Method for producing a wood-concrete composite ceiling, device for applying adhesive mortar, arrangement comprising a wood ceiling and wood-concrete composite element

Abstract

The invention relates to a method for producing a wood-concrete composite ceiling, in which the application of an adhesive mortar to a top surface of a wood ceiling and thereby the creation of a material-bonded connection between the top surface of the wood ceiling and the adhesive mortar, the structuring of a surface of the adhesive mortar facing away from the wood ceiling, in particular during the application of the adhesive mortar, so that the structured surface has elevations and / or depressions, and the application of flowable concrete to form a concrete layer on the structured surface of the adhesive mortar is provided, so that after the concrete has hardened a positive fit is formed between the structured surface of the adhesive mortar and the concrete layer.

Description

[0001] The invention relates to a method for producing a wood-concrete composite ceiling, a device for applying adhesive mortar to a surface of a wood ceiling, an arrangement with a wood ceiling and a wood-concrete composite element.

[0002] Timber-concrete composite construction is primarily used in floor slabs. For this, timber and concrete are connected to each other in a shear-resistant manner, in practice mainly by means of notches, in other words, pockets milled into the timber which are then filled with the concrete topping, or by screws being screwed into the timber slab, which are then encased in concrete after the concrete layer has been applied.

[0003] European patent application EP 3 202 567 A1 discloses a wood-concrete composite slab produced by first applying a layer of adhesive to the wood and then sprinkling this adhesive layer with granules, such as gravel. After the adhesive has cured, the granules are embedded in the adhesive and bonded to it. The adhesive, in turn, bonds to the wood. Concrete is then poured onto the rough granule layer. The bond between the concrete and the granules becomes effective after the concrete has set. A disadvantage is that a device for the regular distribution of the granules is required, and any loose granules must be removed before the concrete is poured.

[0004] A wet-on-wet bonded wood-concrete composite system is known from the international patent application WO 2023 / 099306 A1. In this process, the adhesive is spread evenly over the wood component, and then the concrete is poured while the adhesive is still liquid. The adhesive and concrete harden almost simultaneously. Once hardened, the bond between the concrete and adhesive is effective. Wet-on-wet bonding is highly dependent on weather conditions and is not suitable for on-site application. The adhesive layer can shift upon impact of the fresh concrete, potentially leading to defects in the bond.

[0005] European patent application EP 2 787 140 A1 describes a method for bonding precast elements, in which a precast concrete element is placed on a wooden component that has spacers on its upper surface. The resulting gap is then filled with adhesive. Openings for filling and venting are provided in the precast concrete element for this purpose. These openings must be created either by special components during the casting of the precast concrete element or by drilling. The bonding process is highly dependent on weather conditions and therefore not suitable for on-site application. The components must be properly sealed to ensure that the adhesive is reliably distributed completely.

[0006] German patent application DE 198 08 208 A1 discloses a method for manufacturing a wood-concrete composite element in which the wood is slotted perpendicular to its upper surface. A punched and / or bent sheet metal part is glued into this slot. The concrete is poured after the adhesive has cured, and the bond between the wood and concrete is achieved through interlocking of the concrete with the sheet metal part. A disadvantage is the required mechanical processing of the wood by milling or sawing the slot for gluing in the sheet metal part.

[0007] European patent application EP 4 317 627 A1 describes a method for bonding a precast concrete element to a wooden component, in which the precast concrete element lies on its future top side and its underside faces upwards. The precast concrete element has a recess on its underside, which is filled with adhesive for bonding. The wooden beam is fitted with spacers on the side facing the adhesive, the height of which is slightly less than the thickness of the adhesive layer. The spacers are pressed into the adhesive until they rest on the concrete and the wood surface is in contact with the adhesive. The method requires turning the precast concrete element over twice and special formwork to create the recess. Air pockets may form between the adhesive and the wood.

[0008] The invention aims to improve a method for producing a wood-concrete composite ceiling, a device for applying adhesive mortar, an arrangement with a wood ceiling and a wood-concrete composite element.

[0009] According to the invention, a method with the features of claim 1, a device with the features of claim 13, an arrangement with the features of claim 18, and a wood-concrete composite element with the features of claim 19 are provided for this purpose. Advantageous embodiments of the invention are specified in the respective dependent claims.

[0010] In the inventive method for producing a wood-concrete composite slab, an adhesive mortar is applied to the top surface of a wood slab, thereby creating a material-bonded connection between the top surface of the wood slab and the adhesive mortar. Furthermore, the surface of the adhesive mortar facing away from the wood slab is textured, particularly during the application of the adhesive mortar, so that the textured surface has raised areas and / or depressions. Finally, flowable concrete is applied to form a concrete layer on the textured surface of the adhesive mortar, so that after the concrete has hardened, a positive connection is formed between the textured surface of the adhesive mortar and the concrete layer.

