WO2023041483A1

WO2023041483A1 - Insulating construction element

Info

Publication number: WO2023041483A1
Application number: PCT/EP2022/075278
Authority: WO
Inventors: Julie GODEFROID; Julien BEAUMONT
Original assignee: Saint-Gobain Weber France; Saint-Gobain Isover
Priority date: 2021-09-14
Filing date: 2022-09-12
Publication date: 2023-03-23
Also published as: FR3126975A1

Abstract

The invention relates to a construction element comprising two walls consisting of block work, concrete, mortar, plaster, wood, oriented strand board (OSB) or raw earth materials, said walls facing one another so as to provide at least one cavity therebetween, said at least one cavity being at least partially filled with an insulating material comprising flakes of mineral or vegetable wool or cellulose materials, bound by a cured mineral binder, said cured mineral binder being obtained by curing a hydraulic binder.

Description

Insulating component

The invention relates to the field of construction. It relates more particularly to obtaining construction elements having good thermal insulation properties.

It is known to fill cavities made in construction elements, such as walls or parts of walls, using insulating materials, such as mineral wool or inorganic foams (for example cement foams) or organic (for example polyurethane foams).

However, these different solutions are not without drawbacks. The filling of the cavities by the insulating material is not always homogeneous, leading to the creation of thermal bridges and therefore to a degradation of the thermal insulation performance. These homogeneity defects can occur over time or during the transport of the construction elements to the site, in the case of prefabricated elements. For example, materials based on mineral wool can tend to settle, and we sometimes observe a shrinkage of inorganic foams. Organic foams sometimes exhibit poorly controlled expansion during installation. Some known solutions also do not lend themselves well to automation.

The object of the invention is to obviate these drawbacks by proposing a more effective solution, with simpler and faster implementation, possibly automatic.

To do this, the subject of the invention is a construction element comprising two walls made of breeze blocks, concrete, mortar, plaster, wood, oriented particle board (OSB) or raw earth-based materials, said walls facing each other so as to form between them at least one cavity, said at least one cavity being at least partially filled with an insulating material comprising flakes of mineral or vegetable wool or cellulosic materials, bound by a hardened mineral binder, said hardened mineral binder being obtained by hardening a hydraulic binder.

A subject of the invention is also a process for obtaining such a construction element, comprising comprising mixing with water a composition comprising:
- a pulverulent mineral binder which is a hydraulic binder and
- flakes of mineral or vegetable wool or cellulosic materials,
then depositing the mixture obtained in the cavity.

The use of a composition comprising flakes of mineral or vegetable wool or cellulosic materials, and a pulverulent mineral binder which is a hydraulic binder, to isolate the cavities makes it possible to obviate the aforementioned drawbacks. The invention makes it possible to ensure good adhesion of the insulating material to the walls (in particular, but not exclusively, to the concrete walls), good cohesion of the coating even for the significant thicknesses generally required by the intended insulating performance, good resistance to environment and aging, as well as good mechanical properties, particularly in compression, for a reduced carbon impact and good thermal insulation properties.

Preferably, at least 50%, in particular at least 60%, or even at least 80%, and even in a particularly preferred manner all of the volume of the or each cavity is filled with the insulating material.

After mixing the composition with water and hardening the hydraulic binder, the insulating material obtained comprises flakes of mineral or vegetable wool, or cellulosic materials, bound together by a hardened mineral binder which is a hydraulic binder. The hydraulic binder present in the composition becomes pasty after mixing with water, before hardening. The term "binder" therefore covers both the powdered binder present in the composition and the final cured binder in the insulating material. The following details apply both to the composition and to the insulating material.

Preferably, the insulating material comprises flakes of mineral or vegetable wool bound by a hardened mineral binder obtained by hardening a hydraulic binder. Particularly preferably, the insulating material comprises flakes of mineral wool bound by a hardened mineral binder obtained by hardening a hydraulic binder.

The mineral wool is preferably chosen from glass wool, slag wool, rock wool and mixtures of two or more of these wools. The mineral wool fibers preferably have a chemical composition comprising 30 to 75% by weight of SiO ₂ , 5 to 40% by weight of CaO+MgO, 0-20% by weight of Na ₂ O+K ₂ O, 0- 30% by weight of Al ₂ O ₃ and 0-15% by weight of Fe ₂ O ₃ .

The use of glass wool generally makes it possible to achieve better thermal insulation performance, in particular thanks to a lower density.

