EXTERIOR CLADDING SYSTEM AND EXTERIOR WALLS COMPRISING

THERAMLLY INSULATING MINERAL FOAM

BACKGROUND OF THE INVENTION

[001] Mineral foam designates a material in the form of a foam. This material is lighter than traditional concrete due to the pores or empty spaces that it comprises, it may also be termed cement foam. These pores or empty spaces are due to the presence of a gas in the mineral foam and may be in the form of bubbles. 1 m ³ of raw material, it is possible to produce around 5 m ³ of finished product, i.e. a material composed of 20% of material and 80% of gas (valid for an element of density of 400 kg/m ³ ). Thus, the mineral foam comprises a network of bubbles more or less distant from each other, that is to say gas pockets contained in a solid envelope of mineral binder.

[002] The production of mineral foams requires the liquid pre-product foam to solidify into the solid foam. A network of air or gas bubbles encircled by a hydraulic binder which changes over time into a solid mineral foam. The production of mineral foams involves the passage by a step of production of a liquid foam which must be stable. The stability of the liquid foam is thus important, and it is necessary that the production method can control the phenomena of destabilization of the foams during setting, such as for example coalescence, Ostwald ripening or drainage.

[003] When this mineral foam is used as insulating material, it is advantageous that it can be projected onto a support (substrate). It then becomes important that the foam adheres to this support and that it remains joined together with this support up to its solidification. Thus, it is important that when applying the foam on a vertical support, the foam will not sag, (slip) or fall because of gravity. [004] The building code all over the world regulated by building regulatory authorities require exterior walls (bearing and non-bearing) with rigid cladding to have exterior thermal insulation, in particular with industrialized cladded elements and on-site industrialized cladding methods.

[005] It has become necessary to find a method for thermally insulating exterior walls with effective and easy to apply and safe material.

[006] Also, the problem that the invention proposes solving is finding a method for thermally insulating exterior walls, such as for example industrialized cladded walls, with mineral foam being able to remain in place when it is applied on a support, regardless of the shape and the slope of the support (substrate). SUMMARY OF THE INVENTION

[007] The invention provides a cladding system for exterior walls, comprising: at least one external cladding (covering) unit, followed by at least one thermal insulation layer, followed by at least one concrete cast; and wherein said cladding system further comprises at least one fixing accessory; and wherein said at least one thermal insulation layer comprises at least one mineral foam composition having thermal resistance (r) of at least 0.5 m2 K/W.

[008] It should be understood that the cladding system of the invention as disclosed herein provides the order in which the components of the system are layered: cladding (covering) unit is placed on the external side of the system, followed by at least one thermal insulation layer, followed by at least one concrete cast. Said at least one fixing accessory can be placed at any position in said cladding system of the invention. In some embodiments said at least one fixing accessory is placed between at least one external cladding (covering) unit and at least one thermal insulation layer. In some embodiments said at least one fixing accessory is placed between at least one thermal insulation layer and at least one concrete cast.

[009] In some other embodiments said at least one fixing accessory is placed between at least two external cladding (covering) units. In some other embodiments said at least one fixing accessory is placed between at least two thermal insulation layers. In some other embodiments said at least one fixing accessory is placed between at least two concrete casts.

[0010] In some embodiments, said thermal resistance (r) is between 0.5 to 1 m ² K/W. In other embodiments, said thermal resistance (r) is about 0.6 m ² K/W. In other embodiments, said thermal resistance (r) is about 0.9 m ² K/W.

[0011] In some embodiments, said at least one thermal insulation layer comprises at least one mineral foam composition having a density in the dry condition (d) between about 40 to 600 kg/m ³ .

[0012] In some other embodiments, said thermal isolation composition has density in the dry condition (d) between about 150 to 200 kg/m ³ .

[0013] In some further embodiments, said thickness of said thermal insulation layer is between about 1 to 4 cm.

[0014] It is important to note that said at least one at least one thermal insulation layer comprising said at least one mineral foam composition is positioned in said external cladding system between said at least one cladding (covering) unit and at least one concrete cast. Therefore, said at least one exterior cladding unit is positioned on the exterior side of said exterior wall (positioned at the exterior side of a construction) and said at least one concrete cast is positioned in the opposite interior side of said exterior wall.

[0015] The invention thus provides an exterior wall having an exterior and an interior side, comprising at least one cladding system comprising at least one external cladding (covering) unit position on the exterior side, followed by at least one thermal insulation layer, followed by at least one concrete cast; and wherein said at least one fixing accessory; wherein said at least one thermal insulation layer comprises at least one mineral foam composition having a density in the dry condition (d) between about 40 to 600 kg/m ³ .

