GB2519954A

GB2519954A - Building materials

Info

Publication number: GB2519954A
Application number: GB1319317.2A
Authority: GB
Inventors: Roy Potter
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-11-01
Filing date: 2013-11-01
Publication date: 2015-05-13
Also published as: GB201319317D0

Abstract

The present invention relates to building materials, in particular to blocks and panels for use in construction of buildings. More particularly, it relates to compositions for such blocks and panels. The present invention seeks to provide a building panel having a high thermal insulating function and based largely on volcanic aggregate materials. We describe a building composite material comprising a mixture of an aggregate and a binder, wherein the aggregate comprises at least one vesicular igneous rock and expanded perlite. Preferably, the vesicular igneous rock is pumice and/or scoria. The aggregate may comprise a further igneous rock, such as tuff.

Description

BUILDING MATERIALS

The present invention relates to building materials, in particular to blocks and panels for use in construction of buildings. More particularly, it relates to compositions for such blocks and panels.

The present invention seeks to provide a building panel having a high thermal insulating function and based largely on volcanic aggregate materials.

In its broadest sense, the present invention provides a building composite material comprising a mixture of an aggregate and a binder; wherein the aggregate comprises at least one vesicular igneous rock and expanded perlite.

Preferably, the at least one vesicular igneous rock has a nominal particle size of 0-20 mm, preferably 0-10 mm.

Preferably, the vesicular igneous rock is pumice and/or scoria.

In preferred embodiments, the aggregate further comprises an expanded clay aggregate.

Preferably, the expanded clay aggregate has a nominal particle size of from 5 to 20 mm, preferably about 10mm.

In certain embodiments, the aggregate further comprises a pulverised fly ash material, preferably a sintered pulverised fly ash aggregate. More preferably, the sintered fly ash material has a nominal particle size of up to about 20mm, preferably up to about 10mm, more preferably from 4 to 8 mm.

Preferably, the aggregate comprises a further igneous rock.

Advantageously, the further igneous rock is tuft, preferably having a nominal particle size of from 5 to 20mm, more preferably about 10mm.

Preferably, the binder comprises Portland cement.

Advantageously, the binder further comprises a gypsum-based binder, preferably a calcium sulphate hemihydrate.

Preferably, the material further comprises a fibre reinforcement; more preferably, the fibre reinforcement is a glass fibre; a hair, preferably a horsehair; or a cellulose fibre.

Preferably, the material further comprises a permeability-reducing additive.

Preferably, the perlite has a nominal particle size of from 1 to 5 mm, more preferably from 2 to 5 mm.

Preferably, the material comprises aggregate in an amount of from 65-85% by volume, preferably in an amount of from 70-80% by volume; and from 15- 35% by volume of binder, preferably from 20-30% by volume.

Preferably, the material further includes water.

Preferably, the material comprises from 45 to 70% by volume of aggregate, to 30% by volume of binder and 18-30% by volume of water; more preferably, 55-65% by volume of aggregate, 15-20% by volume of binder and from 20 to 25% by volume of water; most preferably about 59% by volume of aggregate, about 18% by volume of binder and about 23% by volume of water.

Preferably, the aggregate comprises 30-50% by volume of perlite, preferably about 40% by volume.

Preferably, the aggregate comprises up to 70% by volume of vesicular igneous rock.

Preferably, the aggregate comprises pumice and expanded clay aggregate in approximately equal amounts.

Additionally or alternatively, the aggregate comprises pumice and tuff in approximately equal amounts.

The present invention also provides a building block or panel formed of a material as described above.

The above and other aspects of the present invention will now be described in further detail, by way of example only, with reference to the following example and to accompanying drawings, in which: Figure 1 is a perspective view of an embodiment of a first block in accordance with the present invention; Figure 2 is a plan view of the block of Figure 1; Figure 3 is an end view of the block of Figure 1; Figure 4 is a perspective view of an embodiment of a second block in accordance with the present invention; and Figure 5 is an end view of the block of Figure 2.

Figures 1 to 3 illustrate a first embodiment of a building panel 10 in accordance with the present invention. The panel has first and second parallel spaced apart portions 11, 12 of substantially the same dimensions of height, width and thickness, with an intermediate portion 13 therebetween. In this particular embodiment, intermediate portion 13 is of shorter height than first and second portions 11,12 to provide a groove 14 in an upper edge of panel 10. Intermediate portion 13 is of the same width as the first and second portions 11,12, but offset to one side, thereby forming a lateral groove 15 to one vertical edge and a lateral tongue 16 to the opposite edge.