Glass wool is generally formed by electric melting or by flames of a mixture of pulverulent raw materials and cullet (recycled glass), then fiber drawing, in particular by internal centrifugation using a fiber drawing plate. Glass wool fibers preferably have a chemical composition comprising 50-75% SiO ₂ , 12 to 20% Na ₂ O+K ₂ O, 5 to 20% CaO+MgO, 0-8%, in particular 0-3 % Al ₂ O ₃ and 2 to 10% B ₂ O ₃ (the percentages being by weight).

Rock and slag wools are generally formed by fusion in a cupola of raw materials in the form of blocks and/or briquettes, or by electric fusion or by submerged burners of powdery materials, then fiber drawing by external centrifugation by means of of a plurality of rotors. The rock wool fibers preferably have a chemical composition comprising 30-50% SiO ₂ , 10-26% Al ₂ O ₃ , 15-40% CaO+MgO, 0-5% Na ₂ O+K ₂ O and 3 -15% Fe ₂ O ₃ . The slag wool fibers preferably have a chemical composition comprising 30-45% SiO ₂ , 5-18% Al ₂ O ₃ , 30-60% CaO+MgO and 0-3% Na ₂ O+K ₂ O. percentages are by weight.

Mineral wool is usually made of interwoven vitreous fibers. As a general rule, the mineral wool used does not contain any organic binder. However, it may contain some when the flakes come from the recycling of construction or factory waste, for example obtained by grinding mineral wool panels. The flakes may be blowing wool flakes, which normally does not contain an organic binder, but which may nevertheless contain organic additives, for example of the silicone type or antistatic agent. These additives are in particular sprayed on the mineral wool at the time of fiber drawing.

The plant wool comprises plant fibers preferably chosen from the group consisting of lignocellulosic fibers, cellulosic fibers and cotton fibers. The lignocellulosic fibers are preferably chosen from wood fibers, hemp fibers, flax fibers, sisal fibers, cotton fibers, jute fibers, coconut fibers, raffia fibers, abaca, cereal straw, rice straw and mixtures thereof.

Flakes are defined as pieces formed from agglomerates (or clusters) of entangled fibers having a certain size or dimension. It is essential that the composition and the coating include the fibers in the form of flakes and not in the form of dispersed individual fibers or fibers organized in the form of batts, grids, fabrics or nonwovens, in order to be able to achieve good thermal insulation properties. The insulating material therefore differs from a fibre-reinforced plaster or mortar, which does not have any insulating properties.

The flakes of mineral or vegetable wool, in the composition and/or the coating, preferably have a size of between 1 and 10 cm, in particular between 2 and 8 cm, or even between 3 and 7 cm. Too small flakes lead to denser coatings, and therefore less thermally insulating. The obtaining of the flakes and the adjustment of their size can in particular be carried out by means of a carding machine. The flakes can be larger in the composition, in the case where the projection machine is able to reduce their size before projection.

The powdery mineral binder is a hydraulic binder. In the final insulating material, the mineral binder is therefore obtained by hardening a hydraulic binder. In the present description, the term "mineral binder", or "binder" must therefore be understood as referring to a hydraulic binder, either in the powder state in the composition, or in the hardened state in the final insulating material.

The hydraulic binder is preferably chosen from the group formed by Portland cements, belitic cements, aluminous cements, sulfoaluminous cements, pozzolanic mixture cements, slags, fly ash, metakaolins, hydraulic lime, springs of calcium sulphate and mixtures of two or more of these hydraulic binders. The source of calcium sulphate is chosen in particular from gypsum, anhydrite, hemihydrate and mixtures thereof.

The binder may in particular consist of Portland cement, in particular of the CEM I or CEM II type.

According to another embodiment, the binder comprises (in particular consists of) a mixture of Portland cement and a source of calcium sulphate. The presence of a source of calcium sulphate makes it possible in particular to improve the fire resistance properties and to accelerate the setting of the binder. Its carbon impact is also reduced compared to Portland cement. The proportion of calcium sulphate source in this binder is preferably between 2 and 20% by weight, in particular between 5 and 15% by weight.

According to another embodiment, the binder comprises (in particular consists of) a mixture of sulfoaluminate cement and a source of calcium sulphate. The binder then preferably comprises a setting accelerator, for example a lithium salt. The proportion of calcium sulphate source in this binder is preferably between 2 and 20% by weight, in particular between 5 and 15% by weight.

According to yet another embodiment, the binder comprises (or consists of) a mixture of Portland cement, alumina cement and a source of calcium sulphate. The binder can also comprise a setting accelerator, for example a lithium salt. Such a binder makes it possible to finalize the hardening more quickly. In this embodiment, the weight proportions of the constituents in the binder are preferably the following: 65 to 90% Portland cement, 5 to 20% alumina cement and 2 to 15% of a source of calcium sulphate.

