Prefabricated monobloc panel

The present invention relates to the general technical field of construction, more specifically the field of construction elements that are prefabricated in a factory and are then used on a building site in order to form directly the walls, floors or ceilings of a dwelling.

More particularly, the present invention relates to a prefabricated monobloc panel for forming walls of a dwelling and to a method for producing such a prefabricated monobloc panel.

It is known to use prefabricated monobloc panels to reduce the time needed to build a dwelling and thus to reduce the costs by comparison with a dwelling that is constructed by bricklaying at the building site.

Panels that are prefabricated in a factory have dimensions that are rendered precise by the use of digital tools, which on the one hand limits the fitting problems that may be encountered at the building site and on the other hand reduces the numbers and the qualification of the workforce needed for their use at the building site.

However, these prefabricated panels have the disadvantage of having to be transported from the factory to the building site.

Thus, these prefabricated panels have to be easy to transport, and they have to be robust while at the same time being sufficiently light to limit the transportation costs. It is known to use prefabricated panels comprising a wooden framework in order to reduce the weight of the prefabricated panels.

Wood has the advantage of being light, which means that prefabricated panels with a wooden framework are easily transportable at less cost.

However, wood has certain disadvantages, among which its robustness to resist stress, its limited stability over time, its vulnerability to insects, its poor soundproofing and fire resistance despite the use of various wood treatments.

The present invention aims to overcome all or some of the disadvantages mentioned above.

To this end, the present invention relates to a prefabricated monobloc panel for forming walls of a building, said panel having a framework comprising concrete with a density of 1100 kg/m ³ to 1800 kg/m ³ and a compressive strength of at least 16 MPa at 28 days, preferably 30 MPa at 28 days.

This arrangement makes it possible to obtain a prefabricated panel which is both robust and also easy to transport and which has a weight comparable to that of a prefabricated monobloc panel with a wooden framework.

The compressive strength of this concrete allows the prefabricated monobloc panel to be used as a structural element of the building. In addition, the concrete used has good stability over time, is not vulnerable to insects and has good soundproofing and good fire resistance.

According to one aspect of the invention, the framework comprises reinforcing ribs, among which a first number of the reinforcing ribs extend along a first direction and a second number of the reinforcing ribs extend along a second direction, the first direction being substantially perpendicular to the second direction.

According to one aspect of the invention, the first number of the reinforcing ribs extend entirely within a first volume situated between a first plane and a second plane substantially parallel to the first plane, and the second number of the reinforcing ribs extend entirely within a second volume situated between the second plane and a third plane substantially parallel to the second plane.

This arrangement permits deplanarization of the framework of the prefabricated panel, in order to further limit the thermal bridges that may be generated via the framework of the panel.

According to one aspect of the invention, the reinforcing ribs of the frame are in one piece.

According to one aspect of the invention, the framework forms housings in which is inserted an insulating material, especially expanded polystyrene.

According to one aspect of the invention, part of the insulating material entirely covers the face of the framework that is intended to be oriented towards the inside of the building.

This arrangement makes it possible to further limit the thermal bridges.

According to one aspect of the invention, the panel comprises a facing layer connected to the framework and designed to cover a face of the framework intended to be oriented towards the outside of the building, said facing layer being made of concrete, in particular of ultra-high performance fibre-reinforced concrete.

According to one aspect of the invention, the panel . comprises a thermal insulation layer, for example of extruded polystyrene, arranged between the facing layer and the framework of the panel.

The present invention also relates to a method for producing a prefabricated monobloc panel for forming walls of a building, comprising the following steps:

- pouring concrete, in particular ultra-high performance fibre-reinforced concrete, into a formwork in order to form a facing layer of the panel,

- placing a thermal insulation layer in the formwork over the facing layer,

- forming a mould in the formwork by placing several elements of an insulating material over the thermal insulation layer,

- pouring concrete with a density of 1100 kg/m ³ to 1800 kg/m ³ and a compressive strength of at least 16 MPa at 28 days, preferably 30 MPa at 28 days, into the mould in order to form a framework of the panel,

- removing the panel from inside the formwork. This method allows prefabricated monobloc panels to be produced quickly and reproducibly.

According to one implementation of the method, the method comprises a preliminary step which involves arranging a formwork whose base comprises a matrix intended to give the outer surface of the facing layer a defined surface texture .

This arrangement avoids a subsequent step of re-working the outer surface of the facing layer.

