FR3023859A1 - INSULATING CONSTRUCTION ELEMENT, METHOD OF MANUFACTURE AND CORRESPONDING INSULATING MATERIAL - Google Patents

Abstract

The invention relates to a construction element (1) comprising a framework (10) and at least one inner recess (15) in which an insulating material (2) is arranged. According to the invention, the insulating material (2) comprises: a cement slurry (20) comprising: - a first cement (21) based on clinker; a second sulfo-aluminous cement (22); - a setting accelerator (25) of the cement; a plasticizer or superplasticizer (26); and water (27), and - a foam (30) comprising water (32), air (33) and a foaming agent (31).

Description

FIELD OF THE INVENTION The invention relates to the field of construction. The invention relates more particularly to a construction element, for the construction of residential, industrial, agricultural buildings, etc., as well as to a method of manufacturing such an element and an insulating material intended to be integrated in such an element. element. 2. SOLUTIONS OF THE PRIOR ART For several years, it has been sought to reduce the thermal conductivity of building elements, and in particular building blocks, in order to increase the thermal insulation and the energy efficiency of buildings.

Among all the known building blocks, the concrete block or concrete block (abbreviated BBM), commonly referred to as "cinder block", is a molded masonry element that is used for the construction of exterior walls in a large majority of buildings. current constructions. It is usually a molded concrete block, in the form of hollow parallelepiped or not. Although it is one of the cheapest construction materials on the market, it has a low thermal resistance compared to the standards currently imposed for building construction. It is therefore necessary to cover it with a layer of thermal insulation.

To overcome the disadvantages of the concrete block, other types of building blocks have been proposed, among which so-called lightweight concrete blocks. These blocks are obtained by replacing conventional aggregates (sand, gravel) with naturally light and insulating materials, such as pumice, expanded slate or expanded clay, for example. Although the lightweight aggregate concrete block has better insulating properties than the conventional concrete block, it is relatively expensive, which is unsatisfactory. In order to improve the insulating properties of the building blocks, it has been proposed to integrate an insulating material inside the cells formed in these blocks. The insulation materials used are generally rockwool, polystyrene, polystyrene graffiti, cork, hemp wool, cellulose wadding, etc. The addition of these insulating materials known to be expensive is therefore not satisfactory since it substantially increases the construction costs. Thus, building blocks pose problems both in terms of thermal resistance (for the concrete block) and in terms of price (for solutions offering increased thermal resistance). There is therefore a need to find new building elements, including building blocks, to improve the thermal insulation, while maintaining an acceptable mechanical strength and low cost. SUMMARY OF THE INVENTION The invention does not pose these problems related to the building elements of the prior art. Indeed, the invention relates to a construction element comprising a frame and at least one inner recess in which is disposed an insulating material. According to the invention, the insulating material comprises: - a cement slurry comprising: a first clinker cement, a second sulfo-aluminous cement, a setting accelerator cement, a plasticizer or superplasticizer and water; and a foam comprising water, air and a foaming agent. The use of an insulating material in the form of a cementitious foam makes it possible to greatly increase the thermal resistance of the construction element, which may be a parallelepipedal building block, for example. Such a building element has improved insulating properties, due to reduced thermal conductivity, while ensuring acceptable mechanical strength. In addition, it significantly improves the thermal insulation performance of a building constructed with such building elements. In addition, it meets the standards in force in the field of construction, namely the standards RT 2012 and HQE (High Environmental Quality). In addition, the reduced density makes the building element lightweight, and therefore easier to transport, carry and lay. According to a particular characteristic, the cement slurry comprises in percent relative to the total mass of cement slurry: 50 to 80% of said first cement; 1 to 20% of said second cement; 1 to 7% of said cement setting accelerator; 0.1 to 5% of said plasticizer or superplasticizer; and 10 to 30% water. According to a particular characteristic, the foam comprises in percent relative to the total mass of foam: 0.1 to 0.3% of foaming agent; 7 to 8% water; and 90 to 92% of compressed air. According to a particular characteristic, the insulating material has a density of between 50 and 200 kg / m 3. According to one particular characteristic, the insulating material has a thermal conductivity of between 0.03 and 0.2 W / mK. According to a particular characteristic, said framework is based on heavy aggregate concrete, based on concrete of ordinary or light aggregates, based on cellular concrete or with terracotta. The invention also relates to a method of manufacturing a construction element as previously described.