In general, the presence of Portland cement makes it possible to achieve good mechanical performance, particularly in terms of compressive strength, and also makes it possible to reach high pH values which have proven to favor the effectiveness of water-repellent agents. Adding a lime source to the aforementioned binders has also been shown to be beneficial in this regard.

The binder can also consist of a source of calcium sulphate, making it possible to obtain good fire resistance properties, but to the detriment of the mechanical and thermal insulation properties.

The composition (and therefore the insulating material) may include other constituents.

It may in particular comprise lightening fillers, in particular chosen from perlite, vermiculite, expanded glass beads, expanded polystyrene beads, cenospheres, expanded silicates, aerogels and mixtures thereof.

The composition advantageously comprises redispersible polymer powders. The polymer is preferably based on one or more monomers chosen from vinyl esters (in particular vinyl esters of C1-C15 carboxylic acids such as vinyl acetate), (meth)acrylates (in particular of alcohols in C1-C10), vinyl aromatics, alkenes (eg ethylene), dienes and vinyl halides. These polymers make it possible to improve the mechanical resistance of the insulating material, without affecting its thermal insulation properties. The insulating material therefore preferably comprises such a polymer.

The composition (and therefore the insulating material) advantageously comprises thickening agents, which also make it possible to improve the mechanical strength of the insulating material without affecting its thermal insulation properties, and to obtain better cohesion. The thickening agent is preferably a cellulose ether.

The composition (and therefore the insulating material) may also comprise surfactants, in particular in order to facilitate the wetting of the fibers by water during the implementation of the coating deposition process. An advantageous surfactant is in particular sodium dodecyl sulphate.

The composition (and therefore the insulating material) may also comprise mineral or vegetable oils, in order to reduce dust emissions, in particular when the binder contains a source of calcium sulphate such as gypsum.

The content by weight of mineral or plant wool or cellulosic materials is preferably between 50 and 90%, in particular between 55 and 85%, relative to the cumulative weight of mineral or plant wool or cellulosic materials and mineral binder, or even by relative to the total weight of the composition or of the insulating material. Given the low density of mineral or vegetable wool flakes compared to the binder, mineral or vegetable wool is very clearly the majority in volume, making it possible to achieve good thermal insulation properties.

In the composition or in the insulating material, the content by weight of mineral binder is preferably between 10 and 50%, in particular between 15 and 45%, relative to the cumulative weight of mineral or vegetable wool or cellulosic materials and mineral binder. , or even relative to the total weight of the composition or of the insulating material.

In the case of slag wool, the mass proportion of wool relative to the binder preferably varies from 70:30 to 90:10. In the case of glass wool, the mass proportion of wool relative to the binder preferably varies from 50:50 to 70:30.

The composition and/or the insulating material preferably comprise 50 to 90% (in particular 55-85%) by weight of mineral wool (vegetable respectively), 10 to 50% (in particular 15-45%) by weight of mineral binder, for relative to the combined weight of mineral wool (respectively vegetable) and mineral binder, or even relative to the total weight of the composition or of the insulating material.

The total content of any additives is normally less than 40%, even 30% and even 20% or 10%, or greater than 0.1%, always related to the total weight of mineral or vegetable wool (or cellulosic materials ) and mineral binder. It is preferably at most 5% for redispersible polymer powders and thickeners, and at most 2% for oils. In other words, the total weight proportion of mineral or vegetable wool (or cellulosic materials) and of mineral binder in the composition or the insulating material is preferably at least 70%, in particular at least 80% and even at least 90%.

The contents indicated above are valid both for the composition and for the insulating material.

The composition is mixed with water and the resulting mixture is then deposited in the cavity.

The deposition of the mixture is preferably carried out by spraying. Preferably, the composition (generally in dry form) is conveyed to a projection nozzle, and the water is added at the earliest at the outlet of the nozzle. Advantageously, a spraying machine equipped with a central duct through which the composition is sprayed, around which is arranged at least one orifice, in particular a plurality of orifices, through which the water is sprayed, is used. The mixture of the composition and the water is then carried out at the nozzle outlet, before the mixture reaches the cavity.

The amount of water (by weight) relative to the amount of composition is preferably between 0.2 and 1.5, in particular between 0.5 and 1.4, or even between 0.7 and 1.2. The amount of water must be sufficient for the setting and hardening of the binder. It should be adjusted taking into account the fact that the mineral or vegetable wool will absorb some of the water. If the amount of water added is too low, the composition does not adhere sufficiently to the walls and detaches.

