ELECTRICALLY HEATED CONCRETE SLABS

Description

[0001] The invention relates to an electrically heated concrete slab, wherein the concrete slab is provided with fiber reinforcement and comprises at least one planar heating element. The at least one planar heating element comprises at least one heating layer preferably embedded in a synthetic resin-fiber composite. The at least one planar heating element is thus a rigid and flexurally stiff component or semi-finished product, particularly for use on or in the concrete slab. On one side or surface or outer surface of the at least one planar heating element, a concrete top layer is present, and on the opposite side or surface or outer surface of the planar heating element, an insulating layer or a concrete bottom layer is present, wherein the concrete top layer and concrete bottom layer each comprise, for example, a high-strength or other suitable concrete.It is intended that the concrete may contain fiber reinforcement, preferably made of carbon fibers, basalt fibers, or glass fibers. The fiber reinforcement may also be referred to as textile fiber reinforcement. The fiber reinforcement is preferably planar, lattice-like, or grid-like, but may also be spatially lattice-like or grid-like, or have another or a combined planar, lattice-like, and / or grid-like structure.

[0002] Electrically heated concrete slabs are known in various designs, for example as concrete roadway slabs. Electrically heated concrete slabs are known, for example, from EP 0 894 417, DE 10 2006 007349, DE 195 16 909, and DE 22 44 157.

[0003] Heating cables are known as heating elements that can be embedded in concrete. However, although they can be laid close together, these are point or strip-shaped heat sources that can lead to significant thermally induced stresses in the concrete. Therefore, such heating elements may only be installed with a large cross-section and a thick concrete cover. This results in increased energy consumption to reliably achieve desired temperatures on the concrete surface, for example, above the freezing point of water.

[0004] The object of the invention is to provide an electrically heated concrete slab that is highly durable, in particular exhibiting high flexural strength, and is easy to mass-produce and install at its intended location. Furthermore, the concrete slab should be large in area and very thin relative to its surface area, or have a low thickness, so that concrete slabs of any surface area up to approximately 50 square meters and with a thickness between 10 mm and 55 mm, with the thickness increasing only slightly as the surface area increases, can be easily manufactured and quickly installed.

[0005] The invention relates to an electrically heated, mechanically very strong concrete slab, wherein the concrete slab comprises fiber reinforcement and at least one planar heating element, wherein the at least one planar heating element comprises at least one heating layer embedded in a synthetic resin-fiber composite. A concrete top layer is arranged on one side of the at least one planar heating element and an insulating layer or a concrete bottom layer is arranged on the other side of the at least one planar heating element.

[0006] According to the inventive concept, it is provided that the concrete top layer and / or the concrete bottom layer are formed with fiber reinforcement.

[0007] The flat heating element, alone or together with the fiber reinforcement, forms a statically effective element on the concrete surface layer or in or between the concrete surface layer and the concrete sublayer.

[0008] Furthermore, the insulation layer is, for example, a high-strength insulating material. Therefore, the insulation layer can also have a structural effect or at least provide structural support.

[0009] Although the concrete layers are divided into a top layer and a bottom layer for clarity, their specific assignment or designation can be reversed depending on the application and arrangement of the concrete slab. This also applies to the insulation layer. For example, the insulation layer may be located above the heating element, while the concrete layer is located below it.

[0010] Depending on the load it must withstand, the concrete slab can be manufactured with a thin slab thickness of, for example, only 30 mm. Other slab thicknesses of more than 30 mm, more than 40 mm, or less than 30 mm are also possible, for example, with only single fiber reinforcement. This design allows for a reduction in the amount of high-quality material required and, due to the near-surface placement of at least one surface heating element, faster and more cost-effective heating is achieved with lower power consumption compared to similar conventional heating surfaces or elements, since less concrete needs to be heated due to the proximity to the surface. This enables more rapid and demand-oriented operation with lower latency than is possible with conventional methods requiring a high concrete cover.

[0011] The concrete slab can be, for example, a concrete traffic slab, which includes all surfaces on which vehicles of any kind and / or people move about, a wall panel or wall element, a ceiling panel or floor panel, or a step. Other applications or areas of use are also included, even if not explicitly mentioned.

[0012] The invention advantageously fulfills the requirements for so-called LAU facilities (i.e., facilities for storing, filling, and transferring water-polluting substances) according to the Water Resources Act, as well as the freeze-thaw cycle requirements for concrete. Therefore, the invention can also be used, among other things, for mechanically demanding surfaces such as airport runways, storage or transfer areas, and production areas.

[0013] In one embodiment, the fiber reinforcement is partially connected to the flat heating element. This connection is both positive-locking and force-locking. Thus, the flat heating element and the fiber reinforcement together form a structurally effective element. For example, the fiber reinforcement can be vulcanized, bonded, or incorporated into the flat heating element.

