AU2013206165B2

AU2013206165B2 - Bricks and blocks

Info

Publication number: AU2013206165B2
Application number: AU2013206165A
Authority: AU
Inventors: Phil Thurlow
Original assignee: Island Block & Paving Pty Ltd
Current assignee: Island Block & Paving Pty Ltd
Priority date: 2012-06-14
Filing date: 2013-06-04
Publication date: 2019-01-17
Anticipated expiration: 2033-06-04
Also published as: AU2020250269A1; AU2019201262B2; NZ611648A; AU2019201262A1; AU2013206165A1

Abstract

H:\plw\lnmenvovn\NRPortbl\DCC\PLV\5 190739 l.doc-29/05/2013 A brick, block, or paver including an aggregate of recycled glass, at least one face having a surface treatment to expose the glass. In a preferred embodiment the product consists of aggregate mixed with cement, the recycled glass aggregate forming between 10% and 100% of the overall aggregate in the mix.

Description

BRICKS AND BLOCKS [0001] The present invention relates to bricks, building blocks, and retaining wall blocks and more particularly to the use of crushed recycled glass within their composition.

[0002] Concrete bricks, blocks and pavers typically consist of a mixture of aggregate and cement. A ratio of 10:1 of the aggregate to cement in the mix would be typical although that ratio can be changed according to requirements. Although the aggregate may consist wholly of quartz sand, some of that sand in the mix may be replaced by blue metal dust in order to change the colour and/or surface texture of the finished product. For example in a mix where the aggregate is wholly quartz sand used in the general ratio indicated above, the finished product may have a relatively light sandy colour whereas in a mix in which the quartz sand component is replaced by 60 percent blue metal dust, the finished product will be of a grey colour (the percentages given herein are by weight).

[0003] The present invention proposes replacing some or all of the quartz sand and/or blue metal dust in the mix with crushed recycled glass (glass sand). This not only provides an effective usage for recycled bottles, but, importantly, by applying an appropriate surface treatment to the product following casting and curing, the glass sand on the surface of the product is exposed to varying degrees to create a glistening finish. This concept is applicable not only to concrete bricks, blocks and pavers but also to clay bricks.

[0004] According to the invention, there is provided a brick or block including an aggregate of recycled glass within their composition, at least one face thereof having a surface treatment to expose the glass, the aggregate of recycled glass has a particle size distribution with particle sizes varying up to approximately 7mm, and the aggregate of recycled glass represents between 20% and 50% of an overall aggregate in the composition, and wherein the surface treatment includes one of: shot blasting the face with a steel shot, polishing the face, or brushing the face with a diamond brush.

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- 1A[0005] There is further described herein a brick, block, or paver including an aggregate of recycled glass, the brick, block, or paver being subject to a treatment to expose the glass on at least one face.

[0006] In one aspect, the treatment is a surface treatment to expose the glass.

[0006a] In another aspect, the surface treatment includes one of: shot blasting a surface with a steel shot to expose the glass, polishing the face, or brushing the face with a diamond brush.

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-2[0007] In another aspect, the treatment involves splitting the brick, block, or paver prior to, or following, curing whereby the face is formed by the splitting action.

[0008] The invention will now be further described by way of example only. In a preferred embodiment, in the production of concrete bricks, blocks and pavers between 10% and 100% of the aggregate in the mix and normally formed either by quartz sand or a mixture of quartz sand and blue metal dust is constituted by recycled glass aggregate (glass sand) formed from crushed recycled glass bottles of various colours. More particularly the glass sand preferably consists of between 20% and 50% of the overall aggregate in the mix. With a minimum content of 20% recycled glass aggregate the finished product will comply with certain current standards established for use of recycled materials in various building codes and the like. While the use of recycled material within the product is of importance from an environmental consideration, nevertheless what is also of significance is that a range of surface finishes can be achieved with the incorporation of the recycled glass aggregate and for that it is considered that it would represent a maximum of about 50% of the aggregate within the mix. Preferred mixes will now be given by way of example only.

- Natural grey building block mix: 80kg grey cement, 500kg metal dust (max particle size 7mm), 180kg glass sand, 120kg quartz sand. Glass component 20% of overall mix.

- Brick, paving and coloured block mix: 80kg white cement, 250kg glass sand, 550kg quartz sand. Glass component 28% of overall mix.

- Brick, paving and coloured block mix: 80kg white cement, 350kg glass sand, 450kg quartz sand. Glass component 40% of overall mix.

