Multi-layer concrete block for a paving, as well as paving and method for producing a concrete block

Abstract

The invention relates to a concrete block (1), in particular in the form of a planar element that can be laid in combination in order to create a paving, comprising at least one multi-layer concrete block body (2) having at least one concrete-block lower face (2.1) suitable for being laid on a foundation layer (3) of an underlying surface, and a concrete-block upper face (2.2) opposite thereto. The multi-layer concrete block body (2) comprises at least one first concrete-block layer (2a) disposed on the concrete-block upper face (2.2) and in the form of a face concrete layer, at least one second concrete-block layer (2b) in the form of a core concrete layer, as well as a third concrete-block layer (2c). The second concrete-block layer (2b) in the form of a core concrete layer is disposed between the first and the third concrete-block layer (2a, 2c). The third concrete-block layer (2c) is in the form of a high-strength concrete base layer having increased tensile strength, wherein the increased tensile strength of the third concrete-block layer (2c) is increased in comparison with the tensile strength of the second concrete-block layer (2b), specifically preferably by at least 10%.

Description

[0001] Multi-layer concrete block for a surface covering, as well as surface covering and method for producing a concrete block

[0002] Technical area

[0003] The invention relates to a multi-layer concrete block for a surface covering laid in a composite manner, as well as to a surface covering made of such multi-layer concrete blocks. Furthermore, the invention relates to a method for producing a concrete block of the aforementioned type.

[0004] State of the art

[0005] Particularly in urban areas, large areas of the surface are designed as walkable or drivable traffic areas such as streets, paths, squares or parking lots and are covered with surface coverings. The surface coverings are often created by laying individual stones, particularly shaped concrete blocks, in a composite manner. For example, such surface coverings are created by paving, whereby paving stones or corresponding shaped concrete blocks are laid in a composite manner on a bedding layer of the subsoil. As a rule, joints remain between adjacent concrete blocks or shaped stones, particularly concrete paving stones, which are filled with suitable, usually sand-like or chipping-like jointing materials. Such surface coverings in the form of paving are well known in the art.

[0006] It is also known to use multi-layered concrete blocks or concrete paving blocks for the construction of such a surface covering. These multi-layered concrete blocks typically have at least a core layer and a facing layer. The core layer is usually made of core concrete and forms the core of the concrete block, while the facing layer is usually made of facing concrete and forms the walkable or driveable upper surface of the concrete block, namely its visible surface.

[0007] It is also known that the multi-layer concrete blocks of the type mentioned, due to their structure and the nature of the individual layers, in particular due to the nature of the concrete used to produce the individual layers, are designed in such a way that they have a specific or desired water permeability or water permeability and / or a specific or desired water storage capacity. For example, DE 10 2012 100 616 B4 discloses a surface covering made of two-layered shaped blocks, which have a water-absorbing, water-permeable layer below a substantially water-impermeable layer on the surface, so that the impinging rainwater can flow downwards both through the joints and through the water-permeable layer of the shaped blocks, thus via an infiltration path through the concrete blocks themselves.

[0008] If necessary, rainwater can also be stored, which can counteract the so-called urban "heat island effect" through increased water evaporation, since evaporative cooling occurs when water evaporates. Such a water-storing concrete block is known, for example, from EP 3 153 625 A1.

[0009] Furthermore, it is known from the prior art to use so-called grass paving stones in various designs, for example as grass grid stones or grass slabs, to create green surface coverings. Such grass paving stones generally have a grid-like or honeycomb-like basic structure made up of longitudinal and transverse webs, with spaces between these longitudinal and transverse webs forming drainage openings through which rainwater can penetrate into the soil beneath the grass paving stone. This makes them particularly suitable for creating water-permeable paving surfaces, which are desirable for ecological reasons and which can avoid complete or largely complete sealing of the paving surface. In particular, such surface coverings can also be at least partially greened or partially overgrown by plant growth in the drainage openings.

[0010] Also, and especially with regard to grass paving stones, it is desirable that the water permeability, i.e., water absorption and water storage, of the grass paving stones be such that a sufficient and optimal water supply is guaranteed for the vegetation in the drainage holes, possibly even to survive extended dry periods. For example, EP 1 589 149 B1 describes a grass paver with a two-layer structure, with the layers differing in their porosity, so that water storage is possible through the laid grass pavers.

[0011] A problem with all of the above-mentioned concrete blocks with water-absorbing, i.e., porous layers is the resulting loss of stability, since such porous layers in the block structure generally reduce both the compressive and tensile stability of the concrete block. This reduced stability, however, has a detrimental effect, particularly on driveable surfaces that are also driven over by vehicles with high wheel loads. Such instabilities also frequently lead to fractures or cracks in the blocks during processing, namely during laying and fixing of the surface coverings, which disadvantageously results in a high level of waste. Therefore, there is still a need for multi-layer concrete blocks with improved stability.

[0012] Description of the invention

[0013] The object of the present invention is therefore to provide a concrete block that overcomes the disadvantages of the prior art and, in particular, has increased stability. This object is achieved according to the invention by the device according to independent claim 1. Furthermore, to achieve this object, a surface covering made of the aforementioned concrete blocks according to claim 16 and a method for producing such concrete blocks according to claim 17 are proposed. Further advantageous aspects, details, and embodiments of the invention emerge from the dependent claims, the description, and the drawings.