According to one implementation of the method, the method comprises a step in which reinforcements are installed in the mould before pouring the concrete intended to form the framework.

This arrangement makes it possible to consolidate the framework.

In any case, the invention will be clearly understood from the following description and by reference to the attached schematic drawing which shows, as a non-limiting example, an embodiment of a prefabricated panel according to the invention and the steps of a method for producing a prefabricated panel.

Figure 1 shows an exploded schematic view of a prefabricated monobloc panel according to the invention comprising a window bay.

Figure 2 shows a perspective schematic view of a first embodiment of a prefabricated monobloc panel according to the invention. Figure 3 shows a sectional view of the prefabricated panel illustrated in Figure 2.

Figure 4 shows a perspective schematic view of a variant embodiment of a prefabricated monobloc panel according to the invention.

Figure 5 shows a sectional view of the prefabricated panel illustrated in Figure 4.

Figure 6 shows an exploded schematic view of a prefabricated monobloc panel comprising a variant embodiment of a framework.

Figure 7 shows a perspective schematic view of the prefabricated monobloc panel illustrated in Figure 6.

Figure 8 shows a sectional view of the prefabricated monobloc panel illustrated in Figure 7.

Figures 9A to 9F illustrate the steps of a method for producing a prefabricated monobloc panel according to the invention.

In the figures, identical elements are designated by identical reference signs. Moreover, the figures are not drawn to scale.

The prefabricated monobloc panel 1 according to the invention is intended for the formation of the walls of a dwelling, especially outer walls, roof walls or floor walls.

Within the meaning of the present invention, "monobloc" is understood as meaning a panel which is in one piece and of which the various constituent layers are maintained in position relative to one another.

"Prefabricated" is understood as meaning a panel that is made in a factory prior to its use on the building site.

As is shown in particular in Figures 1 and 6, a prefabricated monobloc panel 1 according to the invention comprises a plurality of mutually superposed and/or overlapping layers .

Thus, the prefabricated monobloc panel 1 according to the invention is what is called a multilayer panel.

"Multilayer" is understood as meaning a panel having a plurality of mutually stacked and/or overlapping layers. In this case, the term "sandwich" panel may also be used.

The prefabricated monobloc panel 1 has a framework 2 comprising concrete.

Concrete is understood as a hydraulic composition comprising a hydraulic binder, especially cement, and water, optionally aggregates and optionally adjuvants. The hydraulic compositions include compositions in the fresh state and also those in the hardened state.

In addition, such a concrete used to form the framework 2 of the prefabricated monobloc panel 1 does not comprise a composite material based on concrete and fibres.

Indeed, the use of such composite materials is delicate, which would considerably complicate the method of producing the prefabricated monobloc panel 1. The hydraulic binder and the water form the paste and give cohesion to all the aggregates present in the hydraulic composition.

This concrete has a density of 1100 kg/m ³ to 1800 kg/m ³ and a compressive strength of at least 16 Pa, preferably 30 Pa at 28 days.

This framework 2 may, for example, be made from a concrete of the kind sold by Lafarge under the trademark Thermedia ^® .

The concrete may also wholly or partially comprise lightweight aggregates, for example pumice, pozzolanas, expanded clay, expanded schist and/or aggregates called biosources, for example wood or hemp.

This framework 2 is able to support a plurality of superposed or overlapping layers forming the prefabricated mon- obloc panel 1.

The framework 2 comprises a frame 2c of rectangular shape inside which there extend a plurality of reinforcing ribs 2a, 2b, which give the panel 1 its rigidity.

The reinforcing ribs 2a, 2b and the frame 2c form a mon- obloc assembly.

Thus, the frame 2c has an upper edge, a lower edge and two side edges which are defined with respect to the position of the prefabricated monobloc panel 1 when the latter is placed upright in a normal position of use.

A first number of reinforcing ribs 2a of this plurality of reinforcing ribs extend along a first direction Dl . A second number of reinforcing ribs 2b of this plurality of reinforcing ribs extend along a second direction D2.

The first direction Dl is substantially perpendicular to the second direction D2.

In the examples shown, the first direction Dl is substantially horizontal and the second direction D2 is substantially vertical when the prefabricated monobloc panel is placed in its normal position of use.

In the description below, the reinforcing ribs extending along the first, horizontal direction Dl will be called horizontal reinforcing ribs 2a, and the reinforcing ribs extending along the second, vertical direction D2 will be called vertical reinforcing ribs ^' 2b.