The total flow rate of dry matter (mineral or vegetable wool, cellulosic materials, mineral binder and any solid additives) is preferably between 1 and 10 kg/min, in particular between 2 and 8 kg/min. The water flow is preferably between 5 and 10 l/min. The deposition rate is for example between 0.1 and 5 L/s, in particular between 0.5 and 3 L/s, or even between 0.8 and 1.5 L/s.

The density of the insulating material is preferably between 20 and 250 kg/m ³ , in particular between 50 and 200 kg/m ³ . The thermal conductivity of the insulating material is preferably between 35 and 60 mW/mK When the mineral wool is rock or slag wool, this density is preferably between 100 and 200 kg/m ³ , with a conductivity temperature ranging in particular from 37 to 60 mW/mK When the mineral wool is glass wool, the density of the insulating material is preferably between 50 and 150 kg/m ³ , in particular between 60 and 100 kg/m ³ , or even between 65 and 85 kg/m ³ , for thermal conductivities ranging in particular from 35 to 40 mW/mK

The mechanical resistance of the insulating material is excellent, with resistances ranging in particular from 5 to 20 kPa in traction, from 5 to 60 kPa in bending (in particular from 40 to 60 kPa with slag or rock wool) and from 20 to 110 kPa in compression (especially 90 to 110 kPa with slag or rock wool).

The construction element is preferably a wall, or even part of a wall. In particular, it may be a load-bearing wall or a shear wall. The lateral dimensions of the construction element are preferably between 15 cm and 3 m, in particular between 20 cm and 2.5 m, or even between 1 m and 2 m. By way of example, the construction element, in particular the wall, can have a length of 2 m and a height of 2.5 m. The thickness of the cavity (that is to say the distance separating the walls) is preferably between 5 and 50 cm, in particular between 10 and 40 cm, or even between 15 and 30 cm.

The construction element can be manufactured directly on the construction site of the building.

Preferably, however, the construction element is a prefabricated element, intended to be transported to the construction site of the building. The excellent cohesion between the walls and the insulating material makes it possible on the one hand to carry out the transport without reducing the thermal insulation performance of the element (due to the absence of settling of the insulating material) and on the other hand to proceed on the construction site to cutting stages, before assembly.

The walls of the building element are made of cinder blocks, concrete or mortar, plaster, wood, oriented strand board (OSB) or raw earth materials. Preferably, the walls of the construction element are made of breeze blocks, concrete or mortar. Concrete blocks are notably bricks, blocks, stones or rubble. The walls are then formed by assembling a plurality of concrete blocks, for example by means of a masonry mortar. The two walls can be made of the same material, or of different materials. The walls are generally flat and parallel to each other, but other geometries are of course possible, especially when obtained by additive manufacturing.

According to a preferred embodiment, the deposition of the insulating material, in particular the spraying of the mixture, is carried out in an already formed cavity.

The method can therefore comprise a preliminary step of building the walls (therefore before depositing the mixture in the or each cavity formed by said walls). The construction of the walls can be carried out by any known method. Examples include the assembly of concrete blocks (stones, rubble, bricks, blocks, etc.) or the pouring of concrete walls between two formwork panels. In a preferred mode, the walls are built by additive manufacturing, also called "3D printing", of mortar or concrete. This technique makes it possible in particular to obtain very varied geometries. When the walls are made of concrete or mortar, the deposition of the insulating material can be carried out when the walls are still in a fresh state, or on the contrary after hardening.

In the context of this embodiment, the deposit can be made through the opening made by the walls facing each other. It is for example made from above, the walls being arranged vertically. Alternatively, the deposit can be made via at least one opening made in at least one of the walls.

Whatever the embodiment, the deposition of the mixture, in particular the projection of the mixture, is preferably carried out by means of a robot, in particular is automated. The projection nozzle is then carried by a mobile arm or gantry controlled by computer. This mode is particularly preferred in combination with a construction of the walls by additive manufacturing. This makes it possible to automate the entire manufacturing of the component. In the case of a projection carried out by the opening made by the walls facing each other, it is then preferable to start the projection by placing the nozzle towards the bottom of the cavity, typically lower than the first third, before moving the nozzle to the top of the cavity. This procedure is particularly advantageous in the case of rough walls and of considerable height, in order to fill the entire cavity in a homogeneous manner.