According to the invention, such a method comprises the steps of: mixing a first cement and a second cement to obtain a third cement; adding water to the third cement to obtain a first grout of cement; adding a cement setting accelerator, a plasticizer or a superplasticizer to the first grout of cement to obtain a second grout of cement; - Preparation of a fluid foam by mixing a foaming agent with water and air; - mixing the second cement slurry with the fluid foam to obtain an insulating material; injecting the insulating material into at least one recess of the building element; - Taking the insulating material in said at least recess.

According to a particular feature, the method further comprises a step of leveling the height of insulating material relative to the height of the frame. According to a particular characteristic, the leveling step is carried out by sanding or sawing the surplus of insulating material.

The invention furthermore relates to an insulating material intended to be arranged in a building element as previously described. According to the invention, the insulating material comprises: - a cement slurry comprising: a first clinker cement, a second sulfo-aluminous cement, a setting accelerator cement, a plasticizer or superplasticizer and water; and a foam comprising water, air and a foaming agent. 4. LIST OF FIGURES Other features and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment, given by way of a simple illustrative and nonlimiting example, and the appended drawings, among which: - Figure 1 is a perspective view of a building element of the invention, taking the form of a building block in which the insulating material is not shown; FIG. 2 is a perspective view of the building block of FIG. 1 in which the insulating material is arranged; - Figure 3 schematically illustrates the different steps of the method of manufacturing the insulating material according to a particular embodiment; and - Figure 4 schematically illustrates the composition of the insulating material of the invention. 5. DETAILED DESCRIPTION OF THE INVENTION 5.1 Summary of the Principle of the Invention The invention relates to a construction element, in the form of a building block for example, intended for the construction of a building wall, in particular.

The invention also relates to a method of manufacturing such an element and an insulating composition intended to be implemented in such an element. The invention thus proposes a construction element comprising at least one recess (or a cavity) filled with an insulating material based on mineral foam. Thus, the construction element according to the invention offers numerous advantages and makes it possible in particular to meet the necessary evolutions which the traditional concrete block must face, without, however, presenting the drawbacks of the alternative solutions of the prior art, namely the price , mechanical strength and insulating properties. Subsequently, there is presented in particular an embodiment of a building element according to the invention, which takes the form of a block. It is clear however that the invention is not limited to this particular embodiment, but can also be implemented in many other embodiments and more generally in all cases where the advantages provided by the invention are interesting. . 5.2 Description of an Embodiment The construction element which is the subject of the present invention is described, in a general embodiment, with reference to FIGS. 1 to 2. In this embodiment, the construction element is a block rectangular parallelepiped shape. 5.2.1 Framing The building block 1 comprises a framework 10 based on concrete of heavy aggregates, current or light (Pozzolana, pumice, expanded clay, expanded slate, slag, siliceous volcanic rocks, expanded slag, etc ...) , based on cellular concrete or based on terracotta. The frame 10 is of substantially rectangular parallelepiped shape, and has two longitudinal walls 11, 12 parallel and substantially planar, and two transverse walls 13, 14 parallel. The longitudinal walls 11, 12 define with the transverse walls 13, 14 at least one inner recess 15 of rectangular shape. This recess 15 represents a volume of 30% to 70% of the total volume of the building block 1, and more preferably 50% to 70%. In the example shown, the building block 1 comprises a single opening 15 opening. Note that the building block 1 may include several recesses opening or not.

As will be described later, the internal recess 15 formed, inside the frame 10, by the longitudinal walls 11, 12, and transverse 13, 14, is configured to be filled by means of a material insulation, in the form of a mineral foam 2 obtained from a cement grout and a foaming agent in particular.

As will be seen later, this mineral foam 2 is manufactured so as to trap a maximum of air in the cementitious mass in order to greatly increase the thermal resistance of the building block 1. In addition, the frame 10 comprises several cells 18, open or not, arranged between the longitudinal walls 11, 12 and the recess 15, on each side of the latter. These cells 18 are used to define volumes in which the air is trapped. The air thus trapped participates passively in the thermal resistance offered by the building block 1. It is noted that two of these cells 18 comprise a rounded portion 19, forming a gripping hole which facilitates the handling of the building block 1. As illustrated in Figures 1 and 2, the frame 10 has two gripping holes 19 located in diagonally opposite corners.