In the example shown in Figure 1, the prefabricated monobloc panel 1 comprises a window bay 10.

Thus, in this example, the framework 2 comprises six horizontal reinforcing ribs 2a and two vertical reinforcing ribs 2b.

Of the six horizontal reinforcing ribs 2a, two reinforcing ribs extend between the two vertical reinforcing ribs 2b and contribute to forming the contour of the window bay 10.

The four other horizontal reinforcing ribs 2a extend between a lateral edge of the frame 2c and one of the two vertical reinforcing ribs 2b.

In addition, these four other horizontal reinforcing ribs 2a are aligned in pairs and are offset with respect to the two horizontal reinforcing ribs 2a that contribute to forming the contour of the window bay 10.

The two vertical reinforcing ribs 2b extend between the upper edge and the lower edge of the frame 2c and contribute to forming the contour of the window bay 10.

In the examples shown in Figures 2 to 8, the prefabricated monobloc panel 1 does not comprise a bay.

Thus, in these examples, the framework 2 comprises two horizontal reinforcing ribs 2a extending between the two lateral edges of the frame 2c, and two vertical reinforcing ribs 2b extending between the upper edge and the lower edge of the frame 2c.

Of course, the present invention is not in any way limited to the number of reinforcing ribs 2a, 2b or to their arrangement inside the prefabricated monobloc panel 1.

Thus, the number and the arrangement of the reinforcing ribs 2a, 2b may vary from one panel 1 to another depending on the final use of a panel, for example a full wall, a window bay or a door bay.

In the variant shown in Figures 6 to 8, the horizontal reinforcing ribs 2a extend entirely within a first volume situated between a first plane PI and a second plane P2 substantially parallel to the first plane PI.

In the example proposed in these figures, the first plane PI coincides with the flat surface of the face of the horizontal reinforcing ribs 2a that is intended to be oriented towards the outside of the building. The second plane P2, for its part, coincides with the flat surface of the face of the horizontal reinforcing ribs 2a that is intended to be oriented towards the inside of the building, or with the flat surface of the face of the vertical reinforcing ribs 2b that is intended to be oriented towards the outside of the building.

Similarly, the vertical reinforcing ribs 2b extend entirely within a second volume situated between the second plane P2 and a third plane P3 substantially parallel to the second plane P2.

In the example proposed in Figures 6 to 8, the third plane P3 coincides with the flat surface of the face of the vertical reinforcing ribs 2b that is intended to be oriented towards the inside of the building.

Thus, the horizontal reinforcing ribs 2a and the vertical reinforcing ribs 2b of the second part are referred to as being deplanarized.

The deplanarization also makes it possible to limit the heat losses through thermal bridges.

Indeed, the deplanarization provides a further distance of some of the ribs from the face of the prefabricated mon- obloc panel 1 that is intended to be oriented towards the outside of the building.

In the variant embodiment shown in Figures 4 and 5, each reinforcing rib 2a, 2b joins two opposite edges of the frame 2c. Moreover, the vertical reinforcing ribs 2b are further away than the horizontal reinforcing ribs 2a from the face that is intended to be oriented towards the outside of the building .

In this variant embodiment, the thickness of the horizontal reinforcing ribs 2a is 6 cm for example, and the thickness of the vertical reinforcing ribs 2b is 12 cm for example.

The variant embodiment involving deplanarizing the reinforcing ribs 2a, 2b may also be applied to a prefabricated monobloc panel comprising a bay 10.

The intersecting of the various reinforcing ribs 2a, 2b of the framework 2 forms housings 3.

These housings 3 are filled with an insulating material 4, preferably with expanded polystyrene.

Other insulating materials 4 may be used, especially wood wool or porous concrete.

According to the variant embodiment shown in Figures 2 and 3, the framework 2 is flush with the insulating material 4.

In this variant embodiment, the thickness of the ribs 2a, 2b is 22 cm for example, and the thickness of the insulating material is also 22 cm.

In this variant embodiment, the insulating material 4 comprises a plurality of separate elements arranged in the housings 3. According to the variant embodiment shown in Figures 4 and 5, part of the insulating material 4 completely covers that surface of the framework 2 intended to be oriented towards the inside of the building.

In this variant embodiment, the thickness of the ribs 2a, 2b is 12 cm for example, and the thickness of the insulating material is 22 cm.