Figures 4 and 5 illustrate a second embodiment of a building panel 20 in accordance with the present invention. The panel 20 is of the same general construction as that of Figures 1 to 3, having first and second panels 21,22 of the same dimensions with an intermediate panel 23 therebetween. However, intermediate panel 23 is also of the same dimensions as first and second panels 21,22 and is arranged to be offset with respect to the first and second panels both to one side, as described above, and in the operatively vertical orientation such that a tongue 27 is formed projecting from a lower edge of the panel, in addition to grooves 24,25 and tongue 26 corresponding with the identical features in the embodiment of Figures 1 to 3.

The embodiment of Figures 1 to 3, without lower tongue 27, will be used to form a foundation layer in construction of a building using a row of blocks as necessary, with the embodiment of Figures 4 and 5 then forming a further layer sitting on top of the foundation layer. It will be appreciated that different designs of block will be necessary to form corners, window and door edges etc (not shown).

Example

Pumice is a highly vesicular volcanic rock, typically having an average porosity of about 90%. As such, it is highly insulating as well as being very lightweight. Scoria is of similar origin, but somewhat denser.

Perlite is an amorphous igneous rock having a relatively high water content.

When treated to a high temperature, trapped water vaporises suddenly, causing expansion of the material by up to about 16 times, making an extremely light material.

The following details set out an example of the composition and method for producing a block as described above of dimensions im x O.66m x O.3m.

Materials Expanded clay aggregate (nominal 10 mm) 57 litres Pumice (nominal 0-15mm) 57 litres Perlite (Silvaperl P35 -nominal 1-5mm) 72 litres Cement (Hanson Multicem -includes air 36 litres entraining additive) Gypsum-based adhesive (knauf 21 litres Plasterboard Adhesive bonding compound) Concrete reinforcing fibres (16mm) bOg Water 72 litres Permeability-reducing additive (at lmI per 72 ml litre water) Method A conventional permeability-reducing (waterproofing) additive was added to the water at the recommended dose (imI additive per litre of water). Half of the water (36 litres) was placed in a mixer and blown clay (57 litres) added, with tumbling, followed by cement (36 litres). The mixture was mixed until an even consistency was obtained. With continued mixing, pumice (57 litres) was added along with reinforcing fibres (bOg) and pumice (57 litres).

Further water (18 litres) was added followed by half of the perlite (36 litres) and then gypsum-based adhesive (21 litres), with mixing. Further water (9 litres) was added, followed by the remaining perlite (36 litres). Sufficient water was then added to produce a mix of the desired flowability (approximately 3 litres).

The amount of water required at the final stage typically varies, depending upon the proportion of small size pumice granules to larger grains.

The composite material is then poured into moulds of the desired shape and size and allowed to cure. The compositions of the present invention have a density of about 500kg per cubic meter, around one quarter the mass of a conventional concrete material. As a result, a panel of lxO.66x0.3m has a mass of approximately 100kg, cxmpared with around 400kg for a conventional concrete panel.

One or each face of the panel may be treated further, for example by application of facing treatments such as coating compositions or cladding.

Variations It will be appreciated by those skilled in the art that the method by which cement-based aggregate materials are made can have an impact on the amount of water necessary for satisfactory results. Large-scale batch processes or continuous processes typically require a lower water quantity than smaller batch processes. Temperature and environmental relative humidity also have an effect. As such, the volumes of water given above are purely indicative. The skilled person knows to adjust the volume of water used to achieve an appropriate consistency to the final mix.

Equally, larger or smaller proportions of cement can be used, depending upon the final strength required and the initial setting/curing period desired.

It will also be appreciated that the specific materials used in the above example are merely exemplary. Other manufacturers produce equally suitable materials, such as cement, gypsum and perlite.

Gypsum is considered to be a green material in that it can be obtained by flue-gas desulphurisation from coal-fired power stations.

In preferred embodiments, a further volcanic material is used in place of the expanded clay aggregate, thus providing a panel in which the aggregate is wholly volcanic. Tuff, a type of rock consisting of consolidated volcanic ash is a preferred material.

Additionally, or alternatively to the use of a further volcanic material, the material includes pulverised fly ash, preferably sintered pulverised fly ash formed as a lightweight aggregate. Lytag Limited supply a suitable material.