[0016] The invention thus provides an exterior wall having an exterior and an interior side, comprising at least one cladding system comprising at least one external cladding (covering) unit position on the exterior side, followed by at least one thermal insulation layer, followed by at least one concrete cast, and at least one fixing accessory; wherein said at least one thermal insulation layer comprises at least one mineral foam composition having thermal resistance (r) of at least 0.5 m ² K/W. [0017] The invention further provides a method of thermally insulating a wall having an interior face (facing the inner side of a construction built with said wall) and an exterior face (facing the outter side of a construction built with said wall); said method comprising the step of applying on at least a part of said wall, a mineral foam composition having a density in the dry condition (d) between about 40 to 600 kg/m ³ ; wherein said mineral foam is applied on at least said exterior face of said wall, thereby thermally insulating said wall.

[0018] In the context of construction, thermal insulation/resistance (r-value) is a measure of how well a two-dimensional barrier, such as a layer of insulation, resists the conductive flow of heat. Thermal insulation is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions.

[0019] The r-value is the building industry term for thermal resistance "per unit area." An r-value can be given for a material (e.g. for foam), or for an assembly of materials (e.g. a wall or a window). In the case of materials, it is often expressed in terms of r-value per meter, r-values are additive for layers of materials, and the higher the r-value the better the performance.

[0020] Industrialized elements on-site cladded with rigid cladding relates to cladded concrete elements manufactured on-site in industrialized forms placed in their intended place in the building, with the cladding units arranged in them together with the accessories for their mechanical fixing and the thermal insulation above them, and the concrete cast against the thermal insulation layer. The cladding units, the thermal insulation, the fixing accessories, and the concrete form together the industrialized cladded element.

[0021] Fixing accessories relate to accessories used as mechanical means for fixing between cladding unit and thermal insulation layer and/or between thermal insulation layer and a concrete cast and/or between cladding units and/or between insulation layers and/or between concrete casts and any combinations thereof. Such fixing accessories may be made of at least one metal in any form suitable for fixing between the units of said system.

[0022] Cladding system relates to a system including the following components: at least one cladding unit, at least one thermal insulation layer, at least one concrete cast against the thermal insulation layer (and/or against the cladding units when another concrete layer exists in the system), at least one fixing accessory, and optionally at least one filling mortar for common joints and flexible sealing materials for expansion joints (see examples in Figure 1).

[0023] Bores relate to one or more holes bored in one or more of the cladding units, thermal layers, concrete casts, of the system of the invention, in order to insert in them the fixing accessories.

[0024] Background wall relates to a base wall for cladding with a system of the invention. In some embodiments said background wall is a concrete wall cast in an industrialized construction.

[0025] A cladding unit relates to a unit made of at least one rigid material, (such as for example: natural stone, artificial stone, ceramic tiles) or more (such as for example: concrete and stone, concrete and ceramic tails) and located on the exterior side of the thermal insulation layer.

[0026] Mineral Foam as Thermal insulation relates to the mineral foam used in the present invention provides in addition to thermal insulation at least one of the following properties: (a) stable when lifting the cladding (covering) units with thermal insulation on the intended place; (b) resistant at the expected pressures of the cast concrete during casting; (c) fire resistant; (d) resistant to humidity (i.e. will not lose their properties in the presence of humidity) or protected from the penetration of humidity both from outside and from the water of the cast concrete;.

[0027] Additional materials: In some embodiments of the invention, additional materials are optionally added to the cladding system, such as for example water-repellent materials or sealing coating materials ("sealers") will be suitable for their purpose.

[0028] Description of the cladding methods: Claddings of industrialized elements are performed together with the process of casting the concrete. This method creates elements in which the cladding unit is attached to the external thermal insulation layer toward a background wall. [0029] Fixing accessories of cross-section and shape approved from the engineering point of view, are mounted on the back of the cladding units arranged on the forms.

[0030] The fresh concrete is cast against the insulation layer, taking care to preserve the location of the insulation layer and the cladding units and the stability of the fixing accessories.

[0031] The cladding units and the insulation layer are arranged in a form that makes possible to pour the concrete and to lift the afterwards. The cladding units will usually be arranged in rows and between them rulers, which after the element is detached from the form leave depressions intended to serve as common joins between the cladding units.

[0032] The cladding units are prepared beforehand with bores intended for anchoring the fixing accessories. The accessories are inserted in the bore of the unit before applying the thermal insulation layer and before pouring the concrete. The accessories will be fixed to the cladding unit and their stability during the casting will be ensured.

[0033] The elements are mounted on the building frame as part of the building envelope or of the internal walls.

[0034] The arrangement of the cladding units in the form can be done at the level of the floor where the concrete walls of the front are to be cast when the form is temporarily located on a suspended scaffolding, or at the ground level, when the form is temporarily located there, and after the cladding units are mounted in the form it is lifted to the floor intended for the casting.

[0035] After the reinforcing steel and the internal form are mounted, concrete is poured between the internal insulation layer and the internal form against the unit.

[0036] A system of cladded walls will be a system bearing loads as part of the building frame (in a bearing element) or a system not bearing loads, except its own weight) in a non-bearing element).

[0037] After the casting is completed and the concrete has dried, the form intended for that purpose are lifted together with the element. The elements are stored, transported and assembled in the building.