[0014] Furthermore, the fiber reinforcement can be spaced apart from the flat heating element or in contact with it. For example, a coating on the fiber reinforcement can also form the connection with the flat heating element. Likewise, fiber reinforcement can simply be embedded in the concrete and thus either in contact with or spaced apart from the flat heating element. Depending on its spatial or flat extent, the fiber reinforcement can be connected to or in contact with the flat heating element in certain areas. For example, in the case of a corrugated structure of the fiber reinforcement, the fiber reinforcement is only connected to or in contact with the flat heating element at the crests of the corrugations facing it.

[0015] In a further embodiment, at least one flat heating element has spaced-apart through-openings. Through-openings are defined as openings that pass through the at least one flat heating element. This also includes recesses at the edge of the flat heating element. They can be provided during the manufacture of the flat heating element from the outset or added subsequently, for example, as a bore or by punching.

[0016] The concrete, at least from the top layer, penetrates the openings in the at least one flat heating element. The insulation layer is located on the other side of the at least one flat heating element. The concrete can surround the at least one flat heating element at its edges, or it can surround both the at least one flat heating element and the insulation layer.

[0017] On the other hand, the concrete penetrates through the openings, so that the concrete of the lower layer is bonded to the concrete of the upper layer. Furthermore, the concrete surrounds the at least one flat heating element at its edges. This at least one flat heating element is embedded between the lower and upper layers of concrete, with the lower and upper layers bonding together at the points of contact or surfaces.

[0018] Additionally, the openings in at least one flat heating element will guide further reinforcement elements and / or the fiber reinforcement of the concrete base layer and / or the concrete top layer. The concrete base layer and the concrete top layer are thus additionally and advantageously connected to each other via fiber reinforcement in a force-fit and / or form-fit manner.

[0019] Preferably, in the area of ​​the through-openings, the heating layer embedded in at least one planar heating element is recessed or interrupted or guided around the through-openings, so that sufficient insulation and functionality are ensured.

[0020] Thus, the use of at least one flat heating element allows for a comparatively low component thickness and facilitates the placement of the heating element close to the surface, which in turn shortens the heating time, reduces energy losses, and consequently lowers energy consumption and operating costs.

[0021] During the production of the concrete slabs, the concrete can spread through and into the openings in at least one flat heating element, so that the concrete of the concrete base layer is connected with the concrete of the concrete top layer.

[0022] Advantageously, at least one flat heating element can have an adhesion-enhancing coating or a polymer-modified bonding bridge.

[0023] By constructing two reinforced concrete layers, separated from each other by at least one flat heating element and connected only at points to each other and, if necessary, to the bonded connection via the bonding primer of the at least one flat heating element to the concrete, a very high flexural stiffness of the electrically heated concrete slab is achieved.

[0024] The at least one flat heating element with through-holes does not, therefore, separate the concrete layers. This at least one flat heating element with through-holes also serves as an additional reinforcement element, resulting in a concrete slab with very high compressive strength and flexural stiffness. Consequently, the concrete slab is designed to withstand very high mechanical stresses.

[0025] In addition to the concrete, reinforcing elements are also guided through the openings of at least one flat heating element. These reinforcing elements strengthen the connection between the concrete base and top layers within the openings, thereby increasing the flexural strength and shear strength of the concrete slab. This allows the slab to absorb and dissipate greater forces. Consequently, the thickness of the concrete slab can be further reduced, or a concrete slab of the same thickness can withstand higher loads.

[0026] To improve the bond between the concrete sublayer and the concrete surface layer, the textile reinforcement elements form a unit with the fiber reinforcement of the concrete slab as an integral part of the fiber reinforcement, or are connected to, placed on, or inserted into the fiber reinforcement of the concrete slab. A preferred positive-locking connection can advantageously be achieved, for example, by forming the ends of the reinforcement elements in a hook shape or by weaving the reinforcement elements into the fiber reinforcement of the concrete slab. Preferably, the textile fiber reinforcement is manufactured using three-dimensional knitting and weaving techniques to ensure force-fit and / or positive-locking properties. In this way, the reinforcement elements can have open, for example, rod-shaped or nail-shaped ends woven into the fiber reinforcement and guided through the openings.

