EP3889352B1 - Method for producing a concrete block - Google Patents

Description

The invention relates to a method for producing a concrete block according to the preamble of patent claim 1.

Concrete stones, in particular paving stones, steps, bricks and boundary stones made of concrete are well known from the prior art. Such concrete blocks are often used in road, traffic route and landscaping construction for the production of surface coverings, walls, stairs or other structures permanently built into the ground.

In urban areas, for example, large areas of the surface are often designed as traffic areas that can be walked on or driven on, such as streets, paths, squares or parking lots, and are covered with surface coverings formed from concrete blocks of this type, in particular paving stones or slabs. The concrete blocks or paving stones made of concrete are preferably laid in combination on a bedding layer of the subsoil, specifically in such a way that joints are created between adjacent paving stones or shaped stones. The joints are filled with suitable, mostly sand-like joint materials. Such surface coverings in the form of patches are sufficiently known from the prior art.

For all surfaces provided with a surface covering, care must be taken to ensure that the rainwater that hits the surface of the surface covering is drained off as effectively and sufficiently as possible. In the case of the above-mentioned paving stones made of shaped stones, the rainwater that falls on it is usually drained off by seeping away, whereby the rainwater, depending on the nature of the shaped stones, in particular depending on the type of concrete used to produce the shaped stones, only flows via a seepage path through the joints or via a seepage path through the joints and the shaped bricks themselves.

From the DE 10 2012 100 616 B4 For example, a surface covering made of two-layer shaped blocks is already known, which has a water-absorbing, water-permeable layer on the surface underneath an essentially water-impermeable layer. Due to the water-permeable design of the lower layer, the rainwater can flow down both over the joints and at least partially over the water-permeable layer in the direction of the bedding layer and thus almost completely hits the bedding layer, which means that so-called blocking of the joints can be reduced.

From an urban planning point of view, it is also important to note that large-scale traffic areas with surface coverings make a significant contribution to above-average inner-city warming, especially in the summer months. The surface coverings are heated up by the sunlight that hits them during the day, store this heat and give it off again at night as thermal radiation. This phenomenon is known as the "urban heat island effect". This can result in additional warming of several degrees Celsius in urban areas compared to rural areas, especially at night. In order to counteract this urban "heat island effect", it is already known to provide increased water evaporation, since it is known that the evaporation of water causes evaporation cold. It is therefore desirable to achieve an increased evaporation rate via special surface coverings of urban traffic areas.

According to a drainage plan being considered in Germany, the future goal is to preserve the natural water balance in settlement areas in order to limit damage caused by heavy rain. Optimally, between 34% and 92% of the rainwater should therefore evaporate and perspire and the rest seep away into the ground, i.e. be returned to the groundwater.

There is therefore a need for surface coverings that are able to absorb and store water and release the temporarily stored water back into the environment via evaporation when exposed to heat.

Such surface coverings are already from the US2014/0048542 A1 and the JP2006283447A known. The disadvantage of such surface coverings, however, is that they require specific preparation of the substrate, which is associated with significant additional work and thus higher costs.

Also is from the EP 3 153 625 B1 a concrete block and a surface covering made from it are already known. The concrete block also has a multi-layer structure and is designed to be placed on a bedding layer of a substrate and to be laid in the composite. Here, the molded block comprises at least one water-impermeable, first layer arranged along the upper side of the molded block and at least one immediately adjoining water-permeable, second layer and at least one third layer adjoining the second layer. The third layer is designed as a water-impermeable layer and is arranged on the underside of the concrete block intended to rest on the bedding layer, and the second layer arranged between the first and third layers is designed to absorb and store water. The impermeability of the third layer means that in the second layer Waterlogging forms and the second layer can become oversaturated. The disadvantage of this is that the onset of the evaporation effect is delayed or only occurs to a limited extent if the concrete block is heated too little. A further disadvantage is that the evaporation properties of such a concrete block are therefore limited due to the water-impermeable third layer. The formation of waterlogging during a freeze/thaw cycle can also lead to damage to the concrete block, which is particularly disadvantageous.

Proceeding from this, it is the object of the invention to specify a method for producing a concrete block, in particular a concrete paving block, that eliminates the disadvantages of the prior art and which enables the production of a concrete block that also absorbs moisture from the bedding material underneath the concrete block is trained. The object is achieved by a method for producing a concrete block according to patent claim 1.