[0038] The cladding units and the thermal insulation layer are arranged according to the architectural planning on an external form, of height usually equal to the height of a floor. In the arrangement of the cladding units use are made of means for tightening them to the form according to the plans. These means serve also as "lost spacers" bound to the form by stainless steel wires for form, or by screws, or by other suitable methods. These means will not prevent the full coating of the reinforcing steel. In front of the external form will be placed an internal form for the purpose of casting the concrete in the space between them. The external form will be bound to the internal form by means of rods with a fast screw thread (binding rods) passing through the wall and at times through the cladding unit wall or through the joins between the cladding units. The rods will pass through sleeves (tubes) made of plastic passing from form to form. The forms will be tightened at the extremities of the rods by means of special nuts; at the end of the casting the nuts will be released, and the sleeves ends will be sealed by means of special plugs and/or concrete. It is also possible to use external means that stabilize the forms and reduce the need to use binding rods passing through the background wall, or any other method that will ensure the stability of the forms.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0040] Fig. 1 is showing a cladding system of the invention on a wall of the invention.

[0041] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0042] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0043] The invention provides an exterior wall cladding system comprising at least one exterior cladding (covering) unit, followed by at least one thermal insulation layer, followed by at least one concrete cast, and at least one fixing accessory; wherein said at least one thermal insulation layer comprises at least one mineral foam composition having thermal resistance (r) of at least 0.5 m ² K/W. [0044] The invention further provides an exterior wall having an exterior (shown for example as 101 in Figure 1) and an interior side (shown for example as 102 in Figure 1), comprising at least one cladding system comprising at least one external cladding (covering) unit position on the exterior side of said wall, followed by at least one thermal insulation layer, followed by at least one concrete cast, and at least one fixing accessory; wherein said at least one thermal insulation layer comprises at least one mineral foam composition having thermal resistance (r) of at least 0.5 m ² K/W.

[0045] The invention further provides a method of exterior thermally insulation of an exterior wall having an interior and an exterior face; said method comprising the step of applying on at least a part of said wall, a mineral foam composition having a density in the dry condition (d) between about 40 to 600 kg/m ³ ; wherein said mineral foam is applied on at least said exterior face of said wall, thereby exterior thermally insulating said wall.

[0046] Figure 1 provides an embodiment of the present invention, wherein an exterior wall cladding system (100) is shown to comprise an exterior cladding (covering) unit (103), followed by a thermal insulation layer (104), followed by a concrete cast (105), and fixing accessories (106); wherein said at least one thermal insulation layer comprises at least one mineral foam composition having thermal resistance (r) of at least 0.5 m ² K/W.

[0047] The invention relates to the use of a mineral foam capable of being obtained according to the method disclosed herein above and below in external thermal insulation of walls.

[0048] The present invention aims to provide the use of mineral foams that have one or more of the following characteristics: (1) the mineral foam according to the invention has excellent stability properties. Notably it is possible to obtain a foam that can be projected and adhere to a support, whatever the position of this support and independently of gravity forces; (2) the mineral foam according to the invention has excellent thermal properties, and notably a very low thermal conductivity. Reducing the thermal conductivity of building materials is very desirable since it makes it possible to obtain a heating energy saving in residential or working buildings. In addition, this reduction makes it possible to reduce thermal bridges, particularly in constructions of buildings with several floors and having a thermal insulation from the exterior.

[0049] The present invention relates to a method for thermally insulating exterior walls with a mineral foam composition that can be continuously produced comprising the following steps: (i) mixing cement; a water reducing agent; 0.5 to 10%, % by weight with respect to the total weight of cement, of ultrafine particles having a liquid-solid contact angle comprised from 30° to 140°, and of which the D50 is comprised from 10 to 600 nm; water, with a water/cement weight ratio comprised from 0.3 to 2.5; (ii) adding to the mixture from 0.5 to 10% of a pore-forming agent, % by weight with respect to the weight of cement; (iii) applying the mixture obtained at step (ii) on a support; (iv) leaving the mixture to expand on the support.

[0050] The cement suitable for producing the mineral foam according to the method of the invention is preferably the cement described in accordance with the European standard EN 197-1 of April 2012 or mixtures thereof. The preferred cement suitable according to the invention is CEM I Portland cement, alone or mixed with other cements such as those described in accordance with the European standard EN 197-1 of April 2012.

[0051] Preferably, the mixture of step (i) of the method according to the invention comprises from 60 to 95% of cement, preferentially from 65 to 90%, percentage by weight with respect to the total weight of the mixture of step (I) without water.

[0052] A calcium aluminate cement could also be suitable for producing the mineral foam according to the invention. It could be a cement comprising a mineralogical phase or mixtures thereof, such as for example aluminate cement, sulpho-aluminate cements, calcium aluminate cements in accordance with the European standard EN 14647 of December 2006, the cement obtained from clinker described in the patent application WO 2006/018569 or mixtures thereof. The calcium aluminate cement suitable for producing the mineral foam according to the invention could be either in crystallized form or in amorphous form.