In this variant embodiment, the insulating material 4 comprises a plurality of elements arranged in the housings 3 and connected to one another by the part of the insulating material 4 completely covering the surface of the framework 2.

Completely covering the framework 2 with an insulating material 4 has the effect of further limiting the heat losses through a thermal bridge.

However, with an equal thickness of insulating material 4, the ribs 2a, 2b in this variant embodiment are less thick than when the ribs 2a, 2b are flush with the insulating material 4.

Consequently, in this variant embodiment, the prefabricated monobloc panel 1 is less robust but lighter.

A variant embodiment of this kind will thus be able to be used for applications that do not require strong stresses of the panel 1.

In the variant shown in Figures 6 to 8, first elements of insulating material 4 extending longitudinally with respect to the horizontal reinforcing ribs 2a, and having a thick- ness substantially similar to these, are inserted, on the one hand, between two horizontal reinforcing ribs 2a and, on the other hand, between certain horizontal reinforcing ribs 2a and the frame 2c.

Similarly, second elements of insulating material 4 extending longitudinally with respect to the vertical reinforcing ribs 2b, and having a thickness substantially similar to these, are inserted, on the one hand, between two vertical reinforcing ribs 2b and, on the other hand, between certain vertical reinforcing ribs 2b and the frame 2c.

In addition, this insulating material 4 may comprise conduits for the circulation of a fluid, or sheaths for the passage of electrical wiring.

A prefabricated monobloc panel 1 according to the invention additionally comprises a thermal insulation layer 5, for example of extruded polystyrene, arranged over the insulating material 4.

This thermal insulation layer 5 is in contact with the insulating material 4 and optionally in contact with the framework 2 if the latter is equalized with the insulating material .

The expression "thermal insulation" according to the invention refers to a material that is able to limit the propagation of cold and of heat. Advantageously, it may also be an acoustic insulation material, that is to say a material limiting the propagation of sound waves.

This thermal insulation layer 5 may, for example, be of the kind sold by BASF under the trademark Styrodur ^® . This thermal insulation layer 5 may, for example, have a thickness of 3 cm.

Finally, a prefabricated monobloc panel 1 according to the invention comprises a facing layer 6 arranged over the thermal insulation layer 5.

This facing layer 6 is in contact with the thermal insulation layer 5.

This facing layer 6 is made of concrete, in particular of ultra-high performance fibre-reinforced concrete.

This facing layer 6 is intended to form the outer face of the wall of the building.

Ultra-high performance concrete (UHPC) is understood as concrete having a compressive strength, at 28 days, of greater than or equal to 100 MPa and generally greater than or equal to 120 MPa.

This facing layer 6 can be made, for example, from a fibre- reinforced concrete of the type sold by Lafarge under the trademark Ductal ^® .

This facing layer 6 can have a thickness of 1.8 cm, for example .

This facing layer 6 can be fixed to the framework 2, for example by support rods (not shown) which are sunk in the facing layer 6, still in the fresh state, and pass through the thermal insulation layer 5 and are covered by the concrete used for forming the framework 2 of the panel 1. These support rods are made, for example, of stainless steel or of composite materials.

Thus, this facing layer 6 contributes to the cohesion of the prefabricated monobloc panel 1.

As is shown in Figure 1, the prefabricated monobloc panel 1 may also be covered by plasterboard 7, on its face intended to be oriented towards the inside of the building.

This plasterboard 7 is intended to form the inner face of the wall of the building.

Moreover, two prefabricated monobloc panels may be connected to each other by providing the adjacent edges of two contiguous panels with a means of form-fit engagement.

To form an angle between two contiguous panels, an angle bracket may optionally be used to cover the joint between the two panels.

By way of example, a prefabricated monobloc panel 1 according to the invention has a length of between 4 m and 6 m, depending on the number of bays present on the panel 1, a height of between 2.60 m and 2.80 m, preferably 2.70 m, all of the panels at a same level having a similar height, and a thickness of between 25 cm and 30 cm, preferably 26.8 cm.

In some cases, the prefabricated monobloc panels 1 used to construct the wall of a building may have different thicknesses . The weight of a prefabricated monobloc panel 1 having such dimensions varies between 900 kg and 2100 kg for a panel 1 having no window or door opening.

The present invention also relates to a method for producing a prefabricated monobloc panel for forming walls of a building, in particular a prefabricated monobloc panel 1 as described above.

The steps for producing such a panel 1 are shown in Figures 9A to 9F for a full panel without bays.

