EP3919702A1 - Wood-concrete composite component and method for producing a wood- concrete composite component - Google Patents

Abstract

The invention relates to a wood-concrete composite component (100), comprising at least one wood component (1), in particular a beam or plate-shaped wooden component, and at least one concrete component (2), in particular a beam or plate-shaped precast concrete component, wherein the wooden component ( 1) has an upper side (10) with a support section (11) and with a grouting section (12), the concrete component (2) resting on the supporting section (11) and forming an edge-side boundary of the grouting section (12), whereby a grouting joint ( 30) is formed, and a potting body (3) made of a polymer mortar is introduced into the potting joint (30) in such a way that the potting body (3) has adhesive bonds with the wooden component (1) and with the concrete component (2). The invention also relates to a method for forming a wood-concrete composite component (100).

Description

The present invention relates to a wood-concrete composite component, comprising at least one wood component, in particular a beam-shaped or flat wood component, and at least one concrete component, in particular a beam-shaped or plate-shaped precast concrete component. The invention also relates to a method for forming such a wood-concrete composite component.

STATE OF THE ART

Wood-concrete composite components are used in supporting structures, in particular as floor slabs or bridges. Wood-concrete composite components include wooden components and concrete components which are connected to one another in a shear-proof manner using a suitable connection method or a suitable connecting means and are therefore also referred to as hybrid components. For example, the wooden components are designed as wooden beams or cross-laminated timber panels and the concrete components as plate-shaped prefabricated components, whereby the wooden component is mainly subjected to tensile and bending loads, while the concrete component mainly absorbs compressive loads. In order to prevent the individual components from shifting relative to one another, the joint between the wooden component and the concrete component must be suitable for transferring the corresponding shear forces.

Wood-concrete composite components are used both in the renovation or revitalization of old buildings, where old wood beam ceilings in particular are strengthened using the wood-concrete composite construction method, but also in new storey and new residential buildings and in bridge construction. In order to shorten the construction times, prefabricated concrete components are preferably used, which then only have to be connected to the wooden components on site.

The connection between wooden components and concrete components can be implemented, for example, by means of adhesives, the use of polymer potting in particular for bonding components being known. So reveals the DE 20 2017 004 730 U1 a composite of a beam and a plate element, which is connected by means of an intervening potting compound made of a polymer potting material, in a tensile and shear-proof manner.

Polymer grouting, also known as polymer mortar, synthetic resin mortar or reaction resin concrete, is based on a polymer binder instead of cement and contains mineral or organic aggregates, which are referred to as fillers or fillers. For the hardening process, for example, the addition of a hardener is necessary and, in particular with the use of special accelerators, a significantly higher hardening speed can be achieved than with cement-based grouting. In addition, the achievable strength of polymer mortar is superior to that of conventional mortars. A particular advantage in connection with wood-concrete composite components is the formation of high-strength adhesive bonds between the polymer mortar, both with the concrete component and with the wood component. For one in the DE 20 2017 004 730 U1 The recommended polymer mortar has a general building authority approval with the number Z-10.7-282.

A disadvantage of a wood-concrete composite according to DE 20 2017 004 730 U1 are the high costs for the large quantities of polymer potting required for the full-surface bonding of the components

One possible variant of a glued wood-concrete composite is the gluing of precast concrete parts and wooden components with polymer mortar by laying the precast concrete part over the surface. This method was investigated in a ZIM research project at the University of Kassel, wood construction and building preservation department (see also: Martin Kästner - On the load-bearing behavior of polymer mortar adhesive joints for use in road bridges in Wood-concrete composite construction, dissertation, University of Weimar, December 17, 2019 ). In this process, a polymer mortar is applied as an adhesive to the wooden component and the precast concrete component is placed in a second work step. However, such a composite is comparatively complex in practice, since a very precise timing between the application of the polymer potting on the wooden beams and the subsequent placement of the concrete slabs, taking into account the Joining part unevenness is necessary. In addition, the necessary climatic conditions must be created on the construction site for the polymer mortar to harden. As a rule, this is only possible if there is a sufficiently large, possibly enclosed, storage area on the construction site for intermediate storage, curing and gluing. However, these boundary conditions do not exist on most construction sites. Another disadvantage is that monitoring and quality assurance are difficult because the glue joints are no longer visible after the concrete slab has been placed.