[0027] According to an advantageous embodiment of the concrete slab, the circumferential or lateral outer surfaces of the concrete slab exhibit a wave structure or other corresponding surface texture in the vertical direction, corresponding to the lateral outer surfaces of the adjacent concrete slab. This creates a correspondingly shaped, downward-running wave pattern, such as a sine wave, between the adjacent slabs. This wave pattern advantageously allows for the efficient transmission of vertical forces between the adjacent concrete slabs without the disadvantages of a tongue-and-groove joint, such as material failure. The edges of the slabs are designed such that two adjacent edges are finished with the first wave pattern, and the other two edge areas are finished with the wave pattern corresponding to the first wave pattern.The concrete slabs, each aligned accordingly, can be placed against each other with their wave-like shape and slid together to form a tight fit. Preferably, the wave shape of the edge areas can be realized in the form of a sine wave. Considering or adhering to the corresponding wave structure, in addition to integer multiples, any multiples or non-integer multiples of a sine wave are also possible. Likewise, the corresponding wave structure can be arbitrarily aligned or arranged with respect to the amplitude and / or position of the minimum and maximum points.

[0028] However, other corresponding surface structures are also provided, enabling a reliable bond and / or transition between the adjacent plates. Similarly, lateral outer surfaces are provided.

[0029] According to a further advantageous embodiment of the invention, the circumferential or lateral outer surfaces or the circumferential or lateral boundary of the concrete slab are each formed by concrete edge elements. These edge elements are prefabricated from concrete and provided with edge fiber reinforcement. On their outer surfaces, the concrete edge elements each have a corresponding wave structure or another corresponding surface structure. Reference can be made to the above descriptions regarding this wave structure or other corresponding surface structure. Furthermore, the edge fiber reinforcement of the concrete edge elements projects beyond them as connecting reinforcement, so that they can be well connected to the concrete slab and preferably also to the fiber reinforcement of the concrete slab.The prefabricated edge elements thus form the advantageous wave structure and at the same time serve advantageously as integrated, so-called lost formwork in the production of the concrete slabs.

[0030] In a further development, it is proposed that the fiber reinforcement or edge fiber reinforcement be guided from the concrete base layer to the concrete surface layer in the area of ​​the circumferential or lateral outer surfaces around the at least one planar heating element, thereby increasing stability. Here, the fiber reinforcement can be guided from the concrete base layer to the concrete surface layer around the at least one planar heating element. Likewise, a separate edge fiber reinforcement can be provided, which is guided or arranged around the at least one planar heating element and leads to the respective fiber reinforcement of the concrete base layer and / or concrete surface layer and, if necessary, is connected to it.

[0031] According to an advantageous embodiment of the invention, the fiber reinforcement of the concrete slab, the edge fiber reinforcement, and / or the reinforcement elements comprise planar and / or three-dimensional and / or elongated structures. These structures can be carbon fiber structures, basalt fiber structures, glass fiber structures, or other fiber structures. Such structures are woven or knitted fabrics, nonwovens, meshes, or grids made from planar and / or three-dimensional and / or elongated or linear structures, such as yarn, filament, thread, or fiber arrangements. These structures typically comprise several fibers. Depending on the stress, different fibers, such as carbon fibers, basalt fibers, glass fibers, or other fiber types, as well as different structures or combinations thereof, can be used.

[0032] Spatial and / or elongated fiber or carbon fiber structures, such as corrugated structures, are also suitable. These can be arranged on both sides of the planar heating element or in the concrete top and bottom layers. The wave directions of the respective corrugated fiber or carbon fiber structures are offset from each other, for example by 90 degrees, so that the fiber or carbon fiber structure in the concrete top layer has a preferred force direction that is offset by 90 degrees from that of the fiber or carbon fiber structure in the concrete bottom layer.

[0033] Furthermore, in corrugated structures, the wave crests pointing away from the planar heating element, or the wave crests on one side of the corrugated structures, can be connected with elongated linear fiber or carbon fiber structures or fiber or carbon fiber planar structures.

[0034] The corrugated fiber or carbon fiber structure can also be a fiber or carbon fiber mat or a fiber or carbon fiber mesh, the wave crests pointing away from the planar heating element or the wave crests of one side of the corrugated structures being connected via a fiber or carbon fiber mat or a fiber or carbon fiber mesh.

[0035] According to an advantageous embodiment of the invention, the fiber reinforcement, the edge fiber reinforcement, and / or the reinforcement elements comprise carbon fibers, basalt fibers, glass fibers, and / or other mineral or synthetic fibers. Carbon fibers, in particular, exhibit very high tensile strength. Consequently, concrete slabs with very high flexural strength can be produced using carbon fiber reinforcement, allowing these concrete slabs to be used for high loads with a comparatively thin slab thickness of approximately 4 cm. Such a concrete slab can therefore also be used on airport runways.

[0036] The use of carbon fibers, which exhibit very high tensile strength, is particularly advantageous. The carbon fibers can be used in textile form or in rod form. Concrete combined with carbon fibers is also known as carbon concrete. Rod-shaped carbon fibers are preferably used with a profiled surface to ensure better frictional and / or form-fit with the concrete.