Concrete stones within the meaning of the invention can in particular be paving stones and slabs made of concrete, which can be laid in combination on a bedding layer.

In the method according to the invention for the production of a concrete block, comprising at least one multi-layered concrete block body with at least one level concrete block underside and an essentially flat concrete block upper side lying opposite it, the concrete block body having at least one first concrete layer of facing concrete forming the concrete block upper side, at least one adjoining the first concrete block layer, water-permeable second layer of concrete blocks made of no-fines core concrete and a third layer of concrete blocks directly adjoining the second layer of concrete blocks, the third layer of concrete blocks forming the underside of the concrete blocks, which is intended to be placed on a bedding layer of a substrate, and the second layer of concrete blocks arranged between the first and third layers of concrete blocks for absorbing and storing water, after providing a formwork, the first step is to manufacture In order to fill the third concrete block layer with a lower water permeability compared to the second concrete block layer, fine gravel and/or sand-rich concrete is introduced into the formwork, then in a second step for the production of the water-permeable second concrete block layer the no-fines core concrete is additionally introduced into the formwork and in a third step In the first step, the facing concrete is introduced into the formwork to produce the first layer of concrete blocks, with the concrete material being introduced then being compacted. The production of a water-permeable layer with a lower water permeability is understood in the sense of the invention as a concrete block layer in which water can penetrate through this layer, but with a time delay and/or compared to one water-permeable concrete block layer with normal or higher water permeability with a reduced or reduced speed. This layer is also not designed to absorb and store water. This particularly advantageously avoids waterlogging in the second concrete block layer, ie the amount of water absorbed by the second water-permeable concrete block layer can be adjusted or better regulated in such a way that improved evaporation properties of the concrete block or concrete paving block arise. This also effectively prevents damage to the concrete block in the event of waterlogging and a freeze/thaw cycle. Due to the water-permeable design of the third concrete block layer, there is the further advantage that moisture in the bedding material below the concrete block can be sucked into the concrete block via the third layer due to the capillary effect. This further increases the amount of evaporation from the concrete block into the atmosphere.

After the concrete material has been compacted, the formwork or mold is removed and the compacted concrete material is then preferably cured in a drying chamber, the compacted concrete material already having the shape and dimensions of the concrete block or concrete paving stone after the formwork has been removed.

The production according to the invention of the second layer of concrete blocks from an aggregate core concrete enables optimal absorption and storage of water in the concrete blocks.

In a preferred embodiment variant, the fine concrete rich in chippings and/or sand and the no-fines core concrete introduced into the formwork are pre-compacted in an intermediate step before the facing concrete is introduced.

It is also advantageous to place the fine chippings and/or sand-rich concrete thinly in the formwork with a first concrete distributor and then the no-fines core concrete with a second concrete distributor over it over a thick surface, and to precompact the two concrete layers that have been introduced in the formwork using a stamp and/or vibrating vibration.

Depending on the desired water permeability, coarse-grain crushed stone material can also be added to the fine gravel and/or sand-rich concrete. By using a fine grit and/or sand-rich concrete material with possibly a coarser-grained grit portion for the production of the third concrete block layer, a low level of water permeability is achieved, with the degree of this being determined by the respective mixture can be adjusted at least in part by the proportion of sand and/or chippings added and/or the grain size used in each case. Advantageously, small pores and/or cavities, which produce a capillary effect, are formed in the concrete material mentioned and a correspondingly selected binder content in the third layer of concrete blocks. Because of this capillary effect, moisture that is still present in the bedding layer can be supplied to the second concrete block layer, for example via the third concrete block layer, as a result of which the evaporation properties of the concrete block can be improved even further.

In a further development of the invention, the first layer of concrete blocks is produced from partially water-permeable or water-impermeable facing concrete. By producing a water-permeable facing concrete layer, precipitation water can also be fed via the first concrete block layer to the second, water-storing concrete block layer or escape again in the event of evaporation. The water-impermeable design of the facing concrete layer enables the targeted supply of rainwater via the joints or the joint material located therein, so that effective filtering of the rainwater via this infiltration path is particularly advantageous.

The third concrete block layer can also advantageously be produced with a layer thickness of between 3% and 15% of the total height of the concrete block body, preferably between 3% and 8% of the total height of the concrete block body. In particular, the third layer of concrete blocks can be produced with a layer thickness between 3 mm and 10 mm, preferably between 3 mm and 8 mm.

