GB2600448A

GB2600448A - Concrete material

Info

Publication number: GB2600448A
Application number: GB2017201.1A
Authority: GB
Inventors: Mcgirl James
Original assignee: Utilities & Civils Solutions Ltd
Current assignee: Utilities & Civils Solutions Ltd
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2022-05-04
Anticipated expiration: 2040-10-29
Also published as: GB202017201D0; GB2600448B

Abstract

A concrete material comprising a first aggregate 100 comprising mineral elements 110 and a second aggregate 200 comprising elements 210 of a material comprising a rubber polymer. The mode diameter of the elements of the first aggregate is the same as the mode diameter of the elements of the second aggregate. The elements of the second aggregate may be pieces of vehicle tyres and may further comprise metal sub-elements. The concrete material may be manufactured by providing the first aggregate comprising mineral elements, dividing vehicle tyres 220 into smaller elements to form the second aggregate, followed by combining elements of the first aggregate and second aggregate which have the same mode diameter.

Description

CONCRETE MATERIAL

The present disclosure relates to a concrete material. Background Concrete is an effective and resilient construction material. Aggregate material, which is an important component of concrete, is a broad category of particulate mineral material, including sand and crushed stone. Aggregates are a finite resource and are among the most mined materials in the world. These are capital-intensive operations, utilizing large earth-moving equipment, belt conveyors, and machines designed for crushing and separating various sizes of aggregate. Mining and transporting aggregates contribute to the high carbon footprint of concrete.

Up to three billion vehicle tyres are produced around the world every year, generating close to three billion kilograms of fibre when recycled. Disposal of discarded vehicle tyres is therefore a serious environmental concern. There are uses for the rubber recycled from tyres, such as asphalt, surfaces for playgrounds, and shoes, but a significant proportion of scrap tyres will be burnt as fuel or go to a landfill, which can lead to soil and water contamination.

It is known in the art to add ground rubber (i.e. rubber crumb) that is recycled from vehicle tyres to concrete, sometimes referred to as "Rubbercrete".

However, vehicle tyres are a complex mix of materials, for example natural and synthetic rubber, fibre, and metal. This makes vehicle tyres difficult to process for any kind of recycling. To produce the ground rubber for Rubbercrete, after the tyres are shredded, magnets and screens separate the metal and fibre from the rubber. The metal and fibre are recycled separately to the rubber. Some rubber is generally wasted during the process, so multi-stage separation is required to maximise separation with a minimal loss of rubber. Rubber may then be treated and processed to produce a rubber crumb.

A concrete material that replaces stone aggregate material with material from recycled vehicle tyres which is produced by a simpler method, and which still provides a resilient and efficacious concrete product, is highly desirable.

Summary

According to the present disclosure there is provided a product and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Hence there may be provided a concrete material (10) comprising a first aggregate material (100) comprising mineral elements (110) and a second aggregate material (200) comprising elements (210) of a material comprising a rubber polymer. The mode diameter of the elements (110) of the first aggregate material (100) is the same as the mode diameter of the elements (210) of the second aggregate material (200).

The second aggregate material (200) may be derived from vehicle tyres (220) comprising the rubber polymer material.

The elements (210) of the second aggregate material (200) may be pieces of the vehicle tyres (220).

The elements (210) of the vehicle tyres (220) may further comprise metal sub-elements (230).

The mode diameter of the elements (110, 210) may be in the range of 9.5-37.5 mm.

The mode diameter of the elements (110, 210) may be no greater than 9.5 mm.

The first aggregate material (100) and second aggregate material (200) may be provided 30 as a powder.

The ratio of first aggregate material (100) to second aggregate material (200) may be no less than 50:50 by volume.

The ratio of first aggregate material (100) to second aggregate material (200) may be no less than 60:40 by volume.

The ratio of first aggregate material (100) to second aggregate material (200) may be no less than 80:20 by volume.

The ratio of first aggregate material (100) to second aggregate material (200) may be no less than 30:70 by volume but not more than 70:30 by volume.

There may also be provided a method of manufacture of a concrete material comprising the steps of: providing a first aggregate material (100) comprising mineral elements (110); dividing vehicle tyres (220) comprising a rubber polymer into smaller elements (210) to form a second aggregate material (200); and combining elements (110) of the first aggregate material (100) and elements (210) of the second aggregate material (200) which have the same mode diameter.

The process of dividing the vehicle tyres (220) comprises the steps of: shredding and/or cutting the vehicle tyre (220) into the elements (210); and maintaining the material composition of the elements (210) of the second aggregate material (200) until they are combined with the elements (110) of the first aggregate material (100).

