EP3153625B1 - Concrete paving stone - Google Patents

Description

Technical area

The invention relates to a shaped block for use in a surface covering according to the preamble of claim 1 and to an associated surface covering according to claim 10.

State of the art

Particularly in urban areas, large areas of the surface are designed as walkable or trafficable traffic areas such as roads, paths, squares or parking spaces and covered with surface coverings. The surface coverings are often made by paving, with paving stones or corresponding concrete blocks are laid on a bedding layer of the substrate in the composite. As a rule, joints remain between adjacent paving blocks or shaped blocks which are filled with suitable, usually sand-like jointing materials. Such, in the form of patches trained surface coverings are well known from the prior art.

In the case of all surfaces provided with a surface covering care must be taken that the precipitation water striking the surface of the surface covering is removed as effectively and adequately as possible. In the above pebbles made of molded bricks, the discharge of the incident rainwater is usually by seeping, the rain water depending on the nature of the stones, especially depending on the type of concrete used for the production of the blocks, only via a seeping path through the joints or over a seepage path through the joints and the stones themselves can seep.

For example, the DE 10 2012 100 616 B4 or DE 195 01 091 A1 a surface covering of two-layered molded blocks, which have a water-absorbing, water-permeable layer below a substantially water-impermeable layer on the surface. The precipitation water can flow down in the disclosed surface covering both over the joints and on the water-permeable layer of the stones in the direction of the bedding layer and thus strikes approximately flat on the bedding layer, whereby a so-called blocking of the joints can be reduced.

Another aspect to consider from an urban planning perspective with regard to large-scale traffic areas provided with surface coverings is that these traffic areas contribute significantly to an above-average inner-city warming, especially in the summer months, since the sun's rays during the day heat the surface coverages and This heat is stored by the surface coverings and released at night as heat radiation. This phenomenon is known as the so-called "urban heat island effect" and can lead to additional warming of several degrees Celsius in urban areas compared to rural areas, especially at night when the stored heat is released from the surface coverings. This disadvantageously often results in increased energy consumption through the operation of air conditioning systems.

It is known that this urban "heat island effect" can be counteracted, for example, with an increased evaporation of water, since the evaporation of water creates evaporative cooling. The aim of some measures to improve the urban climate is therefore to achieve an increased evaporation rate via special surface coverings of urban traffic areas.

An increased evaporation of rainwater is also to be striven for under the aspect of an improved urban water balance. In Germany, for example, there is a drainage plan whose main goal in the future will be to preserve the natural water balance in settlement areas in order to limit damage caused by heavy rainfall. Between 34% and 92% of the rainwater should thus, it evaporates and transpires, the rest should be seeped towards groundwater.

Against the background of the above-mentioned aspects of an increased evaporation rate, for example, surface coverings have been developed which are able to absorb and store water and to re-evaporate the cached water when exposed to heat, whereby the water emerges from the surface coverings as evaporative cooling.

Such a water-storing surface coating is used for example in the US2014 / 0048542 A1 described, wherein the surface covering consists of three layers, namely an impermeable layer, a water-absorbing layer and a cover layer. To produce this surface covering, a depression is excavated in a subsoil and the impermeable layer is applied to the soil, the impermeable layer consisting, for example, of aggregated hydrophobic particles or of a treated, water-repellent sand. Subsequently, the water-receiving layer is applied to the impermeable layer by, for example, stacking a sand on the impermeable layer. Finally, on the water-absorbing layer, an existing example of form bricks cover layer is applied by laying the bricks.

Another surface covering is from the JP2006283447 A in which, according to a similar principle as described above, an impermeable layer is introduced into the substrate. Above the impermeable layer, an aggregate layer is arranged as a water-storing layer, on which in turn a water-absorbing material is deposited. Finally, this layer of water-absorbent material serves as a support for water-permeable molded blocks and water-storing shaped blocks, which are laid together in a mixed arrangement. Precipitation water passes predominantly through the water-permeable shaped stones into the aggregate layer and is deposited again when the surface covering heats up from there via the water-storing shaped blocks by evaporation.

The disadvantage of the known from the prior art surface coverings, which are able to absorb and store water, the substrate must be prepared very specific and it must be created on site successive layers on site in the underground. Compared with the production of conventional surface coverings, this entails a considerable additional expenditure and thus higher costs, so that despite the solutions known from the prior art, there is a further need for easily produced surface coverings which can absorb water and thereby permit an increased evaporation of water.

Presentation of the invention

Object of the present invention is therefore to provide a molded block for use in a surface covering available, which overcomes the disadvantages of the prior art, which in particular is simple and inexpensive to produce and with the establishment of a water-absorbing surface covering easily and without specific on-site measures feasible is. This object is achieved by a shaped block according to the independent claim 1 and by a surface covering according to the independent claim 10. Further advantageous aspects, details and embodiments of the invention will become apparent from the dependent claims, the description and the drawings.

