WO2013076503A1

WO2013076503A1 - Building material

Info

Publication number: WO2013076503A1
Application number: PCT/GB2012/052907
Authority: WO
Inventors: Keith Robert SOUTHEY; Joseph John ORSI
Original assignee: Fibrelime Limited
Priority date: 2011-11-24
Filing date: 2012-11-23
Publication date: 2013-05-30
Also published as: GB201221107D0; GB2500744A; GB2500744B

Abstract

The invention described herein relates to a pliable material for use in building, the material comprising water and an aggregate of particle size less than 50 micron. Additionally, a binding agent is included comprising at least 70% calcium hydroxide. Further, fibres are included to give additional advantageous properties. The fibres can be formed of non-biological material or coated with a non-biological material and be of a length of from 2 -150 mm. Aggregate can be selected from chalk, marble, limestone, calcium silicate or sand and can additionally include or consist of pumice, expanded clay perlite or silica glass.

Description

BUILDING MATERIAL

Field of the Invention

The invention relates to building materials, in particular lime-based building materials. Background to the Invention

A number of different pliable building materials are used to form specific building features once they have hardened, such as plasters/renders, screeds, flooring, foundations, mortars, grouts and the like. Lime-based building materials have substantial sustainable credentials when compared with, for example, gypsum- or cement-based materials; they are for example readily recyclable and biodegradable and absorb carbon dioxide during the setting process (especially for non-hydraulic products). Carbon emissions and energy consumption during the production of lime-based products is also relatively modest. Furthermore, lime- based materials provide great visual appeal and are self-healing and breathable (i.e. water permeable, so that moisture can be absorbed and later released). Despite this, the characteristics of prior lime-based materials have meant that their use for particular features and in particular building types has been limited (e.g. to plasters for traditional buildings), as will be described below.

When employed as a plaster/render, lime-based products have a number of limitations. For example, their adherence to a variety of common building material substrates is modest or poor, particularly for light-weight blocks, plasterboard, ply board, fireboard, glass, metals, some insulation materials, plastics products etc., making them unsuitable for some historic building work but in particular for new build work. In addition, variation of substrate, for example in a wall where masonry, daub, lath, reed, timber and other building materials can occur in a single area to be plastered, can lead to cracking at the interface or junctions. It is also difficult to build up the lime plasters to the desired thickness, by applying one or multiple coats, due to delamination from the substrate or shearing between coats.

Shrinkage and cracking are also problems, on both mixed and single substrate materials. To reduce these problems, reinforcement can be added in the form of natural fibres, such as hair (e.g. horse, goat or pig hair), straw, reed fibres, hemp and the like, though such biological materials degrade over relatively short timescales, especially on external areas which get wet. Synthetic fibres (e.g. polypropylene, glass and asbestos) that are resistant to such degradation have also been used but such fibres have a tendency to push through the plaster surface leaving a bristle finish that is often unacceptable to the user. In addition, the resultant materials show limitations in their general performance (e.g. poor or modest adherence, impact resistance, etc).

Lime plasters require specialist knowledge and skills to apply them. For example, the setting of e.g. non-hydraulic lime plaster requires carbonation, which needs to be controlled to achieve a reliable set. This in turn requires fairly arduous pre- and after-care in the form of damping down with water.

Finally, lime-based building materials have a relatively low impact resistance, making them largely unsuitable for load-bearing surfaces or indeed as load-bearing structural elements in themselves. They also have relatively modest structural flexibility, tensile strength, and resistance to fire and freeze/thaw cycles.

It is an object of the present invention to provide a solution to these problems. Summary of the Invention

In a first aspect of the invention there is provided a pliable material for use in building, said material comprising; water,

an aggregate of particle less than 50μ,

a binding agent comprising at least 70% calcium hydroxide, and

a plurality of fibres, preferably of non-biological origin or coated with a coating of non- biological origin.

Preferably, the aggregate is selected from chalk, marble, limestone, calcium silicate or sand or mixture thereof. Alternatively or additionally, the aggregate can include, or be entirely of: pumice, expanded clay perlite or expanded silica glass in order to improve insulation.

Conveniently, the binder includes a clay, linseed oil or casein to provide the pliable material with improved breathing.

The fibres are conveniently of a non-biological origin or natural fibres coated with a material of non biological origin, and especially conveniently selected from polypropylene (PP), PMF, alkaline resistant glass fibre, cellulose or casein.