[0053] Preferably, the cement of the mixture of step (i) of the method according to the invention has a Blaine specific surface area greater than or equal to 5000 cm2/g, more preferentially greater than or equal to 6500 cm2/g. Preferably, the cement of the mixture of step (i) of the method according to the invention is a cement of which the Blaine specific surface area is comprised from 5000 to 9000 cm2/g.

[0054] It may be envisaged to use several cements in the mixture of step (i) of the method according to the invention of different Blaine specific surface areas. For example, a cement of Blaine specific surface area greater than or equal to 5000 cm2/g may be used, mixed with a cement of Blaine specific surface area less than or equal to 5000 cm2/g, for example a Portland cement.

[0055] The cement which can be used according to the present invention may be ground and/or separated (by a dynamic separator) in order to obtain a cement having a Blaine specific surface area greater than or equal to 5000 cm2/g. This cement may be qualified as ultrafine. The cement may for example be ground according to 2 methods. [0056] According to a method, the cement or the clinker may be ground until a Blaine specific surface area from 5000 to 9000 cm2/g is obtained. A second generation or third generation high efficiency separator, or a very high efficiency separator, may be used in this first step to separate cement having the desired fineness and to discard cement not having the desired fineness. This cement is then sent into the mill.

[0057] According to a method, a cement may go through a very high efficiency separator, designated VHF (very high fineness), in order to separate the particles of cement having a Blaine specific surface area greater than or equal to the target fineness (the target fineness being greater than 5000 cm2/g) and the particles of cement having a Blaine specific surface area less than the target fineness. The particles of cement having a Blaine specific surface area greater than or equal to the target fineness may be used as such. The particles of cement having a Blaine specific surface area less than the target fineness may be excluded or milled separately until the desired Blaine specific surface area is obtained. The mills that may be used in the two methods are for example a ball mill, a vertical mill, a roller press, a horizontal mill (for example of Horomill© type) or an agitated vertical mill (for example of Tower Mill type).

[0058] The mixture of step (i) of the method according to the invention could also contain calcium sulphate, which may be gypsum, anhydrous calcium sulphate or semihydrate calcium sulphate.

[0059] The mixture of step (i) of the method according to the invention comprises a water reducing agent, a plastifier or a superplastifier. A water reducing agent makes it possible to reduce by around 10 to 15% by weight the quantity of mixing water for a given workability time. As an example of water reducing agent may be cited lignosulphonates, hydroxycarboxylic acids, carbohydrates, and other specific organic compounds, such as for example glycerol, polyvinyl alcohol, sodium alumino- methyl siliconate, sulphanilic acid and casein (see Concrete Admixtures Handbook, Properties Science and Technology, V. S. Ramachandran, Noyes Publications, 1984).

[0060] Superplastifiers belong to the new generation of water reducing agents and make it possible to reduce by around 30% by weight the quantity of mixing water for a given workability time. As an example of superplastifier, it is possible to cite superplastifiers of PCP type without antifoaming agent. The term “PCP” or “polycarboxylate polyoxide” is taken to mean according to the present invention, among others, a copolymer of acrylic acids or methacrylic acids; and their esters of poly (ethylene oxide) (POE). [0061] Preferably, the mixture of step (i) of the method according to the invention comprises from 0.01 to 1%, more preferentially from 0.05 to 0.5%, of a water reducing agent, a plastifier or a superplastifier, percentage expressed by weight with respect to the weight of the mixture of step (i). [0062] When the water reducing agent, the plastifier or the superplastifier is used in solution, the quantity is expressed in active ingredient in the solution.

[0063] According to an alternative embodiment of the invention, the mixture of step (i) or of step (ii) of the method according to the invention does not comprises an antifoaming agent, or any agent having the property of destabilising an air emulsion in a liquid. Some commercially available superplastifiers may contain antifoaming agents and consequently these superplastifiers would not be suitable according to the invention.

[0064] The mixture of step (i) or of step (ii) of the method according to the invention could comprise a retarding agent. The retarding agent corresponds to the definition of the setting retarder mentioned in the European standard NF EN 934-2 of September 2002.

[0065] According to an alternative embodiment of the invention, the mixture of step (i) or of step (ii) of the method according to the invention does not comprise a foaming agent.

[0066] Preferably, the mixture of step (i) or of step (ii) of the method according to the invention further comprises a transition metal salt, for example a manganese salt or an iron salt. It may be envisaged that the transition metal salt could be a catalyst precursor facilitating the decomposition of the pore-forming agent into oxygen. As an example of catalyst precursor, manganese salts and oxides may be cited, such as for example permanganates and manganates, salts and oxides of iron, of cobalt, of copper, of molybdenum, of tungsten, of chromium, of silver and enzymes preferably catalases. In certain cases, the transition metal salt may be supplied by the cement itself, when it is notably a cement containing a lot of iron, whether it is in the form of oxide or not.