[0014] The present invention provides a concrete block, in particular in the form of a surface element that can be laid in a composite manner for creating a surface covering. The concrete block has at least one multi-layer concrete block body with at least one concrete block underside suitable for laying on a bedding layer of a subsurface and a concrete block top side opposite this. The multi-layer concrete block body comprises at least one first concrete block layer arranged on the concrete block top side and designed as a facing concrete layer, and at least one second concrete block layer designed as a core concrete layer, wherein the multi-layer concrete block body further comprises at least one third concrete block layer. The second concrete block layer designed as a core concrete layer is arranged between the first and third concrete block layers.According to a particular aspect of the invention, the third concrete block layer is designed as a high-strength concrete base layer with increased tensile strength, wherein the increased tensile strength of the third concrete block layer is increased compared to a tensile strength of the second concrete block layer, preferably by at least 10%.

[0015] The present concrete block is thus constructed in at least three layers. The third concrete block layer provided in the present concrete block, which is designed according to the invention as a high-strength concrete base layer and has increased tensile strength compared to the other concrete block layers, especially compared to the core concrete layer, results in the particular advantage that the concrete block is extremely stable, particularly dimensionally stable, fracture-resistant, and highly resistant to mechanical stresses, for example, due to tensile and bending forces.

[0016] Due to the high-strength concrete base layer provided according to the invention, the exceptionally high stability of the concrete block is ensured and guaranteed, regardless of the design and dimensions of the at least two additional concrete block layers. The concrete block according to the invention can therefore be manufactured with a significantly lower height or thickness compared to conventional concrete blocks, resulting in particularly advantageous, versatile savings, ranging from material savings during production to space savings during transport and storage, which in turn result in cost savings.

[0017] The high-strength concrete base layer provided according to the invention also allows the concrete block to be manufactured in an application-specific manner with a core concrete layer that has only a low structural density and is, for example, so coarse, porous, or open-pored that it would not meet the desired and necessary stability requirements on its own. However, the high-strength concrete base layer also supports and stabilizes a porous core concrete layer in such a way that the concrete block is sufficiently stable.

[0018] According to a preferred embodiment of the concrete block according to the invention, the third concrete block layer is made of high-strength concrete that forms a dense and capillary-poor structure, i.e., a dense, high-strength concrete. The concrete base layer made of high-strength concrete is advantageously resistant to tensile and compressive forces, in particular to tensile bending forces and / or splitting forces, whereby the high resistance of the concrete base layer to tensile and compressive forces is transferred to the entire concrete block. This effectively prevents the formation of fractures or cracks, both during the laying of the concrete blocks and in the laid state, for example, when high mechanical compressive and tensile bending forces act, which can occur when heavy vehicles drive over laid concrete blocks.

[0019] The unit N / mm 2The specified tensile strength can be derived indirectly from the compressive strength, using the rough rule of thumb that the tensile strength is approximately 10% of the measured compressive strength value. However, the tensile strength can also be determined by testing or measuring the splitting tensile strength (e.g., DIN EN 12390-6) or flexural tensile strength (DIN EN 12390-5).

[0020] The unit N / mm 2 The specified compressive strength can be measured on test specimens. For example, according to DIN EN 206-1 / DIN 1045-2, the compressive strength to determine the characteristic strength and assign the strength class must be demonstrated on test specimens aged 28 days.

[0021] The third concrete block layer preferably has an increased flexural tensile strength and / or an increased splitting tensile strength and thus, in particular, has a predetermined minimum tensile strength. The third concrete block layer most preferably also has an increased compressive strength. The concrete blocks laid in a surface covering are primarily subjected to flexural tensile stress, so that in this case, an increased flexural tensile strength, in particular a minimum flexural tensile strength, is considered a key property for the third concrete block layer, and the concrete block preferably has an increased flexural tensile strength, in particular a minimum flexural tensile strength.

[0022] Due to the increased strength and compliance with a specified, predetermined minimum tensile strength, the concrete block can be optimally designed for its intended use and, for example, specifically adapted for use in walkable surface coverings or surface coverings for heavy-duty traffic. The third concrete block layer preferably has a tensile strength of at least 3 N / mm². 2 or at least 4 N / mm 2 and in particular a tensile strength of more than 5 N / mm 2 on.

[0023] Most preferably, the third concrete block layer is made of a high-strength concrete, in particular a high-strength concrete with a compressive strength of at least 50 N / mm 2manufactured. For the purposes of the present invention, the term "high-strength concrete" can also be referred to as "high-performance concrete," which is characterized not only by high compressive strength and high resistance to mechanical stress, but also by high durability. High-strength concrete is a special concrete composition that meets stringent processing and usage requirements, in particular, it exhibits high resistance to mechanical, physical, or chemical influences. The classification or classification of concrete compositions defined as "high-strength concrete" is carried out, for example, using a set of rules or standards familiar to those skilled in the art.