The concrete reinforcing fibres used have been conventional glass fibres, typically of about 18mm nominal length. These have been found to give good results. The fibres are particularly suitable for enhancing the initial strength of the block before curing is complete, thereby allowing blocks to be removed from their moulds at an early stage. In the context of seeking to produce a block of substantially natural materials, natural fibres are preferred. Traditional materials, such as horsehair, are suitable, as are newer materials coming onto the market, such as cellulose fibres.

The permeability-reducing (waterproofing) additive added to the water is suitably a conventional additive. A modified polydimethylsiloxane-based additive has been found to be particularly suitable. Alternatively, or additionally, the perlite used is pre-coated with a polydimethylsiloxane (PDMS) additive. Suitable additives are well known, including those available from Dow Corning.

The cement is preferably of the type that includes an air-entrainment additive, such as Multicem cement supplied by Hanson. Alternatively, an air-entrainment additive can be added separately. Suitably, such additives are surfactants.

In further embodiments, viscosity modifying admixtures are added. The volcanic materials used in materials of the present invention tend to absorb atmospheric moisture and do so with some variability from one batch to another. The addition of a viscosity modifying admixture, or combination of admixtures, aids the uniformity of workability of the mixed materials. Suitable admixtures include those from BASE, such as those sold under their Rheomac registered trade mark.

Claims

CLAIMS: 1. A building composite material comprising a mixture of an aggregate and a binder; wherein the aggregate comprises at least one vesicular igneous rock and expanded perlite.
2. A material as claimed in Claim 1, wherein the at least one vesicular igneous rock has a nominal particle size of 0-20 mm, preferably 0-10 mm.
3. A material as claimed in Claim 1 or Claim 2, wherein the vesicular igneous rock is pumice and/or scoria.
4. A material as claimed in any preceding claim, wherein the aggregate further comprises an expanded clay aggregate.
5. A material as claimed in Claim 4, wherein the expanded clay aggregate has a nominal particle size of from 5 to 20 mm, preferably about 10mm.
6. A material as claimed in any preceding claim, further comprising a pulverised fly ash material, preferably a sintered pulverised fly ash aggregate.
7. A material as claimed in Claim 6, wherein the sintered fly ash material has a nominal particle size of up to about 20mm, preferably up to about 10mm, more preferably from 4 to 8 mm.
8. A material as claimed in any preceding claim, wherein the aggregate comprises a further igneous rock.
9. A material as claimed in Claim 8, wherein the further igneous rock is tuff.
10. A material as claimed in Claim 9, wherein the tuff has a nominal particle size of from 5 to 20mm, preferably about 10mm.
11. A material as claimed in any preceding claim, wherein the binder comprises Portland cement.
12. A material as claimed in Claim 11, wherein the binder further comprises a gypsum-based binder, preferably a calcium sulphate hemihydrate.
13. A material as claimed in any preceding claim, further comprising a fibre reinforcement.
14. A material as claimed in Claim 13, wherein the fibre reinforcement is a glass fibre; a hair, preferably a horsehair; or a cellulose fibre.
15. A material as claimed in any preceding claim, further comprising a permeability-reducing additive.
16. A material as claimed in any preceding claim, wherein the perlite has a nominal particle size of from 1 to 5 mm, preferably from 2 to 5 mm.
17. A material as claimed in any preceding claim, comprising aggregate in an amount of from 65-85% by volume, preferably in an amount of from 70-80% by volume; and from 15-35% by volume of binder, preferably from 20-30% by volume.
18. A material as claimed in any preceding claim. further comprising water.
19. A material as claimed in Claim 18, comprising from 45 to 70% by volume of aggregate, 10 to 30% by volume of binder and 18-30% by volume of water.
20. A material as claimed in Claim 19, comprising from 55-65% by volume of aggregate, 15-20% by volume of binder and from 20 to 25% by volume of water.
21. A material as claimed in Claim 19, comprising about 59% by volume of aggregate, about 18% by volume of binder and about 23% by volume of water.
22. A material as claimed in any preceding claim, wherein the aggregate comprises 30-50% by volume of perlite, preferably about 40% by volume.
23. A material as claimed in any preceding claim, wherein the aggregate comprises up to 70% by volume of vesicular igneous rock.
24. A material as claimed in Claim 22 or 23, wherein the aggregate comprises pumice and expanded clay aggregate in approximately equal amounts.
25. A material as claimed in Claim 22 or 23, wherein the aggregate comprises pumice and tuft in approximately equal amounts.
26. A building composite material substantially as herein described with reference to the examples.
27. A building block or panel formed of a material as claimed in any one of claims ito 26.
28. A building block or panel substantially as herein described with reference to the examples and the accompanying drawings.