[0067] The catalyst precursor may notably be selected from manganese salts (II) soluble in water, such as manganese acetate (II), manganese sulphate (II), manganese chloride (II) and manganese nitride (II). These salts can decompose, in a basic medium, into insoluble compounds comprising manganese with a +4 degree of oxidation, such as Mn02, which is a known catalyst for the decomposition of peroxides.

[0068] The mixture of step (i) of the method according to the invention comprises from 0.5 to 10%, % by weight with respect to the total weight of cement, of ultrafine particles having a liquid-solid contact angle comprised from 30° to 140°, and of which the D50 is comprised from 10 to 600 nm. [0069] Preferably, the mixture of step (i) of the method according to the invention comprises from 1 to 9%, % by weight with respect to the total weight of cement, of ultrafine particles having a liquidsolid contact angle comprised from 30° to 140°, and of which the D50 is comprised from 10 to 600 nm.

[0070] Preferably, the mixture of step (i) of the method according to the invention comprises from 2 to 8%, % by weight with respect to the total weight of cement, of ultrafine particles having a liquidsolid contact angle comprised from 30° to 140°, and of which the D50 is comprised from 10 to 600 nm.

[0071] Preferably, the ultrafine particles of the mixture of step (i) of the method according to the invention are partially rendered hydrophobic, for example by a stearic acid. It is also possible to speak of functionalization.

[0072] The ultrafine particles of the mixture of step (i) of the method according to the invention have a liquid-solid contact angle comprised from 30° to 140°, preferably comprised from 40° to 130°, even more preferentially from 70° to 130°.

[0073] This contact angle is also called wetting angle. The expression “contact angle” or “wetting angle” is taken to mean the angle formed between a liquid/vapour interface and a solid surface. It is the angle formed between the interface of a liquid and the solid surface on which the liquid is deposited. It is generally considered that a wall is hydrophilic when the static contact angle of a drop of water arranged on the wall is less than around 30 degrees and that the wall is hydrophobic at variable hydrophobic levels when the static contact angle of a drop of distilled water arranged on the wall is greater than around 30 degrees and less than around 140°. The wall is designated superhydrophobic when the static contact angle of a drop of distilled water arranged on the wall is greater than around 140 degrees. To produce a foam from the method according to the invention, it would be desirable that the ultrafine particles of the mixture of step (i) are not superhydrophobic, that is to say do not have a contact angle strictly greater than 140°.

[0074] Preferably, the ultrafine particles of the mixture of step (i) of the method according to the invention are not hydrophilic.

[0075] The ultrafine particles suitable according to the method of the invention have a D50 comprised from 10 to 600 nm, preferably comprised from 20 to 500 nm, more preferentially comprised from 30 to 200 nm. The D50, also noted Dv50, corresponds to the 50th percentile of the volume distribution of the size of particles, that is to say that 50% of the volume is constituted of particles of which the size is less than the D50 and 50% of size greater than the D50. [0076] It may be noted that the ultrafine particles generally comprise elementary particles having a diameter comprised from 10 to 50 nm. These elementary particles may agglomerate to form agglomerated particles having a diameter from 40 nm to 150 nm. These agglomerated particles may agglomerate to form aggregates having a diameter from 100 nm to 600 nm.

[0077] The ultrafine particles suitable according to the method of the invention may come from one or more materials selected from calcareous powders, precipitated calcium carbonates, natural and artificial pozzolans, pumice stones, ground fly ashes, hydrated silica, in particular the products described in the document FR 2708592, and mixtures thereof.

[0078] According to an alternative embodiment, the mixture of step (i) of the method according to the invention further comprises a mineral addition such as a pozzolan, a slag, calcium carbonate, a fly ash, a sand or mixtures thereof, and of which the particles have a D50 comprised from 0.1 to 4 mm.

[0079] Preferably, the mixture of step (i) of the method according to the invention may comprise from 15 to 50% of mineral additions, preferably from 15 to 40%, even more preferably from 20 to 35%, the percentages being expressed by weight with respect to the weight of the mixture of step (i). [0080] Preferably the D50 of the particles of mineral additions suitable for the mixture of step (i) of the method according to the invention is comprised from 0.2 to 500 pm, for example from 0.25 to 250 pm. The D50 of the mineral particles is preferably from 0.1 to 150 pM, more preferentially from 0.1 to 100 pm.

[0081] The mineral additions suitable for the mixture of step (i) of the method according to the invention are selected from calcium carbonate, silica, ground glass, solid or hollow glass beads, glass granules, expanded glass powders, silica aerogels, silica fumes, slags, ground sedimentary silica sands, fly ashes or pozzolanic materials or mixtures thereof.

