Hemp fibre-containing construction element, in particular for the construction of buildings

Abstract

The invention relates to a construction element (2), preferably a wall construction element, more preferably an outer wall construction element, in particular for the construction of buildings, comprising a frame (5), preferably made of a wood material. The frame (5) is filled with a hemp-containing, in particular a hemp fibre-containing, filling (6). The invention further relates to a method for producing such a construction element and to a structure comprising at least one construction element.

Description

[0001] Building component containing hemp fibers, especially for the construction of buildings

[0002] The invention relates to a building component, in particular for the construction of buildings, the use of a hemp-containing, in particular hemp fiber-containing, filling for the manufacture of a building component, a method for the manufacture of a building component and a building with such a building component according to the preambles of the independent claims.

[0003] Buildings are responsible for approximately 40% of global greenhouse gas emissions. One source of these emissions is the building materials themselves. It is therefore desirable to increasingly use low-greenhouse-gas-emission and renewable building materials.

[0004] A well-established and relatively low-carbon-emission building material is hempcrete, also known as hemplime. It is produced by mixing cellulose-rich shives (broken, wood-like particles generated during the deforestation of the hemp plant stalk) with lime and water. The resulting mixture can be poured into or used to construct walls, bricks, and floor slabs. The hardened hempcrete exhibits excellent thermal insulation properties, while weighing only a fraction of conventional concrete. The combination of the high silicon content of the hemp shives with the magnesite content of the lime triggers carbonation (petrification), and the material slowly turns into stone.

[0005] Because carbonation is a slow process, walls made solely of hempcrete are not immediately load-bearing and structurally sound; they are typically constructed as non-load-bearing structures. While adding sand or aggregates can make the material harder and more resistant to pressure, it loses its insulating properties in the process.

[0006] To produce hempcrete, the fresh concrete is poured into molds and compacted, for example, by tamping. The process is time-consuming. Furthermore, shrinkage can occur during the drying process, so that the hardened hempcrete no longer corresponds to the original dimensions of the fresh concrete.

[0007] It is therefore an object of the present invention to overcome the disadvantages of the prior art. In particular, it is an object of the invention to provide a low-carbon-emission building component with good insulating properties. It is also an object of the invention to provide a method for manufacturing such a building component as well as a building incorporating such a building component.

[0008] The tasks are solved by the items defined in the independent claims. Specific implementation methods are described in the dependent claims.

[0009] A first aspect of the invention relates to a building element, preferably a wall element, more preferably an exterior wall element, particularly for the construction of buildings. The building element comprises a frame, preferably made of a heating material. The frame is filled with a hemp-containing, in particular hemp fiber-containing, filling. The hemp-containing, in particular hemp fiber-containing, filling refers to both fresh concrete and hardened hempcrete, as well as all intermediate stages. In the following, "hemp" is understood to mean products grown from hemp, in particular products from the hemp plant stem.

[0010] Preferably, the frame is load-bearing.

[0011] Wood material used in the invention can include, among other things, solid wood, laminate, plywood, medium-density fiberboard, or particleboard. The wood material can be derived from all common tree species, for example, oak, beech, spruce, ash, larch, fir, bamboo, bangkirai, or Douglas fir. It is also possible to use wood polymer composite (WPG).

[0012] The filling may contain not only hemp fibers but also other fibers such as cellulose, wood fibers, steel fibers, plastic fibers, glass fibers, basalt fibers, or carbon fibers. It may also contain purified hemp fiber components such as cellulose, lignin, pectin, wax, fat, or minerals.

[0013] Preferably, the building components are vapor-permeable, meaning they allow water vapor to pass through, thus enabling a reciprocal exchange of moisture from the inside to the outside. Such moisture exchange minimizes mold growth and other moisture damage.

[0014] Preferably, the frame has stiffeners. The stiffeners can be configured as a truss. In particular, the stiffeners can be designed as struts, beams, intermediate or tie posts, and / or as plates. The stiffeners can be configured to form a grid with at least one grid cell. Preferably, the grid has at least two grid cells. Different types of stiffeners can be combined. For example, it is possible to form grid cells with intermediate or tie posts, the intermediate or tie posts being connected by plates.