In addition to the establishment of adhesive connections, another established connection technology for wood-concrete composite components in the prior art is the use of mechanical connecting means, in particular screws. This has the practical advantage that the connection can be established at any point in time after the positioning of the concrete components, but screwing is a disadvantageously time-consuming process and a connection that is much more flexible than gluing is achieved.

Another method for forming the composite after positioning the concrete components on the wooden components is disclosed in the CH 713 461 A1 , wherein a concrete slab element is provided with a slab recess, and a filling element of freshly poured quick-setting cement or concrete is formed in the slab recess, which forms a shear connection between the slab element and a carrier element made of wood. Due to the lack of adhesive action between the filling element and the carrier element made of wood and concrete, this method has the disadvantage that either a positive connection has to be established to form a shear-resistant connection between the filling element and the carrier element, which requires additional processing steps on the carrier element , or but the use of additional mechanical fasteners is necessary.

DISCLOSURE OF THE INVENTION

It is therefore the object of the present invention to propose a wood-concrete composite component and a method for its formation, whereby the aforementioned disadvantages of the prior art are overcome and an economical and efficient construction of high-quality, shear-resistant wood-concrete composites is made possible.

This object is achieved on the basis of a wood-concrete composite component according to claim 1 and a method according to claim 8. Advantageous further developments of the invention are given in the dependent claims.

The technical teaching of the invention discloses a wood-concrete composite component, comprising at least one wood component, in particular a beam or plate-shaped wooden component, and at least one concrete component, in particular a beam or plate-shaped precast concrete component, the wooden component having a top side with a support section and a Having potting section, wherein the concrete component rests on the support section and forms an edge-side boundary of the potting section, whereby a potting joint is formed, and wherein a potting body made of a polymer mortar is introduced into the potting joint, such that the potting body has adhesive bonds with the wooden component and with the Has concrete component.

The invention is based on the idea of using the excellent technical properties of a polymer mortar on the one hand, namely its adhesive effect to form high-strength adhesive bonds both with the wooden component and with the concrete component, as well as with the mortar high shear strength, but on the other hand, the use of material for the polymer mortar is limited to the formation of a grouting body in the typically small-volume grouting joint. In effect, this results in a potting body to be applied subsequently, i.e. after the concrete component has been positioned on the support section of the wooden component, which forms shear-resistant connections to the wooden component and to the concrete component without the need for additional effort to form a form fit or to introduce mechanical fasteners would.

The concrete components used can, for example, extend between two wooden components each, i.e. rest on the edge side on the upper side of the wooden beams. The contact surfaces with the concrete components on top represent the support section of the top of each wooden component and the area in between and not covered by the concrete components corresponds to the potting section of the top. The grouting joint, into which the polymer mortar is introduced to form a grouting body, is formed by the grouting section and the edge-side end faces of the adjoining concrete components.

In a further embodiment of the wood-concrete composite component according to the invention, the concrete component can be dimensioned so large that it spans several wooden components, and in particular in this case the concrete component preferably comprises at least one recess, a contour of the grouting joint being formed by a contour of the recess . The concrete component is positioned in such a way that the recess is arranged completely over the top of the wooden component, and the composite is produced by subsequent application of the polymer mortar into the recesses.

Due to the adhesive effect of the potting body made of polymer mortar, there can be practically no relative displacement of the wooden component and the concrete component, as a result of which the components are rigidly connected to one another. Such a rigid composite of the wood-concrete composite component is characterized by a high section modulus, low deflection in the center of the field and a high natural frequency. Compared to cross-sections that are not rigidly connected, advantages in terms of vibration behavior, deformation behavior and load-bearing behavior are achieved with the rigid connection.

Another advantage of the wood-concrete composite component according to the invention consists in its particularly favorable load-bearing behavior under constrained stresses from swelling and shrinking. Since wood and concrete have different thermal and hygric expansion coefficients, tensions can arise in the outer layers of the components. In a conventionally bonded composite, in which there is a flat layer of adhesive between the wooden component and the concrete component, expansion of the wooden component induces potentially supercritical shear stresses in the outer edge layer of the concrete component. In contrast to this, in the wood-concrete composite component according to the invention, the stresses from the wood component are transmitted as normal stresses into the concrete component via the potting body. The grouting body made of polymer mortar is characterized by a significantly higher shear strength compared to concrete and is therefore predestined to absorb shear stresses from the expanding wooden component.