In a preferred embodiment variant, the second concrete block layer is produced with a layer thickness between 60% and 90% of the total height of the concrete block body, preferably between 70% and 85% of the total height of the concrete block body. The second concrete block layer thus forms a large part of the concrete block body, so that a large amount of water can be stored in it and released again.

The concrete block is advantageously produced in one piece or in one piece, i.e. all three concrete block layers are produced in one production process in the form of a complete block.

In a development of the invention, the third layer of concrete blocks is produced with a water permeability which is reduced by at least 30%, preferably by 50%, compared to the water permeability of the second layer of concrete blocks. This ensures sufficient saturation of the second layer of concrete blocks with rainwater guaranteed, but effectively prevents oversaturation. This significantly improves the evaporation properties of the concrete block.

In one embodiment of the invention, a photocatalyst such as titanium dioxide is incorporated into the first concrete block layer. The surface of the concrete block is thus designed for photocatalytic air purification. Irradiation with light, preferably sunlight, can particularly advantageously oxidize harmful gases present in the ambient air, such as nitrogen oxides or volatile organic substances, and thus remove them from the air.

In the context of the invention, the expressions “approximately”, “substantially” or “roughly” mean deviations from the exact value in each case by +/-10%, preferably by +/-5% and/or deviations in the form of changes that are insignificant for the function . Further developments, advantages and possible applications of the invention also result from the following description of exemplary embodiments and from the figures. The content of the claims is also made part of the description.

Fig. 1

eine perspektivische, Ansicht eines gemäß dem erfindungsgemäßen Verfahren hergestellten Betonsteins,

Fig. 2

einen schematischen Schnitt durch den Betonstein gemäß Figur 1,

Fig. 3

einen schematischen Schnitt durch einen Flächenbelagabschnitt hergestellt unter Verwendung der Betonsteine gemäß der Figuren 1 und 2,

Fig. 4

einen schematischen und vergrößert dargestellten Schnitt durch den Flächenbelagabschnitt gemäß Figur 3 zur Erläuterung des Versickerungswegs und

Fig. 5

einen schematischen und vergrößert dargestellten Schnitt analog zu Figur 4 mit eingezeichnetem Verdunstungsweg.

The invention is explained in more detail below with reference to the figures of exemplary embodiments. Show it:

1

a perspective view of a concrete block produced according to the method according to the invention,

2

according to a schematic section through the concrete block figure 1 ,

3

a schematic section through a surface covering section made using the concrete blocks according to figures 1 and 2 ,

4

a schematic and enlarged section through the surface covering section according to FIG figure 3 to explain the infiltration path and

figure 5

a schematic and enlarged section analogous to figure 4 with a marked evaporation path.

Identical reference symbols are used in the figures for elements of the invention that are the same or have the same effect. Furthermore, for the sake of clarity, only reference numbers that are required for the description of the respective figure are shown in the individual figures.

In figure 1 is an example of a perspective view of a concrete block 1 produced according to the method according to the invention and FIG figure 2 a schematic section along a sectional plane running parallel to the central longitudinal axis MLA and the longitudinal axis LA of the concrete block 1 is shown.

The concrete block 1 is preferably designed in the form of a surface element that can be laid in combination to create a surface covering. In the present case, concrete block or concrete slab are understood to be essentially structurally identical elements that can be used in a manner known per se to create a surface covering. Depending on the selected laying pattern, these are interlocked with one another and laid flush with one another, so that a preferably level surface covering 10 is produced.

A concrete block 1 produced according to the method according to the invention comprises at least one multi-layered concrete block body 2 with at least one level concrete block underside 2.1 and an essentially flat concrete block upper side 2.2 opposite this, which preferably forms the tread surface or trafficable surface or traffic surface. 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 chosen almost arbitrarily without departing from the idea of the invention.

In the present exemplary embodiment, the concrete block 1 is cuboid and has two concrete block sides 2.3, 2.4 that are opposite one another and have the same surface area. The underside of the concrete block 2.1 and the upper side of the concrete block 2.2 run perpendicular or approximately perpendicular to the central longitudinal axis MLA of the concrete block body 2 or concrete block 1, with the concrete block sides 2.4 being oriented perpendicularly and the concrete block sides 2.3 parallel to the longitudinal axis LA of the concrete block body 2 or concrete block 1.