[0024] The third concrete block layer of the present concrete block is preferably made of a high-strength concrete whose concrete structure is optimized, in particular by optimal coordination of aggregate and cement block properties, wherein, for example, the cement content of the high-strength concrete for producing the third concrete block layer of the present concrete block is greater than approximately 350 kg / m 3 or 360 kg / m 3 or 370 kg / m 3 and in particular in a range between 380 kg / m 3 and 450 kg / m 3 Preferably, the cement content of the high-strength concrete used to produce the third concrete block layer is around 390 kg / m 3 or 400 kg / m 3 or 420 kg / m 3 .

[0025] For example, the high-strength concrete used to produce the third layer of concrete blocks can also contain additives such as stone flour, carbon dust, or so-called silica dust, especially microsilica or nanosilica, which further increase the density of the structure. For example, adding a plasticizer or superplasticizer to the composition of the high-strength concrete can facilitate workability during the formation of the third layer of concrete blocks.

[0026] The high-strength concrete for the production of the third concrete block layer is particularly preferably assigned to a predetermined strength class, but can, for example, be high-strength normal-weight concrete or high-strength lightweight concrete. The strength class of the high-strength concrete is preferably selected from the following strength classes for normal-weight concrete: C55 / 67 or C60 / 75 or C70 / 85 or C80 / 95 or C90 / 105 or C100 / 115, or from the following strength classes for lightweight concrete: LC55 / 67 or LC60 / 66 or LC70 / 77 or LC80 / 88.

[0027] The term "strength class" is used here as a synonym for the term "concrete compressive strength classes", which is also commonly used in specialist circles. The strength classes (for example according to DIN EN 1992-1-1) refer to the characteristic cylinder compressive strengths (f ck), which are determined on specially manufactured concrete test specimens after a defined storage period of 28 days. High-strength concrete is defined in the standards as concrete with a cylinder compressive strength of greater than 50 N / mm 2 up to and including 100 N / mm 2 (C 100 / 115) classified.

[0028] According to the invention, the increased tensile strength of the third concrete block layer is increased compared to the tensile strength of the second concrete block layer. In particular, the third concrete block layer thus has a higher tensile strength relative to the second concrete block layer. A ratio of the tensile strengths, namely the ratio of the increased tensile strength of the third concrete block layer to the tensile strength of the second concrete block layer (determined via fracture: "value of the increased tensile strength of the third concrete block layer" / "value of the tensile strength of the second concrete block layer"), is greater than 1.

[0029] Particularly preferably, the increased tensile strength of the third concrete block layer is at least 15% higher than the tensile strength of the second concrete block layer. Further preferably, the increased tensile strength of the third concrete block layer is at least 20% higher than the tensile strength of the second concrete block layer, particularly preferably at least 22%, at least 25%, or at least 27% higher than the tensile strength of the second concrete block layer, and especially preferably at least 30% or at least 35% higher than the tensile strength of the second concrete block layer. The ratio of the increased tensile strength of the third concrete block layer to the tensile strength of the second concrete block layer is thus preferably a value of at least 1.1, at least 1.2, or at least 1.3.

[0030] According to a particularly preferred embodiment of the concrete block according to the invention, the third concrete block layer is made of reinforced concrete or concrete reinforced with at least one embedded reinforcing material. Reinforcement or reinforcement with metallic or non-metallic reinforcing or reinforcement materials further effectively increases the tensile strength of the third concrete block layer.

[0031] The reinforcement or reinforcing material can particularly preferably be a fibrous material embedded in the concrete, such as natural or synthetic fibers, textile fibers or glass fibers, or fibrous wire elements, for example, steel wire fibers or steel fibers. The third concrete block layer is thus preferably made of fiber-reinforced concrete, in particular steel fiber concrete. Due to the good and easy handling of such fiber-reinforced concrete, the third concrete block layer can be manufactured in a particularly advantageous manner, simply and precisely.

[0032] The third concrete block layer preferably has a layer thickness in a range of 14 mm to 20 mm, preferably in a range of 16 mm to 18 mm, and can particularly preferably be approximately 15 mm, 17 mm, or 19 mm thick. With a layer thickness in the specified range, the third concrete block layer, designed as a concrete base layer, is optimally designed to provide the concrete block with the required stability while maintaining the lowest possible overall height, preferably independently of the concrete block's other layer structure.

[0033] Preferably, the second concrete block layer formed as a core concrete layer is made of a porous core concrete and in particular forms a porous layer with increased porosity, wherein the second concrete block layer is particularly preferably water-permeable and / or designed to absorb and store water. The concrete block advantageously contributes to ensuring that the creation of a surface covering made up of several such concrete blocks does not result in complete surface sealing, but rather improves the infiltration of precipitation water. This can also counteract the so-called urban "heat island effect" by allowing the precipitation water stored in the porous layer to evaporate again when exposed to warmth or heat on the surface covering, creating evaporative cooling.

[0034] The second concrete block layer, formed as a core concrete layer, has, for example, a core concrete layer thickness that is greater than the layer thickness of the third concrete block layer. In preferred embodiments, the core concrete layer thickness is approximately 1.5 to 10 times, preferably 2 to 8 times, particularly preferably 3 to 6 times, and especially preferably 4 to 5 times the layer thickness of the third concrete block layer. For example, the core concrete layer thickness is approximately 2.5 or 3.5 times, or 4.5 or 5.5 times the layer thickness of the third concrete block layer.