[0015] Advantageously, the stiffeners are made of wood, preferably the same material as the frame. However, other materials are also conceivable. The materials used should have the lowest possible carbon dioxide emissions, thus enabling sustainable construction.

[0016] Preferably, an additional layer containing hemp, in particular hemp fiber, filler covers the frame and / or the stiffeners on the exterior and / or interior wall side of the building element. This has the advantage that no intermediate layer needs to be applied to the interior wall side, especially to protect the stiffeners. A further advantage is that applying such a covering layer positively contributes to the building physics properties of the building element and, in particular, simplifies the application of plaster.

[0017] Preferably the thickness of the additional layer is 6 to 30 cm, more preferably 6 to 20 cm, and particularly preferably 6 to 12 cm.

[0018] Furthermore, at least one tenon (dowel) can project from the frame into the hemp-containing, especially hemp fiber-containing, infill. Preferably, such tenons are installed every 50 cm within the frame and / or the stiffeners, particularly in the truss. Thus, four tenons can be incorporated per grid cell in a 50 cm x 50 cm grid. Any number of tenons can be installed, depending on requirements. The tenons provide additional anchoring of the frame and / or stiffeners in the infill, thereby offering additional support and increasing durability. Preferably, at least two, and particularly preferably four, tenons project into the hemp-containing, especially hemp fiber-containing, infill.

[0019] Preferably, at least two pins project into each grid cell. It is particularly preferred that four pins project into each grid cell. This allows for an even stronger hold.

[0020] The cones can have a length between 5 and 50 cm, preferably between 10 and 35 cm, and even more preferably between 12 and 20 cm. The length of the cones refers to a dimension of the cone portion that projects from a base surface into the hemp-containing, in particular hemp fiber-containing, filling.

[0021] The cones can be cylindrical, cuboid, pyramidal or conical, with a base area between 4 and 400 cm². 2 , preferably between 8 and 100 cm 2 , even more preferably between 10 and 35 cm 2 amounts .

[0022] Preferably, at least one tenon is made of wood. However, it is also possible for the tenons to be made of metal and, for example, to be in the form of long screws. It is preferred that the tenons do not extend continuously from one side to the opposite side. Continuous tenons can crack during drying. Furthermore, continuous tenons can contribute to cracking in the hemp-containing, especially hemp fiber-containing, filling.

[0023] The frame and / or stiffeners may have seals that are in contact with the hemp-containing, especially hemp fiber-containing, filling. These seals serve to seal gaps after the filling has dried. Slight shrinkage can typically occur during drying, so that without appropriate seals, cavities or holes may form.

[0024] Suitable seals include, for example, swelling tapes that expand upon contact with water. These can be made of acrylate, which offers high moisture and chemical resistance. Rubber seals and sealing tapes, such as those used in the automotive industry, are also suitable. Automotive seals are characterized by high weather resistance, durability, and are maintenance-free. These seals are typically made of EPDM (ethylene propylene diene monomer rubber). Hoses with a lip in their profile are also an option.

[0025] The seals guarantee an airtight seal against the masonry. Masonry, as defined below, refers to a wall comprised of bricks, hemp fiberboards, wood fiberboards, or straw panels. Furthermore, the seals contribute to the insulating properties of the building element.

[0026] The hemp-containing, in particular hemp fiber-containing, filling is preferably a mixture comprising hemp fibers, slaked lime, and preferably cement. Such mixtures are commonly referred to as hempcrete or hemplime. A lime-based binder is generally used in its production. While slaked lime alone is sufficient, it is also possible to add cement. The frame and / or stiffeners can have a thickness of 10 to 45 cm, preferably 18 to 32 cm, and particularly preferably 20 to 32 cm. A thickness of 10 to 50 cm, preferably 14 to 32 cm, and particularly preferably 18 to 24 cm, is also possible. The frame thickness can be achieved by one or more frames. For example, formwork can be applied to a first frame.The first frame can be, for example, 20 cm thick, and the formwork can be 12 cm thick. It goes without saying that other combinations of dimensions are possible. The hardened hempcrete can have the same thickness as the frame. The formwork can extend across several grid cells.

