WO2003035571A1

WO2003035571A1 - Flame resistant, thermal and phonic insulating compositions, building elements made therefrom and methods of production

Info

Publication number: WO2003035571A1
Application number: PCT/IB2002/004433
Authority: WO
Inventors: Yvan Werner; Pierre Noel Ventalon
Original assignee: Yvan Werner; Pierre Noel Ventalon
Priority date: 2001-10-23
Filing date: 2002-10-23
Publication date: 2003-05-01
Also published as: FR2831162B1; FR2831162A1

Abstract

The present invention relates to flame resistant, thermal and phonic insulating compositions, comprising a mixture of: a hydraulic binding agent; water; sand; and a particulate rubber material, wherein the particulate rubber material has a particle size comprised between about 2 mm to about 7 mm and is present in a proportion of between about 20% to about 80% with respect tot he total volume of the dry mixture. Building elements and methods for the manufacture of said compositions and building elements are also included.

Description

FLAME RESISTANT, THERMAL AND PHONIC INSULATING COMPOSITIONS, BUILDING ELEMENTS MADE THEREFROM AND METHODS OF PRODUCTION

The present invention relates to the field of building techniques, and in particular to building materials, and more specifically compositions that are used as building elements' or can be used to make building elements. The invention is more particlularly concerned with compositions that have improved phonic, and thermal properties, that are intended to be incorporated or used in the primary or secondary structure of a building, and may therefore also include prefabricated building elements that are made up of the compositions of the invention.

One well known example of a building material is concrete. Such a material, before curing or setting, generally comprises cement, sand and water. It is known to add various additives to improve the properties of the concrete, or to lend the properties of these additives to the concrete. Once set or cured, the concrete has a given set of thermal and phonic capabilities that are generally rather limited and do not enable satisfactory dampening of sound transmission.

For example, it is known from prior art document FR 1 259 487 to make a composite material intended to provide a composite concrete screeding having phonic insulation properties. The composition contains portland cement, powdered rubber and a polymer emulsion.

Another document, NL 69 02 138 describes a screeding composition containing portland cement, an acrylic-styrene resin suspension, rubber flour, rubber granules and rubber fibres.

Still yet another document, FR E 50 140 discloses the use of styrene-butadiene suspensions in cement compositions also comprising rubber, for the manufacture of screeding.

In another document, FR 2 437 478, a composition for a phonically insulating screeding to be placed beneath tiling is described. The composition contains a mixture of an emulsion of carboxylated polymer with a solid component containing cement and rubber grains and fibres.

All of these prior art compositions use polymer emulsions or suspensions, or polymerisable emulsions, and that they are intended for all types of screeding composition, that is to say, for finishing works of buildings, for which a particular mechanical resistance is not required, but more so of a capability to bind an underlying concrete slab and an overlaid tiling floor or other floor covering, as well as a relative flexibility designed to absorb shocks.

The problem with the solutions proposed by the prior art is the cost of the concrete or cement compositions that use polymer or polymerisable dispersions or suspensions. The addition of such expensive additives makes any building elements made therefrom too costly to be of any large scale industrial interest, and thus limits their field of application. Accordingly, it is an object of the invention to provide a composition that will be applicable over a broad spectrum of building applications, and also applicable to several types of building element, while maintaining or improving the known thermal and phonic insulating properties, and also providing fire resistance. One of the objects of the present invention is therefore a composition comprising a mixture of :

-a hydraulic binding agent ;

-water ;

-sand;

-and a particulate rubber material, wherein the particulate rubber material has a particle size comprised between about 2 mm to about 7 mm and is present in a proportion of between about 20% to about 80% by volume with respect to the total volume of the dry mixture.

It is to be noted that these four components alone are sufficient to provide the necessary flame resistance, and phonic and thermal properties which the invention intends to provide, but that it will also be possible to optionally provide for the addition of one or more additives, or other improvers, such as setting retarders or accelerators, colorants, dyes, fillers, surface smoothing agents, etc.

Surface smoothing agents are substances that are designed to smooth the outer surface of the structures that are made with hydraulic binding agents, e.g. screed floorings. A commonly used surface smoothing agent is anhydrous calcium sulfate. Where a surface smoothing agent is used in the compositions of the present invention, this is therefore preferably anhydrous calcium sulfate, but other agents known to the skilled person may be used instead. A composition according to the invention incorporating such a smoothing agent has faster drying characteristics, and improved water infiltration resistance, and can therefore be used in buildings where water infiltration can be a problem, or in bathrooms, water closets, showers and the like.