[0011] The concrete layer is expediently applied after the applied adhesive mortar has at least partially hardened. The adhesive mortar must be dimensionally stable, at least on its surface, before the flowable concrete is applied, so that the concrete can penetrate the depressions of the structured surface and enclose the raised areas of the structured surface, thereby allowing a positive connection to form between the concrete layer and the adhesive mortar layer after the concrete has hardened. Consequently, in the wood-concrete composite slab or wood-concrete composite system according to the invention, force transmission between the concrete and the adhesive mortar occurs through a positive connection, whereby the concrete layer and the adhesive mortar interlock in the area of ​​the structured surface. Force transmission from the adhesive mortar to the wood and vice versa, however, occurs through a material-bonded connection.The adhesive mortar is textured on its upper surface, facing away from the wooden ceiling, for example with grooves, particularly during application, and then hardens. After hardening, the concrete is poured directly onto the wood coated with the adhesive mortar. Once hardened, the composite component is load-bearing. The adhesive mortar consists of at least an adhesive and mineral fillers. The adhesive component of the mortar consists, for example, of an epoxy resin and an amine hardener. Common epoxy resins that are liquid at ambient temperature are suitable. Bisphenol A diglycidyl ethers or bisphenol F diglycidyl ethers are preferred. The amine hardener is suitable for curing the epoxy resin.Suitable fillers include mineral sands or flours, preferably calcium carbonate, silicon dioxide, or calcium-magnesium carbonate (dolomite), but also fly ash, cement, gypsum, metal powder, glass beads, or hollow glass spheres. Fibers, such as glass fibers, basalt fibers, polypropylene fibers, polyethylene fibers, or acrylic fibers, can also be added. Thixotropic agents, such as pyrogenic silica, can also be added. Thinners, such as benzyl alcohol, can also be added. Pigments, plasticizers, accelerators, nanofillers, and stabilizers can also be added. The adhesive mortar is supplied in two or three components. The resin and hardener are separate components and supplied in the appropriate stoichiometric ratio.The fillers and additives are preferably already mixed with the resin and / or the hardener, so that two components are provided. The components are to be mixed dynamically or statically until a macroscopically homogeneous mass is obtained. The adhesive mortar is preferably to be processed at ambient temperature, i.e., between 10 °C and 35 °C. The open time of the adhesive depends on the ambient temperature but is at least 20 minutes. During the open time at ambient temperature, the adhesive mortar has a viscous, stable consistency, so that the applied structure is retained during curing and does not run. The layer thickness of the adhesive mortar application is between 0 mm and 10 mm. The adhesive mortar can be applied to the wood surface completely or partially. The continuous layer thickness is between 1 mm and 3 mm. The surface structure protrudes a further 0 mm to 7 mm from this.Alternatively, if there is no continuous layer, the height of the grooves or surface structure is between 3 mm and 10 mm. In this case, if there is no continuous layer, the wood is visible between the grooves.

[0012] In a further development of the invention, the simultaneous application and structuring of the adhesive mortar is provided.

[0013] As explained, the adhesive mortar layer can be applied to the wooden ceiling over the entire surface or partially over the entire surface and simultaneously given a textured surface.

[0014] In a further development of the invention, the application and structuring is carried out by means of a sled or carriage which is moved over the surface of the wooden ceiling, wherein a layer of adhesive mortar is applied to the wooden ceiling by means of the sled or carriage and at the same time the adhesive mortar layer is provided with grooves and / or projections to produce the structured surface.

[0015] For example, the adhesive mortar is applied using a mortar sled, which has a toothed metal plate in the shape of a notched trowel. The adhesive mortar flows through the spaces between the teeth of the sled. From the sled's reservoir, the adhesive mortar flows onto the surface of the wooden ceiling. As the sled is moved, the toothed plate distributes the mortar across the ceiling and also creates a textured surface. Such a mortar sled can be width-adjustable and have a side stop on one side that acts as a guide alongside the wooden beam. The width of the sled is adjustable to accommodate different beam widths. The stop can be removed to create larger, continuous layers of adhesive mortar, for example, on cross-laminated timber (CLT). The height of the toothed plate can be adjusted so that the teeth either rest on the wood surface or extend up to 3 mm above it.The toothed sheet metal is advantageously replaceable.

[0016] In a further development of the invention, the application and structuring of the adhesive mortar is carried out using nozzles, in particular by means of 3D printing.