[0027] Another aspect of the invention relates to the use of a hemp-containing, in particular hemp fiber-containing, filling for the manufacture of a building element as described above, wherein the filling comprises hemp fibers, slaked lime and preferably cement.

[0028] Another aspect of the invention relates to a method for manufacturing a building component as described above, preferably a wall component. The method comprises the steps: a) providing a frame, b) filling the frame in a horizontal position with the hemp-containing, in particular hemp fiber-containing, filling, c) optionally: solidifying the hemp-containing, in particular hemp fiber-containing, filling, d) drying the hemp-containing, in particular hemp fiber-containing, filling to produce hardened hempcrete. Solidification is preferably achieved by tamping in the horizontal position. Tamping makes the hemp-containing, in particular hemp fiber-containing, filling denser, more pressure-resistant, and more durable.

[0029] Filling the frame in a horizontal position allows for faster and more cost-effective production of the component. Furthermore, the surface can be made more uniform compared to vertical filling.

[0030] Drying in step d) can be carried out in a horizontal and / or vertical position.

[0031] The hemp-containing, especially hemp fiber-containing, filling contains a very high water content of approximately 250 L / m³ immediately after filling. 3 .

[0032] After filling the frame and the optional hardening step, the filling is preferably left to dry horizontally for one day. This time is sufficient to allow enough hardening for vertical positioning.

[0033] Drying can be active or passive. It can, for example, take place under normal ambient conditions. However, drying can also be enhanced with fans. Fans allow air circulation and thus accelerate drying. The total drying time is typically six to eight weeks. However, it is also possible to carry out the drying in drying chambers. This would reduce the total drying time to approximately one week, particularly 2-7 days. Preferably, before step b), the hemp-containing, especially hemp fiber-containing, filling is produced by mixing hemp, especially hemp fibers, slaked lime, and water. Preferably, the filling also contains cement.

[0034] Preferably, a formwork is additionally used in the method for manufacturing a building component. Such a formwork makes it possible to cover the frame and / or the stiffeners on the outer and / or inner wall side of the building component with the additional layer using the hemp fiber-containing filling. Preferably, the filling of the frame and the filling of the formwork take place in the same work step.

[0035] A formwork thickness of 6 to 30 cm is preferred, 6 to 20 cm is even more preferred, and 6 to 12 cm is particularly preferred.

[0036] Another aspect of the invention relates to the use of a building element as described above as insulating material. The building element can be used as thermal insulation and / or sound insulation for walls and / or subfloors. In particular, such a building element can be used as insulating material on the exterior wall side and / or on the interior wall side. Preferably, a building element can be used as a partition wall, especially without masonry.

[0037] The sound insulation can range between 35 and 45 dB, depending on the chosen thickness. The thermal conductivity can range from 0.06 to 0.07 W / m²K. -1 -K -1 They lie. In addition, the building elements are characterized by good fire resistance, since hempcrete is fire-resistant.

[0038] Another aspect of the invention relates to a structure comprising at least one structural element as described above, optionally with an interior and / or exterior wall made of bricks, preferably hempcrete bricks. Instead of bricks, hemp fiberboards, wood fiberboards, or straw panels may also be used.

[0039] For example, a building can be constructed that has a layered structure of wall elements as described above and an additional brick wall on the outside of the wall element.

[0040] Examples of suitable structures include single-family homes, multi-family homes, office buildings, and even individual floor extensions. In principle, however, any structure that can be built using at least one of the building elements described above is conceivable.

[0041] The invention is explained in more detail using examples. These examples show:

[0042] Figure 1 A plan view of an exterior wall with a building element according to the invention.

[0043] Figure 2 A sectional view of the outer wall.

[0044] Figure 3 A perspective view of the component before filling.

[0045] Figure 4a A section plane view of the component after the

[0046] Filling.

[0047] Figure 4b A first sectional view of the component after the

[0048] Filling.

[0049] Figure 4c A second sectional view of the component after filling.