[0037] According to an advantageous embodiment of the invention, the planar and / or three-dimensional structures of the fiber reinforcement, edge fiber reinforcement, and / or the reinforcement elements, such as those made of carbon fibers, are stiffened. This stiffening can be achieved, for example, by a coating treatment, impregnation, or by encasing the reinforcing fibers with suitable materials. This stiffening allows the planar and three-dimensional structures of the reinforcing fibers to be advantageously manufactured with dimension stability during the production of the concrete slabs.

[0038] Furthermore, a sizing treatment, impregnation or coating of the reinforcing fibers can create an adhesion-enhancing or friction-increasing or a three-dimensional surface structure.

[0039] According to an advantageous embodiment of the invention, the planar and / or spatial reinforcement structures have a grid or grid dimension of, for example, between 8 and 40 mm. Preferably, the grid or grid dimension can have, for example, between 10 and 20 mm. Square, rectangular, or honeycomb-shaped grids are suitable, for example. This allows the edge fiber reinforcements and the reinforcement elements guided through the openings to be easily integrated into the fiber reinforcement of the concrete slab. At the same time, the use of the expensive carbon material is optimized.

[0040] According to an advantageous embodiment of the invention, the through-openings in at least one planar heating element are arranged in a grid pattern. This improves the compressive strength and flexural strength. The compressive strength and flexural strength can be adjusted depending on the type of grid.

[0041] Preferably, the openings in at least one planar heating element have a clear opening of 0.5 to 2.5 cm. Preferably, the openings are 1.25 to 2 cm in diameter, and particularly preferably 1.4 to 1.7 cm. The openings can be round, but can also have other shapes, such as angular or hybrid forms. This allows for adjustment of the bond or connection between the concrete base layer and the concrete top layer, thereby improving the compressive and flexural strength.

[0042] Furthermore, it is advantageously provided that 9 to 100 through-openings per square meter are distributed throughout the at least one planar heating element. Preferably, between 20 and 80, and particularly preferably between 30 and 60 through-openings per square meter are distributed throughout the at least one planar heating element. These features regarding the through-openings in the at least one planar heating element advantageously represent an optimum between, on the one hand, the strength and flexural strength of the concrete slab and, on the other hand, good handling and efficient material usage during the production of the concrete slab. However, a different, unspecified number of through-openings is not excluded.

[0043] According to an advantageous embodiment of the invention, the heating layer, as the actual heating unit for converting electrical energy into heat, comprises a heating fabric, a heating mat, a heating braid, or a heating film. It is preferably provided according to the invention that the heating fabric, heating mat, heating braid, and / or heating film each have a conductive coating with metal and / or carbon. However, the heating fabric, heating mat, heating braid, and / or heating film can already be conductive. A combination of a conductive heating fabric, heating mat, heating braid, and / or heating film with a conductive coating is also provided.

[0044] Preferred embodiments of the concrete slab according to the invention are hereby specified, which advantageously enable an efficient provision of low-temperature heat in conjunction with the concrete slab designed according to the aforementioned features.

[0045] In a particularly preferred embodiment, the heating layer is designed such that the heating fabric, heating mat, or heating braid is enclosed on both sides by prepreg material as a resin-fiber composite for protection and stability. During the manufacturing process, the prepreg material and the heating layer are pressed and cured to form a flat heating element, creating a strong bond. This embedding of the heating layer within the resin-fiber composite is achieved through the prepreg layers. Using the prepreg material results in a laminated structure that improves compressive and flexural strength.The special feature of the at least one planar heating element is that it has a maximum thickness of between 0.7 mm and 2.5 mm, preferably between 0.9 mm and 2 mm, and particularly preferably between 1 mm and 1.5 mm, thus enabling the production of the thin and mechanically highly resilient concrete slab. The prepreg layers also achieve high dielectric strength, allowing the heating layer to be operated, for example, at voltages between 110 V and 1000 V, and therefore also at 220 V, 230 V, 380 V, or 400 V, or at other voltage ranges.

[0046] Advantageously, at least one flat heating element with the laminated structure of the synthetic resin-fiber composite and the embedded heating layer can be prefabricated, making it easy to handle as a component, part, or semi-finished product during the production of the concrete slab. Furthermore, the heating layer is well protected from damage during the production of the concrete slab by the cured prepreg layers.

[0047] According to an advantageous embodiment of the invention, the outer surface of the concrete sublayer and / or the outer surface of the concrete toplayer has a three-dimensional and / or adhesion-enhancing or friction-enhancing surface structure on the side or surface opposite the at least one planar heating element, in order to improve the bond to a substrate as required and / or to increase slip resistance or sliding friction. Furthermore, traffic safety can be increased.