[0017] For example, a prepared section of wooden ceiling passes through a system where nozzles apply adhesive mortar to the surface of the wooden ceiling at predefined points, simultaneously creating a textured surface. Alternatively, a 3D printer can be used, whose nozzle moves across the surface of the wooden ceiling, applying the adhesive mortar to the predefined areas.

[0018] In a further development of the invention, the milling of grooves into the top surface of the wooden ceiling is provided for before the application of the adhesive mortar.

[0019] In this way, in addition to the material bond between the adhesive mortar and the wooden ceiling, an additional form bond between the wooden ceiling and the adhesive mortar can be achieved.

[0020] In a further development of the invention, the arrangement of screws in the wooden ceiling before the application of the concrete layer, particularly in edge areas of the wooden ceiling, is provided.

[0021] Screws can improve the positive connection between the timber ceiling and the concrete layer and / or the adhesive mortar layer, especially by creating a positive connection perpendicular to the timber ceiling, thus preventing the concrete layer from lifting. Typically, screws are driven vertically or diagonally into the timber ceiling, either against the main forces or at an angle in different directions. In edge areas where the timber-concrete composite ceiling rests on supports, such screws are used to prevent the concrete layer from separating from the adhesive mortar layer or the timber ceiling. The screws are positioned so that they are completely encased by the concrete layer after its application, thereby ensuring optimal force transmission between the screws and the concrete.

[0022] In a further development of the invention, the surface of the adhesive mortar is structured by introducing grooves into a top surface of the adhesive mortar facing away from the top surface of the wooden ceiling.

[0023] For example, a notched trowel, a moving spatula or texture rollers can be used for structuring.

[0024] In a further development of the invention, the grooves are created by moving a spatula perpendicular to the top of the wooden ceiling and simultaneously moving the spatula parallel to the top of the wooden ceiling.

[0025] In this way, grooves can be created perpendicular to the direction of movement of the spatula.

[0026] In a further development of the invention, the spatula is designed as a notched spatula and the grooves are made using the notched spatula.

[0027] In a further development of the invention, the surface of the adhesive mortar is structured by introducing a sawtooth pattern into a top surface of the adhesive mortar facing away from the top surface of the wooden ceiling.

[0028] A sawtooth pattern can be used to achieve a directional positive fit. Shear forces, for example, are only absorbed on a steep flank of the sawtooth. This can be particularly advantageous if the direction of shear forces between the concrete layer and the adhesive mortar is known in the installed state.

[0029] In a further development of the invention, the sawtooth pattern is applied by means of at least one roller whose outer circumference has a sawtooth structure, wherein the outer circumference of the roller rolls on the top of the adhesive mortar layer to apply the sawtooth pattern, by means of a roller which is moved perpendicular to a top of the wooden ceiling during the rolling process, or by means of a notched trowel which is moved parallel and perpendicular to a top of the wooden ceiling.

[0030] In this way, a sawtooth pattern can be introduced in a very simple way.

[0031] In a further development of the invention, the introduction of the sawtooth pattern with changing orientation of the sawtooths is provided according to a direction of forces acting parallel to the top of the wood ceiling at the boundary layer between adhesive mortar and concrete layer, which is to be expected in the installed state of the wood-concrete composite ceiling.

[0032] For example, in a rectangular or square timber-concrete composite slab supported at its edges, the direction of the shear forces between the timber slab and the concrete layer under load is known. If a sawtooth pattern with alternating orientation, aligned with the main direction of the expected shear forces, is incorporated, the transfer of shear forces within the timber-concrete composite slab can be significantly improved, and the raised and / or recessed areas of the structured surface of the adhesive mortar can be made smaller than with a non-alternating sawtooth orientation.

[0033] A device according to the invention for applying adhesive mortar to a surface of a wooden ceiling has a sled or carriage, wherein the sled or carriage has a storage container for the adhesive mortar and at least one device for structuring the adhesive mortar applied to the wooden ceiling.

[0034] Using a sled or cart, the adhesive mortar can be applied and textured simultaneously on the wooden ceiling.

[0035] In a further development of the invention, the device for structuring has at least one toothed spatula.

[0036] In a further development of the invention, the device for structuring comprises a scraper blade with a straight or toothed scraper edge and a mechanism for moving the scraper blade perpendicular to the surface of the wooden ceiling.

[0037] In a further development of the invention, the device for structuring has rollers with a structured outer circumference.

[0038] In a further development of the invention, the structured outer circumference of the rollers has teeth, serrations, saw teeth and / or projections circumferential to the rollers.

[0039] In an arrangement according to the invention with a wooden ceiling, an adhesive mortar layer is provided on a top surface of the wooden ceiling and a concrete layer is provided on the adhesive mortar layer, wherein the adhesive mortar layer is bonded to a top surface of the wooden ceiling, wherein a top surface of the adhesive mortar layer facing away from the wooden ceiling is structured and wherein a bottom surface of the concrete layer engages in a form-fitting manner with the structuring of the top surface of the adhesive mortar layer.