Hence there is provided a concrete material and method of manufacture of a concrete material. There may also be provided a method of filling a void and/or chamber and a method of disposing of vehicle tyres comprising a rubber material or the like.

Fragments of vehicle tyres are used to replace selected amounts of the coarse aggregates that form the concrete. Replacing a portion of stone aggregates with an aggregate comprising a rubber polymer (tyre fragments), increases flexural strength of the concrete product. Hence the concrete material of the present disclosure has particular efficacy when used to fill unwanted voids, for example mine shafts, sewer, disused fuel tanks, building foundations, structure stabilisation (for example to stabilise the edges of waterways -rivers and canals etc), since such substrates which the concrete product interfaces with are prone to movement.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 illustrates a concrete material according to the present disclosure; Figure 2 illustrates a concrete block according to the present disclosure; and Figure 3 illustrates the method of manufacture of a concrete material according to the present disclosure.

Detailed Description

The present disclosure relates to a concrete material and method of manufacture of a concrete material. The present disclosure also relates to a concrete block, a method of manufacture of a concrete block, a method of filling a void and/or chamber and a method of disposing of vehicle tyres comprising a rubber material or the like.

The concrete material 10 of the present disclosure may comprise a first aggregate material 100 comprising mineral elements 110 and a second aggregate material 200 comprising elements 210 of a material comprising a rubber polymer. The mineral elements 110 may comprise stone chippings. The rubber polymer may be a natural rubber and/or synthetic rubber. An example of a concrete material 10 of the present disclosure is illustrated in Figure 1.

The mineral elements 110 of the first aggregate material 100 may be crushed rocks, for example crushed limestone rocks or granite rocks.

The mode diameter of the elements 110 of the first aggregate material 100 is the same as the mode diameter of the elements 210 of the second aggregate material 200.

The first aggregate material 100 and second aggregate material 200 may comprise elements 110, 210 which have a range of diameters, and the mode diameter is intended to define the most prevalent diameter in the material provided.

As is understood in the art, the mode is the peak of a frequency distribution. Hence the mode diameter is the most common element size (i.e. diameter), or size range (i.e. diameter range) in the aggregate of the concrete material 10, before and after being cured.

The diameter of the elements 110, 210 is taken to be the smallest dimension across a length/width of the element such that the element may fall through an aperture of the same size/diameter in a sieve.

In some examples the concrete material 10 comprises additional mineral elements 130 which may have a different mode diameter to that of the primary mineral elements 110.

For example, the primary mineral elements 110 may be stone chippings, and the additional mineral elements 130 may be sand. Hence the mode diameter of the sand elements will be smaller than that of the stone chippings. In other examples the first (primary) aggregate material 100 may be sand, and hence the elements 210 of the second aggregate material 200 are provided having a similar granular size to that of the sand.

In some examples the mode diameter of the elements 110, 210 may be in the range of 9.5 to 37.5 mm. In other examples the mode diameter of the elements 110, 210 may be less than 9.5 mm.

Stone chippings are generally provided with diameters in the range of 9.5 mm to 37.5 mm, and are termed "coarse aggregate". Any element having a diameter of less than 9.5 mm is termed a "fine aggregate".

The second aggregate material 200 may be derived from one or more vehicle tyres 220 comprising the rubber polymer material. In particular, tyres which have been in service (i.e. materials to be recycled) may be used.

The elements 210 of the second aggregate material 200 are pieces of the vehicle tyre 220 or tyres, which have been provided having a predetermined size.

That is to say, the recycled vehicle tyres may be shredded or otherwise taken apart into smaller pieces. Depending on the shredding/cutting method used, the smaller pieces may be regular or irregular in formation.

For the avoidance of doubt, a vehicle tyre is a ring-shaped component that, in use, is provided on a wheel rim to transfer a vehicle's load to the ground, to provide traction on the surface over which the wheel travels and, to some extent, dampen shock loads as the tyre rolls over a surface. They may be hollow and/or pneumatically inflated. Such tyres may be used on automobiles, motorcycles, bicycles, scooters, buses, trucks, vans, wheel barrows, aircraft and heavy equipment.

Vehicle tyres for use in the concrete material 10 of the present invention comprise a rubber polymer material, which is typically synthetic rubber and/or natural rubber. They also may contain wire to maintain their structural integrity. They may also comprise fabric, carbon black and other chemical compounds.