By "building element", it is meant precast, cast or otherwise formed structures, that form part of, or are used to create a building. Such elements are well known in the art and comprise, breeze blocks, pillars or columns, generally non-load bearing cast walls or partitions, cast floors, screeds, drawn floors, and filler walls, e.g. walls that are created by pouring concrete between two pre-existing load bearing walls, ceilings and the like.

By "hydraulic binding agent", it is meant a generally powdered or particulate natural or synthetic mineral compound or composition that when mixed with water will set hard to form a solid material. Suitable "hydraulic binding agents" are various types of cements, e.g portland cement, CPA portland cement, CPJ portland cement, plaster, gypsum, aluminosilicates, and the like that are well known as such to the skilled person and commonly available.

By "particulate rubber material", it is meant rubber particles that are obtained from shredding, tearing or grinding of rubber, for example, waste rubber originating from cut offs from the manufacture of drive or conveyor belts, or for example rubber originating from used tyre recovery and recycling. The size of the rubber particles has advantageously been determined by the present inventors as being comprised from about 2 mm to about

7 mm, and preferably from about 3 mm to about 5 mm, and most preferably 4 mm.

According to the compositions of the present invention, it has been possible to incorporate particulate rubber material as defined above in quantities that were never thought possible before while maintaining the resistance to inflammation.

For screed floors, an average granulometry of about 4 mm for the particulate rubber material is preferred.

For application of the compositions in the manufacture of building elements such as precast walls having a thickness greater than or equal to 25 mm, the applicants have determined that a granulometry of between about 3 mm to about 7 mm is preferred, and most preferably one can use an average granulometry of 5 mm. For other building element applications, the applicants prefer to use an average granulometry in the range of from about 2 mm to about 7 mm, and most preferably an average granulometry of 4 mm. When used herein with respect to the rubber particle size, the term "average" refers to the median of a distribution of particles of particulate rubber material.

The shredding, tearing or grindin process of the particulate rubber material has an impact on the compositions of the present invention, and preferably the rubber particles advantageously have a completely irregular shape. Rubber particles prepared in this way have the required elasticity and surface roughness enabling them to be incorporated into the cement and water mix and to produce the flame resistant, thermal and phonic insulating compositions according to the invention.

Preferably, the particulate rubber material is used in a quantity corresponding to about 20% to about 60% of the total volume of dry components, which represents about 10% to about 30% by weight with respect to the total weight of the mixture. In general, the ratio of cement to water in the compositions of the present invention is about 0.75:1 , whereas traditional concrete compositions have a ratio of cement to water of about 0.5:1. It will therefore be appreciated that the compositions of the present invention have far less water than those of traditional concrete compositions, whilst still maintaining inflammability, mechanical properties, and advantageous thermal and phonic insulating properties. Indeed, excess water content is a disadvantage in compositions of the present invention, since it makes them too liquid to be able to work with, causes loss of integration of the particulate rubber material and of course leads to much longer curing times, the latter being especially redhibitory for its economic impact on construction and manufacturing turn around times. Furthermore, too much water is deleterious to the compositions of the present invention, because it washes the particulate rubber material and reduces the adhesion of the hydraulic binding agent to the former. This is one of the problems that occurs with compositions such as that proposed in German DE 2 213 034, which have a very high water content. In particular, where screed compositions according to the invention are made, the water content is preferably only from about 7 to about 12% water by total weight of the other dry components.

In another preferred embodiment, the hygrometry, that is to say, the percentage of water vapour present in the element as measured by an electric current sent across the element between two electrodes, of precast building elements made from compositions according to the invention will be about 5% humidity, whereas for building elements that are demolded after curing for, say 12 to 48 hours, it will preferably be about 7 to 12%. Another object of the present invention is a concrete, having improved flame resistance, phonic and thermal absorption or insulation properties, that can be used to manufacture building elements or components that are not load bearing in buildings, for example by pouring the concrete in situ into preplaced and prefixed building moulds, or by pouring it into moulds of a suitable size and shape for making prefabricated, non-load bearing building elements.

In a preferred embodiment, another object of the invention is to make prefabricated building elements, but this should not exclude from view the possibility of producing other forms of elements and other modes of use or application of the compositions according to the present invention.

When the present applicants refer to non load-bearing building elements, it is to be understood that these include, but are not limited to, horizontal or vertical building elements, such as outer non load-bearing walls, partitions, flooring blocks, and breeze blocks.

The invention will also find application in building elements that are not strictly speaking structural building elements, such as cladding panels, curtain walls and alabaster type or cement based wall coverings.