Furthermore, the transverse walls 13, 14 each have assembly means 16, 17 of the building block 1 to another building block. Each transverse wall thus comprises a male part 17 and a female part 16 adapted to cooperate respectively with the female part 16 and the male part 17 of the adjacent building block. 5.2.2 Insulating mineral foam The insulating material intended to fill the recess 15 of the building block 1 is a mineral foam 2 obtained by a mixture of several elements / components, namely: a cement slurry obtained by the mixture of two cements 21, 22 to which is added a grout setting accelerator 20 and a plasticizer or a superplasticizer 26; a foam 30 obtained by means of an organic foaming agent 31; and water 32 and compressed air 33. The insulating mineral foam 2 is manufactured according to the steps of the method described below and illustrated schematically in FIG. 3. The cement grout 20 used in the composition of the insulating mineral foam 2 comprises a first cement 21 based on clinker. in accordance with the European standard NF EN 197-1. The proportion of this first cement 21 is between 50 and 80% of the total mass of the cement slurry 20. Preferably, this proportion is 55 to 75%, more preferably 60 to 70%. The second cement 22 is a sulfo-aluminous cement. In a known manner, such a cement consists of a mixture of sulfo-aluminous clinker and hydrated calcium sulphate (gypsum) or not (anhydrite). The proportion of second cement 22 relative to the total mass of the cement slurry 20 is between 1 and 20%. Preferably, this proportion is from 10 to 20%, and even more preferably from 10 to 15%.

By mixing the first cement 21 with the second cement 22 (step 101), a third cement 23 is obtained, to which water 27 is added (step 102), the proportion of water 27 relative to the total mass of the cement slurry 20 being between 10 and 30%, preferably between 15 and 25%, even more preferably between 20 and 25%. A first grout 24 is thus obtained, to which a cement setting accelerator 25 is then added (step 103A). It is recalled that a cement setting accelerator is a component allowing to reduce the time between the hydration of the cement and the beginning of the setting of the cement.

The proportion of setting accelerator 25 relative to the total mass of the cement slurry 20 is between 1 and 7%. Preferably, this proportion is from 1 to 5%, and even more preferably from 3 to 5%. In addition, a plasticizer or a superplasticizer 26 is added to the first cement slurry 24 (step 103B). It is recalled that a plasticizer or superplasticizer is a dispersant. The role of these molecules is to disperse the grains of cement to allow better hydration of the grains and thus improve the effectiveness of the cement. A plasticizer or superplasticizer allows, in addition, to reduce the amount of cement needed and thus lighten the mineral foam 2. Moreover, these molecules temporarily neutralize the attractive forces between the cement grains and make fluid, and therefore malleable The slurry of cement 24. The proportion of plasticizer or superplasticizer 26 with respect to the total mass of cement slurry 20 is less than 5%. Preferably, this proportion is less than 3%, and even more preferentially between 0.1 and 1%. Once all these constituents / components are added to the mixture, a cement slurry 20 is thus obtained to be mixed with the foam 30 described hereinafter.

The foam 30 is made from a foaming agent 31. The foaming agent is a compound that modifies the surface tension between two surfaces, and more particularly here between a liquid and a gas. This foaming agent 31 is based on organic compounds. By way of example, mention may be made of polysaccharides comprising hydrophobic groups. In order to obtain the foam 30, the foaming agent 31 is mixed with water 32 and compressed air 33 via a mixing bowl (step 104). Air 33 must be dry and deoiled. It must be injected through the mixing bowl at a pressure between 5 and 8 bar, and more preferably between 6 and 7 bar. By way of example, for 1 m3 (or 1000 liters) of foam 30, 2 kg of foaming agent 31, 80 kg of water 32 and a volume of air of 918 liters are provided. The air pressure should be between 5 and 8 bar and ideally between 6 and 7 bar. The air must be dry and deoiled. The insulating material, that is to say the mineral foam 2, of the invention is obtained after mixing the cement slurry 20 and the foam 30 by light stirring (step 105) so as to coat the air bubbles. of the foam 30 by a thin layer of cement grout 20. The production of the mineral foam 2 requires the cement slurry 20 to harden before the foam 30 collapses. After the setting of the cement 20, the air bubbles are trapped and then the insulating mineral foam 2 of the invention is obtained. The resulting mineral foam 2 is a lightweight material with high thermal performance. Indeed, its density is preferably between 50 and 550 kg / m3, preferably between 50 and 400 kg / m3, more preferably between 50 and 200 kg / m3.