The fibre lengths in the first aspect are preferably from 2 - 150 mm in length, especially preferred in 2 - 40mm and particularly preferred from 2 - 18 mm in length.

The width of the fibres in the first aspect is conveniently from 2 - 70μ.

The fibre can be present at an amount up to 20 kgnr³. However, the fibre is preferably present in the material in an amount of from 2 - 4 kg per cubic metre, 2.1 - 4.0 and further preferably 3.0 - 4.0. In a second aspect, the invention provides a pliable building material comprising: water;

an aggregate;

a binding agent, comprising at least 70% calcium hydroxide; and

a plurality of fibres of non-biological origin each having a maximum diameter of

In preferred embodiments each of said fibres has a maximum diameter of <48μιη.

In preferred embodiments said fibres comprise a plastics material, preferably polypropylene or alkaline resistant fibreglass fibres, and/or said fibres are coated with a surfactant.

In preferred embodiments the pliable building material further comprises an insulation material and/or a non-binding material that produces a pozzolanic effect. Preferably, said aggregate and/or said insulation material comprises perlite or pumice.

Also provided is a substantially solid building material formed by the setting of the pliable building material set out above, together with a panel for a building comprising said substantially solid building material, a structural element for a building comprising said substantially solid building material, and a floor, wall, door or ceiling of a building to which said substantially solid building material has been applied.

The invention additionally provides the use of said substantially solid building material as a plaster or render for a wall, door or ceiling, as a masonry mortar or grout, as an adhesive, fire retardant or thermal insulation material, as a screed for a floor, or as a structural element for a building.

Further provided is a composition suitable for the manufacture of the pliable building material of the invention, said composition comprising said binding agent and said plurality of fibres. In one aspect, said composition is substantially free of water. In preferred embodiments of that aspect, the composition additionally comprises the following components of the pliable building material: the aggregate and/or

the insulation material and/or

the non-binding material that produces a pozzolanic effect.

In an alternative aspect, said composition comprises water.

Also within the scope of the invention is a pliable building material substantially as described herein, a substantially solid building material substantially as described herein, and a composition suitable for the manufacture of a pliable building material, said composition substantially as described herein.

Detailed description of Preferred Embodiments

The invention relates to a pliable building material, such as a material that can for example be poured, moulded, spread or sprayed. The material of the invention is a lime-based building material i.e. one where the binding agent comprises at least 70% calcium hydroxide.

In a series of results relating to a first aspect of the invention, the improvements to the quality of plaster produced using an aggregate of particle size <50μιη is shown. These further results are set out in the following Tables 1 - 17. Without being limited to theory, it is believed that the smaller the particle size of the aggregate, the better the performance due to the adherent properties of the composition increasing. In addition, there is a reduced chance of water accumulating into large droplets which can cause damage when under freezing conditions due to their expansion: an effect known as freeze spalling.

The test methods used correspond to those used in the results described earlier, and the assessment scores achieved on these tests also correspond.

In the first aspect of the invention, the reduced particle size of the aggregate allows fibres of larger diameter to be used compared to those of other aspects. The preferable range for said diameter is therefore from 5 - 70μιη when used with a reduced particle size aggregate. In a still further aspect of the invention it is also found advantageous to utilise fibres of mixed length, for example 12mm with 18mm. However fibres of mixed length varying typically from 2 - 40mm, have been shown to be effective and it is expected that lengths of up to 150mm can be utilised. Where required, fibres of length greater than 40mm have been shown to be effective. When a composition is for use as a skim then shorter fibres down to 2mm can be used, whereas an application requires a thick one-coat then longer fibres up to 40mm are suitable.

In general a greater amount of fibres in a mix tends to confer improved properties although where plaster has to be remixed after storage to improve plaster workability, then the greater amount would be disadvantageous.

The use of mixed fibre lengths enables the use of aggregate which includes large particles, especially up to 5mm and in some embodiments up to 10mm. This effect is enhanced when higher quantities of fibres are used. In particular, a concentration of greater than 2kgnr³ of mixed fibres has been found to enable larger size aggregates to be employed.

In both aspects of the invention, the thermal insulation properties can be improved by adding materials such as perlite or pumice.

The compositions tested are detailed in Table 1. As with the compositions indicated in Example 1, the amount of water in the mixed composition can vary. The composition LCF- FF is as per that shown in Example 1.