It is to be noted that in the detailed description of concrete compositions that follows, the cement and particulate rubber material are components that are generally provided in packets or sachets, whereas the sand will be generally available quarry or dredging sand, or whatever form of sand may be available at the building site or in the neighborhood. In addition, in one preferred embodiment of the invention, the sand is a sand obtained by crushing or grinding porous volcanic rock, e.g. pouzzolane, or pumice. The use of such types of sand lowers the mass of the overall composition and any building elements made therefrom, making them easier and cheaper to manipulate, store and transport.

In another aspect of the present invention, there is provided a mixture of CPA or CPJ cement and particulate rubber material, ready for use for the manufacture of concrete, comprising a proportion of particulate rubber material between about 20% to 80% with respect to the total volume of the mixture.

In a preferred embodiment of the present invention, the particulate rubber material is obtained by grinding or shredding rubber that has advantageously been recovered from used tyres, and even more preferably, such particulate rubber will have undergone, at least in part, an expansion step.

The optional, yet advantageous expansion step, involves either hammering the particulate rubber material, for example in a hammer and anvil apparatus, or crushing the particulate rubber material in between rollers. The particulate rubber material passes through the hammer/anvil apparatus or the rollers before being packaged into sachets, bags or sacks. The inventors have noticed that this optional step surprisingly creates one or more cavities within the center of the particulate rubber material, but also lacerates the outer surface of the particles, which consequently become porous. From then on, the air trapped in the central cavities seems to increase the phonic and thermal insulating properties of the particulate rubber material, whereas the porous surface increases adhesion to the mixture of sand and cement. On the whole, the general phonic and thermal insulating properties of the particulate material are noticeably increased with respect to untreated particulate rubber material.

Without wishing to be bound by theory, the present inventors suppose that the increase in favourable properties is due to an electrostatic effect, and in particular, an electrification or electrostatic polarisation of the particles during the expansion step, that is maintained when the particulate material is mixed with the mixture of cement, sand and water. In yet another object of the present invention, there is provided a method for manufacture of the compositions according to the invention, comprising :

-mixing all of the water with the hydraulic binding agent ;

-mixing a particulate rubber material with the water/cement mixture thus formed ;

-mixing the sand with the mixture from the foregoing step,

-wherein the particulate rubber material has a particle size comprised between about 2 mm to about 7 mm and is present in a proportion of between about 20% to about 80% with respect to the total volume of the mixture.. Such a method is applicable both on a small scale, for example for a domestic user or workman wishing to make up a small amount of composition according to the invention, as well as on an industrial, using precast building element apparatus well known to the skilled person, e.g. using vibration molds, immediately followed by a demolding step. In such a case, it is most preferred to use quantities of particulate rubber material in the range from about 23% to about 25% of the total volume of dry mixture.

Where the building elements are only demolded after curing, e.g. for between 12 and 48 hours, it is preferred to use higer quantities of particulate rubber material, and most preferably quantities of particulate rubber material representing 60% of the total volume. An example of a preferred formulation used on an industrial scale is the following: -90 kg particulate rubber material, average granulometry 4 mm

-105 kg cement

-520 sand 0/5

-260 gravel 5/10 The total volume of the mixture is about 800 litres, wherein 90 kg of particulate rubber material represents about 180 I i.e. 1/5 of the total volume of the mixture and therefore 20% of the volume.

Description of the Figures

The present invention will be better understood, and other preferable aspects of the invention come to light, in reference to the detailed description and explanation of the annexed figures in which :

-Figure 1 is a schematic representation of a particulate rubber material obtained from grinding industrial rubber prior to treatment;

-Figure 2 is a similar schematic representation of a particulate rubber material originating from ground rubber from a used tyre before treatment ;

-Figure 3 is a schematic illustration of a particle of Figure 2 after the expansion step treatment ;

-Figure 4 is a section view of the treated particle of Figure 3 ;

-Figure 5 is a schematic side-view representation of a hammer and anvil apparatus used in the expansion step for treating the untreated rubber to provide the particulate rubber material used in the compositions of the present invention ;

-Figure 6 is a schematic side-view representation of a crushing roller apparatus used in the expansion step for treating the untreated rubber to provide the particulate rubber material used in the compositions of the present invention ; -Figure 7 is a schematic side-view representation of a prefabricated slab made with a concrete composition according to the present invention, the shape of which has been optimized to give the best performance ;

-Figure 8 is a chart of the phonic insulating properties taken from Table II.

Detailed Description of the Invention

The following table also provides a list of compositions falling within the scope of the present invention, that provide the desired phonic and thermal insulation properties of a building element product based on those compositions.