[0035] According to a particularly preferred embodiment of the invention, the concrete block body is designed in the form of a lawn paving stone, namely in the form of a grid stone or a grid plate or web plate, in particular in the form of a lawn grid or web plate. The concrete block body designed as a grid or web plate preferably comprises at least two transverse webs and at least two longitudinal webs connecting the transverse webs. The transverse and longitudinal webs are arranged and spaced apart from one another in such a way that at least one continuous drainage opening extending from the top side of the concrete block to the bottom side of the concrete block is formed between the transverse and longitudinal webs.

[0036] It is understood that, in a particularly preferred manner, more than two transverse and longitudinal webs can be provided in the concrete block body. For example, the concrete block body comprises at least three or at least four transverse webs and at least three or at least four longitudinal webs.

[0037] The third layer of concrete paving stones, designed as a high-strength concrete base layer, is particularly advantageous for grass paving stones, namely grid slabs or multi-web slabs or multi-web slabs, since such grid-like concrete stones are perforated due to the drainage openings between the longitudinal and transverse webs, and the stability of these concrete stones is therefore further reduced by these perforations. Due to the three-layer structure with the high-strength concrete base layer as the third layer, the stability of this grass paving stone is significantly increased. The risk of breakage during transport and installation, and thus the amount of waste, can be advantageously reduced to a minimum. This not only brings cost savings but also has a positive impact on sustainability through lower resource and energy consumption.

[0038] According to a particularly preferred embodiment, the longitudinal webs of the grass paving stone have a longitudinal web surface, and the transverse webs have a transverse web surface. A web height of the longitudinal webs is preferably less than a web height of the transverse webs, so that the longitudinal web surface is set back vertically from the transverse web surface. The transverse web surface essentially runs at a lower height in a lower horizontal plane, and the longitudinal web surface runs at a higher height in an upper horizontal plane. The upper horizontal plane simultaneously forms the upper surface of the concrete block's top side.

[0039] Due to the lower height of the longitudinal ribs, they are relatively thin and therefore particularly sensitive to tensile forces, especially flexural forces. In the grass paving stone, the longitudinal ribs, which are thinner than the transverse ribs, thus form areas susceptible to fracture. The high-strength concrete base layer has a particularly stabilizing effect on these thin areas of the grass paving stone.

[0040] The present invention further relates to a surface covering made of a plurality of concrete blocks laid in a composite manner as described above, wherein the concrete blocks are laid on a suitable bedding layer provided or prepared therefor, preferably in such a way that defined joints are formed between adjacent concrete blocks.

[0041] The present invention also relates to a method for producing a concrete block described above. In the method, after providing a formwork, at least one high-strength concrete is introduced into the formwork in at least one first step to produce a third concrete block layer designed as a high-strength concrete base layer. In at least one second step, a porous core concrete is additionally introduced into the formwork to produce a second concrete block layer designed as a core concrete layer, and in at least one third step, a facing concrete is introduced into the formwork to produce a first concrete block layer designed as a facing concrete layer. Finally, the introduced concrete material is then compacted and cured.

[0042] Preferably, the high-strength concrete and / or the porous core concrete placed in the formwork can be pre-compacted in one or two intermediate steps before the facing concrete is placed.

[0043] The high-strength concrete is preferably placed into the formwork as a thin layer using a first concrete distribution agent. The porous core concrete is then preferably filled over a thick layer onto the thin layer of high-strength concrete using a second concrete distribution agent. Finally, the facing concrete is preferably filled over a thin layer onto the core concrete layer using a third concrete distribution agent.

[0044] Short description of the drawings

[0045] The invention will be explained in more detail below using exemplary embodiments in conjunction with the drawings.

[0046] Fig. 1 shows a highly simplified and roughly schematic perspective view of an embodiment of a concrete block according to the invention;

[0047] Fig. 2 shows a roughly schematic section through the concrete block of Figure 1;

[0048] Fig. 3 shows a surface covering in a highly simplified sectional view,

[0049] Fig. 4 shows a schematic view of a section of an embodiment of the concrete block body;

[0050] Fig. 5 shows a schematic side view of a section of another embodiment of the concrete block body;

[0051] Fig. 6 shows a highly simplified and roughly schematic plan view of the top side of a concrete block of an embodiment of a concrete block according to the invention;

[0052] Fig. 7 shows a roughly schematic section through the concrete block of Figure 6;

[0053] Fig. 8 shows a highly simplified and roughly schematic plan view of the concrete block top side of an embodiment of a concrete block according to the invention; Fig. 9 shows a schematic side view of the concrete block of Figure 7 and

[0054] Fig. 10 is a roughly schematic section through the concrete block of Figure 7.

[0055] Ways to implement the invention

[0056] Figure 1 shows, by way of example, in a highly simplified schematic drawing, a perspective view of an embodiment of the concrete block 1 according to the invention and Figure 2 shows a schematic section along a cutting plane running parallel to a central vertical axis MHA and parallel to a longitudinal axis LA of the concrete block 1.

[0057] The concrete block 1 is preferably designed in the form of a surface element that can be laid in a composite manner to create a surface covering 10 (see Figure 3). In the present case, concrete block or concrete slab refers to essentially identical elements that can be used to create a surface covering 10 in a conventional manner. For example, the concrete block 1 can be a concrete paving stone. Depending on the selected laying pattern, the concrete blocks 1 are laid in a composite manner and flush with one another, thus creating a preferably flat surface covering 10.