The following non-limiting examples illustrate the invention and its advantages.

In the examples, the projected composition comprised 66.8% of blowing glass wool flakes marketed by the Applicant under the name Comblissimo, 29.9% of CEM I 52.5R cement, 3.3% of hemihydrate, plus a addition of 0.41% cellulose ether (tylose) and 1.66% mineral oil (percentages by weight). The blowing wool included 0.1-0.4% water repellent (silicone), 1-2% mineral oil and 0.2% antistatic agent, these agents being dispersed on the fibers.

In a first series of tests, the composition was projected so as to fill from above cavities delimited by mortar walls printed by an additive manufacturing technique, 20 cm wide, 20 cm high and 20 cm deep. 'thickness. The dry matter flow rate was 2 to 2.5 kg/min and the water flow rate was 5 to 5.5 L/min.

The insulating materials obtained had densities included according to the tests between 65 and 85 kg/m ³ for thermal conductivities ranging from 37 to 70 mW/mK

The samples of insulating materials had the following mechanical properties:
- compressive strength: 26 kPa (for a density of 65 kg/m ³ ) and 37 kPa (for a density of 85 kg/m ³ )
- tensile strength: 11 kPa (for a density of 65 kg/m ³ )
- bending strength: 6 kPa (for a density of 65 kg/m ³ ) and 18 kPa (for a density of 85 kg/m ³ ).

In a second series of tests, the composition was projected into cavities delimited by wooden walls, 1 m wide, 2 m high and 20 cm thick, with dry matter flow rates of 3 to 3 .5 kg/min and water flow rates of 5.0 to 6.0 L/min.

Claims

Construction element comprising two walls made of breeze blocks, concrete, mortar, plaster, wood, oriented strand board (OSB) or materials based on raw earth, said walls facing each other so as to provide between them at least one cavity, said at least one cavity being at least partially filled with an insulating material comprising flakes of mineral or vegetable wool or cellulosic materials, bound by a hardened mineral binder, said hardened mineral binder being obtained by hardening a hydraulic binder.
Construction element according to claim 1, in which the insulating material comprises flakes of mineral or vegetable wool bound by a hardened mineral binder, the said hardened mineral binder being obtained by hardening a hydraulic binder.
Construction element according to the preceding claim, in which the mineral wool is chosen from among glass wools, slag wools, rock wools and mixtures of two or more of these wools.
Construction element according to one of the preceding claims, in which the flakes of mineral or vegetable wool have a size of between 1 and 10 cm, in particular between 2 and 8 cm.
Construction element according to one of the preceding claims, in which the hydraulic binder is chosen from the group formed by Portland cements, belitic cements, aluminous cements, sulfoaluminate cements, cements of pozzolanic mixtures, slags, ash flywheels, metakaolins, hydraulic lime, sources of calcium sulphate and mixtures of two or more of these hydraulic binders.
Construction element according to the preceding claim, in which the binder consists of Portland cement, in particular of the CEM I or CEM II type, or in which the hydraulic binder comprises a mixture of Portland cement and a source of calcium sulphate, or wherein the hydraulic binder comprises a mixture of Portland cement, alumina cement and a source of calcium sulphate.
Construction element according to one of the preceding claims, comprising 50 to 90% by weight of mineral or vegetable wool or cellulosic materials and 10 to 50% by weight of mineral binder, relative to the cumulative weight of mineral or vegetable wool or cellulosic materials and mineral binder.
Construction element according to one of the preceding claims, in which the density of the insulating material is between 20 and 250 kg/m 3 , in particular between 50 and 200 kg/m 3 .
Construction element according to one of the preceding claims, which is a wall.
Process for obtaining a construction element according to one of the preceding claims, comprising mixing with water a composition comprising:
- a pulverulent mineral binder which is a hydraulic binder and
- flakes of mineral or vegetable wool or cellulosic materials,
then depositing the mixture obtained in the cavity.
Process according to the preceding claim, in which the deposition of the mixture is carried out by spraying, the composition being conveyed to a spray nozzle, and water being added as soon as possible at the outlet of the nozzle.
Process according to one of Claims 10 or 11, in which the quantity of water by weight relative to the quantity of composition is between 0.2 and 1.5, in particular between 0.5 and 1.4.
Process according to one of Claims 10 to 12, in which the deposition of the mixture is carried out in an already formed cavity.
Method according to the preceding claim, comprising a prior step of building the walls, in particular by additive manufacturing of mortar or concrete.
Process according to one of Claims 10 to 14, in which the deposition of the mixture is carried out by means of a robot.