Table 1 Plaster mix:

Table 2a

Table 2b

Adherence Test

Table 3

Ambient Temp: 17°C

Sample size (over substrate): 100x100x8mm

In conclusion -

LFC-FF.CC50, CS50 and M4 has significantly greater adherence compared with the other plaster materials (generally), and shows a substantial and reliable adherence to a number of substrates that previously could not be effectively plastered/rendered using a lime- based product, such as dry blocks, glass and construction board.

Interface Crack Test

Ambient Temp: 17°C

Sample size: 700x250x3-12mm

In conclusion:

LFC-FF, CC50, CS50 and M4 shows significantly less interface cracking compared with the other plaster materials.

Impact test

Ambient Temp: 17°C

Sample size: 75x65x6mm

In conclusion:

LFC-FF, CC50, CS50 and M4 can withstand a significantly greater impact than the other materials.

Pre-form test

Table 6

Ambient Temp: 17°C

Sample size: 500x150x12mm

In conclusion:

LCF-FF, CC50, CS50 and M4 performs significantly better than the other materials in withstanding failure under deflection.

Skim work

Table 7

Ambient Temp: 19°C

Sample size: 75x440x2-3mm

In conclusion:

LFC-FF, CC50, CS50 and M4 have significantly improved properties in respect of skim work.

Flexibility Test

Table 8

Ambient Temp: 19°C

Sample size: 180x60x4mm

In conclusion:

LFC-FF, CC50, CS50 and M4 are significantly more flexible than the other materials.

Tensile Strength Test

Table 9

Ambient Temp: 17°C

Sample size: 130x100x12mm

In conclusion:

LFC-FF, CC50, CS50, CC5, CS5 and M4 had a significantly greater breaking strain compared with the other materials.

Fire Resistance Test

Table 10

Ambient Temp: 17°C

The plasters tested show significantly similar fire resistance.

Finished Appearance Test

Ambient Temp: 19°C

Sample size: 390x680x20mm

The finished appearance of all plasters gave a good or excellent finished appearance with few or no defects.

Shrinkage Crack Test

Ambient Temp: 19°C

Sample size: 390x680x20mm

LFC-FF, CC50-M2, CC50, CS50, CC5 and M4 showed no or minimal signs of shrinkage, in contrast to the other plaster materials.

Shear test

Table 13

Ambient Temp: 19°C

Sample size: 440x215x75mm

LFC-FF, CC50, CS50 and M4 showed no signs of shearing compared with the other plaster materials.

Freeze-thaw Test

Table 14

Ambient Temp: 20°C

Sample size: 70x24x12mm

CC50, CS50 and M4 can withstand low temperatures without significant damage, in contrast with the other plaster materials

Thermal Resistance Test

Ambient Temp: 21°C

Sample size: 240x1 0x12mm

PB = plasterboard

PS = polystyrene

LFC-FF improves on CC100-62. There are no significant differences between LFC-FF and other plasters, however the addition of pumice or perlite in PUM and PER further improved the thermal resistance of plaster materials.

Permeability test 1

Table 16

Ambient Temp: 19°C

Sample size: 330x330x330x20mm box

There was no significant difference in permeability between plaster materials.

Permeability test 2

Table 17

100g samples had 35g (35ml) water added to them and placed in a room at 30' time taken for the samples to return to a mass of 100g was measured (hours):

Ambient Temp: 30°C

Sample size: 95x65x1 mm

There was no significant difference in permeability plaster materials.

The binding agent, in the presence of water, binds together (with adhesive action) the components of the pliable building material. In the material of the invention at least 70% of the binding agent is calcium hydroxide (also known as "slaked lime" or "hydrated lime"), in contrast to e.g. cement-based or gypsum-based materials where the binding agent comprises a majority of calcium silicates and calcium sulphates, respectively.

The lime-based binding agent can be adapted such that it is non-hydraulic i.e. that the building material comprising it sets primarily or solely via the process of carbonation (i.e. reaction with atmospheric carbon dioxide). In such instance if the building material itself is to be non-hydraulic then no non-binding material that produces a pozzolanic effect should be further included in the material. A non-hydraulic lime-based binding agent will preferably comprise at least 95% calcium hydroxide, more preferably at least 99% calcium hydroxide, and most preferably will consist of essentially pure calcium hydroxide. A non- hydraulic building material of the invention is advantageous because it can be stored for extended periods of time without setting (using appropriate storage conditions i.e. those that limit the access of the material to carbon dioxide). Alternatively, the lime-based binding agent can be adapted such that it is hydraulic i.e. that the building material comprising it can sets via reaction with the water in the building material. In such instance the hydraulic nature of building material itself can be increased by further including in the material a non-binding material that produces a pozzolanic effect. A hydraulic lime-based binding agent will preferably comprise at least 5%, more preferably at least 10% (and up to 30%) of other minerals that confer hydraulic nature, preferably silicates (deriving e.g. from clay and silica). A hydraulic building material of the invention is advantageous because it enables relatively thick layers/structures of the material to set in wet environments, especially under water or very wet conditions where setting via carbonation is too slow or not possible.