Different brands and models of vehicle tyres may have different compositions. A vehicle tyre may contain (by weight): 70% recoverable rubber; 15% steel; 3% fibre and 12% extraneous material (e.g. inert fillers). Other examples of vehicle tyres may contain different relative proportions, and/or different combinations of these materials and/or additional materials. Additionally, the various materials of vehicle tyres are not distributed uniformly throughout the vehicle tyre structure. Hence the composition of the fragments/pieces/elements may not all be the same and may have different physical (i.e. mechanical) properties compared to one another. Put another way, some, but not all, of the elements 210 of the second aggregate material 200 may have the same composition as one another. Some, but not all, of the elements 210 of the second aggregate material 200 may have the same mechanical properties as one another. Some, but not all, of the elements 210 of the second aggregate material 200 may have the same structure as one another. There may be a distribution (i.e. gradient) of compositions of the elements 210 of the second aggregate material 200. There may be a distribution (i.e. gradient) of mechanical properties of the elements 210 of the second aggregate material 200. There may be a distribution (i.e. gradient) of structure of the elements 210 of the second aggregate material 200.

However, this is acceptable for the application of the concrete material 10 of the present disclosure since uniform properties of the material are not required. Indeed, given the inherent variety of aggregate geometry of a conventional concrete material, even a conventional concrete material does not necessary have uniform material properties.

Hence the elements 210 of the vehicle tyre 220 (or tyres) may further comprise metal sub-elements 230. The metal sub-elements may be the metal wire of the tyre 220, at least some of which is bonded to and/or embedded in the rubber polymer material. This variety of composition results in a resilient concrete product.

In some examples conventional admixtures may be added in the concrete material 10 of the present disclosure to modify the cure rate or properties. Such mineral admixtures include fly ash (a by-product of coal-fired power plants), ground granulated blast furnace slag (a by-product of steelmaking) and/or silica fume (a by-product of industrial electric arc furnaces).

Fly ash may be pre-blended with a binding agent to enhance properties such as durability.

In some examples the first aggregate material 100 and second aggregate material 200 may be provided as a powder. Hence in these examples, the second aggregate material 200 may be provided instead of, or in addition to, fly ash.

That is to say, the concrete material 10 of the present disclosure may comprise the second aggregate material 200 provided with a consistency (i.e. particle size) of fly ash. That is to say, the elements 210 will be provided in crumb/powder form (for example up to 4 mm in diameter). This has particular efficacy when a fluid (i.e. flowable) concrete mix is required, for example a foamed concrete mix, to flow through a void which may have a convoluted shape.

In some examples of the concrete material 10 of the present disclosure, the ratio of first aggregate material 100 to second aggregate material 200 is no less than 50:50 by volume, but not greater than 95:5 by volume.

In further examples of the concrete material 10 of the present disclosure, the ratio of first aggregate material 100 to second aggregate material 200 is no less than 60:40 by volume but not greater than 95:5 by volume.

In other examples of the concrete material 10 of the present disclosure, the ratio of first aggregate material 100 to second aggregate material 200 is not less than 80:20 by volume but not greater than 95:5 by volume.

In further examples of the concrete material 10 of the present disclosure, the ratio of first aggregate material 100 to second aggregate material 200 is not less than 30:70 by volume but not more than 70:30 by volume.

In some examples, the first aggregate material 100 and second aggregate material 200 may comprise more than 30% of the concrete material 10 by volume, the remainder of the concrete material 10 comprising a secondary mineral aggregate material (for example sand), a binding agent and/or non-cemenfifious binding agents.

Hence the concrete material 10 may comprise a binding agent. That is to say, the concrete material 10 may comprise a material configured to bond the fragments of first aggregate material 100 and fragments of second aggregate material 200.

The binding agent may be envisaged to be cementitious, for example Portland cement.

In some examples of the concrete material 10 of the present disclosure the binding agent may comprise lime-based cement binders, such as lime putty, and/or other hydraulic cements, such as a calcium aluminate cement.

In some examples of the concrete material 10 of the present disclosure the binding agent may comprise other non-cementitious binding agents, including bitumen binder, such as used for road surfaces, and polymer binder.

In some examples of the concrete material 10 of the present disclosure additives or known admixtures such as pozzolans or superplasticizers may be included in the mixture to improve the physical properties of the wet mix or the finished concrete.

In some examples of the concrete material 10 the concrete material 10 may be combined with reinforcing materials such as steel bars or rebar, which may be embedded in the concrete material 10, and hence the resultant concrete product, to provide tensile strength.

Some examples of the concrete material 10 of the present disclosure may comprise use of decorative stones such as quartzite, river stones or crushed glass added to the surface of the resultant concrete product (e.g. block) for a decorative "exposed aggregate" finish, popular among landscape designers.