[0058] The concrete block 1 comprises at least one multi-layered concrete block body 2 with at least one flat concrete block underside 2.1 and, opposite this, a substantially flat concrete block upper side 2.2, which preferably forms the walking surface or driveable surface or traffic area. The specific design of the lateral surface sections of the concrete block 1 is not relevant to the invention, i.e., the specific cross-sectional shape of the concrete block 1 can be selected almost arbitrarily without departing from the inventive concept.

[0059] In the present exemplary embodiment, the concrete block 1 is cuboid-shaped and has two pairs of two opposing concrete block sides 2.3, 2.4 with equal areas. The concrete block bottom side 2.1 and the concrete block top side 2.2 run perpendicular or approximately perpendicular to the central vertical axis MHA of the concrete block body 2, respectively.

[0060] Concrete block 1. The concrete block sides 2.4 extend substantially perpendicular to the longitudinal axis LA and the concrete block sides 2.3 extend substantially parallel to the longitudinal axis LA.

[0061] The multi-layer concrete block body 2 comprises at least one first concrete block layer 2a formed as a facing concrete layer and forming the concrete block top 2.2, at least one second concrete block layer 2b formed as a core concrete layer and adjoining the first concrete block layer 2a in the direction of the central vertical axis MHA, and a third concrete block layer 2c formed as a core concrete layer and adjoining the second concrete block layer 2b in the direction of the central vertical axis MHA, forming the concrete block bottom 2.1 and intended to rest on a bedding layer 3 of a subsurface. The second concrete block layer 2b formed as a core concrete layer is thus arranged between the first and third concrete block layers 2a, 2c.

[0062] The third concrete block layer 2c is designed as a high-strength concrete base layer and has an increased tensile strength, in particular an increased flexural strength.

[0063] In the example shown in Figures 1 and 2, the third concrete block layer 2c is made of a high-strength concrete, wherein the high-strength concrete of the third concrete block layer 2c is a dense concrete with a cement content in a range between approximately 350 kg / m 3 and 450 kg / m 3 , preferably between 380 kg / m 3 and 400 kg / m 3 The high-strength concrete of the third concrete block layer 2c, for example, has a compressive strength of at least 55 N / mm 2 and a flexural strength of at least 5 N / mm 2The third concrete block layer 2c is made, in particular, of a high-strength concrete, as defined in the standards, whereby the concrete used to produce the third concrete block layer 2c is, for example, a high-strength concrete of compressive strength class C55 / 67.

[0064] The third concrete block layer 2c of the concrete block 1 of the illustrated example has a layer thickness d that lies in a range between approximately 16 mm and 18 mm. In the exemplary concrete block 1 shown in Figures 1 and 2, the first concrete block layer 2a, designed as a facing concrete layer, has a facing concrete layer thickness dV that can lie in a range between 10 mm and 20 mm. The second concrete block layer 2b, designed as a core concrete layer, with its core concrete layer thickness dK, is the layer with the greatest layer thickness in the exemplary concrete block 1 shown in Figures 1 and 2, i.e. the core concrete layer here takes up the largest portion of the concrete block body 2, which has a total height H that preferably corresponds to the sum of the layer thicknesses dV, dK, d of the first to third concrete block layers 2a, 2b, 2c.

[0065] The second concrete block layer 2b, designed as a core concrete layer, is made of a porous concrete and thus forms a water-permeable or water-absorbing layer in the concrete block body 2. The concrete composition of the porous, second concrete block layer 2b is such that the second concrete block layer 2b is equipped with pores, in particular with a desired or defined number of pores and a desired or defined average pore size. Rainwater that strikes the concrete block 1 laid in a surface covering 10 in use can be absorbed in the pores of the second concrete block layer 2b or can drain through the pores. The second concrete block layer 2b can also serve, in particular, to store water.For optimal absorption and storage of water, the core concrete layer thickness dK of the second concrete block layer 2b is between 40% and 80% of the total height H of the concrete block body 2, preferably between 50% and 70% of the total height H of the concrete block body 2.

[0066] In the illustrated embodiment, the concrete block 1 has so-called spacers or spacer lugs 9, which ensure uniform joints 11 (see Figure 3) of approximately uniform width when laying the concrete block 1 in the composite and ensure a minimum width of the joints 11.

[0067] Figure 3 shows, by way of example, a section through a surface covering 10 formed from the present concrete blocks 1. The surface covering 10 comprises a plurality of multi-layered concrete blocks 1 laid in a composite manner on a bedding layer 3 of a subsurface. Between adjacent concrete blocks 1 of the surface covering 10, joints 11 are formed, which are filled with a joint material 12 and form an infiltration path for draining rainwater from the surface of the surface covering 10 facing away from the bedding layer 3. The bedding layer 3 is a conventional bedding layer, which essentially consists of a material mixture with a grain size of 0.1 mm to 5 mm.