The aggregate of the pliable building material of the invention is the component that constitutes the voluminous bulk and structural strength of the material. The aggregate can be chosen from e.g. sand, perlite, pumice, gypsum, expanded glass, vermiculite and crushed (or powdered) stone or chalk. Chalk or stone, especially powdered chalk, is a preferred material because of its general performance within the building material (as shown by the Examples). Perlite is another preferred material because it can, in addition, provide insulation, increased hydrophobicity and increased freeze/thaw resistance.

In a second aspect, the invention provides a pliable building material comprising: water;

an aggregate;

a binding agent, comprising at least 70% calcium hydroxide; and

a plurality of fibres of non-biological origin or coated with a material of non- biological origin each having a maximum diameter of <50μιη.

The pliable building material of the second aspect of the invention also comprises a plurality of fibres of non-biological origin each having a maximum diameter of <50μιη (and in preferred embodiments no other fibre material is included in the building material). Each of said fibres can be any substantially elongate structure provided that its largest cross-sectional distance is <50μιη, preferably <48μιη, preferably <45μιη, preferably <40μιη, more preferably <30μιη (and wherein its smallest cross-sectional distance is preferably >5μιη, more preferably >10μιη). In preferred embodiments each of said fibres has a substantially uniform cross-section, and preferably said cross-section is substantially circular. Preferably, the length of each fibre is between 2mm and 150mm, more preferably between 5mm and 50mm, more preferably between 5mm and 40mm most preferably between 8mm and 28mm.

Each of the said fibres for use with both aspects of the invention is of non-biological origin or has a coating of non-biological origin, i.e. has not been synthesized by a biological organism and is not a biopolymer (a polymer that can be synthesized by an organism and including nucleic acids, polypeptides, polysaccharides and lipids). The use of alternative, so- called synthetic fibres avoids the problem of degradation of the fibre (either in a stored wet mix or in the set material itself).

It has surprisingly been found that the use of said plurality of fibres in the building material of the invention provides at least one of the following (in relation to the pliable building material and/or a substantially solid building material formed by the setting of said pliable building material, as appropriate): increased adherence to many different building substrates, including a substantial and reliable adherence to a number of substrates that previously could not be effectively plastered/rendered using a lime-based product, such as dry blocks and construction board (enabling the use of lime-based plasters in the new build environment) reduced cracking at junctions/interfaces of mixed-material substrates, increasing the versatility of the material (especially in the traditional build environment). improved impact resistance, enabling the use of lime-based building materials for load-bearing finishes or structures skim work is enabled; this in turn enables quick and efficient repair of (and thus conservation of) worn or damaged walls and ceilings. increased structural flexibility; this enables the material to yield better to thermal changes and to structural movement of building fabric, which is particularly useful in historic buildings without foundations. increased tensile strength; this reduces the breakage of plaster keys and helps to prevent the cracking of the set material when dimensional changes pull against its width. improved fire resistance improved surface appearance (the fibres do not breach the surface of the material) decreased shrinkage and perimeter cracking and shearing improved freeze/thaw resistance improved thermal insulation

Furthermore, the skill and time required to apply the pliable building material of the invention is decreased, whilst the need for pre- and after-care (and corresponding volume of water for damping down) is reduced (in turn reducing labour and water costs).

In addition, the building material of the invention retains a number of properties of prior limed-based and synthetic fibre-containing building materials, such as: permeability/breathability of the material substantial longevity of the fibre and hence of the pliable (e.g. stored) building material and the set product itself the ability to be pumped or sprayed

In preferred embodiments the fibres comprise a plastics material, preferably polypropylene. An additional advantage of using polypropylene is that this particular plastics material is readily recycled. Alternatively, the fibres comprise carbon fibres or glass fibres. Optionally the fibres are not metallic. In preferred embodiments the fibres are coated (partially or fully) with a surfactant; in particular this assists with the dispersion of the fibres within the building material.