The multi-layer concrete block body 2 comprises at least one first concrete block layer 2a forming the concrete block upper side 2.2, at least one water-permeable second concrete block layer 2b adjoining the first concrete block layer 2a and a third concrete block layer 2c immediately adjoining the second concrete block layer 2b, with the third concrete block layer 2c forming the concrete block underside 2.1 forms, which is intended to rest on a bedding layer 3 of a substrate, and wherein between the first and third concrete block layer 2a, 2c arranged second concrete block layer 2b is designed for receiving and storing water.

The third concrete block layer 2c is made water-permeable according to the invention, with the third concrete block layer 2c having a lower water permeability in comparison to the second concrete block layer 2 . A water-permeable layer with low water permeability is understood in the present context to mean a concrete block layer through which water can be transported or passed, but with a time delay and/or with a reduced flow rate compared to the second, water-permeable concrete block layer 2b.

The method according to the invention for producing or manufacturing the concrete block 1 with improved evaporation properties can be carried out by means of industrial production methods in which concrete blocks are produced in a process-controlled manner, preferably in layers, i.e. several concrete blocks at the same time in one layer.

As part of the production method according to the invention, a concrete formwork known per se is first provided for the production of concrete blocks 1, in particular in the form of paving blocks or slabs.

After the formwork or mold has been prepared, in a first step to produce the at least partially water-permeable third concrete block layer 2c, fine gravel and/or sand-rich concrete is introduced into the formwork or mold and, in a second step, to produce the water-permeable second concrete block layer 2b, additional no-fines Core concrete introduced into the formwork or form. Finally, in a third step for producing the first concrete block layer 2a, facing concrete is introduced into the formwork or mold, with the concrete material introduced being subsequently compacted. After compacting, the formwork or mold is removed, with the compacted concrete block 1 remaining on a support and holding plate. The hardening of the compacted concrete block 1 preferably takes place in a drying chamber. Preferably, the fine chippings and/or sand-rich concrete and the no-fines core concrete introduced into the formwork are pre-compacted in an intermediate step before the facing concrete is introduced. In particular, the fine grit and/or sand-rich concrete can be introduced into the formwork over a thin surface using a first concrete spreader and then the no-fines core concrete can be thickly introduced into the formwork using a second concrete spreader, and the concrete layers introduced using a stamp and/or shaking vibration of the support and holding plate in the formwork or mold are pre-compacted. Lowering the stamp onto the formwork or form introduced concrete material and the subsequent exposure to a vibrating impact on the part of the support and holding plate is also referred to as "intermediate sinking". Subsequently, the ram is raised again and the facing concrete is introduced into the formwork or form and then the ram is lowered again in order to compact the concrete material in the formwork or form again. Here, too, there is preferably a renewed vibration shock, which is transmitted to the concrete material via the support and holding plate. This work process is also referred to as "final compaction".

The third concrete block layer 2c is preferably made from a fine concrete material rich in chippings and/or sand, which has at least moderate water permeability. If necessary, a coarse-grained grit portion can be added.

The concrete block 1 or the concrete block body 2 is produced with an overall height H, which preferably corresponds to the sum of the layer thicknesses Da, Db, Dc of the first to third concrete block layers 2a, 2b, 2c. In the present exemplary embodiment, the first concrete block layer 2a has a first layer thickness Da, the second concrete block layer 2b has a second layer thickness Db and the third concrete block layer 2c has a third layer thickness Dc.

According to the invention, the third layer thickness Dc of the third concrete block layer 2c is between 3 mm and 15 mm, preferably between 3 mm and 8 mm. Based on the total layer thickness H of the concrete block, the third layer thickness Dc is between 3% and 15% of the total height H of the concrete block body 2, preferably between 3% and 10% of the total height H of the concrete block body 2.

For optimal absorption and storage of water, the second layer thickness Db of the second concrete block layer 2b is between 60% and 90% of the total height H of the concrete block body 2, preferably between 70% and 85% of the total height H of the concrete block body 2.

The second layer thickness Db of the second concrete block layer 2b is, for example, in the present exemplary embodiment approximately 80% of the total height H of the shaped block 1. Starting from a total height H of 10 cm, for example, the first layer thickness Da is 1.5 cm, for example, and the second layer thickness Db is 8, for example cm and the third layer thickness Dc is, for example, 0.5 cm.