[0040] The arrangement according to the invention is relatively simple and quick to manufacture and ensures reliable shear transfer between the wooden ceiling and the concrete layer. The arrangement according to the invention can also be used, for example, in the renovation of old buildings and can be constructed from prefabricated elements if necessary.

[0041] A wood-concrete composite element according to the invention comprises a wooden ceiling, an adhesive mortar layer on a top surface of the wooden ceiling and a concrete layer on the adhesive mortar layer, wherein the adhesive mortar layer is bonded to a top surface of the wooden ceiling, wherein a top surface of the adhesive mortar layer facing away from the wooden ceiling is structured and wherein a bottom surface of the concrete layer engages in a form-fitting manner with the structure of the top surface of the adhesive mortar layer.

[0042] Such a wood-concrete composite element according to the invention can, for example, be prefabricated in a factory and then transported to the construction site in its finished state and installed there. Alternatively, the wooden ceiling can be prepared in a hall or factory by applying and structuring the adhesive mortar layer to the top surface of the wooden ceiling. The wooden ceiling prepared in this way can then be covered with the concrete layer on site at the construction site, possibly already in its intended installation position in the building.

[0043] Further features and advantages of the invention will become apparent from the claims and the following description of preferred embodiments of the invention in conjunction with the drawings. Individual features of the various illustrated and / or described embodiments can be combined with one another in any way without exceeding the scope of the invention. This also applies to the combination of individual features without other individual features with which they are illustrated and / or described. The drawings show: Fig. 1 a schematic, section-by-section representation of a timber-concrete composite slab according to a first embodiment, Fig. 2 the timber-concrete composite slab of the Fig. 1 From another perspective, Fig. 3 shows a section-by-section schematic representation of a wooden ceiling with a structured surface adhesive mortar layer according to a second embodiment, Fig. 4 shows a section-by-section schematic representation of the wooden ceiling with a structured adhesive mortar layer. Fig. 1 Fig. 5 a section-by-section schematic representation of a wooden ceiling with an adhesive mortar layer having a structured surface according to a third embodiment, Fig. 6 a section-by-section schematic representation of a wooden ceiling with an adhesive mortar layer having a structured surface according to a fourth embodiment, Fig. 7 a section-by-section schematic representation of a wooden ceiling with an adhesive mortar layer having a structured surface according to a fifth embodiment, Fig. 8 a section-by-section schematic representation of a wooden ceiling with an adhesive mortar layer having a structured surface according to a sixth embodiment, Fig. 9 a section-by-section schematic sectional view of a timber-concrete composite ceiling in the area of ​​a lateral support, Fig. 10 a section-by-section schematic sectional view of a timber-concrete composite ceiling according to the invention, Fig.Fig. 11 shows a schematic representation of a device for applying adhesive mortar according to one embodiment of the invention, and Fig. 12 shows a schematic representation of a device for applying adhesive mortar according to a further embodiment of the invention.

[0044] Fig. 1 Figure 1 shows, section by section and in schematic representation, a wood-concrete composite ceiling 10 according to a first embodiment of the invention, wherein a concrete layer 16 of the wood-concrete composite ceiling 10 is shown transparently.

[0045] The timber-concrete composite ceiling 10 has a timber ceiling 12, wherein in Fig. 1 Only a single wooden beam is shown to illustrate the wooden ceiling 12.

[0046] On the upper side of the wooden ceiling 12, which is in Fig. 1 A layer of adhesive mortar 14 with a structured surface has been applied to the top of the wooden ceiling 12. The adhesive mortar layer 14 is applied over the entire surface of the wooden ceiling 12 and has grooves and rib-shaped projections running parallel to each other along the longitudinal direction of the wooden ceiling 12 or the illustrated wooden beam. According to the invention, the thickness of the adhesive mortar layer 14 in the area of ​​the grooves is between 1 mm and 3 mm. According to the invention, the thickness of the layer in the area of ​​the rib-shaped projections is between 3 mm and 10 mm.

[0047] The concrete layer 16 is applied to the structured surface of the adhesive mortar layer 14, as formed by the application of liquid concrete to the top of the adhesive mortar layer 14. The liquid or flowable concrete penetrates the grooves of the structured surface of the adhesive mortar layer 14. After the concrete has hardened, a positive connection exists between the concrete layer 16 and the adhesive mortar layer 14 in the directions indicated by the double arrow 18. A material bond exists between the underside of the adhesive mortar layer 14 and the top of the wooden ceiling 12 or the depicted wooden beam. Shear forces in the directions indicated by the double arrow 18 can thus be reliably transferred from the concrete layer 16 to the wooden ceiling 12 and vice versa.