Moreover, the thermal conductivity A of such a mineral foam is between 0.03 and 0.2 W / mK, preferably between 0.03 and 0.1 W / mK, and still more preferably between 0.03 and 0.06 W / mK Taking the cement 20 of the resulting mineral foam 2 within 1 to 4 hours, it is therefore necessary to fill the recess 15 of the building block 1 within this time (step 106). This filling operation can be carried out before or after setting concrete heavy, common or light aggregates forming the frame 10 of the building block 1.

In the case where the frame 10 is terracotta, it is necessary to fill the recess 15 with the mineral foam 2 after firing the terracotta. In the case where the framework 10 is of cellular concrete, it is necessary to carry out the filling operation of the recess 15 with the mineral foam 2 after the autoclaving phase.

In the case of an opening opening, the building block 1 is preferably positioned on a drying support (this operation is not necessary when the recess 15 is not opening). The filling process uses a tank receiving the mineral foam 2 fluid in which an agitator allows a permanent movement of the foam 2. This foam 2 is then cast / injected by conventional metering systems (worm, or valves, for example) in the recess 15. It is necessary to allow the mineral foam 2 to cure for at least three hours before palletizing the building blocks thus obtained. Furthermore, each building block 1 filled with insulating material 2 can be ground to ensure an identical height between the frame 10 and the mineral foam 2. An alternative solution consists of sanding by sanding or sawing the mineral foam 2 overflowing.

The construction element (or constructive element) of the invention may take other forms than a block as described above, and may be, for example, a wall or floor element. Of course, the present invention is not limited to the examples and embodiments described and shown. The shape of the building block is not limited to that illustrated in the previously described embodiment. Other forms can indeed be considered. Several recesses can be made in the frame and several separate insulators can be inserted. The building element of the invention is suitable for different types of constructions, such as individual houses and collective dwellings.

Claims (10)

REVENDICATIONS1. Construction element (1) comprising a framework (10) and at least one inner recess (15) in which an insulating material (2) is arranged, characterized in that the insulating material (2) comprises: a cement slurry (20); ) comprising: a first cement (21) based on clinker; a second sulfo-aluminous cement (22); a cement accelerator (25); a plasticizer or superplasticizer (26); and water (27), and a foam (30) comprising water (32), air (33) and a foaming agent (31). 2. Construction element (1) according to claim 1, characterized in that the cement slurry (20) comprises in percent relative to the total mass of cement slurry (20): 50 to 80% of said first cement (21). ); 1 to 20% of said second cement (22); 1 to 7% of said cement setting accelerator (25); 0.1 to 5% of said plasticizer or superplasticizer (26); and 10 to 30% water (27). 3. Construction element (1) according to claim 1 or 2, characterized in that the foam (30) comprises in percent relative to the total mass of foam (30): 0.1 to 0.3% of agent foaming (31); 7 to 8% water (32); and 90 to 92% of compressed air (33). 4. Construction element (1) according to one of claims 1 to 3, characterized in that the insulating material (2) has a density of between 50 and 200 kg / m3. 5. Construction element (1) according to one of claims 1 to 4, characterized in that the insulating material (2) has a thermal conductivity (A) of between 0.03 and 0.2 W / m.K. 6. Construction element (1) according to one of claims 1 to 5, characterized in that said frame (10) is based on heavy aggregate concrete, based concrete common or light aggregates, concrete-based cellular or terracotta-based. 7. A method of manufacturing a construction element (1) according to one of claims 1 to 6, characterized in that it comprises the following steps: - mixing a first cement (21) and a second cement (22) to obtain a third cement (23); adding water (27) to the third cement (23) to obtain a first cement slurry (24); adding a cement setting accelerator (25), a plasticizer or a superplasticizer (26) to the first cement slurry (24) to obtain a second cement slurry (20); - preparing a fluid foam (30) by mixing a foaming agent (31) with water (32) and air (33); - stir the second grout of cement (20) with the fluid foam (30) to obtain the insulating material (2); - injecting the insulating material (2) in at least one recess (15) of the frame (10); - Taking the insulating material (2) in said at least one recess (15). 8. Method according to claim 7, characterized in that it further comprises a step of leveling the height of insulating material (2) relative to the height of the frame (10). 9. The method of claim 8, characterized in that the leveling step is performed by sanding or sawing the surplus of insulating material (2). 10. Insulating material intended to be arranged in a building element (1) according to one of claims 1 to 6, characterized in that it comprises: a cement slurry (20) comprising: a first cement (21) to clinker base; a second sulfo-aluminous cement (22); a cement accelerator (25); a plasticizer or superplasticizer (26); and water (27), and a foam (30) comprising water (32), air (33) and a foaming agent (31).