The potting body is preferably exposed on the upper side, which enables a visual inspection of the potting body. This can reduce the quality of the connection between the wooden component, potting body and Concrete component can be checked retrospectively and any necessary repairs can be made.

In an advantageous embodiment, the wood-concrete composite component according to the invention has at least one metallic connecting means, which is received in sections in the wood component and extends into the potting body. Such a connecting means serves as a redundant securing means to ensure a high level of shear strength of the composite and can, for example, be designed as a reinforcing rod or screw protruding essentially vertically from the top of the wooden component.

With a further advantage, the wood-concrete composite component has at least one metallic reinforcement which is received in sections in the concrete component and extends in the potting body. Such a reinforcement is used to redundantly secure the connection between the concrete component and the potting body and is designed, for example, as a reinforcement rod or a reinforcement grid that runs horizontally through a recess in the concrete component or protrudes from the edge of the concrete component.

The wood-concrete composite component preferably has a sealant which seals a bearing joint delimiting the potting section between the wood component and the concrete component. Such a seal serves to prevent the freshly poured polymer mortar from undesirably escaping from the grouting joint, in particular in order to keep the underside visible area clean when the wood-concrete composite component is used as a floor slab. The sealant is designed, for example, as a sealing tape or a sealing foam and is, for example, introduced into the bottom area of the grouting joint on the edge side before the polymer mortar is applied.

In particular, the wood-concrete composite component forms a floor slab or a bridge component. For example, the composite component can comprise a combination of prefabricated concrete components of different dimensions, and the casting joints accordingly have sections in which they are designed as recesses in concrete components or are delimited by the edges of adjacent concrete components. In practice, the shape of the grouting joints formed is left to the choice of the user, whereby a wood-concrete bond that is as continuous as possible is recommended for reasons of statics and also due to the requirements for sound insulation and impermeability. Due to the high shear strength of the wood-concrete composite component according to the invention, it can in principle also be used as a wall.

• Bereitstellen des Holzbauteils mit einer Oberseite, welche einen Auflageabschnitt und einen Vergussabschnitt aufweist,
• Auflegen des Betonbauteils auf den Auflageabschnitt unter Bildung einer randseitigen Begrenzung des Vergussabschnitts, wodurch eine Vergussfuge gebildet wird,
• bringen eines Polymermörtels in die Vergussfuge,
• Aushärten des Polymermörtels unter Bildung eines Vergusskörpers mit adhäsiven Bindungen mit dem Holzbauteil und mit dem Betonbauteil, und
• Erhalt des Holz-Beton-Verbundbauteils.

To achieve the object, the invention further relates to a method for forming a wood-concrete composite component comprising at least one wooden component, in particular a wooden beam, and at least one concrete component, in particular a plate-shaped precast concrete component, the method comprising at least the following steps:

• Providing the wooden component with a top side which has a support section and a potting section,
• Placing the concrete component on the support section with the formation of an edge-side delimitation of the grouting section, whereby a grouting joint is formed,
• bringing a polymer mortar into the grouting joint,
• Curing of the polymer mortar with the formation of a potting body with adhesive bonds with the wooden component and with the concrete component, and
• Preservation of the wood-concrete composite component.

In practice, the method according to the invention allows the tradespeople and suppliers to work independently, for example hanging up the concrete components are carried out for a large number of floor slabs and the introduction of the polymer mortar into the grouting joints formed takes place at a later point in time, for example only after completion of the shell and the introduction of the windows. In this way, constant climatic conditions can be created, which is necessary for reliable hardening of the polymer mortar.

The concrete component is preferably provided with at least one recess, a contour of the grouting joint being formed by a contour of the recess and the polymer mortar being applied into the recess after the concrete component has been placed. Alternatively or in combination, at least two concrete components are provided and placed on the support section, the edge-side boundary of the grouting section, and thus the grouting joint, being formed by the edges of the concrete components.

In an advantageous embodiment of the method according to the invention, the wooden component and / or the concrete component are provided with at least one position securing means, by means of which the concrete component is prevented from slipping on the support section of the wooden component before the polymer mortar is applied. Such a positional securing can be formed, for example, by a form fit between the wooden component and the concrete component, for example by providing a step or a tongue and groove connection, or by a mechanical means which is inserted or introduced into holes in the wood and concrete component lying one above the other.