[0068] The present concrete block 1 can be manufactured or produced using industrial manufacturing processes in which concrete blocks 1 are produced in a process-controlled manner, preferably in layers, i.e., several concrete blocks 1 simultaneously in one layer. First, as part of the manufacturing process, a known concrete formwork for producing concrete blocks 1 is provided. After the formwork has been provided, at least one high-strength concrete is introduced into the formwork in at least one first step to produce the third concrete block layer 2c, which is designed as a high-strength concrete base layer.In at least a second step, a porous core concrete is additionally introduced into the formwork to produce the water-permeable second concrete block layer 2b, designed as a core concrete layer. In at least a third step, a facing concrete is introduced into the formwork to produce the first concrete block layer 2a, designed as a facing concrete layer. The introduced concrete material is then compacted and cured.

[0069] Figures 4 and 5 show, based on a schematic section of the concrete block body 2 of a respective embodiment of the present concrete block 1, a schematic sketch of the layer structure of the concrete block body 2. The third concrete block layer 2c, designed as a high-strength concrete base layer, is made in the example in Figure 4 from a dense, high-strength concrete, as already described above. In the concrete block body 2 of the example in Figure 5, the third concrete block layer 2c is additionally reinforced. In this case, reinforcement or a reinforcing material is embedded in the concrete of the third concrete block layer 2c in order to further increase the tensile strength, in particular the flexural tensile strength. In the example shown, fiber reinforcement orFiber reinforcement is provided, wherein the fibers 13 embedded in the concrete are, for example, steel fibers or steel wire fibers and the third concrete block layer is therefore a layer of steel fiber concrete.

[0070] With reference to Figures 6 to 10, further, particularly preferred embodiments of the present concrete block 1 are described, namely variants of the concrete block 1 that are designed as a grid block or as a web plate, namely as a grass grid block 4 or a grass web plate 5. The grass grid block 4 can also be synonymously referred to as a grass grid plate 4, and the grass web plate 5 can also be synonymously referred to as a grass web block 5.

[0071] The concrete block body 2 of the grass grid or grass walkway slab 4, 5 has transverse webs 6a, 6b and longitudinal webs 7a, 7b connecting the transverse webs 6a, 6b. The transverse and longitudinal webs 6a, 6b, 7a, 7b are arranged and spaced apart from one another such that one or more drainage openings 8 are formed between the transverse and longitudinal webs 6a, 6b, 7a, 7b. Each drainage opening 8 extends continuously from the concrete block top side 2.2 to the concrete block bottom side 2.1 and forms a hollow or free space open on both the top and bottom sides, or an opening in the concrete block body 2.

[0072] The grass grid or grass slabs 4, 5 can also be used to create a surface covering laid in a known manner and are used, for example, specifically for overgrown or green surface coverings or for paving surfaces in green areas. The drainage openings 8, which are open upwards toward the top of the concrete block 2.2 and downwards toward the bottom of the concrete block 2.2, are filled with soil, sand, or the like when installed and serve as a planting space in which the vegetation, such as grass, can grow, even allowing their roots to reach directly into the underlying soil.

[0073] The concrete block body 2 of the grass paver 4 shown in Figures 6 and 7, which is shown in Figure 6 in a plan view of the concrete block top side 2.2 and in Figure 7 in a section along the line AA, is essentially cuboid-shaped and comprises two outer transverse webs 6a, one central transverse web 6b, and two outer longitudinal webs 7a and two central longitudinal webs 7b. The transverse webs 6a, 6b run essentially parallel to one another and perpendicular to the longitudinal webs 7a, 7b, which in turn are arranged parallel to one another. The outer transverse and longitudinal webs 6a, 7a form the peripheral sides of the concrete block body 2, namely the concrete block sides 2.3, 2.4, and are designed as a circumferential peripheral surface. It is understood that the number and arrangement of the transverse and longitudinal webs 6a, 7a is merely exemplary and may of course differ from the representation in Figures 6 and 7 without thereby departing from the concept of the invention.In the example shown in Figure 4, the transverse and longitudinal webs 6a, 6b, 7a, 7b have the same height, so that respective transverse web surfaces 6al, 6bl and respective longitudinal web surfaces 7al, 7bl are substantially received in a common plane and together form an upper, substantially flat surface of the concrete block top side 2.2.

[0074] The grass paver 4 shown as an example has six drainage openings 8 and thus six continuous openings. As can be seen from the sectional view in Figure 7, both the transverse webs 6a, 6b and the longitudinal webs 7a, 7b are constructed in three layers and include the first concrete block layer 2a, designed as a facing concrete layer, the second concrete block layer 2b, designed as a core concrete layer, and the third concrete block layer 2c, designed as a high-strength concrete base layer.

[0075] Figures 8 to 10 show, by way of example, a preferred variant of the present lawn walkway slab 5, which is shown in Figure 8 in a plan view of the concrete block upper side 2.2, in Figure 9 in a side view and in Figure 10 in a section along the line BB indicated in Figure 8.

[0076] The concrete block body 2 of the example shown has four transverse webs 6a, 6b and three longitudinal webs 7a, 7b, wherein the three longitudinal webs 7a, 7b are essentially zigzag-shaped and connect the four straight transverse webs 6b, 6b, in such a way that adjacent transverse webs 6a, 6b are arranged offset from one another along their length. The transverse webs 6a, with their ends aligned flush with one another, form an outer edge side defining the outer circumference at a first edge of the concrete block 2 (on the right in Figure 8), and analogously, the transverse webs 6b, with their ends aligned flush with one another, form an opposite outer edge side at an opposite edge of the concrete block 2 (on the left in Figure 8).