The present invention provides a concrete shaped block for use in a paving surface covering which has at least one underside provided for resting on a bedding layer of a substrate and an upper surface opposite the underside. The molded block has a multilayer structure and has at least one water-impermeable, first layer arranged along the upper side and at least one water-permeable, second layer. The molded block is characterized in particular by the presence of at least one third layer, wherein the third layer is formed as a water-impermeable layer and disposed on the intended for resting on the bedding layer of the substrate underside of the molded block. The second layer is arranged between the first layer and the third layer and formed for receiving and storing water.

Under a concrete block is understood in the present case that it is a molded block, which is produced by compression molding in a mold and whose main component is a cement-bonded material, in particular concrete. In addition to concrete as the main component, a concrete block as understood in the present understanding, other materials or materials as minor constituents, which are introduced or applied during manufacture in the form of additions or aggregates before or during compression molding or in the form of applications or coatings after molding can.

Very particular advantages result from the molded block according to the invention that the multi-layer structured and at least three layers comprising stone as such is able to absorb water and temporarily store and that by the water-permeable, water-absorbing second layer between two impermeable layers is arranged , An incident on the top in the use state of the shaped stone water, such as rain water, is substantially derived at the impermeable first layer and drains over the peripheral sides of the block. On the peripheral sides, it can penetrate into the water-absorbing, second layer, which represents a middle layer. Since the water, due to the impermeable third layer, can not flow off and exit unhindered from the second, middle layer, the absorbed water is temporarily stored in the second layer.

Under heating of the molded block, in the installed state, for example due to solar radiation, there is an evaporation of the stored water, the evaporating water is released in the form of water vapor again. The evaporation cold occurring during the evaporation acts cooling on the surface of the molded block, which can therefore be understood as Klimastein. In the use state of the molded block, namely, when a plurality of shaped bricks are laid in a surface covering, the molded block according to the invention can produce a cooling effect in heat and regulating influence on the Ambient temperature and thus take on the microclimate in the area of traffic areas. Particularly advantageous can be counteracted by an urban heat island effect.

The inventive integrally formed molded block has as such particularly advantageous all necessary for water absorption and storage characteristics. In particular, the underside impermeable or sealing layer is already provided on the suitable stone for paving itself and is therefore provided with the molded block, so that there are very particular advantages that when making a surface covering from a variety of the present shaped blocks no special and elaborate precautions or preparations on the ground must be created. The provision of water-impermeable layers or water barriers in the background is eliminated, but is sufficient for a common and commonly used for paving bedding layer.

In the present case, a water-impermeable layer of the molded block is understood as meaning a layer in which impinging water is not absorbed and transported by the layer due to the specific properties and properties of this layer, but is at least largely rejected or diverted. However, a layer of the molded block, which is not completely "waterproof", but greatly slows down or substantially reduces or substantially prevents uptake of water and transportation of water through that layer, thus becomes, according to the present understanding understood as a water-impermeable layer.

The water-impermeable, first layer preferably consists of a layer-dense facing concrete forming the upper side of the shaped block, which thus also forms the surface of the shaped block. This surface is preferably wear-resistant, abrasion, frost, and oil resistant. By way of the facing concrete layer, it is also possible with particular advantage to take formative influence on the shaped block, whereby different colored and / or structural configurations of the shaped block are possible.

The water-permeable, second layer preferably consists of a core porous concrete core, wherein the core concrete is preferably adapted to an optimized water absorption or water retention and water storage. For example, a core concrete is used, in which predominantly fine pores and micropores are formed, which retain the water in the manner of a capillary against gravity. At the same time, as few macropores as possible are formed in the core concrete which is preferably used, which would promote a rapid seepage of the water downwards.

The water-impermeable third layer is preferably made of a sealing material, the sealing material being, for example, a cementitious material or a synthetic resin such as e.g. Epoxy resin or polyurethane can be. In the present case, a layer of sealing material is understood to mean that most of the pores of the core concrete arranged above are closed with this layer and thus sealing in the broadest sense takes place. However, a complete seal or impermeability to water is not absolutely necessary, in particular not so long as it is ensured that the water-impermeable, third layer directed at a built-in surface condition of the stone form a directed over the bottom transport of water from the second layer of the molded block in the To reduce or prevent bedding layer is able. The water-impermeable, third layer can be applied, for example, during or after the compression molding, wherein the material of the third layer penetrates into and closes the pores of the material of the second layer at an interface between the layers.