Of course, this same method can be applied for producing a prefabricated monobloc panel having one or more openings.

A first step shown in Figure 9B involves pouring concrete, in particular ultra-high performance fibre-reinforced concrete, into a formwork 20 in order to form the facing layer 6 of the panel 1.

This formwork 20 comprises a contour 21 of substantially rectangular shape, of which the size is substantially similar to the size of the prefabricated monobloc panel 1.

This contour 21 is made of wood, for example.

In addition, as is shown in Figure 9A, the formwork 20 has a closed base 22, of which the surface has a matrix 23 designed to give the outer surface of the facing layer 6 a defined surface texture.

The formwork is open on its upper face 24 situated opposite the base 22. Thus, the ultra-high performance fibre-reinforced concrete is introduced via the upper face 24 in order to be poured on the matrix 23.

The concrete is then distributed homogeneously over the entire base 22 of the formwork 20, in such a way that the facing layer 6 has a uniform thickness across the entire surface of the panel 1. This thickness is 1.8 cm, for example .

Advantageously, the fluidity of the concrete permits uniform spreading over the base 22 of the formwork 20.

The support rods are placed on the thermal insulation layer 5 at locations intended to lie opposite the median axes of the future frame 2c and the future reinforcing ribs 2a, 2b of the framework 2.

These rods extend right through the thermal insulation layer 5, in a direction substantially transverse with respect to the two opposite surfaces of the thermal insulation layer 5, and are held in position on the thermal insulation layer 5, for example by a connection of the screw and nut type.

During a second step, shown in Figure 9C, the thermal insulation layer 5 is placed in the formwork 20 over the facing layer 6.

Thus, when the concrete of the facing layer 6 is still in the fresh state, the portions of the support rods opposite the facing layer 6 are immersed in the fresh concrete without passing completely through the facing layer 6. During a third step, shown in Figure 9D, several elements of insulating material 4 are arranged on the thermal insulation layer 5.

The placement of these elements 4 corresponds to the position of the future housings 3 that are formed in the framework 2 of the prefabricated monobloc panel 1.

Thus, the positioning of these elements of insulating material 4 on the thermal insulation layer 5 forms channels 25 inside the formwork 20.

These channels 25 are centred on the median axes of the future frame 2c and of the future reinforcing ribs 2a, 2b of the framework 2.

These channels 25 together form a mould 26 for the future reinforcing ribs 2a, 2b and the future frame 2c of the framework 2 of the prefabricated monobloc panel 1.

The height of these elements of insulating material 4 is substantially similar to the thickness of the future framework 2 of the prefabricated monobloc panel 1.

The various corners of these channels 25 formed at the interface of the elements of insulating material 4 and of the insulation layer 5 are sealed, on the one hand in order to prevent concrete from pouring between the elements of insulating material 4 and the insulation layer 5 and, on the other hand, to keep the elements of insulating material 4 in their position.

These elements of insulating material 4 may also be directly affixed to the insulation layer 5. At this stage of the method, the portions of the support rods protruding from the surface of the thermal insulation layer 5, opposite the facing layer 6, are positioned substantially on or near the median axis of the grooves 25.

These rod portions extend along a length that is less than the depth of the channels 25.

As is shown in Figures 9C and 9D, reinforcements 27 are placed in all of the channels 25 forming the mould 26.

These reinforcements 27 may be put place before or after the elements of insulating material 4 have been put in place .

Advantageously, these reinforcements 27 are kept at a distance from the edges of the channels 25.

The support rods can be fixed to the reinforcements 27.

In a step shown in Figure 9E, concrete with a density of 1100 kg/m ³ to 1800 kg/m ³ and with a compressive strength of at least 16 MPa at 28 days, preferably 30 MPa at 28 days, is poured into the mould 26 in order to form the frame 2c and the reinforcing ribs 2a, 2b of the framework 2 of the panel 1.

Advantageously, rails 28 for subsequently fixing plasterboard are fixed to the surface of the elements of insulating material 4 and of the framework thus formed.

Finally, in a step of the method shown in Figure 9F, the prefabricated monobloc panel 1 is removed from the interior of the formwork 20. For this purpose, lifting means, for example lifting rings may have been provided and fixed to the frame 2c of th panel 1 by the hardening of the concrete forming the frame work 2.

Although the invention has been described on the basis o specific embodiments, it is of course not in any way lim ited to these and it covers all the technical equivalent of the means described and their combinations.