[0009] In the preferred embodiment the particle size of the recycled glass aggregate is approximately 7mm or less with the majority of it having a particle size of approximately 2.5mm or less. The following below gives the particle size distribution of a batch of suitable recycled glass aggregate determined in accordance with AS 1289.3.6.1

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-3TABLE

AS Sieve (mm)	% Passing
9.5	100
6.7	98
4.75	91
2.36	67
1.18	42
0.600	27
0.425	21
0.300	17
0.150	10
0.075	6

[00010] Following casting and curing of the cement/aggregate mix to a required degree that or those surfaces of the product which are likely to be exposed in use are subject to a surface treatment to expose the glass aggregate to different degrees and to provide different surface finishes. In practice one of the following surface treatments may be used, to be selected in accordance with the finish required.

1. Washing the surface with hydrochloric acid or similar to expose and highlight the glass to create a smooth finish with highlighted glass. This may be termed as a washed finish.

2. Shot blasting the face with steel shot or blast sand to expose the glass to create a rough but even finish with highlighted glass. This may be termed as an exposed finish.

3. Grinding the face with grinding wheels or similar to expose the glass to create a smooth even finish with highlighted glass. This may be termed as a honed finish.

4. Polishing the face using normal concrete polishing techniques to expose the glass to create a smooth polished finish with highlighted glass. This may be termed as a polished finish.

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5. Brushing the face with diamond brushes or similar to expose the glass to create a rough but even finish with highlighted glass. This may be termed as a brushed finish.

6. Saw cutting the face of the finished product with a brick cutting saw or similar to expose the glass to create a smooth but even finish with highlighted glass. This may be termed as a saw cut finish.

[00011] The recycled glass aggregate can also be incorporated into the mix for producing clay products, particularly bricks, up to a maximum of about 15% as the presence of significant amounts of sand in the mix can cause difficulties in manufacturing. Suitable surface finishes for clay bricks to expose the glass include shot blasting and grinding as discussed to provide required surface finishes with exposed and highlighted glass. As an alternative, the glass aggregate could be incorporated just into the surface zone of the brick during manufacture, followed by an appropriate surface treatment such as shot blasting or grinding.

[00012] In an alternative, to create a rough face finish with highlighted glass the concrete or clay product can be split to expose the recycled glass aggregate at the split face. This may be termed as a split face finish.

[00013] The split face finish can be created in one or other of the following

1. During the casting process prior to curing. While the product is wet at casting stage , the product is 'wet split to expose the recycled glass aggregate. This occurs by the formed product being split out of the mould at casting with a portion of a face of the product being retained in the mould. This process can occur at up to four sides of the product but may occur only at one side. More specifically, the 'wet split exposed finish occurs due to the mould configuration retaining part of the wet aggregate within the mould at the stripping stage which splits across the wet surface to achieve the exposed /split finish, ie. a rough finish with highlighted recycled glass aggregate.

2. After the casting process following curing. This occurs by applying force to the product to split or break the product into the desired size. By way of example, the

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-5splitting of the cured product can occur using hydraulic, pneumatic, mechanical or physical force to achieve a exposed/split finish ie. a rough finish with highlighted recycled glass aggregate.

[00014] The embodiment has been described by way of example only and modifications are possible within the scope of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A brick or block including an aggregate of recycled glass within their composition, at least one face having a surface treatment to expose the glass, wherein the aggregate of recycled glass has a particle size distribution with particle sizes varying up to approximately 7mm, and the aggregate of recycled glass represents between 20% and 50% of an overall aggregate in the composition, and wherein the surface treatment includes one of: shot blasting the face with a steel shot, polishing the face, or brushing the face with a diamond brush.
2. A brick or block according to claim 1, wherein a majority of particles in the aggregate of recycled glass has a particle size of approximately 2.5mm or less.
3. A brick or block according to claim 1, wherein the surface treatment includes a washed finish formed by an acid wash to expose the glass.
4. A brick or block according to claim 1, wherein the surface treatment is shot blasting with the steel shot to expose the glass.
5. A brick or block according to claim 1, wherein the surface treatment consists of grinding to create a smooth even finish.
6. A brick or block according to claim 1, wherein the surface treatment is polishing to provide a smooth polished finish.
7. A brick or block according to claim 1, wherein the surface treatment consists of brushing with the diamond brush to expose the glass to create a relatively rough but even finish.
8. A brick or block according to claim 1, wherein the surface treatment consists of a saw cut finish to expose the glass to create a relatively smooth but even finish.
9. A brick or block according to claim 1, wherein the treatment involves splitting the brick or block prior to, or following, curing whereby the face is formed by the splitting

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-7action.
10. A brick or block according to any one of claims 1 to 9 consisting of aggregate mixed with cement.
11. A brick or block according to claim 7, wherein the remainder of the aggregate in the mix is quartz sand or quartz sand and blue metal.
12. A brick or block according to any one of claims 1 to 9 composed of clay.
13. A brick or block according to any one of the preceding claims, wherein the brick or block is a retaining block.