaces between the stacks 20, as seen in Fig. 7b, to form ribs 24. This improves the strength and stability of the constructional unit. The ribs 24 may suitably be between 25 mm and 75 mm thick at their narrowest point.

Fig. 8 shows one method of making a constructional unit, which is particularly useful with truck tyres. The side wall portions 14 are stacked inside a conventional flexible intermediate bulk container or "big bag" 26 of the type conventionally used for delivering sand and other bulk materials.

The central aperture is then filled with rolled tread portions 16. A timber form or mould 28 in the form of an open-topped box is used. A layer of concrete 30, which is suitably 75 mm thick, is placed in the bottom of the form 28. The big bag 26 and its contents are then positioned in the form 28 on top of the concrete layer 30. This can be done easily by engaging the lifting loops 32 of the big bag 26 with a fork lift or telehandler. The form 28 is dimensioned such that when the big bag 26 is placed on the base concrete layer 30 a space of 75 mm minimum is available at each side, and a similar space between the top of the big bag 26 and the top of the form 28. The lifting loops 32 can be arranged to extend above the top of the form 28, if necessary by threading supports through them. Concrete is then poured to fill the remainder of the form 28 as seen at 34.

Consolidation of the concrete can be assisted by use of a vibrating poker, or by placing the form on a vibratory table.

The resulting constructional unit has the lifting loops 32 partially extending from the top. The loops 32 can be used to handle the unit for transport and placement. Once the block is in its final position, the loops can be cut off with a sharp knife, if necessary.

A constructional unit of this type can typically contain up to 3 truck and 60 car or van tyres.

Fig. 9 shows another process suitable for car tyres. In this case a form or mould is used which comprises a metal base plate 36 and removable sides 38. Four metal rods 40 are screwed into threaded holes in the base plate 36, and plastic tubes 42 are slid over the rods 40. A base layer 30 of concrete 75 mm thick is poured. Four tyre stacks 20 are placed on the base layer; the tyre stacks 20 may for example be formed outside the form 34 and held together for ease of handling by binding with wire or rope.

More concrete is then poured to fill the form to give a minimum thickness of 75 mm around the tyre stacks 20. Once the concrete has sufficiently set, the rods 40 and tubes 42 are removed to leave cylindrical through holes 44 in the finished constructional unit 46. The through holes 44 may be used for engagement by lifting devices, and may also be used as locations for dowels for locking superposed blocks together.

A constructional unit of this type can typically contain up to 160 tyres.

The above embodiments relate to forming constructional units in the first sense given above. The following embodiment relates to forming a constructional unit in situ.

Referring to Figs. 10 and 11 a constructional unit, which may for example form a base or foundation for a building, is constructed as follows. A shuttering is set up in a suitable excavation, the shuttering in this example being a rectangle of planks 48 supported by posts 50. A concrete base layer 52 suitably about 25 mm thick is poured; this layer may not be necessary if the underlying surface is sufficiently solid. Tyre stacks 54 are then placed on top of the base layer 52, preferably so that the tyre stacks 54 are touching. The shuttering is then filled with concrete 56. The thickness of concrete above the tyre stacks 54 is suitably about 100 mm.

The height of the stack as arranged in Fig. 11 is suitably around 200 mm.

Thus the total depth of the constructional unit as illustrated in Fig. 11 is the combined thickness of the base layer, the height of the tyre stacks, and the thickness of the concrete above the tyre stacks making, in this embodiment, a total depth of approximately 325 mm. Clearly this depth can be varied depending in the thickness of the tyre stacks, and the desired structural strength of the constructional unit.

Fig. 12 shows a suitable tyre stack 54 for this purpose. This consists of a complete tyre 58 containing severed side wall portions 16 stacked to form a central aperture in which are positioned rolled-up tread portions 14.

Typically, the stack will contain one complete tyre and severed portions of ten tyres, making eleven tyres per stack. Such a stack may be formed off-site and transported to the point of use, and in this case the stack may be bound together with metal strapping or the like.

Modifications may be made to the above embodiments within the scope of the present invention. For example, the constructional units may be cast with formations such as lips and recesses for interfitting with other units.