[0048] A three-dimensional surface structure formed on the underside of the concrete sublayer increases the contact area and interlocks with the underlying concrete or substructure, enabling shear forces in particular to be transferred more effectively to the underlying concrete or substructure.

[0049] A three-dimensional surface structure applied to the top of the concrete surface layer creates a surface roughness that improves the adhesion of tires to the concrete, especially on smooth surfaces. This three-dimensional surface structure can be easily achieved, for example, by placing coarse-grained material, such as gravel, on the respective side of the concrete base layer and / or the concrete surface layer, or by using a formwork matrix during production with a negative or complementary structure to the desired or required surface texture.

[0050] According to an advantageous embodiment of the invention, the at least one planar heating element is provided on its surfaces with an adhesion-enhancing coating or a polymer-modified bonding bridge, or has an adhesion-enhancing three-dimensional surface structure. This advantageously improves the adhesion between the at least one planar heating element and the concrete sublayer as well as the concrete surface layer. Consequently, the flexural strength of the concrete slab is increased, and the transfer of horizontal and / or vertical forces from the concrete surface layer to the concrete sublayer via the at least one planar heating element is improved, so that ultimately the concrete slab can withstand higher stresses.

[0051] The contact of at least one flat heating element can be led to the side surfaces towards the adjacent concrete slab or downwards to enable the electrical connection to a supply network.

[0052] Furthermore, the fiber reinforcements, insofar as they are electrically conductive, can be used for electromagnetic shielding, for example with carbon fibers. Likewise, electrically conductive fiber reinforcements can be used for grounding, preferably routed out through the concrete sublayer.

[0053] A reflective layer and / or thermal insulation can be advantageously arranged below the concrete sublayer of the concrete slab to reduce heat loss.

[0054] To reduce energy costs, the heating layer is controlled by a regulation dependent on the road surface temperature.

[0055] The electrically heated concrete slabs according to the invention are particularly suitable for taxiway heating at airports due to their excellent mechanical properties, where a monolithic construction of the described layers is not feasible, e.g., for reasons of time.

[0056] Several embodiments of the invention are shown in the drawings and are described in more detail below.

[0057] They show: Fig. 1 an electrically heated concrete slab in a cross-sectional view, Fig. 2 Top view of an electrically heated concrete slab cut horizontally in the plane of the heating element, Fig. 3 an electrically heated concrete slab in a perspective view, Fig. 4 a section of an electrically heated concrete slab with edge elements in a perspective view, Fig. 5 A detailed sectional view of an electrically heated concrete slab with reinforcement elements in a perspective view, Figs. 6a and 6b a cross-sectional view of an electrically heated concrete slab with reinforcement elements and different perspectives and Fig. 7 An electrically heated concrete slab in a cross-sectional view showing a concrete layer and an insulating layer.

[0058] In Figure 1 Figure 1 shows a cross-sectional view of an electrically heated, planar concrete slab 1 according to the invention. The concrete slab 1 according to the invention is described below, starting from the bottom. The base of the concrete slab 1 is the concrete sublayer 4, which is provided with fiber reinforcement 2 made of carbon fibers. Here, the fiber reinforcement 2 is advantageously arranged as a woven grid of carbon fibers, horizontally oriented in the center of the concrete sublayer 4. Several layers of fiber reinforcement 2 can also be provided. Such carbon fiber-reinforced concrete is also known as carbon concrete. Concrete reinforced with other fibers is also known as textile-reinforced concrete. Other fibers can be, for example, basalt fibers or other types of fibers.

[0059] High-strength and ultra-high-strength concrete is preferably used. The flat heating element 3 is arranged above the concrete sublayer 4.

[0060] The planar heating element 3 comprises an electrically operated heating layer embedded in a resin-fiber composite. The heating layer preferably comprises a metal-coated fabric. The resin-fiber composite surrounding the heating layer is preferably prepreg material in the form of prepreg mats, which are pressed and cured as a stack with the heating layer arranged between at least two prepreg mats, thus forming a laminated structure or composite. The resin-fiber composite stiffens the planar heating element 3, making it easy to handle. At the same time, the resin-fiber composite provides mechanical protection for the heating layer and ensures high dielectric strength. The heating layer is provided with externally extending waterproof contacts (not shown).

[0061] On one side, in this case above the flat heating element 3, a concrete top layer 5 is arranged, the basic structure of which corresponds to that of the concrete base layer 4. For example, 49 round through-openings 6 with a diameter of 15 mm are arranged in a grid pattern in the flat heating element 3. During the production of the concrete slab, concrete flows through these through-openings 6, so that the concrete top layer 5 is advantageously bonded to the concrete base layer 4, forming a homogeneous concrete body that penetrates the flat heating element 3 at intervals. This significantly increases the flexural strength of the concrete slab 1. In particular, the bond between the concrete top layer 5 and the concrete base layer 4 allows the concrete slab 1 to absorb horizontally and / or vertically acting shear forces much more effectively.