PREFERRED EMBODIMENTS OF THE INVENTION

Fig. 1a

eine Querschnittsansicht eines ersten erfindungsgemäßen Holz-Beton-Verbundbauteils,

Fig. 1b

eine Draufsicht zu Fig. 1a,

Fig. 2a

eine Querschnittsansicht eines zweiten erfindungsgemäßen Holz-Beton-Verbundbauteils,

Fig. 2b

eine Draufsicht zu Fig. 2a,

Fig. 3

eine Querschnittsansicht eines dritten erfindungsgemäßen Holzverbundbauteils,

Fig. 4

eine Querschnittsansicht eines vierten erfindungsgemäßen Holzverbundbauteils, und

Fig. 5a, 5b

Querschnittsansichten zur Darstellung von optionalen Lagesicherungsmitteln.

Further measures improving the invention are shown in more detail below together with the description of preferred exemplary embodiments of the invention with reference to the figures. It shows:

Fig. 1a

a cross-sectional view of a first wood-concrete composite component according to the invention,

Figure 1b

a top view too Fig. 1a ,

Fig. 2a

a cross-sectional view of a second wood-concrete composite component according to the invention,

Figure 2b

a top view too Fig. 2a ,

Fig. 3

a cross-sectional view of a third wood composite component according to the invention,

Fig. 4

a cross-sectional view of a fourth wood composite component according to the invention, and

Figures 5a, 5b

Cross-sectional views to show optional position securing means.

Fig. 1a Figure 13 shows a cross-sectional view and Figure 1b a corresponding top view of a first embodiment of a wood-concrete composite component 100 according to the invention, the section shown in the figures comprising two wooden components 1 in the form of wooden beams and three concrete components 2 in the form of plate-shaped precast concrete components. Each concrete component 2 rests with its edge regions on the upper sides 10 of adjacent wooden components 2, the respective support section 11 being formed by the contact surface between concrete component 2 and wooden component 1. The grouting joints 30, the underside of which is formed by the grouting section 12 on the top 10 of the respective wooden component 1, extend between the front edge sides 21 of adjacent concrete components 2. The polymer mortar applied into the grouting joints 30 forms the grouting bodies 3, which form high-strength adhesive bonds both with the wooden components 1 and with the concrete components 2. The wood-concrete composite part 100 according to the invention represents a shear-resistant, rigid composite and is suitable for absorbing compressive, tensile and bending loads.

Fig. 2a Figure 13 shows a cross-sectional view and Figure 2b a corresponding top view of a second embodiment of a wood-concrete composite component 100 according to the invention, a larger-sized concrete component 2 being shown here, which spans the two wooden components 1. In this case, the edge-side delimitation of the casting sections 12, and thus the casting joints 30, is formed by the various recesses 20 of the concrete component 2. The lateral end faces of the concrete components 2 are also designed beveled.

Fig. 3 shows a cross-sectional view of a third embodiment of a wood-concrete composite component 100 according to the invention, which has a flat wood component 1, the formation of the grouting joints 30 and the grouting bodies 3 introduced therein corresponding to the description of the preceding figures.

Fig. 4 shows a cross-sectional view of a fourth embodiment of a wood-concrete composite component 100 according to the invention, which comprises a metallic connecting means 4, two metallic reinforcing means 5 and the sealing means 6 and 7. The connecting means 4 is designed as a screw which is received in sections in the wooden component 1 and extends into the potting body 3. The reinforcement means 5 are designed as horizontally arranged reinforcing bars, which are received in sections in the concrete component 2 and extend into the potting body 3. For example, such a reinforcement means can also be designed in the form of a reinforcement bar spanning the entire grouting joint 30, which also provides the possibility of handling, ie grasping, the concrete component 2 when it is positioned on the wooden component 1. The sealing means 6 and 7 seal the bearing joints delimiting the potting section 12 between the wooden component 1 and the concrete component 2 and are arranged on both sides of the bearing joints before the polymer mortar is introduced.