[0048] A bond also exists between the structured surface of the adhesive mortar layer 14 and the concrete layer 16 in directions parallel to the grooves of the structured surface, allowing shear forces to be transferred parallel to the top surface of the wooden ceiling 12 and parallel to the grooves. The adhesive mortar layer is rough and consequently exhibits raised areas and depressions, for example, due to solids, particularly small stones, contained in the adhesive mortar or through deliberate structuring of the adhesive mortar. These raised areas and depressions are enclosed or filled by the concrete layer during its application. This creates a frictional connection, and possibly also a partial form-fit connection, between the top surface of the adhesive mortar layer and the underside of the concrete layer in directions parallel to the grooves, thus enabling the transfer of shear forces parallel to the grooves.

[0049] The adhesive mortar layer 14 is applied to the top surface of the wooden ceiling 12 by applying and simultaneously structuring flowable adhesive mortar. This can be done with a mortar sled or mortar trolley, such as those used, for example, in Fig. 11 and Fig. 12 This is illustrated and explained in more detail below. The adhesive mortar layer 14 must be dimensionally stable before the liquid or flowable concrete is applied to the top of the adhesive mortar layer 14. After the concrete layer 16 and the adhesive mortar layer 14 have hardened, the described interlocking bond between the concrete layer 16 and the adhesive mortar layer 14, as well as the material bond between the adhesive mortar layer 14 and the top of the wooden ceiling 12, is established.

[0050] When producing the timber-concrete composite slab 10, the top surface of the timber slab 12 or the top surface of the timber beam must first be free of dust and dirt. The components of the adhesive mortar are mixed in a forced-action mixer to form a macroscopically homogeneous mass. Using a suitable device, for example the one described in Fig. 11 The adhesive mortar is applied using the devices shown in the 12 illustrations, or by means of 3D printing or purely manually, in such a way that the in Fig. 1 The adhesive mortar layer shown forms a flat layer with a grooved surface. After the adhesive mortar has hardened, the beam is placed in formwork, see [image / reference]. Fig. 2 Only the adhesive mortar layer 14 protrudes into the formwork. If necessary, a reinforcing mesh is placed in the formwork on spacers. If necessary, the formwork is treated with a release agent before or after the installation of the beam or the timber ceiling 12. It is essential to ensure that the release agent does not come into contact with the adhesive mortar layer 14. Subsequently, the concrete layer 16, in the form of flowable fresh concrete, is poured into the formwork and onto the textured adhesive mortar layer 14. After the concrete of layer 16 has hardened, the composite component, in other words the timber-concrete composite ceiling 10, is complete.

[0051] Fig. 2 shows another view of the timber-concrete composite ceiling of the Fig. 1 The view is directed lengthwise along the wooden beam of the wooden ceiling 12, and the concrete layer 16 is again shown translucently, so that the adhesive mortar layer 14 with its grooved structure on the upper side is clearly visible. The representation of the Fig. 2 is executed as a perspective drawing. In Fig. 2 A formwork 20 is schematically indicated, which, as already described, is attached to the beam of the wooden ceiling 12 before the application of the concrete layer 16 and into which flowable fresh concrete is then poured to produce the concrete layer 16.

[0052] Fig. 3 Figure 1 schematically shows the top surface of a wooden beam in a wooden ceiling 12, onto which a layer of adhesive mortar 24 with a textured surface has been applied. The adhesive mortar layer 24 is applied partially to the top surface of the wooden ceiling 12. Consequently, the top surface of the wooden ceiling 12 is visible between the several slat-like projections of the adhesive mortar layer 24. The adhesive mortar layer 24 in Fig. 3 The layer thickness in the area of ​​the ridge-like projections is between 3 mm and 10 mm.

[0053] Fig. 4 shows the wooden beam of the wooden ceiling 12 with the adhesive mortar layer 14, which is already evident from the Fig. 1 and 2 This was explained. The adhesive mortar layer 14 was applied over the entire surface of the top of the wooden ceiling 12. In the area of ​​the grooves, the thickness of the adhesive mortar layer 14 is between 1 mm and 3 mm, and in the area of ​​the ledge-like projections, for example, 10 mm, and in particular between 3 mm and 10 mm.