The first, the concrete block top 2.2 forming concrete block layer 2a is made of a water-permeable or water-impermeable facing concrete, as water-impermeable facing concrete, a structurally dense, impermeable concrete material is used. The first concrete block layer 2a is preferably directly followed by the second concrete block layer 2b, which is made of no-fines core concrete with a large proportion of fine and micropores. This no-fines concrete layer 2b supports the absorption and storage of water and thus enables water to penetrate through the concrete block sides 2.3, 2.4 into the second concrete block layer 2b. Under thermal conditions that promote evaporation of water, the water temporarily stored in the second layer of concrete block 2b can be released to the outside again, in vapor form again via the concrete block sides 2.3, 2.4 and/or, if the first layer of concrete block 2a is permeable to water, via these escape from the concrete block 1 or be released into the environment.

In the illustrated embodiment, the concrete block 1 has so-called spacers or spacer noses 4, which ensure uniform joints 5 of approximately equal width when the concrete block 1 is laid in the composite and ensure a minimum width of the joints 5.

In the figure 3 a section through a surface covering 10 formed by means of concrete blocks 1 designed according to the invention is shown as an example. The surface covering 10 comprises a multiplicity of multi-layered concrete blocks 1 laid on a bedding layer 3 of a subsoil. The concrete blocks 1 used to produce the surface covering 10 are designed in three layers according to the invention and each have a first, a second and a third concrete block layer 2a, 2b, 2c up. Joints 5 are formed between adjacent concrete blocks 1 of the surface covering 10 , which are filled with a joint material 6 and form a seepage 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. After the concrete blocks 1 have been laid in the composite, the joint material 6 is swept dry into the joints 5 . Following this, the surface covering 10 is shaken off and, if necessary, grouted again, ie additional joint material 6 is filled into joints 6 that are not yet completely filled. This process can be repeated again after a certain time.

The joint material 7 of the present exemplary embodiment consists, for example, of a mixture of a proportion of sand, a proportion of fines and an artificial molecular sieve, and thus forms a filter layer for removing pollutants from the rainwater. Alternatively, however, conventional joint material can also be used if no pollutant filtering is desired.

To illustrate the water cycle taking place on the surface covering 10 is in the figures 4 and 5 a section of the surface covering 10 is shown in a sectional view, with figure 4 the seepage and absorption route for rainwater and in figure 5 the evaporation path for precipitation water temporarily stored in the concrete block 1 and there in particular in the second concrete block layer 2b is indicated.

Precipitation water impinges on the surface of the surface covering 10 on the first concrete block layer 2a of the concrete blocks 1 and preferably seeps through the joints 5 into the joint material 6, with the rainwater also being conducted away from the first concrete block layer 2a if it is at least partially water-permeable. Irrespective of this, at least part of the precipitation water that is moving in the direction of the bedding layer 4 and seeps away from the joint material 6 gets into the second concrete block layer 2b, which preferably absorbs the water like a sponge. Preferably, the supply takes place via the concrete stone sides 2.3, 2.4 bordering on the joint material 7. The seepage and transport route of the rainwater is shown in figure 4 indicated by black arrows. Due to the at least partially water-permeable design of the third concrete block layer 2c according to the invention, part of the precipitation water absorbed in the second concrete block layer 2b can also be discharged into the bedding layer 3 or the subsoil, so that optimal water flow is achieved. In particular, this avoids oversaturation of the second concrete block layer 2b with rainwater, which would impair the evaporation properties.

The rainwater temporarily stored in the second concrete block layer 2b of the concrete blocks 1 can therefore evaporate significantly better than in the case of concrete blocks 3 known from the prior art, which have a water-impermeable provide a third layer of concrete blocks. The evaporating water reaches the surface in the form of water vapor from the second concrete block layer 2b of the concrete block 1 either via the joint material 6 and/or the water-permeable first concrete block layer 2a, where it is released into the air above. A possible evaporation path of the water is in figure 5 indicated by double arrows.

On the one hand, evaporation can counteract an urban heat island effect due to the resulting evaporation cooling, and on the other hand, the natural water cycle can be supported and thus the urban water balance can be improved. The sheet material 10 is particularly suitable for an effective contribution to a to provide environmentally friendly drainage planning, in particular to achieve an evapotranspiration of between 34% and 92% of the rainwater.

Due to the capillary effect generated in the third concrete block layer 2c, moisture can be supplied from the bedding layer 3 or the subsoil into the second concrete block layer 2b, thereby additionally improving the evaporation properties of the concrete block 1, in particular increasing the evaporation rate.