[0082] The mineral additions suitable for the mixture of step (i) of the method according to the invention may be pozzolanic materials (for example as defined in the European standard NF EN 197- 1 of February 2001 paragraph 5.2.3), silica fumes (for example such as defined in the European standard NF EN 197-1 of February 2001 paragraph 5.2.7), slags (for example as defined in the European standard NF EN 197-1 of February 2001 paragraph 5.2.2), materials containing calcium carbonate, for example calcareous materials (for example as defined in the European standard NF EN 197-1 paragraph 5.2.6) siliceous additions (for example as defined in the standard “Concrete NF P 18-509”, fly ashes (for example those as described in the European standard NF EN 197-1 of February 2001 paragraph 5.2.4) or mixtures thereof. [0083] A fly ash is generally a powdery particle comprised in the fumes from coal-fired thermal power stations. It is generally recovered by electrostatic or mechanical precipitation. The chemical composition of a fly ash mainly depends on the chemical composition of the coal burned and of the method used in the power plant from which it comes. The same is true for its mineralogical composition. The fly ashes used according to the invention may be of siliceous or calcic nature.

[0084] Slags are generally obtained by rapid cooling of the molten slag coming from the melting of iron ore in a blast furnace. Slags suitable for the mixture of step (i) of the method according to the invention may be selected from granulated blast furnace slags according to the European standard NF EN 197-1 (2001 paragraph 5.2.2).

[0085] Silica fumes suitable for the mixture of step (i) of the method according to the invention may be a material obtained by reduction of high purity quartz by carbon in electric arc furnaces used for the production of silica and ferrosilica alloys. Silica fumes are generally formed of spherical particles comprising at least 85% by weight of amorphous silica.

[0086] Preferably, the silica fumes suitable for the mixture of step (i) of the method according to the invention may be selected from silica fumes according to the European standard NF EN 197-1 (2001 paragraph 5.2.7).

[0087] Pozzolanic materials suitable for the mixture of step (i) of the method according to the invention may be natural siliceous or silico-aluminous substances, or a combination thereof. Among pozzolanic materials may be cited natural pozzolans, which are in general materials of volcanic origin or sedimentary rocks, and natural calcinated pozzolans, which are materials of volcanic origin, clays, schists or sedimentary rocks, thermally active.

[0088] Preferably, the pozzolanic materials suitable for the mixture of step (i) of the method according to the invention may be selected from pozzolanic materials according to the European standard NF EN 197-1 (2001 paragraph 5.2.3).

[0089] Preferably, the mineral additions suitable for the mixture of step (i) of the method according to the invention may be calcareous powders and/or slags and/or fly ashes and/or silica fumes. Preferably, the mineral additions suitable for the mixture of step (i) of the method according to the invention are calcareous powders and/or slags.

[0090] Other mineral additions suitable for the mixture of step (i) of the method according to the invention are calcareous, siliceous or silico-calcareous powders, or mixtures thereof.

[0091] The mineral additions suitable for the mixture of step (i) of the method according to the invention may come in part or in totality from the cement when it is a blended cement. [0092] The mixture of step (i) of the method according to the invention comprises water. The water/cement weight ratio is comprised from 0.45 to 1.3, preferably from 0.5 to 1.2, more preferentially from 0.6 to 0.8. This total water/cement ratio may vary for example due to the water demand of the ultrafine particles or mineral additions when they are used. This total water/cement ratio is defined as being the ratio by weight of the quantity of water (E) over the weight of all the cements (C).

[0093] According to an alternative embodiment, the mixture of step (i) of the method according to the invention may comprise hydraulic lime.

[0094] Preferably, the mixture of step (i) of the method according to the invention does not comprise light aggregates as described in accordance with the European standard EN 206-1 of April 2004, for example perlite.

[0095] According to another alternative embodiment of the invention, the mixture of step (i) of the method according to the invention does not comprise light fillers, for example polystyrene beads.

[0096] Step (ii) of the method according to the invention comprises the addition to the mixture of step (i) of 0.5 to 10% of a pore-forming agent, % by weight with respect to the weight of cement.

[0097] Preferably, step (ii) of the method according to the invention comprises the addition of 2 to 8% of a pore-forming agent.

[0098] The pore-forming agent added at step (ii) of the method according to the invention may be a solution of hydrogen peroxide, a solution of peroxomono sulphuric acid, a solution of peroxodisulphuric acid, a solution of alkaline peroxides, a solution of alkaline earth peroxides or a solution of organic peroxide such as peroxoacetic acid or peroxobenzoic acid, or a suspension of aluminium particles or mixtures thereof.

[0099] Preferably, the pore-forming agent is hydrogen peroxide. Preferably, it is hydrogen peroxide of which the concentration is comprised from 8% to 35%.

[00100] At the end of step (ii) of the method according to the invention a mixture is obtained. This mixture may be produced according to the method of the invention using a device comprising pipes, potentially of different sizes, the whole forming a piping. This piping may comprise or not a mechanical auxiliary to the mixing such as a static mixer. The reaction between the pore-forming agent and the transition metal salt (catalyst precursors) and/or the cement starts immediately, and a fraction of the total oxygen is immediately released, in such a way that the piping contains bubbles. At the output of the piping, the mixture that contains a fraction of bubbles is intended to be immediately poured into a mould or projected onto a support. During this operation of making the mixture come out from the piping, said mixture is not fractionated.

[00101] Preferably, the mixture obtained at step (ii) of the method according to the invention is not fractionated.