For optimized, effective water absorption and storage, the water-permeable, second layer has a layer thickness distributed between 70% and 90% of a total height of the molded block. The layer thickness of the second layer is preferably between 75% and 85% and particularly preferably around 80% of the total height of the molded block. For example, with a total height of the shaped stone of around 8 cm, which is generally used for surface coverings of traffic areas, the second layer occupies 6.5 cm, making up about 81% of the overall height of the molded block.

The molded block is formed for example as a straight prism with a polygonal base and has at least three adjoining peripheral sides. Particularly preferably, the shaped brick is cuboid and comprises four peripheral sides. The peripheral sides are permeable to water and water vapor, at least in the region of the second layer of the molded block, so that the uptake of water or the entry of water into the second layer can take place over the peripheral sides or over the surfaces of the peripheral sides. Likewise, evaporating water can escape from the second layer again via the peripheral sides. In order to additionally improve the precipitation or evaporation of evaporating water, according to a particularly preferred embodiment of the present invention, openings for the exit of water vapor are optionally provided in the water-impermeable, first layer.

In alternative embodiments, the shaped brick may comprise at least one further layer arranged between the first and the third layer, it being possible for the at least one further layer to be a water-permeable or a water-impermeable layer. By way of example, a further water-permeable layer, which is formed from a core concrete of a different nature, can subsequently be arranged on the water-permeable, second layer. Furthermore, it is conceivable that an additional further layer in the form of a water-impermeable coating is applied to the first and / or the third layer.

The invention also provides a surface covering comprising a multiplicity of multilayer shaped blocks according to the invention laid on a bedding layer of a substrate by paving in composite fashion. Each of the molded blocks used for the surface covering has at least one water-impermeable first layer, a water-permeable second layer and a water-impermeable third layer. Grooves are formed between adjacent shaped bricks of the surface covering, wherein the joints are filled with a substantially splitt- and / or sand-like joint material and form a percolation path for discharging precipitation water from a surface of the surface covering.

From the surface covering according to the invention results in analogous advantages, as already explained above in connection with the molded block. On the surface covering incident water, such as rain water is derived at the surface of the surface covering by means of the impermeable, first layers of the stones and infiltrated in the filled with grout joints between the stones. The water from the adjoining joint material penetrates into the shaped blocks via the peripheral sides of the molded blocks and is temporarily stored there. The cached water is then returned to the atmosphere at a later time by evaporation. Due to the evapotranspiration resulting in evaporation can be counteracted on the one hand particularly distributed an urban heat island effect.

On the other hand, evaporation and the concomitant return of rainwater to the atmosphere can also support the natural water cycle and thus improve the urban water balance. In particular, the present surface covering can effectively contribute to achieving a central goal of future drainage planning in Germany, according to which the local natural water balance in the settlement area must be preserved in order to limit the increasing damage caused by heavy rainfall. According to the drainage plan, between 34% and 92% of rainwater must evapotranspire, ie evaporate and transpire. The rest should preferably be seeped towards groundwater and the surface runoff be limited. In contrast to many systems for rainwater management, by means of which, in particular, the infiltration is increased, the present surface covering distributes the required evapotranspiration and thus contributes to achieving the desired evaporation values.

Distributively, the respective circumferential sides of the plurality of molded bricks form an inlet path for the precipitation water, which seeps into the joints filled with grout, into the water-permeable second layer of the bricks. Likewise, the peripheral sides of the plurality of molded bricks simultaneously form an outlet path for evaporating water from the water-permeable, second layer of the molded bricks into the joints filled with grout.

Particularly advantageously, the surface covering has a predetermined water absorption capacity and is set up for receiving and temporarily storing a predetermined amount of precipitation water per unit area of the surface covering. The water absorption capacity is at least so great that a noticeable cooling effect can be achieved by evaporating water. A water absorption capacity given as the amount of water per unit area is essentially dependent on the volume fraction of the water-absorbent, second layer of the molded blocks present per unit area of the surface covering and can therefore also be understood as the water volume per unit volume of the second layer. The water absorption capacity of the surface covering thus depends primarily on the dimensioning and nature of the second layer of the molded blocks. For example, the second layer of the bricks in a water-saturated state per unit volume can store so much water that the volume of water is between 10% and 30%, preferably between 15% and 25% and particularly preferably around 20%.

The joint material preferably consists of a mixture of a grit and / or sand-like portion, a fine fraction and an artificial molecular sieve and forms a filter layer for removing pollutants from the precipitation water outflows.