[0062] This basic design provides an electrically heated concrete slab 1 that enables the heating of traffic areas and simultaneously withstands high mechanical stress. Thanks to the lightweight and durable carbon concrete, the concrete slab can be manufactured with a comparatively low thickness of only 3 cm or even 4 cm, making it suitable for high-stress applications. The concrete slabs 1 according to the invention are therefore particularly suitable for runways and other traffic areas at airports, as well as for walkways, stairs, or driveways.

[0063] The electrically heated concrete slabs 1 according to the invention can be laid on existing concrete surfaces or other suitable existing surfaces.

[0064] The electrically heated concrete slabs 1 are formed with a vertically oriented wave structure 8 on their lateral outer edges or outer surfaces, wherein the wave structures 8 are each designed such that the adjacent wave structures 8 of adjacent concrete slabs 1 correspond to each other. For illustration, the following is shown in the Figure 1 A neighboring concrete slab 1 is indicated in the illustration. The wave structures 8 are as shown, preferably correspondingly sinusoidal.

[0065] Here, the vertically oriented wave structure 8 is realized by prefabricated concrete edge elements 9, which are provided with edge fiber reinforcement 2r made of carbon fibers. The concrete edge elements 9, which are also made of carbon concrete, are cast during the production of the concrete slab 1, in particular during the creation of the concrete base layer 4 and the concrete top layer 5, and are thus integrated into the concrete slab 1 as permanent formwork.

[0066] To integrate the edge fiber reinforcement 2r of the concrete edge elements 9 into the concrete sublayer 4 and the concrete toplayer 5 and their fiber reinforcements 2, the edge fiber reinforcement 2r protrudes from the prefabricated concrete edge elements 9 as connection reinforcement on the side opposite the wave structure 8. A further fundamental advantage of using carbon fibers for the fiber reinforcement 2 and edge fiber reinforcement 2r is that, unlike steel reinforcement, corrosion cannot occur, so no concrete cover is required for the fiber reinforcement 2. Therefore, the fiber reinforcement 2 and edge fiber reinforcement 2r can be extended from the concrete sublayer 4 as carbon reinforcement on the underside for connection to the concrete substructure and / or for grounding.

[0067] In Figure 2Figure 1 shows a horizontally cut, electrically heated concrete slab 1 in the plane of the planar heating element 3, viewed from above. The electrically heated concrete slab 1 shown is like the one in Figure 2. Fig. 1 as shown.

[0068] The through-openings 6 arranged in the heating element, through which the concrete of the upper layer (not shown) is connected to the concrete of the lower layer 4, are arranged in a grid pattern. Here, for example, 60 through-openings 6 are provided per square meter.

[0069] Beneath the heating element 3, the concrete sublayer 4 with the fiber reinforcement 2, shown as a dashed line, is arranged. The concrete edge elements 9, arranged on the side faces of the concrete slab 1, are also shown. The edge fiber reinforcement 2r of the concrete edge elements 9, which is simplified and shown only in sections, is actually continuous around the perimeter and embedded in the concrete and the fiber reinforcement 2 of the concrete slab 1.

[0070] The through-openings 6 in the planar heating element 3 can be excluded from both the heating layer and the prepreg layers during the manufacture of the planar heating element 3, or they can be added subsequently, for example by punching or drilling.

[0071] The Figure 3 Figure 1 shows an electrically heated concrete slab 1 in a perspective view. The concrete slab 1 shown here is based on the one described in Figure 1. Fig. 1The embodiment shown, in which no concrete edge elements are present or not shown, is described. The concrete slab 1 shown is connected not only to the concrete passing through the openings 6 and connecting the concrete base layer 4 to the concrete top layer 5, but also to carbon reinforcement elements 7. These carbon reinforcement elements 7 are also guided through the openings 6 in the planar heating element 3. The reinforcement elements 7 can be subsequently or additionally integrated into the fiber reinforcement 2 of the concrete base layer 4 and / or the concrete top layer 5, for example, by weaving them in, or they can already be an integral part of the reinforcement 2 as a unit. The carbon reinforcement elements 7 improve the connection between the concrete base layer 4 and the concrete top layer 5, so that, for example, larger mechanical forces, such as shear forces, can be transferred here.