[00102] The expression “is not fractionated”, is generally taken to mean that the mixture comes out of the piping in the form of a jet and retains its integrity, and in particular it is not sprayed in the mold or onto the support, even if several occasional drops can form during contact with the support. [00103] Step (iii) of the method according to the invention comprises the application of the mixture obtained at step (ii) on a support. This application step may take place without using spray nozzles or equivalent. In addition, this application may take place without using elements at the output of the device.

[00104] In fact the spray will generally end in the fractionation of the mixture or in the formation of drops. The application may take place by leaving the mixture obtained at step (ii) to flow naturally on the support. Thus the mixture, in flowing naturally, is not propelled or accelerated, which could destabilise the mixture and form drops.

[00105] Preferably, at step (iii) the mixture is applied without using a spray nozzle.

[00106] Preferably, step (iii) of the method according to the invention is carried out without spray. [00107] According to an alternative embodiment of the invention, step (iii) may be repeated in order to obtain successive or superimposed layers. Preferably, the most recently deposited layer is deposited on a layer having already acquired a mechanical strength by hydration of the cement.

[00108] The support implemented at step (iii) of the method according to the invention may be vertical, horizontal, sloping or in any position. It may also be a receptacle, a mould, a hollow or solid construction block, a hollow or solid wall, a ceiling, a floor (underfloor form or insulating screed). [00109] The support used at step (iii) of the method according to the invention may be treated prior to the application of the mixture obtained at step (ii).

[00110] According to an alternative embodiment, the method according to the invention further uses a hydration accelerator of the cement, which is present either in the mixture of step (i) or (ii), or on the surface of the support of step (iii).

[00111] Preferably, the mixture of step (i) of the method according to the invention further comprises a hydration accelerator of the cement, for example calcium chloride. [00112] When a hydration accelerator of the cement is present in the mixture of step (i) or (ii), it is preferably a calcium salt, such as for example calcium chloride. The hydration accelerator of the cement may be incorporated continuously before step (iii) of the method according to the invention. [00113] When a hydration accelerator of the cement is present on the surface of the support of step (iii), it is preferably aluminium sulphate.

[00114] The hydration accelerator of the cement may be introduced at step (i) before or after the addition of water, or sprayed onto the support of step (iii).

[00115] Water may be applied on the support implemented at step (iii) of the method according to the invention before step (iii).

[00116] Other additives may also be used in the method according to the invention such as for example colored pigments, hydrophobic agents, depolluting agents (for example zeolites or titanium dioxide).

[00117] At step (iv) of the method according to the invention, the mixture expands. This expansion has begun as soon as the pore-forming agent chemically reacts, that is to say at step (ii) and ends at step (iv). The aerated mineral foam thereby obtained may be smoothed and have a thickness greater than 1 cm. Then the setting takes place until a solid mineral foam is obtained.

[00118] This expansion corresponds to the gaseous release following the chemical reaction of the pore-forming agent, potentially in the presence of a catalyst. When the pore-forming agent is peroxide based, the decomposition reaction of the pore-forming agent carried out in the presence of a catalyst is an exothermic reaction generating oxygen molecules and water. It is in fact known that the decomposition of peroxides is accelerated in the presence of a metal.

[00119] The mixture of step (i) may be prepared using mixers conventionally used for producing cement grouts. It may be a grout mixer, a concrete plant mixer, a mixer described in the European standard NF EN 196-1 (2006 — Paragraph 4.4), or a mixer-beater with planetary movement.

[00120] The mixture of step (i) may be prepared by introducing into the mixer the different materials in the form of powders. The powders are mixed to obtain a homogeneous mixture. Then water is introduced into the mixer. Next the mineral particles, the adjuvants such as for example the water reducing agent, the plastifier, the superplastifier, the accelerator, the thixotropic agent, the viscosifier, the water retaining agent or the retarder, are introduced when they are present in the formulation of the mineral foam. The paste obtained is mixed to obtain a mixture of cement grout. [00121] Preferably, the mixtures of step (i) or (ii) are maintained under stirring using the deflocculating blade, throughout the duration of the method for producing the mineral foam according to the invention.

[00122] Preferably, the mineral foam produced according to the method of the invention has a density in the dry condition from 50 to 600 kg/m3, more preferentially from 60 to 500 kg/m3, even more preferentially from 70 to 450 kg/m3. It may be noted that the density of the mineral foam in the fresh condition (wet density) differs from the density of the mineral foam in the dry condition, that is to say after setting (density of hardened material). The density of the mineral foam in the fresh condition is always greater than the density of the foam in the dry condition.

[00123] The invention offers as advantage that the mineral foam according to the invention has considerable lightness, and notably a very low density.

[00124] The invention offers as other advantage that the mineral foam according to the invention has excellent stability properties. Notably the bubbles that compose the mineral foam in the fresh condition are little degraded after pouring into the mold or depositing on the support.

[00125] The support may be of different natures and different shapes.