The first concrete block layer 2a forming the top side 2.2 of the concrete block can be produced in one embodiment from a concrete material with incorporated photocatalysts such as, for example, titanium dioxide. For this purpose, nanoparticles of titanium dioxide (TiO2), preferably in powder form or in liquid form, are added to the concrete material provided for the production of the first concrete block layer 2a. The first concrete block layer 2a with incorporated photocatalysts serves as a photocatalyst, via which photocatalytic air purification takes place under solar radiation.

The invention has been described above using exemplary embodiments. It goes without saying that numerous changes and modifications are possible without departing from the inventive idea on which the invention in the patent claims is based.

reference list

1

concrete block

2

concrete block body

2a

first concrete block layer

2 B

second concrete block layer

2c

third concrete block layer

2.1

concrete block bottom

2.2

concrete block top

2.3

concrete block side

2.4

concrete block side

3

bedding layer

4

spacers

5

Put

6

joint material

10

surface covering

There

Layer thickness of the first concrete block layer

db

Layer thickness of the second concrete block layer

dc

Layer thickness of the third concrete block layer

H

Total height of the concrete block

MLA

central longitudinal axis

L.A

longitudinal axis

Claims (12)

1. A method for producing a concrete block (1) comprising at least one multi-layered concrete block body (2) having at least one even concrete block underside (2.1) and a substantially flat concrete block top side (2.2) opposite said underside, wherein the concrete block body (2) comprises at least one first concrete block layer (2a) which is made of face concrete and forms the concrete block top side (2.2), at least one water-permeable second concrete block layer (2b) which is made of no-fines core concrete and adjoins the first concrete block layer (2a), and a third concrete block layer (2c) which directly adjoins the second concrete block layer (2b), wherein the third concrete block layer (2c) forms the concrete block underside (2.1) which is provided for resting on a bed layer (3) of a subsoil, and wherein the second concrete block layer (2b) arranged between the first and third concrete block layers (2a, 2c) is designed to receive and store water, characterised in that after a formwork is provided, in a first step fine high-grit and/or high-sand concrete is introduced into the formwork to produce the third concrete block layer (2c) with a lower water permeability as compared to the second concrete block layer (2b), wherein the no-fines core concrete is additionally introduced into the formwork in a second step to produce the water-permeable second concrete block layer (2b), and wherein the face concrete is introduced into the formwork in a third step to produce the first concrete block layer (2a), wherein the introduced concrete material is then compacted.
2. The method according to claim 1, characterised in that the fine and/or high-sand concrete introduced into the formwork and the no-fines core concrete are precompacted in an intermediate step before introduction of the face concrete.
3. The method according to claim 1 or 2, characterised in that the fine and/or high-sand concrete is introduced into the formwork in a thinly spread manner using first concrete-spreading means and then the no-fines core concrete is introduced into the formwork thereabove in a thickly spread manner using second concrete-spreading means, and the introduced concrete layers are precompacted in the formwork by means of a ram and/or shaking vibration.
4. The method according to any one of the preceding claims, characterised in that the first concrete block layer (2a) is produced from partially water-permeable or water-impermeable face concrete.
5. The method according to any one of the preceding claims, characterised in that the third concrete block layer (2c) is produced with a layer thickness (Dc) between 3% and 15% of the total height (H) of the concrete block body (2), preferably between 3% and 10% of the total height (H) of the concrete block body (2).
6. The method according to any one of the preceding claims, characterised in that the third concrete block layer (2c) is produced with a layer thickness (Dc) between 3 mm and 10 mm, preferably between 3 mm and 8 mm.
7. The method according to any one of the preceding claims, characterised in that the second concrete block layer (2c) is produced with a layer thickness (Db) between 60% and 90% of the total height (H) of the concrete block body (2), preferably between 70% and 85% of the total height (H) of the concrete block body (2).
8. The method according to any one of the preceding claims, characterised in that the concrete block is produced in one piece or part.
9. The method according to any one of the preceding claims, characterised in that the third concrete block layer (2c) is produced with a water permeability which is reduced by at least 30%, preferably by 50%, in comparison with the water permeability of the second concrete block layer (2b).
10. The method according to any one of the preceding claims, characterised in that a photocatalyst such as titanium dioxide is incorporated into the first concrete block layer (2a).
11. The method according to any one of the preceding claims, characterised in that the formwork is removed after the introduced concrete material has been compacted.
12. The method according to claim 11, characterised in that the compacted concrete material is preferably set in a drying chamber after the formwork has been removed.

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