[0072] In Figure 4 An electrically heated concrete slab 1 with edge elements 9 is shown in a perspective view. In principle, the concrete slab 1 shown is made of Fig. 3 and therefore from Figs. 1 and 2 known. Here are, as in Fig. 2 The outer edge elements 9, which have a wave-like shape, are shown. The edge fiber reinforcement 2r, which stabilizes the edge elements 9 and is made of carbon, is brought close to the fiber reinforcement 2 of the concrete slab 1 and preferably connected to it. The connections can be designed, for example, as hooks, loops and / or eyelets, or be braided or tied. As already shown in Fig. 3 As is known, only individual reinforcement elements 7 are shown here as an example through the passage openings 6 in the flat heating element 3 in order to improve the bond between the concrete underlayer 4 and the concrete toplayer 5.

[0073] The Figure 5The detailed sectional view of an electrically heated concrete slab 1 with fiber reinforcement 2 and reinforcement elements 7 is shown in a perspective view, as can be seen in particular from Fig. 3 The cross-sectional view is shown here through a passage opening 6. The reinforcement elements 7, encased in concrete, extend through the passage opening 6. Here, the reinforcement elements 7 are shown with hook-shaped ends, ensuring at least a positive connection between the reinforcement elements 7, which are placed on or inserted into the fiber reinforcement 2, both in the concrete and with the fiber reinforcement 2 of the concrete slab 1. Accordingly, the strength properties of the concrete slab 1 are further improved.

[0074] An embodiment of the reinforcement elements 7, not shown, consists in the fact that open, for example rod-shaped, ends woven into the fiber reinforcement 2 are led through the passage openings as reinforcement elements 7 and thus the reinforcement elements 7 are also positively integrated into the fiber reinforcements 2.

[0075] Another version of the electrically heated concrete slab 1 is in the Figures 6a and 6b The concrete slab 1 is shown offset or rotated by 90 degrees around an axis perpendicular to the concrete slab 1.

[0076] On a planar heating layer 3 embedded in a synthetic resin-fiber composite, forming a planar heating element 3, a fiber reinforcement 2 in the form of a corrugated carbon fiber structure is arranged on each of the two opposing surfaces or outer surfaces. The orientation of the corrugated carbon fiber structure is offset from each other by 90 degrees on the two opposing surfaces or outer surfaces of the planar heating element 3, as shown in the Figures 6a and 6bThe fiber reinforcement 2, a corrugated carbon fiber structure, is vulcanized or bonded to the flat heating element 3 at the crests facing the flat heating element 3. The fiber reinforcement 2, a corrugated carbon fiber structure, has a stabilizing coating. Depending on the coating, the coating can also serve as a connection to the flat heating element 3. A flat carbon fiber structure is present on each of the crests of the fiber reinforcement 2, a corrugated carbon fiber structure, that points away from the flat heating element 3 and is connected to the crests. The flat heating element 3, with the fiber reinforcement 2, a corrugated carbon fiber structure, connected on both sides, is surrounded by concrete. The concrete below the flat heating element 3 forms the concrete base layer 4, and the concrete above the flat heating element 3 forms the concrete top layer 5, thus forming the electrically heated concrete slab 1.In the lateral areas, away from the heating layer 3, the concrete base layer 4 is connected to the concrete top layer 5. The flat heating element 3 has an electrical supply line 10 that leads out of the concrete slab 1.

[0077] In Figure 7 In a further embodiment of the invention, a heating element 3 is provided on a planar heating layer 3 embedded in a synthetic resin-fiber composite. Figure 7On the upper surface or outer surface, a fiber reinforcement 2 in the form of a corrugated carbon fiber structure is arranged. The fiber reinforcement 2, as a corrugated carbon fiber structure, is vulcanized or bonded to the flat heating element 3 at the crests of the corrugations facing the flat heating element 3. The fiber reinforcement 2, as a corrugated carbon fiber structure, has a stabilizing coating. On each of the crests of the fiber reinforcement 2, as a corrugated carbon fiber structure, pointing away from the flat heating element 3, a flat carbon fiber structure is present and connected to the crests. The flat heating element 3 with the connected fiber reinforcement 2, as a corrugated carbon fiber structure, is surrounded by concrete as a concrete top layer 4. On the in Figure 7An insulating layer 11 made of a solid or stable insulating material is arranged on the lower surface or outer surface of the flat heating element 3 and connected to the flat heating element 3. This assembly forms the electrically heated concrete slab 1. The flat heating element 3 has an electrical supply line 10 (not shown) that leads out of the concrete slab 1 (not shown). Compilation of reference symbols

[0078] 1 - Concrete slab, electrically heated concrete slab 2 - Fiber reinforcement 2r - Edge fiber reinforcement 3 - Heating element, heating layer embedded in a synthetic resin-fiber composite 4 - Concrete sublayer 5 - Concrete top layer 6 - Openings in the heating element 7 - Reinforcing element 8 - Edge of the concrete slab, corresponding wave structure 9 - Edge elements 10 - Electrical supply line 11 - Insulation layer