[0077] It is understood that both the shape of the longitudinal webs 7a, 7b and the number and arrangement of the transverse and longitudinal webs 6a, 7a are merely exemplary and can of course deviate from the representation in Figures 8 to 10 without thereby departing from the concept of the invention.

[0078] In the example of Figures 8 to 10, the transverse webs 6a, 6b have a web height hQ and the longitudinal webs 7a, 7b have a web height hL, wherein the web height hL is less than the web height hQ. Relative to an upper surface defined by the concrete block top side 2.2, the respective longitudinal web surfaces 7al, 7bl are thus set back vertically downwards relative to the transverse web surfaces 6al, 6bl. As can be seen from Figure 10, the grass walkway slab 5 is also constructed in three layers and comprises the first, second, and third concrete block layers 2a, 2b, 2c. In the exemplary grass slab 5 shown, the downwardly recessed longitudinal slab surfaces 7a1, 7bl are covered or filled with soil and / or sand in the application case, i.e., in the installed state, so that essentially only the transverse slab surfaces 6a1, 6bl are visible from the outside.Greening is therefore possible not only in the area of ​​the drainage openings 8, but also in the entire area between the transverse webs 6a, 6b, that is to say over the entire area located between the transverse webs 6a, 6b, which is why in these special applications it is also possible, for example, to dispense with the first concrete block layer 2a designed as a facing concrete layer in the concrete block body 2 in the area of ​​the longitudinal webs 7a, 7b, as is shown by way of example in Figure 10.

[0079] In the case of concrete blocks 1 designed as grass grid blocks or grass walkway slabs 4, 5, the third concrete block layer 2c designed as a high-strength concrete base layer has a particularly advantageous effect, since the concrete block bodies 2 of these embodiments are fundamentally less stable than solid blocks due to the existing drainage openings 8 formed by respective perforations. However, the stability losses resulting from the perforated structure can be more than compensated for particularly advantageously with the high-strength concrete base layer, resulting in extremely stable, particularly break-resistant grass grid blocks or grass walkway slabs 4, 5. In particular, in these embodiments as grid blocks or web slabs, it is particularly advantageous that the concrete block bodies 2 can be manufactured to a lower height due to the high-strength concrete base layer.

[0080] In combination with the third concrete block layer 2c, i.e., with the high-strength concrete base layer, the present grass grid or grass walkway slabs 4, 5 also allow the porous second concrete block layer 2b to be particularly advantageously adapted in terms of its density and porosity in an ideal, optimal manner for particularly effective and good water conduction and storage capacity, without having to accept the disadvantage of low stability and fracture resistance of the concrete block 1. The grass grid or grass walkway slabs 4, 5 are thus particularly well adapted to their intended use and, in particular, ensure an effective water supply to the greenery or growing plants.The porous second concrete block layer 2b can thus be specially adapted to store water and later, particularly during longer dry periods, gradually release it back to the plants, so that the concrete blocks 1 can also make a significant contribution to supplying the plants with water to survive dry periods. List of reference symbols.

[0081] 1 concrete block

[0082] 2 concrete stone bodies

[0083] 2a first concrete block layer

[0084] 2b second concrete block layer

[0085] 2c third concrete block layer

[0086] 2.1 Concrete block underside

[0087] 2.2 Concrete block top

[0088] 2.3, 2.4 Concrete block sides

[0089] 3 bedding layer

[0090] 4 Grid plate

[0091] 5-web plate

[0092] 6a, 6b crosspieces

[0093] 6a 1, 6bl crossbar surface

[0094] 7a, 7b Longitudinal webs

[0095] 7a 1, 7bl Longitudinal web surface

[0096] 8 Drainage opening

[0097] 9 spacers

[0098] 10 Surface covering

[0099] 11 joints

[0100] 12 Joint material

[0101] 13 fibers d Layer thickness of the third concrete block layer dK Core concrete layer thickness dV Face concrete layer thickness

[0102] H Total height of the concrete block hL Height of the longitudinal webs hQ Height of the transverse webs

[0103] MHA central vertical axis

[0104] LA longitudinal axis

Claims

Patent claims 1. Concrete block (1), in particular in the form of a surface element that can be laid in a bonded manner for the creation of a surface covering, comprising at least one multi-layered concrete block body (2) with at least one concrete block underside (2.1) suitable for laying on a bedding layer (3) of a substrate and a concrete block upperside (2.2) opposite this, wherein the multi-layered concrete block body (2) has at least one on the concrete block upperside (2.2) comprising a first layer of concrete blocks (2a) arranged and designed as a facing concrete layer, and at least one second layer of concrete blocks (2b) designed as a core concrete layer, wherein the multi-layered concrete block body (2) further comprises a third layer of concrete blocks (2c), and wherein the second layer of concrete blocks (2b) designed as a core concrete layer is arranged between the first and the third layer of concrete blocks (2a, 2c), characterized in that the third layer of concrete blocks (2c) is designed as a high-strength concrete base layer with increased tensile strength, wherein the increased tensile strength of the third layer of concrete blocks (2c) is increased compared to a tensile strength of the second layer of concrete blocks (2b), preferably by at least 10%.