[0054] Fig. 5 Figure 1 shows a wooden beam of a wooden ceiling 12, on the top of which a layer of adhesive mortar 34 has been applied. The adhesive mortar layer 34 is applied to a partial surface and thus does not form a continuous layer, but rather several parallel, ledge-like projections. In contrast to the adhesive mortar layer 24 of the Fig. 3 The rib-like projections of the adhesive mortar layer 34 extend transversely to the longitudinal direction of the wooden beam of the wooden ceiling 12. The orientation of the rib-like projections of the adhesive mortar layers 24, 34 can be selected according to the direction of the shear forces expected between the concrete layer and the wooden ceiling in the installed state of the wood-concrete composite element according to the invention, but can also be selected, for example, based on the spatial conditions. As already explained, it is also possible to transfer forces that run parallel to the top surface of the wooden ceiling and parallel to the grooves of the rib-like projections between the top surface of the adhesive mortar layer and an underside of a concrete layer that rests on the adhesive mortar layer. In the case of the adhesive mortar layer 34 of the Fig. 5 The top of the wooden ceiling 12 can be seen between the slat-like projections.

[0055] Fig. 6 Figure 1 shows a wooden beam of a wooden ceiling 12 onto which a layer of adhesive mortar 44 with a textured surface has been applied. Like the adhesive mortar layer 34, the adhesive mortar layer 44 exhibits the following characteristics: Fig. 5 The wooden beams of the wooden ceiling 12 have stave-like projections running perpendicular to their longitudinal direction. The adhesive mortar layer 44 was applied over the entire surface. The thickness of the adhesive mortar layer 44 is between 1 mm and 3 mm in the grooves between the stave-like projections and between 3 mm and 10 mm in the area of ​​the stave-like projections.

[0056] Fig. 7 shows a wooden beam of a wooden ceiling 12, which is provided on its upper side with an adhesive mortar layer 54 with a structured surface.

[0057] The adhesive mortar layer 54 has several parallel, rib-like projections 56 that run parallel to the longitudinal direction of the wooden beam of the wooden ceiling 12. Furthermore, one upper surface of these rib-like projections is provided with spaced-apart teeth 58.

[0058] Grooves 60 are arranged between the rib-like projections 56. The groove base of the grooves 60 is provided with spaced-apart teeth 62.

[0059] After pouring a layer of concrete onto the top of the adhesive mortar layer 54, a positive fit is formed after the concrete layer 16 has hardened, both parallel to the longitudinal direction of the wooden beam of the wooden ceiling 12 and transverse to the longitudinal direction of the wooden beam of the wooden ceiling 12.

[0060] Fig. 8 Figure 1 shows a wooden beam of a wooden ceiling 12, the upper surface of which is coated with an adhesive mortar layer 64 with a textured surface. The adhesive mortar layer 64 has several rib-like projections 66 running parallel to the longitudinal direction of the wooden beam of the wooden ceiling 12. One upper surface of the rib-like projections has a sawtooth structure 68.

[0061] Grooves 70 are arranged between the rib-like projections 66. The base of the grooves 70 is provided with a sawtooth structure 72.

[0062] After the application of the concrete layer 16 to the adhesive mortar layer 64, forces running in a longitudinal direction along the wooden beam of the wooden ceiling 12 can be transferred. Fig. 8 from bottom left to top right. A positive fit can form in directions perpendicular to the wooden beam of the wooden ceiling 12, in Fig. 8 that is, from right to left or from left to right.

[0063] The adhesive mortar layer 64 is preferably used when the direction of the expected shear forces between the wooden ceiling 12 and the concrete layer 16 is known. The orientation of the sawtooth structure can be changed between different sections of the adhesive mortar layer 64 to accommodate the direction of the expected shear forces.

[0064] The adhesive mortar layers 65, 64 of the Fig. 7 und 8 They are applied over the entire surface and have a layer thickness of 1 mm to 3 mm in the area of ​​the grooves and a layer thickness between 3 mm and 10 mm in the area of ​​the ledge-like projections.

[0065] Fig. 9 Figure 1 shows a section view of an arrangement 80 with a timber-concrete composite slab 90 and a lateral support 82. It can be seen that the timber slab 12 does not rest on the support 82, only the concrete layer 16 of the timber-concrete composite slab. The adhesive mortar layer 64 has a sawtooth structure on its upper surface. Main shear forces are expected to act on the concrete layer 16 from the lateral support 82, directed against the sawtooth pattern on the upper surface of the adhesive mortar layer 64. Fig. 9 that is, from right to left.

[0066] To prevent the concrete layer 16 from lifting off the timber slab 12 in the depicted edge region of the timber-concrete composite slab 90, at least one screw 92 was screwed through the adhesive mortar layer 64 into the timber slab 12 before the concrete layer 16 was applied. The screw 92, whose screw head is completely enclosed by the concrete layer 16, prevents forces that would separate the concrete layer 16 and the timber slab 12 and consequently cause damage to the timber slab 12. Fig. 9 The forces acting from bottom to top or from top to bottom would be absorbed and introduced into the wooden ceiling 12 or into the concrete layer 16. Alternatively, the screw 92, or another screw, could also be screwed diagonally into the wooden ceiling 12, so that the screw head of the screw 92 is located above the support 82 in the concrete layer 16.