Shapes other than rectangular may be useful in some cases, for example a triangular unit containing three tyre stacks, or a cross-shaped unit containing five.

The constructional units of the present invention have numerous uses such as retaining walls, roadways, and coastal armour.

The term "concrete" is used herein to mean any suitable settable cementitious material. Typically a standard Portland cement:sand:aggregate mix will be used with a strength of M25 to M40.

However, other cementitious materials may be used where suitable, such as a cement:sand mortar, or a material incorporating cement with one or more of fly ash, slag, clinker or broken rubble. Cements other than Portland may be used, for example pozzolanic. Concrete containing reinforcing fibres may also be used.

The invention thus provides a method of recycling tyres which is simple, cheap, and disposes of a large number of tyres in a single unit. The resulting constructional units are capable of a wide variety of useful applications. The tyre material is completely encased in concrete which eliminates or greatly reduces leaching, and this is enhanced where the tyre material is contained in a bag.

Claims

CLAIMS1. A method of making constructional units from tyres, comprising the steps of: -providing anumberoftyres; -severing each tyre into a tread portion and a pair of sidewall portions; -forming at least one annular stack of side wall portions defining a central aperture; -placing tread portions within the central aperture to form a substantially solid cylindrical block of tyre parts; and -encasing one or more of said blocks in concrete to form a constructional unit.
2. The method of claim 1, in which a single block is encased to form a substantially cubic unit.
3. The method of claim 2, in which the unit is approximately 1.4 m3 containing 65 tyres.
4. The method of claim 1, in which two or more blocks are arranged in a line and encased to form a rectangular unit.
5. The method of claim 1, in which four blocks are arranged in a square formation and encased to form a rectangular unit.
6. The method of claim 5, in which the unit is approximately 1400 mm x 1400 mm x 1 meter high containing 160 tyres.
7. The method of any preceding claim, in which the tyre material is bounded on all sides by at least 30 mm concrete, preferably at least 70 mm.
8. The method of any of claims 4 to 6, in which the blocks are placed in contact with each other before the concrete is cast.
9. The method of any of claims 4 to 6, in which the blocks are spaced apart to leave spaces in which concrete is cast to form ribs.
10. The method of any preceding claim, in which each tread portion is cut transversely at least once to form one or more strips before being placed in said central aperture.
11. The method of any preceding claim, in which the block (or each block) is formed by stacking sidewall portions within a bag and filling the central aperture with tread portions, the bag then being placed within a form into which concrete is cast.
12. The method of claim 1, in which a number of said blocks are placed in a layer at a point of use and concrete is poured around them in situ.
13. The method of claim 12, in which each block comprises a single tyre containing a number of severed tread portions and severed side wall portions.
14. A constructional unit comprising at least one block of tyre material encased in concrete, the block (or each block) comprising an annular stack of severed side wall portions filled with severed tread portions.
15. A constructional unit as claimed in claim 14, comprising a single block of tyre material and forming a rectangular, preferably cubic, unit.
16. A constructional unit as claimed in claim 14, comprising two or more blocks of tyre material and forming a rectangular unit.
17. A constructional unit according to claim 16, in which the blocks of tyre material are spaced apart to provide concrete ribs between them.
18. A constructional unit according to any of claims 14 to 17, including formations to facilitate interfitting with other constructional units.
19. A constructional unit according to any of claims 14 to 18, including means for engagement by lifting apparatus.
20. A constructional unit according to claim 19, in which said means comprises apertures in the concrete of the unit.
21. A constructional unit according to claim 19, in which said means comprises lifting loops cast into the concrete of the unit.
22. A constructional unit according to claim 21, in which said lifting loops form part of a big bag within which the block of tyre material is located.
23. A constructional unit made according to the method of any of claims Ito 13.
24. An article for use in making a constructional unit, comprising a block of tyre material comprising an annular stack of severed side wall portions filled with severed tread portions.
25. An article according to claim 24, in which the side wall portions are located within a complete tyre.
26. An article according to claim 24 or claim 25, including means binding the article together for ease of handling and transport.