When used, and the concrete material 10 has been converted to concrete, the resultant composite material is composed of the aggregates bonded together with the cement.

The concrete material 10 of the present disclosure has particular efficacy when used to fill unwanted voids, for example mine shafts, sewers, disused fuel tanks, building foundations, structure stabilisation (for example to stabilise the edges of waterways -rivers and canals etc).

Hence there may be provided a method of forming a concrete product comprising the step of delivering the concrete material/mix of the present disclosure to a void, and at least part filling and/or covering the void.

In such a concrete material, 30-70% of the concrete mix is composed of the second aggregate material 200. In one example 60% of the aggregate is composed of the second aggregate material 200, and 40% is composed of the first aggregate material 100. The remainder of the concrete mix may comprise sand and/or cement.

The use of this combination of materials results in good flow properties. The use of the second aggregate material 200 may obviate the need for use of foaming agents such as hydrolysed proteins or synthetic surfactants used in examples of the related art.

The concrete material 10 of the present disclosure has particular efficacy when used to manufacture blocks 400, for example security and/or traffic barriers. A block 400 according to the present disclosure is illustrated by the example shown in Figure 2. Hence there may be provided a concrete block unit comprising the concrete material 10 of the present disclosure. In some examples the block 400 may comprise reinforcing materials, for example metal rods.

The block 400 may be manufactured by a conventional method, for example comprising the step of providing a mould, delivering the concrete mix/material to the mould, and allowing it to cure, at least in part, before removing the mould. The block 400 may be a cuboid or a rectangular prism.

A method of manufacture of a concrete material 10 according to the present disclosure may comprise a number of steps as illustrated in Figure 3.

The mineral elements 110 of the first aggregate material 100 are provided (i.e. produced).

Vehicle tyres 220 comprising the rubber polymer are processed such that they are divided (i.e. shredded, torn and/or cut) into smaller elements 210 to form the second aggregate material 200.

In one example, the process of dividing the vehicle tyres 220 comprises the steps of shredding/cutting the vehicle tyre 220 into the elements 210, sorting the elements 210 into groups 210-1, 210-2 based on size (e.g. mode diameter and/or range of diameters).

Then, without further processing (i.e. without further disintegration of the elements of the second aggregate, such that the composition of a sorted group 210-1 of elements 210 of the second aggregate material 200 is maintained), a group 210-1 of the elements 210 of the second aggregate material 200 are combined with the elements 110 of the first aggregate material 100.

In another example, the process of dividing the vehicle tyres 220 comprises the steps of shredding and/or cutting the vehicle tyre 220 into the elements 210, and maintaining (i.e. not changing) the material composition of the elements 210 of the second aggregate material 200 until they are combined with the elements 110 of the first aggregate material 100. That is to say, once cut/shredded, the material composition of the elements 210 of the vehicle tyres 220 is not actively altered, for example to remove other tyre parts of the tyre structure, such as metal or fabric, before being combined with the elements 110 of the first aggregate material 100.

However, only the elements 110 of the first aggregate material 100 and elements 210 of the second aggregate material 200 of the same mode diameter, or same range of diameters, are combined to form the concrete material 10.

During mixing of the concrete material 10, the elements 110 of the first aggregate material 100, the elements 210 of the second aggregate material 200 and a cement binder 300 (for example cement, and/or the other materials herein described with reference to the concrete material 10) are combined to form a concrete mix. Additional mineral elements 130 may also be added during mixing.

As is well known, the cement reacts with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material.

The resultant concrete product may comprise interconnected air voids of approximately 15 to 25% by volume A tyre shredder may be operated on the site on which the concrete is mixed. Hence a concrete mixer and tyre shredder may form a concrete material production system. The present disclosure thus also provides a method of disposing of (i.e. reusing or recycling) vehicle tyres, for example vehicle tyres comprising a rubber material or the like.

Hence there is provided a concrete material, method of manufacture of a concrete material, a concrete block, method of manufacture of a concrete block, a method of filling a void and/or chamber and a method of disposing of vehicle tyres comprising a rubber material or the like.

Fragments of vehicle tyres are used to replace selected amounts of the coarse aggregates from the concrete. Up to three billion tyres are produced around the world every year, providing potential for billions of kilograms of fragments of rubber polymer composites for use as a replacement for stone aggregate.

Replacing a portion of stone aggregates with an aggregate comprising a rubber polymer (tyre fragments) increases flexural strength of the concrete product. This is in part due to the mechanical properties of the shredded tyre fragments, but also because there is good cohesion and adhesion between cement and edges of the fragments which are inherently rough from the shredding process.