Claims

1. Electrically heatable concrete slab (1), wherein the concrete slab (1) comprises at least one fibre reinforcement (2) and at least one flat heating element (3), wherein at least one heating element (3) comprises at least one heating layer embedded in a synthetic resin-fibre composite, and the concrete slab (1) on one side or surface of the flat heating element (3) has a concrete top layer (5) with the fibre reinforcement (2) and on the opposite side or surface of the flat heating element (3) an insulation layer (11) or a concrete underlayer (4) with the fibre reinforcement (2), - wherein the fibre reinforcement (2) in some areas with at least one flat heating element (3) is form and force-fitting connected or - wherein at least one flat heating element (3) are distributed to each other spaced through holes (6) and the concrete of the concrete underlayer (4) with the concrete of the concrete upper layer (5) through the through holes are arranged (6) is connected through the flat heating element (3) and that reinforcement elements (7) are present which are guided through the through holes (6) of at least one flat heating element (3), wherein the reinforcing elements (7) with the fibre reinforcement (2) of the concrete slab (1) as part of the fibre reinforcement (2) form a unit or are connected to the fibre reinforcement (2) or are placed on the fibre reinforcement (2) or inserted into the fibre reinforcement (2).

2. Electrically heatable concrete slab (1) according to claim 1, characterised in that the fibre reinforcement (2) is partially spaced to at least one flat heating element (3) or is connected to at least one flat heating element (3).

3. Electrically heated concrete slab (1) according to any one of the preceding claims, characterised in that the circumferential or lateral outer surfaces (8) of the concrete slab (2) in the vertical direction have a wave structure (8) corresponding to the lateral outer surfaces of an adjacent concrete slab.

4. Electrically heatable concrete slab (1) according to claim 3, characterised in that a circumferential or lateral boundary of the concrete slab (1) in the form of concrete edge elements (9) is present with an outside and an inside, wherein the concrete edge elements (9) on the outside have the corresponding wave structure (8) and the concrete edge elements (9) have an edge fibre reinforcement (2r), wherein edge fibre reinforcement (2r) on the inside of the concrete edge elements (9) protrudes as a connecting reinforcement in the direction of the fibre reinforcement (2) of the concrete slab (2) and is connected to the fibre reinforcement (2) of the concrete slab (1) and / or that the fibre reinforcement (2) or the edge fibre reinforcement (2r) from the concrete underlayer (4) to the concrete top layer (5) in the region of the circumferential or lateral outer surfaces (8) around which at least one flat heating element (3) is guided.

5. Electrically heated concrete slab (1) according to any one of the preceding claims, characterised in that the fibre reinforcement (2), edge fibre reinforcement (2r) and / or the reinforcement elements (7) have planar, spatial and / or elongated structures and / or that the fibre reinforcement (2), edge fibre reinforcement (2r) and / or the reinforcement elements (7) comprise carbon fibres, basalt fibres, glass fibres or other mineral or synthetic fibres.

6. Electrically heatable concrete slab (1) according to claim 5, characterised in that the planar and / or spatial structures of the fibre reinforcement (2), edge fibre reinforcement (2r) and / or the reinforcement elements (7) are stiffened.

7. Electrically heated concrete slab (1) according to any one of the preceding claims 1 and 3, characterised in that the through-holes (6) in at least one flat heating element (3) have a size of 0.5 cm to 2.5 cm, preferably a size between 1.25 cm to 2 cm and particularly preferably a diameter between 1.4 cm and 1.7 cm.

8. Electrically heated concrete slab (1) according to any one of the preceding claims 1, 3 and 7, characterised in that the through-holes (6) in at least one flat heating element (3) distributed with a number between 9 and 100, preferably between 20 and 80 and particularly preferably between 30 to 60 per square meter are arranged and / or that the through-holes (6) in at least one flat heating element (3) are arranged in a grid form.

9. Electrically heated concrete slab (1) according to any one of the preceding claims, characterised in that the heating layer (3) has a heating fabric, a heating mesh, a heating braid or a heating foil, wherein the heating mesh, heating mesh, and / or the heating foil is conductive or conductive coated.

10. Electrically heated concrete slab (1) according to any one of the preceding claims, characterised in that the heating layer (2) is designed such that the heating fabric, the heating layer and / or the heating mesh is enclosed, pressed and cured on both sides by pre-impregnated material.

11. Electrically heated concrete slab (1) according to any one of the preceding claims, characterised in that the concrete underlayer (4) and / or the concrete top layer (5) has a three-dimensional and / or adhesion-improving or friction-increasing surface structure on the side or surface opposite the flat heating element (3).

12. Electrically heated concrete slab (1) according to any one of the preceding claims, characterised in that at least one flat heating element (3) is provided with an adhesion-improving coating on its surfaces or has an adhesion-improving three-dimensional surface structure.