In preferred embodiments, the fibres constitute at least 0.01 % of the mass of the pliable building material, preferably at least 0.02%, more preferably at least 0.1 %, and more preferably at least 0.2%.

A number of additional components can be added for a range of purposes. For example, in preferred embodiments the pliable building material further comprises an insulation material (i.e. a material that can reduce the rate of heat transfer through the material). Such material could be for example hemp, perlite, pumice, vermiculite, expanded clay or expanded glass. Alternatively (or in addition) the pliable building material further comprises a non-binding material that produces a pozzolanic effect (i.e. a material that can be considered not to be used within the binding agent but as an additional, pozzolan component), such as fly ash. Such material increases the hydraulic set of the pliable building material and typically increases the compressive strength of the set material.

Set products

The invention also provides a substantially (or completely) solid building material formed by the setting of the pliable building material of the invention. As described above, this setting might require carbonation (for non-hydraulic material) or might occur under water (for hydraulic material).

The invention thus further provides a panel for a building (e.g. suitable for constructing or covering walls and ceilings, such as a wallboard [further e.g. as a fireboard]) comprising said substantially solid building material. Also provided is a structural element for a building (such as structures made in situ such as a foundation or floor, or portable structures such as lintels) comprising (or consisting of) said substantially solid building material. Further provided is a floor, wall, door or ceiling of a building to which the substantially solid building material of the invention has been applied.

The invention provides the use of the substantially solid building material of the invention as a plaster or render for a wall (internal or external), door or ceiling, where the substance can act as a finishing material or a base for a finishing material, an insulating material, a waterproofing material and/or fireproofing material. The substantially solid building material of the invention can also be specifically used as a fireproofing material (where the material reduces the transfer of fire between two spaces and/or reduces the adverse effects of fire on an underlying material) or thermal insulation material (where the material reduces heat transfer between two regions separated by the material).

The substantially solid building material of the invention can further be used as a masonry mortar or grout, as an adhesive, as a screed for a floor, or as a structural element for a building.

The invention further provides the use of a plurality of fibres of non-biological origin, each having a maximum diameter of <50μιη, to have any one, any combination, or all of the following effects on a lime-based building material: to increase adherence to a substrate (especially a wall or ceiling substrate), in particular to a plasterboard, fireboard, plyboard, foil-faced PIR insulation, scratched glass, metal (e.g. aluminium), dry brick, dry block and/or adobe to reduce cracking at a junction/interface of a mixed-material substrate to increase impact resistance to enable skimming to increase structural flexibility to increase tensile strength to improve fire resistance to improve surface appearance (e.g. to provide a finish whereby the fibres do not breach the surface of the material) to decrease shrinkage and/or perimeter cracking and/or shearing to improve freeze/thaw resistance to improve thermal insulation to reduce the skill and/or time required to apply to reduce the need for or amount of pre- and after-care (and/or corresponding volume of water for damping down)

Precursor Products

The invention also provides a composition suitable for the manufacture of the pliable building material of the invention, said composition comprising said binding agent and said plurality of fibres. Such a composition offers a relatively lightweight and less bulky product that can be more efficiently stored and transported and provided to a user who can then add standard components as necessary to complete the building material (e.g. an aggregate of choice). In an aspect of this composition of the invention, said composition is substantially free of water. This aspect is preferred if the composition provides a hydraulic set - otherwise water in the composition would immediately initiate a setting process (irrespective of carbonation), reducing the potential for storage of the composition. In preferred embodiments of this aspect of the invention, said composition additionally comprises the following components of the pliable building material: the aggregate and/or

the insulation material and/or

the non-binding material that produces a pozzolanic effect.

To form the pliable building material of the invention the user then simply needs to add an appropriate amount of water (and any further required components) and mix.

In an alternative aspect of the composition of the invention, said composition comprises water (and is e.g. in the form of a paste). This aspect can be chosen if the composition provides a non-hydraulic set - the composition can be stored in 'wet' form without setting provided that access of the material to carbon dioxide is limited. To form the pliable building material of the invention the user then simply needs to add an aggregate, and any required insulation and/or non-binding material that produces a pozzolanic effect, and mix. To manufacture this aspect of the invention, a dry mix (i.e. substantially free of water) comprising the binding agent and the fibres can be mixed with water. Alternatively, a solution comprising the fibres (e.g. in suspension) can be formed, and then mixed with the binding agent (which can be provided e.g. in dry form or as a water-comprising form e.g. a lime putty).