[0050] Figure 5 shows an overview view of the components of the frame and the stiffeners of the building element. Figure 1 shows a plan view of an exterior wall 1 with a building element 2 according to the invention. The exterior wall comprises a layer of exterior plaster 3, followed by a hemp brick wall 4. The building element 2 adjoins the hemp brick wall 4. The building element 2 comprises stiffeners 9 and a hemp fiber-containing infill 6. Wooden tenons 8 project into the hemp fiber-containing infill 6 for added stability.

[0051] On the inside, an additional layer of plaster (7) is applied to the hardened hempcrete.

[0052] Figure 2 shows the outer wall in a sectional view. The stiffeners 9, which adjoin a frame 5, are indicated by a dashed line. An additional layer 61 of hemp fiber-containing filling 6 covers the frame 5 and the stiffeners 9 on the inner wall side of the building element 2.

[0053] Figure 3 shows a perspective view of the component 2 before filling. The frame 5 and the stiffeners 9 form a grid 11 with four grid cells 111, each measuring 60 cm x 120 cm. Both the frame 5 and the stiffeners 9 are 20 cm thick. Four 15 cm long, cylindrical pins 8 per grid cell 111 project into the space to be filled with the hemp fiber-containing filling 6. Each pin has a base area 81 at a transition to the frame 5 or the stiffener 9. In this example, the base area is 13 cm². 2Seals 10 made of EPDM, designed as lips, are installed on the infill side of each grid cell 111, enclosing the inside. All visible parts, except for the seals 10, are made of solid wood. A formwork 12 is installed for filling to allow the stiffeners 9 and the frame 5 to be covered with the additional layer (not shown) 12 cm thick. The formwork 12 can be repositioned after a grid cell 111 has been filled. Figure 4a shows a section view of the component 2 after filling. The component 2 is penetrated by a first section plane S1 and a second section plane S2. In this view, only the frame 5 is visible as part of the component 2.

[0054] Figure 4b shows a first sectional view resulting from the section through the first section plane S1 of the component 2. The grid 11, formed by the frame 5 and the stiffeners 9, is visible. Each grid cell 111 is filled with hemp fiber-containing infill 6. Wooden tenons 8 project from the base surfaces 81 on opposite sides into the infill 6. The second sectional view shown in Figure 3b, resulting from the section through the second section plane S2 of the component 2, additionally shows the seals 10.

[0055] Figure 5 shows an overview view of the components of the frame 5 and the stiffeners 9 of the structural element. The frame 5 comprises a top plate 5a and a bottom sill 5b. The stiffeners 9 comprise a post 9b and two crossbeams 9a.

[0056] Example

[0057] In one specific implementation, 20 cm thick frames were filled with a hemp fiber-containing concrete mixture in a horizontal position. An additional 12 cm thick formwork made of wooden boards was applied, resulting in a total concrete thickness of 32 cm. This corresponds to a U-value (thermal transmittance coefficient in W / m²K). -2 x K -1 ) of 0.2. The building element was then dried. To achieve a U-value of 0.15 (Minergie EcoP - Passive House), an additional wall made of hempcrete bricks was installed on the inside or outside. The total wall construction thus amounted to 12 cm + 20 cm + 12 cm. The hemp fiber-containing filling was mixed as follows:

[0058] 5 x 200 L hemp

[0059] 5 x 23 kg slaked lime

[0060] 2 x 25 kg cement per 200 L hemp 50 L water .

[0061] The mixing took place in a mixing plant similar in design to a feed mixer. The tough hemp fibers are difficult to process in standard concrete mixers.

Claims

Patent claims 1. Building element (2) , preferably a wall building element, more preferably an exterior wall building element , in particular for the construction of buildings, comprising a frame (5) , preferably made of a wood material, wherein the frame (5) is filled with a hemp-containing, in particular hemp fiber-containing, filling (6).

2. Component (2) according to claim 1, wherein the frame (5) has stiffeners (9), wherein the stiffeners (9) are preferably designed as struts, bars, intermediate or tie posts, and / or as plates.