2. Concrete block (1) according to claim 1, characterized in that the third layer of concrete block (2c) is made of a dense, high-strength concrete, wherein the high-strength concrete in particular has a cement content of more than 380 kg / m³ 3 exhibits.

3. Concrete block (1) according to claim 1 or 2, characterized in that the third layer of concrete block (2c) has an increased flexural strength and / or an increased splitting strength and the third layer of concrete block (2c) thereby has in particular a predetermined minimum tensile strength.

4. Concrete block (1) according to one of claims 1 to 3, characterized in that the third layer of concrete block (2c) further has an increased compressive strength.

5. Concrete block (1) according to one of the preceding claims, characterized in that the increased tensile strength of the third concrete block layer (2c) is at least 15% higher than the tensile strength of the second concrete block layer (2b) and preferably at least 20% higher than the tensile strength of the second concrete block layer (2b), particularly preferably at least 22%, at least 25% or at least 27% higher than the tensile strength of the second concrete block layer (2b) and particularly preferably at least 30% or at least 35% higher than the tensile strength of the second concrete block layer (2b).

6. Concrete block (1) according to one of the preceding claims, characterized in that the third layer of concrete block (2c) is made of reinforced concrete or concrete reinforced with at least one embedded reinforcing material. Concrete block (1) according to claim 6, characterized in that the third concrete block layer (2c) is made of fiber-reinforced concrete, in particular steel fiber reinforced concrete. Concrete block (1) according to any one of the preceding claims, characterized in that the third concrete block layer (2c) has a layer thickness (d) in the range of 14 mm to 20 mm, preferably in the range of 16 mm to 18 mm. Concrete block (1) according to any one of the preceding claims, characterized in that the second concrete block layer (2b), which is designed as the core concrete layer, is made of open-pore core concrete and in particular forms a porous layer with increased porosity. Concrete block (1) according to claim 9, characterized in that the second concrete block layer (2b) is water-permeable and / or designed to absorb and store water.A concrete block (1) according to one of the preceding claims, characterized in that the second concrete block layer (2b), which is designed as a core concrete layer, has a core concrete layer thickness (dK) wherein the core concrete layer thickness (dK) is greater than the layer thickness (d) of the third concrete block layer (2c). A concrete block (1) according to one of the preceding claims, characterized in that the concrete block body (2) is designed in the form of a grid plate (4) or web plate (5), in particular in the form of a grass grid or grass web plate. Concrete block (1) according to claim 12, characterized in that the concrete block body (2) designed as a grid or web plate (4, 5) comprises at least two transverse webs (6a, 6b) and at least two longitudinal webs (7a, 7b) connecting the transverse webs (6a, 6b), wherein the transverse and longitudinal webs (6a, 6b, 7a, 7b) are arranged and spaced apart from each other such that at least one continuous web extending from the top surface of the concrete block (2.2) a drainage opening (8) extending to the underside of the concrete block (2.1) is formed between the transverse and longitudinal ribs (6a, 6b, 7a, 7b). Concrete block (1) according to claim 12 or 13, characterized in that the concrete block body (2) comprises at least three transverse ribs (6a, 6b) and at least three longitudinal ribs (7a, 7b). Concrete block (1) according to one of claims 12 to 14, characterized in that the longitudinal ribs (7a, 7b) have a longitudinal rib surface (7a1, 7bl) and the transverse ribs (6a, ab) have a transverse rib surface (6al, 6bl), wherein a rib height (hL) of the longitudinal ribs (7a, 7b) is less than a rib height (hQ) of the transverse ribs (6a, 6b), so that the. The longitudinal web surface (7a 1, 7bl) is recessed relative to the transverse web surface (6a 1, 6bl). The surface covering (10) comprises a plurality of multi-layered concrete blocks (1) laid bonded on a bedding layer (3) of a substrate according to one of claims 1 to 15, wherein each concrete block (1) has at least a first, a second and a third concrete block layer (2a, 2b, 2c) and wherein the third concrete block layer (2c) is partially water-permeable, wherein the concrete block layer (2c) is designed as a high-strength concrete base course with increased tensile strength and wherein the increased tensile strength of the third concrete block layer (2c) is increased compared to the tensile strength of the second concrete block layer (2b), preferably by at least 10%.Method for producing a concrete block (1) according to one of claims 1 to 15, in which, after providing a formwork, at least one high-strength concrete is introduced into the formwork in at least one first step to produce a third concrete block layer (2c) designed as a high-strength concrete base layer, in which at least one core concrete is additionally introduced into the formwork in at least one second step to produce a second concrete block layer (2b) designed as a core concrete layer, and in which at least one third step to produce a first concrete block layer (2a) designed as a facing concrete layer, a facing concrete is introduced into the formwork, wherein the introduced concrete material is subsequently compacted and hardened.The method according to claim 17, characterized in that the high-strength concrete and / or the core concrete placed in the formwork are pre-compacted in one or two intermediate steps before the facing concrete is placed. The method according to claim 17 or 18, characterized in that the high-strength concrete is placed in the formwork as a thin layer over a thin area using first concrete distribution means, then the core concrete is poured over the thin layer of high-strength concrete over a thick area using second concrete distribution means, and finally the facing concrete is poured over the core concrete layer as a thin layer over a thin area using third concrete distribution means.

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