[0067] Fig. 10 shows a section-by-section schematic sectional view of the timber-concrete composite ceiling 90 of the Fig. 9 , where a first section 94 and a second section 96 of the timber-concrete composite ceiling 90 are shown.

[0068] The in Fig. 10 The left section 94 is arranged in the area of ​​a left support 82. The in Fig. 10 The right section is shown in the area of ​​or adjacent to a right support (not shown). Consequently, when the timber-concrete composite slab 90 is installed, shear forces act between the timber slab 12 and the concrete layer 16 in the left section, which are Fig. 10 are directed from right to left, as in the one in Fig. 9 The section of the timber-concrete composite slab shown is 90. This section is in Fig. 10 Shear forces directed to the left can be absorbed by the surface of the adhesive mortar layer 64, which has a sawtooth structure, and introduced into the wooden ceiling 12 via the material bond between the adhesive mortar layer 64 and the top of the wooden ceiling 12.

[0069] In the area of ​​the Fig. 10 In section 96 shown on the right, shear forces act in the concrete layer 16, directed from left to right. These shear forces can be absorbed by the adhesive mortar layer 64 through the sawtooth structure of the surface of the adhesive mortar layer 64, whose vertical flanks of the saw teeth are oriented to the left, and transferred into the wooden ceiling 12 via the bond between the adhesive mortar layer 64 and the top surface of the wooden ceiling 12.

[0070] According to the invention, the orientation of a sawtooth structure or, more generally, a structured surface can be adapted to the load case expected in the installed state of the timber composite ceiling 90.

[0071] Fig. 11 Figure 1 shows a schematic representation of a device for applying adhesive mortar to the surface of a wooden ceiling in the form of a mortar sled 100 or mortar trolley. The mortar trolley 100 has a reservoir 102 for flowable adhesive mortar, which is at least partially open at the bottom. Stops 104 are arranged on the side walls of the reservoir 102. These stops abut a side wall of a wooden beam of a wooden ceiling 12, thereby preventing the adhesive mortar from running laterally over the edge of the surface of the wooden beam. Fig. 11 On the right-hand side of the rear of the storage container 102, a notched trowel or a sheet metal blade 104 with serrated underside is arranged. Adhesive mortar contained in the storage container 102 is applied to the top of the wooden beam of the wooden ceiling when the mortar carriage 100 is moved along its surface. Then, when the serrated underside of the sheet metal blade 104 is drawn over this layer of adhesive mortar, it is textured. The structuring is then carried out in such a way that, as shown in the Fig. 1 bis 4 As shown, longitudinal, rib-like projections with intervening grooves are created along the wooden beam. The consistency of the adhesive mortar is chosen so that the resulting structure is stable and does not run. The toothed sheet 104 is arranged height-adjustably on the rear wall of the storage container 102, so that, optionally, the in Fig. 3 The adhesive mortar layer 24 shown can be produced, in which the top of the wooden beam is visible between the strip-like projections, or that the in Fig. 4 The adhesive mortar layer 14 shown, which is applied over the entire surface, can be produced.

[0072] Fig. 12 Figure 1 shows another device according to the invention for applying adhesive mortar to the surface of a wooden ceiling in the form of a further mortar sled 110. The mortar sled 110 has the reservoir for adhesive mortar 102 and the stops 104. A screed plate 114 with a flat underside is arranged on the rear of the reservoir 102. When the mortar sled 110 is moved longitudinally along a wooden beam of a wooden ceiling, a layer of adhesive mortar with a flat upper surface is created by means of the lower edge of the screed plate 114. To structure this flat upper surface of the adhesive mortar layer downstream of the screed plate 114, a roller 120 with a structured outer circumference is provided. The outer circumference of the roller 120 has several adjacent rings with alternating teeth and recesses. The outer circumference is divided into a total of ten sections.Between each section, the angular arrangement of the teeth changes such that a tooth of a first section is arranged next to a recess between two teeth of the adjacent second section.

[0073] The outer circumference of the roller 120 rolls on the flat surface of the adhesive mortar layer and then creates a textured surface of the adhesive mortar layer 54. Fig. 7 similar tooth pattern. The roller 120 is driven by a drive wheel 122, which rolls upstream of the storage container 102 on the top of the wooden ceiling. A rotary motion of the drive wheel 122 is transmitted to the roller 120 via a belt 124. As explained, the representation of the Fig. 12This diagram is schematic and merely illustrates one possible way to achieve a rotary movement of the roller 120. Of course, within the scope of the invention, the roller 120 can also be driven by an electric motor or by other suitable purely mechanical devices.