Figures 5a and 5b show cross-sectional views to illustrate optional position securing means 71, 72, 73 and 74 which, on the process side, serve to prevent the concrete component 2 from slipping on the upper side 10 of the wooden component 1 before the polymer mortar is poured into the casting joint 30. For this purpose, the formation of form-fitting connections is advantageous, which in the case of the position securing means 71 is realized by the provision of a planar or beveled step representing the support section 11 in the top 10 of the wooden component 1, or in the case of the position securing means 72 by suitable notches of the Support section 11 on the wooden component 1 and the concrete component 2 to form a tongue and groove connection. The mechanical position securing means 73 and 74 are designed as preferably metallic connecting means. The screw 73 is screwed into the wooden component 1 under the support section 11 through a recess provided in the concrete part 2. The bolt 74, which can be used alternatively or in combination, is received in bores correspondingly assigned to one another in the wooden component 1 and in the concrete component 2.

The implementation of the invention is not restricted to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable which make use of the solution shown even in the case of fundamentally different designs. All of the features and / or advantages arising from the claims, the description or the drawings, including structural details or spatial arrangements, can be essential to the invention both individually and in a wide variety of combinations.

List of reference symbols:

100

Wood-concrete composite component

1

Wooden component

10

Top

11th

Support section

12th

Potting section

2

Concrete component

20th

Recess

21

Marginal side

3

Potting body

30th

Grouting joint

4th

Lanyard

5

Reinforcement

6, 7

sealant

71, 72

form-fitting position securing means

73, 74

mechanical position securing means

Claims (11)

Wood-concrete composite component (100), comprising at least one wood component (1), in particular a beam or plate-shaped wooden component, and at least one concrete component (2), in particular a beam or plate-shaped precast concrete component, the wooden component (1) having an upper side ( 10) with a support section (11) and with a grouting section (12), the concrete component (2) resting on the support section (11) and forming an edge-side boundary of the grouting section (12), whereby a grouting joint (30) is formed, and wherein a potting body (3) made of a polymer mortar is introduced into the potting joint (30) in such a way that the potting body (3) has adhesive bonds with the wooden component (1) and with the concrete component (2). Wood-concrete composite component (100) according to claim 1,
characterized,
that the concrete component (2) comprises at least one recess (20), a contour of the casting joint (30) being formed by a contour of the recess (20). Wood-concrete composite component (100) according to Claim 1 or 2,
characterized,
that the potting body (3) is exposed on the top, which enables a visual inspection of the potting body (3). Wood-concrete composite component (100) according to one of the preceding claims,
characterized,
that the wood-concrete composite component (100) has at least one metallic connecting means (4) which is received in sections in the wood component (1) and extends into the potting body (3). Wood-concrete composite component (100) according to one of the preceding claims,
characterized,
that the wood-concrete composite component (100) has at least one metallic reinforcement (5) which is received in sections in the concrete component (2) and extends into the potting body (3). Wood-concrete composite component (100) according to one of the preceding claims,
characterized,
that the wood-concrete composite component (100) has a sealant (6, 7) which seals a bed joint delimiting the potting section (12) between the wood component (1) and the concrete component (2). Wood-concrete composite component (100) according to one of the preceding claims,
characterized,
that the wood-concrete composite component (100) forms a floor slab or a bridge component. A method for forming a wood-concrete composite component (100), comprising at least one wood component (1), in particular a beam or plate-shaped wood component, and at least one concrete component (2), in particular a bar-shaped or plate-shaped precast concrete component, the method comprising at least the following steps: - Provision of the wooden component (1) with an upper side (10) which has a support section (11) and a potting section (12), - Placing the concrete component (2) on the support section (11) with the formation of an edge-side boundary of the grouting section (12), whereby a grouting joint (30) is formed, - Introducing a polymer mortar into the grouting joint (30), - Curing of the polymer mortar with the formation of a potting body (3) with adhesive bonds with the wooden component (1) and with the concrete component (2), and - Preservation of the wood-concrete composite component (100). Method according to claim 8,
characterized,
that the concrete component (2) is provided with at least one recess (20), a contour of the grouting joint (30) being formed by a contour of the recess (20), and the polymer mortar after the concrete component (2) has been placed in the recess (20) is introduced. Method according to claim 9,
characterized,
that at least two concrete components (2) are provided and placed on the support section (11), the edge-side boundary of the grouting section (12) and the grouting joint (30) being formed by the edge sides (21) of the concrete components (2). Method according to one of Claims 8 to 10,
characterized,
that the wooden component (1) and / or the concrete component (2) are provided with at least one position securing means (71, 72, 73, 74) by means of which the concrete component (2) can slip on the support section (11) of the wooden component (1) is prevented before the application of the polymer mortar.

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