TABLE

Table II shows the results of testing the compositions of the invention as indicated above for the phonic insulation capabilities, using the percentage of sound transmitted through samples of precast and set building elements that were 6cm thick, in accordance with the French and European standards NF EN ISO 140-3 and 140-6. TABLE II

In the above table, the mixture of particulate rubber material at 40% by. volume corresponds to the mixture II of table I, and the mixture of particulate material at 80% by volume corresponds to mixture V of table I. It is evident from these tests that a composite material made from the compositions of the present invention has far better phonic absorption or insulation capabilities than rockwool.

As mentioned briefly above, Figure 1 shows a particle of untreated particulate rubber material, when viewed under a microscope with 20x enlargement. The particle is obtained from the grinding or shredding of industrial rubber, for example from waste or cut-offs from conveyor belt manufacture. The structure is smooth, compact and homogenous, even though the particle has a generally angular relief.

In Figure 2, one can see another particle of rubber material that originates from used tyre recovery. The particle is not so smooth, and has greater general surface roughness. Concrete building elements made from compositions containing such particles have better phonic properties than those of the particles of Figure 1.

Figure 3 shows a particle of particulate rubber material according to the invention that has been expanded by hammer and anvil treatment. The particle has a much higher volume, its surface appears more fibrous, and the particle has become softer to the touch.

In the section of Figure 4 of a particle similar to that of Figure 3, one can distinguish cavities 2, 3 near to the centre^" of the particle 1 , and the open, alveolar 4 aspect of the outer surface of the particle.

In Figure 5, a hammer and anvil apparatus is shown schematically in a side-view, where the anvil 5 is sloping and one or more hammers 6 are arranged along the slope. The untreated particles are poured down the slope from a hopper 7, and as they fall down, are hammered by the falling movement of the hammers against the slope of the anvil. The particles exit the apparatus at the bottom of the slope and are collected on a belt that takes them on to a bagging unit. In Figure 6, a crushing roller unit is shown schematically from the side. The apparatus comprises a series of paired 11 parallel rollers 12, separated only by a very short distance, for example, between 1/10 and 5/10 of a millimeter. Preferably, the apparatus comprises three pairs of rollers, superposed in a vertical channel 13.

In Figure 7, a slab is shown comprising pretensioned struts 15 or girders and ribbed Hourdis stones or bricks 16. The bricks are made from compositions according to the present invention and fit ideally into the gaps between the pretensioned struts 15 with slight compression, such that the ribbed ears or extended shoulders 17 slot in and around the I shaped struts. This construction is a very efficient fire barrier, since the prefabricated Hourdis bricks made with compositions of the present invention are also fire resistant. Furthermore, the lower surface 18 of the extended shoulder 17 enables other components to be affixed underneath, by screwing, such as a false ceiling, whereas the vaulted space remaining 19 enables the run through of cabling and electrical wiring, heating and air conditioning ducts and the like. This extra space also offers complementary sound absorption in addition to that provided by the compositions of the present invention.

In the chart in Figure 8, one can see the noteworthy performances with regard to phonic insulation of the mixtures numbers II, represented as curve (b), and V, represented as curve (c), in comparison to curves (a), representing traditional concrete, and curve (d), representing rockwool. This shows that the particulate rubber material incorporated into compositions adapted for building elements shows excellent phonic insulation characteristics compared to known solutions.

Furthermore, the applicants have also discovered that compositions according to the present invention have exceedingly good resistance to fire. In industry standard tests, known as M1 and M2 classification of inflammable materials, the compositions of the present invention were capable of obtaining these classifications. Some examples are given hereafter : Example 1 :

A first composition according to the invention was prepared with the following :

-150 kg sand

-30 kg cement

-25 kg water

-18 kg of particulate rubber material, with an average granulometry of 4 mm Ratio of particulate rubber present : (150+30)/ 10 =18

18 kg of particulate rubber represents about 36 I, i.e. 20% of the total volume of the mixture.

Example 2 :

A second composition was according to the invention was prepared with the following :

-150kg sand

-40 kg cement

-30kg water

-57 kg particulate rubber Ratio of particulate rubber present : ((150+40)/10)x3 = 57

57 kg of particulate represents about 114 1, i.e. 60% of the total volume of the mixture. This formulation was also tested for its phonic insulation properties

Example 3 : M1 and M2 flame resistance test

Set or cured concrete compositions containing cement, sand, water, and particulate rubber material, in accordance with examples 1 and 2 respectively, were prepared for M1 and M2 testing. The tests M1 and M2 are standard tests corresponding to French norm NF-P-92- 501. In the M1 and M2 flame resistance test standard, a 30x40 cm sample of the concrete is angled at 45° to a radiating electrical heat source placed at 3 mm from the sample. The gases that evolve during heating passed over igniters that are arranged around the sample. The test lasts 20 minutes. The criteria retained for assessing flame resistance are : initial time to inflammation, flame height, and duration of inflammation. The material according to the invention did not even catch fire, and easily attained the M1 and M2 classification with an effective index of 0/15 for M1 and 3.99/15 for M2 respectively, where an index of 15 indicates a product that is highly inflammable, and an index of 0 means a product that does not essentially catch fire.