3. Component (2) according to claim 2, wherein the stiffeners form a grid (11) with at least one grid cell (111).

4. Component (2) according to claim 3, wherein the grid (11) has at least two grid cells (111).

5. Component (2) according to claim 3 or 4, wherein the stiffeners (9) are arranged as a truss.

6. Component (2) according to one of claims 2 to 5, wherein the stiffeners (9) are made of a wood material and preferably of the same material as the frame (5).

7. Component (2) according to one of the preceding claims, wherein an additional layer (61) with the hemp-containing, in particular hemp fiber-containing, filling (6): - the frame (5) and / or the stiffeners (9) ; - on the exterior wall side and / or on the interior wall side; of the component (2) covered.

8. Component (2) according to claim 7, wherein the thickness of the additional layer (61) is 6 to 30 cm, more preferably 6 to 20 cm, and particularly preferably 6 to 12 cm.

9. Component (2) according to one of the preceding claims, wherein at least one pin (8) projects from the frame (5) into the hemp-containing, in particular hemp fiber-containing, filling (6).

10. Component (2) according to claim 9, wherein at least two, preferably four, of the pins (8) project into it.

11. Component (2) according to claim 9, wherein at least two, preferably four, of the pins (3) project into each of the grid cell (n) (111).

12. Component (2) according to one of claims 9 to 11, wherein the pins (8) have a length between 5 and 50 cm, preferably between 10 and 35 cm, more preferably between 12 and 20 cm.

13. Component (2) according to one of claims 9 to 12, wherein the pins (3) are cylindrical, cuboid, pyramidal or conical, and wherein the base area of ​​the pins (3) is between 4 and 400 cm² 2 , preferably between 8 and 100 cm 2 , even more preferably between 10 and 35 cm 2 amounts.

14. Component (2) according to one of claims 9 to 13, wherein the at least one tenon (8) is made of wood material.

15. Component (2) according to one of the preceding claims, wherein: - the frame (5) ; and / or - the stiffeners (9) ; have seals (10) that are in contact with the hemp-containing, in particular hemp fiber-containing, filling (6).

16. Component (2) according to claim 15, wherein the seals (10) are made of EPDM.

17. Component (2) according to claim 15 or 16, wherein the seals (10) are designed as tubes with a lip in the profile.

18. Component (2) according to one of the preceding claims, wherein the hemp-containing, in particular hemp fiber-containing, filling (6) is a mixture comprising hemp fibers, slaked lime and preferably cement.

19. Components (2) according to one of the preceding claims, wherein the frame (5) and / or the stiffeners (9) have a thickness of 10 to 45 cm, preferably 18 to 32 cm, and particularly preferably 20 to 32 cm.

20. Use of a hemp-containing, in particular hemp fiber-containing, filling (6) for the manufacture of a building element (2) according to one of the preceding claims, wherein the filling (6) comprises hemp fibers, slaked lime and preferably cement.

21. Method for producing a building element (2) according to any one of claims 1 to 19, preferably a wall building element, comprising the steps: a) providing the frame (5); b) filling the frame (5) in a horizontal position with the hemp-containing, in particular hemp fiber-containing, filling (6); c) Optionally: solidifying the hemp-containing, in particular hemp fiber-containing, filling (6); d) drying the hemp-containing, in particular hemp fiber-containing, filling (6) to produce hardened hempcrete.

22. Method according to claim 21, wherein, for the production of the component (2), a formwork (12) is additionally used for applying the additional layer 61 according to claim 7.

23. Method according to claim 22, wherein the formwork (12) has a thickness of 6 to 30 cm, more preferably 6 to 20 cm, and most preferably 6 to 12 cm.

24. Method according to one of claims 21 to 23, wherein the drying in step d) takes place in a horizontal and / or vertical position.

25. Method according to one of claims 21 to 24, wherein prior to step b) the hemp-containing, in particular hemp fiber-containing, filling (6) is produced by mixing hemp fibers, slaked lime, water and preferably cement.

26. Use of a building element (2) according to any one of claims 1 to 19 as insulating material.

27. Structure comprising at least one structural element (2) according to any one of claims 1 to 19, optionally: Inside; and / or - Exterior; with a wall (4) made of bricks, preferably hempcrete bricks .

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