Hence the shredded tyres may be used as a bulking agent to be encapsulated within the concrete as an environmentally responsible means of disposal of vehicle tyres. The concrete material of the present disclosure has particular efficacy when used to fill unwanted voids, for example mine shafts, sewer, disused fuel tanks, building foundations, structure stabilisation (for example to stabilise the edges of waterways -rivers and canals etc), since such substrates which the concrete product interfaces with are prone to movement.

By replacing the amounts of course aggregates used in the manufacture of concrete with shredded tyre fragments, an environmental and space efficient means of disposing of waste tyres is provided. This reduces pressure on landfill capacity for waste, reduces emission of greenhouse gases from landfill as tyres degrade, and provides an alternative to incineration which reduces the amount of harmful chemicals and carbon particulates released into the atmosphere.

Another consequence is that less stone aggregate is required per unit volume of concrete, meaning that less aggregate needs to be quarried and transported to site.

Hence the product and methods of the present disclosure also aid in reducing the carbon footprint within the concrete manufacturing industry.

By using the fragments of composite materials produced by cutting up and/or shredding tyres, there may also be produced a resilient concrete product with an extended lifespan compared to examples of the related art.

Since only the shredding of vehicle tyres is required to produce the fragments of composite materials required for a concrete material of the present disclosure there is no requirement to remove other materials (steel, fibre, etc) from the shredded material.

This reduces the amount of processing (and hence cost, time and energy) required to produce the polymer containing aggregate compared to examples of the related art. Indeed, the materials present in the fragments of shredded material (for example steel wire) actually benefit the strength and density of the concrete of the present disclosure.

Additionally, since the rubber of the tyres will not corrode, the properties of the concrete product of the present disclosure will be long lived compared to methods of the art, for example using metal as reinforcement material to provide extra strength. This is because the metal may corrode over time and degrade the properties of the concrete product.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A concrete material (10) comprising: a first aggregate material (100) comprising mineral elements (110); and a second aggregate material (200) comprising elements (210) of a material comprising a rubber polymer; wherein the mode diameter of the elements (110) of the first aggregate material (100) is the same as the mode diameter of the elements (210) of the second aggregate material (200).
2. A concrete material (10) as claimed in claim 1 wherein: the second aggregate material (200) is derived from vehicle tyres (220) comprising the rubber polymer material.
3. A concrete material as claimed in claim 2 wherein: the elements (210) of the second aggregate material (200) are pieces of the vehicle tyres (220)
4. A concrete material (10) as claimed in claim 3 wherein: the elements (210) of the vehicle tyres (220) further comprise metal sub-elements (230).
5. A concrete material (10) as claimed in any one of claims 1 to 4 wherein the mode diameter of the elements (110, 210) is in the range of 9.5-37.5 mm.
6. A concrete material (10) as claimed in any one of claims 1 to 4 wherein the mode diameter of the elements (110, 210) is no greater than 9.5 mm.
7. A concrete material (10) as claimed in any one of claims 1 to 4 wherein the first aggregate material (100) and second aggregate material (200) are provided as a powder.
8. A concrete material (10) as claimed in any one of claims 1 to 7 wherein the ratio of first aggregate material (100) to second aggregate material (200) is no less than 50:50 by volume.
9. A concrete material (10) as claimed in any one of claims 1 to 7 wherein the ratio of first aggregate material (100) to second aggregate material (200) is no less than 60:40 by volume.
10. A concrete material (10) as claimed in any one of claims 1 to 7 wherein the ratio of first aggregate material (100) to second aggregate material (200) is no less than 80:20 by volume.
11. A concrete material (10) as claimed in any one of claims 1 to 7 wherein the ratio of first aggregate material (100) to second aggregate material (200) is no less than 30:70 by volume but not more than 70:30 by volume.
12. A method of manufacture of a concrete material 00) comprising the steps of: providing a first aggregate material (100) comprising mineral elements (110); dividing vehicle tyres (220) comprising a rubber polymer into smaller elements (210) to form a second aggregate material (200); and combining elements (110) of the first aggregate material (100) and elements (210) of the second aggregate material (200) which have the same mode diameter.
13. A method as claimed in claim 12 wherein: the process of dividing the vehicle tyres (220) comprises the steps of: shredding and/or cutting the vehicle tyres (220) into the elements (210); and maintaining the material composition of the elements (210) of the second aggregate material (200) until they are combined with the elements (110) of the first aggregate material (100).