Claims

1. Method for producing a wood-concrete composite ceiling, characterized by Applying an adhesive mortar to the top surface of a wooden ceiling, thereby creating a material-bonded connection between the top surface of the wooden ceiling and the adhesive mortar; structuring a surface of the adhesive mortar facing away from the wooden ceiling, particularly during the application of the adhesive mortar, so that the structured surface has elevations and / or depressions; and applying flowable concrete to form a concrete layer on the structured surface of the adhesive mortar, wherein the adhesive mortar is dimensionally stable at least on its structured surface before the flowable concrete is applied, so that after the concrete has hardened, a positive connection is formed between the structured surface of the adhesive mortar and the concrete layer.

2. Method according to claim 1, characterized by Simultaneous application and structuring of the adhesive mortar.

3. Method according to claim 1 or 2, characterized by Application and structuring by means of a sled or cart that is moved over the surface of the wooden ceiling, whereby a layer of adhesive mortar is applied to the wooden ceiling by means of the sled or cart, and at the same time the adhesive mortar layer is provided with grooves and / or protrusions to create the structured surface.

4. Method according to claim 1 or 2, characterized by Application and structuring of the adhesive mortar using nozzles, especially using 3D printing.

5. Method according to any of the foregoing claims, characterized by Milling grooves into the top surface of the wooden ceiling before applying the adhesive mortar, and / or characterized by Positioning screws in the wooden ceiling before applying the concrete layer, especially in the edge areas of the wooden ceiling.

6. Method according to at least one of the preceding claims, characterized byStructuring the surface of the adhesive mortar by introducing grooves into a surface of the adhesive mortar facing away from the top of the wooden ceiling, in particular characterized by The grooves are created by moving a spatula perpendicular to the top of the wooden ceiling and simultaneously moving the spatula parallel to the top of the wooden ceiling.

7. Method according to claim 6, characterized by the fact that The spatula is designed as a notched spatula and the grooves are made using the notched spatula.

8. Method according to at least one of the preceding claims, characterized by Structuring the surface of the adhesive mortar by introducing a sawtooth pattern into a surface of the adhesive mortar facing away from the top of the wooden ceiling, in particular characterized byThe sawtooth pattern is applied using at least one roller whose outer circumference has a sawtooth structure, wherein the outer circumference of the roller rolls on the top of the adhesive mortar layer to apply the sawtooth pattern, using a roller which is moved perpendicular to a top of the wooden ceiling during the rolling process, or using a notched trowel which is moved parallel and perpendicular to a top of the wooden ceiling.

9. Method according to claim 8, characterized by The sawtooth pattern is created with alternating orientation of the saw teeth according to the direction of forces acting parallel to the top of the wood ceiling at the boundary layer between the adhesive mortar and the concrete layer, as expected in the installed state of the wood-concrete composite ceiling.

10. Device for applying adhesive mortar to the surface of a wooden ceiling, characterized bya sled or cart, wherein the sled or cart has a storage container for the adhesive mortar and at least one device for structuring the adhesive mortar applied to the wooden ceiling.

11. Device according to claim 10, characterized by the fact that The device for structuring has at least one notched trowel.

12. Device according to claim 10 or 11, characterized by the fact that The device for structuring includes at least one scraper blade with a straight or toothed scraper edge and a mechanism for moving the scraper blade perpendicular to the surface of the wooden ceiling.

13. Device according to claim 10, 11 or 12, characterized by the fact that the device for structuring has at least one roller with a structured outer circumference, in particular characterized by the fact that The structured outer circumference of the roller has teeth, serrations, saw teeth and / or projections circumferential to the roller.

14. Arrangement with a wooden ceiling, characterized by a layer of adhesive mortar on a top surface of the wooden ceiling and a layer of concrete on the adhesive mortar layer, wherein the adhesive mortar layer is bonded to a top surface of the wooden ceiling, wherein a top surface of the adhesive mortar layer facing away from the wooden ceiling is structured and wherein a bottom surface of the concrete layer engages in a form-fitting manner with the structuring of the top surface of the adhesive mortar layer.

15. Wood-concrete composite element with a wooden ceiling, characterized by an adhesive mortar layer on a top side of the wooden ceiling and a concrete layer on the adhesive mortar layer, wherein the adhesive mortar layer is bonded to a top side of the wooden ceiling, wherein a top side of the adhesive mortar layer facing away from the wooden ceiling is structured and wherein a bottom side of the concrete layer engages in a form-fitting manner with the structuring of the top side of the adhesive mortar layer.

Images