[00126] The support may be a receptacle to fill. In this case, it is envisaged to fill building blocks with the mineral foam according to the invention. For example, they may be building blocks, terra cotta blocks, cellular concrete blocks, precast exterior wall, that it is wished to fill with the foam according to the invention.

[00127] The support may be a wall to cover with mineral foam according to the invention. For example, it may be a concrete cast wall, a shuttered concrete, a wall of building blocks, a wall of terra cotta blocks, a wall of cellular concrete blocks, a wall covered with mortar or coating.

[00128] The support may be of different natures such as concrete, terracotta, plaster, untreated wood, plasterboard, cardboard sheet, or any other material used in building.

[00129] The support may be treated or covered with a first layer of mineral foam according to the invention. The support could be treated before deposition of the foam. The treatment could for example consist in one or more projections of water, the projection of setting accelerator solutions such as aluminium sulphate, or in the deposition of bonding primers, or any other solution of physical or chemical nature making it possible to accelerate the setting of the cement at the interface between the support and the mixture, or to enable better adhesion of the mixture on the support or to increase the roughness of the support. [00130] The invention offers as other advantage that the mineral foam according to the invention has excellent thermal properties, and notably a very low thermal conductivity. Reducing the thermal conductivity of building materials is highly desirable since it makes it possible to obtain a saving in heating energy in residential or working buildings. In addition, the mineral foam according to the invention makes it possible to obtain good insulation performances over small thicknesses and thus to preserve the surfaces and habitable volumes. The thermal conductivity (lambda) is a physical quantity characterizing the behavior of materials during the transfer of heat by conduction. The thermal conductivity represents the quantity of heat transferred per surface unit and per time unit under a temperature gradient. In the international units system, the thermal conductivity is expressed in watts per meter Kelvin, (W/m-K). Classical or traditional concretes have a thermal conductivity between 1.3 and 2.1 measured at 23° C. and 50% relative humidity.

[00131] The mineral foam according to the invention has a thermal conductivity comprised from 0.03 to 0.5 W/m-K, preferably from 0.04 to 0.15 W/m-K, more preferentially from 0.045 to 0.10 W/m-K.

[00132] The invention offers as another advantage that the mineral foam according to the invention has good mechanical properties, and notably good compressive strength compared with known mineral foams. The mineral foam according to the invention has a compressive strength comprised from 0.04 to 5 MPa, preferably from 0.05 to 2 MPa, more preferentially from 0.05 to 1 MPa.

[00133] The invention also relates to the use of the mineral foam according to the invention as building material. For example, the mineral foam according to the invention may be used to pour walls, floors, roofs on a worksite. It is also envisaged to produce elements prefabricated in a preproduction factory from the foam according to the invention such as blocks, panels.

[00134] The mineral foam according to the invention may be poured onto walls on a worksite.

[00135] The invention also relates to the use of the mineral foam according to the invention as insulating material, in particular as thermal or phonic insulating material.

[00136] Advantageously, the mineral foam according to the invention makes it possible in certain cases to replace glass wool, mineral wool, asbestos or insulants made of polystyrene and polyurethane.

[00137] Advantageously, the mineral foam according to the invention may be used for backfilling or filling of an empty or hollow space of a building, a wall, a partition, a masonry block for example a breeze-block, a brick, of a floor or of a ceiling. Such materials or composite building elements comprising the mineral foam according to the invention are also objects of the invention per se. [00138] Advantageously, the mineral foam according to the invention may be used as plugging material.

[00139] Advantageously, the mineral foam according to the invention may be used as fatjade covering for example to insulate a building from the outside. In this case, the mineral foam according to the invention could be coated with a finish coat.

[00140] The subject matter of the invention is also a system comprising the mineral foam according to the invention. The foam may be present in the system as insulating material. It may be poured vertically between two walls, chosen for example from concrete cast walls, brick walls, plasterboard, wooden sheet, for example wood panels with oriented thin strips, fibre-cement panels, the whole forming the system.

[00141] The system according to the invention is advantageously capable of withstanding or reducing air and thermo-hydric transfers, that is to say that this element has a controlled permeability to transfers of air, of water in the form of vapour or liquid.

[00142] The system according to the invention preferably comprises at least one framework or structural element. This framework may be made of concrete (columns/beams), metal (uprights or rails), wood, plastic or composite material or synthetic material. The mineral foam according to the invention may also coat a structure for example of wire mesh type (plastic, metal) or a pillar or beam of a building.

[00143] The system according to the invention may be used to produce or manufacture a cladding, an insulation system, or a partition, for example a separating partition, internal partition or a rigid wall lining.

[00144] The invention also relates to a building element comprising the mineral foam according to the invention.

[00145] When the mineral foam according to the invention is intended to be projected on a vertical wall, said wall could be provided with elements which facilitate the adherence of the foam, for example metal wire meshes or wire meshes based on plastic materials, spaced or not from the wall, and joined together or not with the wall. Vertical armatures could be positioned along the wall to serve as anchoring points for wire meshes. This wire meshes could be simple horizontal wires.

[00146] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.