The following examples exemplify the second aspect of the invention. Examples

Example 1 - preparation of building material and of comparator materials.

Example building material of the invention - LFC-FF

Composition:

1 X 15L gauge of water

1 X 15L gauge of lime putty [L]

3 X 15L gauge fine (powdered) chalk [FC] (<50μιη)

100g of polypropylene monofilament fibres (PPMF) at 18mm length and 22 micron diameter, coated in surfactant [FF]

The fibres were mixed with the water until evenly dispersed. The lime putty was then added and mixed into an even consistency. With further mixing the fine chalk (an aggregate) was finally added.

Comparator building material - LCC-H

• Crushed chalk [CC] was used instead of FC

• 200g goat hair [H] was used instead of FF

Preparation as per LFC-FF, except that the hair was added last in the mixing process.

Comparator building material - LFC-H

• 200g goat hair [H] was used instead of FF

Comparator building material - LFC-CF

• 100g coarse fibre [CF] - polypropylene fibrillated fibres at 20mm length and 50 micron diameter, coated in surfactant - was used instead of FF

Preparation as per LFC-FF. Example 2 - summary of results from experiments of Examples 3 to 24. NB - PP = polypropylene

Perimeter test mm 513.3 1773.3 1558.3 1233.3 Significantly less perimeter shrinkage in LFC-FF when compared with the other materials

Shear test 1-5 scale 5.0 1.0 1.3 3.3 LFC-FF showed no signs of shearing compared with the other materials

Freeze-thaw 1-5 scale 4.6 2.0 2.0 2.0 LFC-FF can test withstand low

temperatures without significant damage, in contrast with the other materials

Thermal SEE EXAMPLE

resistance test 16

Application Minutes 5.2 10.4 10.0 6.7 LFC-FF can be time test applied and finished in reduced time compared with the other materials

Water Litres 0.4 0.7 0.6 0.5 The other materials consumption require more water to produce and control compared with LFC-FF

Permeability Hours 98.3 96.0 100.7 96.0 No significant test 1 differences

Permeability Hours 23.0 24.3 24.0 24.3 No significant test 2 differences

Reinforcement Years 100.0 1.2 1.2 100 PP fibres in external life renders have an extended life when compared to hair reinforcement

Reinforcement Months 60.0 1.0 1.0 60.0 PP fibres have storage life significantly

increased storage life in a wet alkaline environment.

Spray test 1-5 scale 4.0 1.0 1.0 4.0 PP fibres have

enabled reinforced lime to be sprayed.

Reinforcement 15L bucket 0.0 1.4 4.0 0.0 Clump rate requiring clump rate discard was

eliminated in LFC-FF and LFC-CF. Example 3 - Adherence Tests

13 common construction substrates were tested (see next page) using the 5-point scale below:

1 = When dry, test plaster can be lifted off by hand

2 = When dry, test plaster can be torn off by hand

3 = When dry, test plaster can be removed by tapping one-three times with a 75mm wide bolster

4 = When dry, test plaster will not come off by tapping one -three times with a 75mm bolster but has cracked and shows some small signs of background separation

5 = When dry, plaster has full adherence, tested by trying to repeatedly chisel off with 75mm bolster showing no sign of background separation

An average for each building material was calculated; this series of tests was repeated twice over:

Series Ambient Sample size Average LFC- LCC-H LFC-H LFC- No Temp Sample FF CF weight +/- 2g

1 17°C 100 x 100 x 80g 4.1 2.3 2.5 2.8

8mm

2 17°C 100 x 100 x 80g 4 1.9 2.4 3

8mm

3 17°C 100 x 100 x 80g 4.1 1.8 2.4 2.8

8mm

Total 12.2 6.0 7.3 8.6 score

Mean 4.1 2.0 2.4 2.9 score Series 1 data -

Conclusion -

LFC-FF has significantly greater adherence compared with the other materials (generally), and shows a substantial and reliable adherence to a number of substrates that previously could not be effectively plastered/rendered using a lime-based product, such as dry blocks and construction board.

Example 4 - Interface Crack Test

Panels were made with 6 different substrates resulting in 5 interfaces. The panels were plastered over with 3-12mm of building material and the interface cracking was measured. Results show length of interface cracks (mm).

LFC-FF shows significantly less interface cracking compared with the other materials.

Example 5 - Impact test

A sphere of 60mm diameter weighing 300g was dropped on the samples from a height of 300mm; the number of times a sample withstood the impact before being compromised was counted for each sample.