Claims

Claims :

1 )Flame resistant, thermal and phonic insulating composition, comprising a mixture of :

-a hydraulic binding agent ;

-water ;

-sand;

-and a particulate rubber material,

-wherein the particulate rubber material has a particle size comprised between about 2 mm to about 7 mm and is present in a proportion of between about 20% to about 80% with respect to the total volume of the dry mixture.

2)Composition according to claim 1 , wherein the composition also contains one or more additives, or other improvers, such as setting retarders or accelerators, colorants, dyes, fillers, surface smoothing agents

3)Composition according to claim 2, wherein the surface smoothing agent is anhydrous calcium sulphate.

4)Composition according to any one of claims 1 to 3, wherein the hydraulic binding agent is chosen from the group consisting of portland cement, CPA portland cement, CPJ portland cement, plaster, gypsum, aluminosilicates, and the like.

5)Composition according to any preceding claim, wherein the particulate rubber material is made up of rubber particles that are obtained from shredding, tearing or grinding of rubber.

6)Composition according to claim 5, wherein the rubber is waste rubber originating from cut offs from the manufacture of drive or conveyor belts, or rubber originating from used tyre recovery and recycling.

7)Composition according to claim 1 , wherein the size of the particulate rubber material is comprised from about 3 mm to about 5 mm. 8)Composition according to claim 1 , wherein the size of the particulate rubber material has an average granulometry of about 4 mm.

9)Composition according to claim 1 , wherein the size of the particulate rubber material has an average granulometry of about 5 mm.

10)Composition according to claim 1 , wherein the particulate rubber material consists of particles having a completely irregular shape.

1 1 Composition according to claim 1 , wherein the particulate rubber material is used in a proportion of about 20% to about 60% with respect to the total volume the dry mixture.

12)Composition according to claim 1 , wherein the particulate rubber material is used in a proportion of about 10% to about 30% by weight with respect to the total weight of the mixture.

13)Composition according to claim 1 , wherein the ratio of cement to water is about 0.75:1.

14)Composition according to claim 1 , wherein the water content is about 7 to about 12% water by total weight of the- other dry components.

15)Composition according to claim 1 , wherein the sand is quarry or dredging sand.

16)Composition according to claim 1 , wherein the sand is pouzzolane sand or pumice sand.

17)Composition according to claim 1 , wherein the particulate rubber material is at least partially expanded. 18)Precast building element consisting of a set or cured composition according to any one of claims 1 to 17

19)Precast building element according to claim 18, wherein the element is a breeze block.

20)Precast building element according to claim 18, wherein the element is a pillar or column.

21)Precast building element according to claim 18, wherein the element is a non load bearing wall or partition.

22)Precast building element according to claim 18, wherein the element is a cast floor.

23)Precast building element according to claim 18, wherein the element is selected from the group consisting of cladding panels, curtain walls and alabaster type or cement based wall coverings.

24)Precast building element according to claim 18, wherein the element contains about 5% humidity.

25)Precast building element according to claim 18, wherein the element contains about 7 to 12% humidity.

26)Method for manufacture of a composition according to any one of preceding claims 1 to 17, comprising : -mixing water with a hydraulic binding agent ;

-mixing a particulate rubber material with the water/cement mixture thus formed ; -mixing sand with the mixture from the foregoing step,

-wherein the particulate rubber material has a particle size comprised between about 2 mm to about 7 mm and is present in a proportion of between about 20% to about 80% with respect to the total volume of the mixture. 7)Method for the manufacture of a precast building element according to any one of claims 18 to 25, comprising

-mixing water with a hydraulic binding agent ;

-mixing a particulate rubber material with the water/cement mixture thus formed, wherein the particulate rubber material has a particle size comprised between about 2 mm to about 7 mm and is present in a proportion of between about 20% to about 80% with respect to the total volume of the mixture ;

-mixing sand with the mixture from the foregoing step,

-pouring the whole mixture into a mold ;

-curing or drying the mixture in the mold.