LFC-FF can withstand a significantly greater impact than the other materials. Example 6 - Pre-form test

Using a spring balance (kilo scale) the material preforms were bridged between two points 450mm apart and pulled at their centre. The action was recorded on video to establish the true failure point; measurements given in kg:

LFC-FF performs significantly better than the other materials in withstanding impact. Example 7 - Skim work

Lightweight blocks were turned on their sides to create a maximum background suction rate; these blocks were skimmed with 2mm of plaster. A 5-point scale was used to assess skimming:

1 = complete delamination of skim

2 = partial delamination of skim

3 = adherence of skim but with defects

4 = good adherence with small amount of defects

5 = complete adherence with no defects

Skim work is not possible with any of the other materials but has been enabled by the development of LFC-FF.

Example 8 - Flexibility Test

Samples were slowly bent over graph paper until a significant crack appeared at which point the profile was plotted on the graph. The crack point was also plotted. One side was held at 90° to the graph and the point at which the crack appeared was measured against the vertical plane; results given in angle degrees.

LFC-FF is significantly more flexible than the other materials.

Example 9 - Tensile Strength Test

The samples were clamped between timber jaws at each end, and pulled apart using a 25kg spring balance until they fractured. A video was taken of the spring balance scale to see clearly what strain it reached before fracture; measurements given in kg:

LFC-FF had a significantly greater breaking strain compared with the other materials.

Example 10 - Fire Resistance Test

Sample sizes 80mm x 30mm x 3mm with an exposure area of 50mm x 30mm x 3mm had a 1995°C torch held at a 50mm distance and heated until they could no longer support their weight and collapsed; this was timed and outcome provided below in minutes:

LFC-FF is significantly more resistant to a flame than the other materials, especially in comparison with LFC-CF.

Example 1 1 - Finished Appearance Test

A 5-point scale was used to score the level of finish of each material:

1 = Poor surface texture with high defect rate

2 = Poor surface texture with defects

3 = Acceptable surface texture with low defect rate

4 = Good surface texture with no defects

5 = Excellent surface texture with no defects

(where defects include cracks, unevenness and visible reinforcement showing through the material surface).

The finished appearance of LFC-FF is significantly better than the other materials, especially in comparison with LFC-CF.

Example 12 - Shrinkage Crack Test

Wood lath panels were constructed, divided into two, and then plastered; the total all visible cracks was then determined (mm):

LFC-FF showed no signs of shrinkage, in contrast to the other materials.

Example 13 - Perimeter Test

Wood lath panels were constructed, divided into two, and then plastered; the total all individual perimeter cracks was then determined (mm):

There was significantly less perimeter shrinkage in LFC-FF when compared with the other materials.

Example 14 - Shear test

A 5-point scale was used to score the level of shear of each material from 3.6N aerated blocks (which were chosen as substrate because of their high background suction rate):

1 = significant shrinkage leading to total delamination

2 = shrinkage with partial delamination

3 = shrinkage with delamination by removing by hand

4 = a mix of delamination and adherence with small signs of shearing

5 = no delamination or shear

LFC-FF showed no signs of shearing compared with the other materials.

Example 15 - Freeze-thaw Test

Samples were immersed in water for 10 minutes and placed in a freezer for 24 hours at -20°C. Samples were allowed to defrost for 8 hours and the process repeated 4 times for each sample. A 5-point scale was used to score the level of freeze-thaw resistance:

1 = sample has been completely compromised

2 = sample has been compromised but still holds together

3 = sample has been affected requiring repair

4 = sample shows some signs of damage

5 = sample shows no signs of damage.

LFC-FF can withstand low temperatures without significant damage, in contrast with the other materials

Example 16 - Thermal Resistance Test

Two boxes of PIR insulation board were constructed with a partition space between the two; samples were sealed in the partition space and the resistance of 40°C from the lower box through the sample to the upper box (starting temperature 21 °C) was measured at equilibrium (3-4hr):

LP-FF: as per LFC-FF except perlite [P] was used instead of FC

LS-FF: as per LS-FF except sand [S] was used instead of FC

PB = plasterboard

PS = polystyrene

LFC-FF performed better than, inter alia, LFC-CF. The insulation properties of LFC-FF were further improved by using perlite instead of fine chalk as the aggregate. Example 17 - Application Time Test

Three wood lath panels were constructed, each divided into two and then plastered with a 20mm layer of building material. Pre- and after-care was employed when required. Total application time was recorded in minutes:

LFC-FF can be applied and finished in reduced time compared with the other materials. Example 18 - Water Consumption Test

Lightweight blocks were plastered with building material and the water requirement was measured. [Pre- and post-damping down water was measured as well as product content] Measurements given in L:

The other materials require more water to produce and control compared with LFC-FF. Example 19 - Permeability test 1

Boxes of each building material were made. Once dried to 11 % wood moisture equivalent (wme), 500ml of water was sprayed inside through an entry hole. The hole was plugged and wme readings were taken at timed intervals on all box sides to determine the rate of diffusivity (until the box returned to 1 1 % wme). The same box was used to repeat the test. Measurements given in wme/hr:

There was no significant difference in permeability between LFC-FF and the other materials.

Example 20 - Permeability test 2

100g samples had 35g (35ml) water added to them and placed in a room at 30°C. The time taken for the samples to return to a mass of 100g was measured (hours):

Example 21 - Reinforcement Life

Accelerated degradation of PP fibres in a wet alkaline environment was tested and shown to have a life expectancy of at least 100 years. In contrast, three recently lime-plastered properties (Dedham, Nedging and Weatheringsett, all in Suffolk, UK) were checked for surviving hair content; as a result the expected lifespan of hair in these external renders was estimated to be 1.2 years. (Note that LFC-H is assumed to have the same degradation rate as LCC-H.) Thus PP fibres in external renders clearly have an extended life when compared to hair reinforcement.

Example 22 - Reinforcement Storage Life

Accelerated degradation of PP fibres in a wet alkaline environment was tested and shown to have a life expectancy of at least 100 years. It is thus expected that materials comprising PP fibres as reinforcement can be stored for at least 5 years (i.e. 60 months). In contrast, LCC-H and LFC-H displayed an average reinforcement degradation of 75% after only one month. Thus PP fibres clearly provide significantly increased storage life in a wet alkaline environment in comparison with hair reinforcement.

Example 23 - Spray Test

The building materials were put into a spray hopper to determine the ability to apply the materials via spraying; both single and triple nozzle spray heads were used. A 5-point scale was used to score the results:

1 = the material failed to spray

2 = the material sprayed but not effectively

3 = the material sprayed but gave poor performance

4 = the material sprayed effectively enough to be productive

5 = the product sprayed with full efficiency

PP fibres have enabled reinforced lime to be sprayed. Example 24 - Reinforcement Clump Rate Test

12 X 15L buckets of LFC-FF and of LFC-CF were made on the production site and no clumps were found. In contrast, when 12 X 15L buckets of LCC-H and LFC-H were made, 17 and 12 clumps (respectively) were found which required discard. Clump rate requiring discard was therefore eliminated in LFC-FF and LFC-CF.

Claims

1. A pliable material for use in building, said material comprising: water,

an aggregate of particle size less than 50μ,

a binding agent comprising at least 70% calcium hydroxide, and

a plurality of fibres.

2. A material according to Claim 1, wherein the aggregate is selected from chalk, marble, limestone, calcium silicate or sand or mixture thereof.

3. A material according to Claim 1 or Claim 2, wherein the aggregate is selected from pumice, expanded clay perlite or silica glass or a mixture thereof.

4. A material according to any preceding claim wherein the binder includes a clay, linseed oil or casein.

5. A material substantially as herein described wherein the fibres are of non-biological origin or coated with a material of non-biological origin.

6. A material according to Claim 5, wherein the fibres are selected from polypropylene (PP), PMF, alkaline resistant glass fibre, cellulose or casein.

7. A material according to any preceding claim, wherein the fibre lengths are from 2 - 150 mm in length.

8. A material according to Claim 7, wherein the fibre length is from 2 - 40 mm.

9. A material according to Claim 8, wherein the fibre length is from 2 - 8 mm.

10. A material according to any preceding claim, wherein the width of the fibres is from 2 - 70μ.

1 1. A material according to any preceding claim, wherein the fibre is present to an amount up to 20 kgm³

12. A material according to Claim 1 1, wherein the fibre is present in the material in an amount of fro 2 - 4 kg per cubic metre.

13. A material according to Claim 12, wherein the material is present in an amount of from 2.1 - 4.0 kg per cubic metre.

14. A material according to Claim 13, wherein the material is present in an amount of from 3.0 - 4.0 kgm ³.

15. A pliable material substantially as herein described.