Brief description of the drawings

Fig. 1a

schematisch dargestellt eine perspektivische Ansicht einer Ausführungsform eines Formsteins gemäß der vorliegenden Erfindung;

Fig. 1b

schematisch dargestellt einen vertikalen Schnitt durch eine weitere Ausführungsform des Formsteins gemäß der vorliegenden Erfindung;

Fig. 2

ausschnittsweise schematisch dargestellt einen vertikalen Schnitt durch eine Ausführungsform eines Flächenbelages gemäß der vorliegenden Erfindung;

Fig. 3a

ausschnittsweise einen vertikalen Schnitt einer Ausführungsform eines Flächenbelages mit angedeutetem Versickerungs- und Aufnahmeweg für Niederschlagswasser und

Fig. 3b

den Ausschnitt der Figur 3a mit angedeutetem Verdunstungsweg für zwischengespeichertes Niederschlagswasser.

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it

Fig. 1a

schematically shows a perspective view of an embodiment of a molded block according to the present invention;

Fig. 1b

schematically shows a vertical section through another embodiment of the molded block according to the present invention;

Fig. 2

1 schematically, a vertical section through an embodiment of a surface covering according to the present invention;

Fig. 3a

a section of a vertical section of an embodiment of a surface covering with indicated infiltration and absorption path for rainwater and

Fig. 3b

the clipping of the FIG. 3a with indicated evaporation path for cached precipitation water.

Ways to carry out the invention

In the FIGS. 1a and 1b In each case, an embodiment of a molded block 1 according to the invention for use in a producible by paving surface covering is shown schematically, wherein the FIG. 1a a perspective view of the molded block 1 and the FIG. 1b a vertical section through the molded block 1 shows. The molded block 1 is substantially cuboid-shaped and has one for the support on a bedding layer 4 (see Fig. 2 ) provided on a substrate underside 2 and an underside 2 opposite upper side 3, wherein the upper side 3 forms a surface of the shaped block 1. Four peripheral sides 5, 5 ' , 5 '' , 5 ''' of the molded block 1 oriented perpendicularly to the lower and upper sides 2, 3 each adjoin each other at right angles to each other.

According to the invention, the molded block 1 is multi-layered and has a water-impermeable, first layer 1.1, a water-permeable, second layer 1.2 and a water-impermeable, third layer 1.3, wherein a water-impermeable layer in the present context is understood to mean that water does not penetrate unhindered into this layer and / or can penetrate through this layer but is at least largely rejected or derived.

The water-impermeable, first layer 1.1 is arranged on the upper side 3 of the molded block 1 and consists of a potted, impermeable facing concrete. At the water-impermeable, first layer 1.1 includes the water-permeable, second layer 1.2, which consists of a core porous core concrete with a large proportion of fine and micropores. The water-impermeable, third layer 1.3 arranged on the underside 2 of the molded block 1, in turn, adjoins the second layer 1.2 and consists of a sealing cement-bonded material. The third layer 1.3 is applied during the production of the molded block 1 to the second layer 1.2, such that the material of the third layer 1.3 at an interface between the second and third layer 1.2, 1.3 at least partially into the pores of the haufwerksporigen core concrete of the second layer 1.2 penetrates and largely closes them.

The water-permeable, second layer 1.2 arranged between the first and the third layer 1.1, 1.3 is designed to receive and store water, whereby water passes into the second layer 1.2 via the peripheral sides 5, 5 ', 5 ", 5 ''' Under conditions favoring the evaporation of water, the water cached in the second layer 1.2 can evaporate again and in turn escape from the shaped brick 1 in vapor form via the peripheral sides 5, 5 ', 5 ", 5 '" .

Each of the layers 1.1, 1.2, 1.3 has a predetermined layer thickness d ₁ , d ₂ , d ₃ , wherein the layer thickness d _{2 of} the second layer 1.2 is about 80% to 85% of a total height h of the shaped block 1. The illustrated embodiment of the molded block 1 has, for example, an overall height h of 8 cm, the first layer 1.1 having a layer thickness d ₁ of 1 cm, the second layer 1.2 a layer thickness d ₂ of 6.5 cm and the third layer 1.3 a layer thickness d ₃ by 0.5 cm. The second layer 1.2, with its layer thickness d _2, thus occupies about 81% of the total height h of the shaped block 1.

The illustrated example of the molded block 1 has spacers 9, which when laying the blocks 1 joints 6 (see Fig. 2 ) ensure in approximately uniform width and ensure a minimum width of the joints 6.

In the FIG. 2 a section of a vertical section through an embodiment of a surface covering 10 is shown. The surface covering 10 is produced by patches and comprises a multiplicity of multilayered shaped bricks 1 laid in a composite on a bedding layer 4 of a substrate. The molded bricks 1 used to produce the surface covering 10 are designed to have three layers and have first, second and third layers 1.1, 1.2, 1.3 (see FIG Fig. 1a and 1b ) on. Between adjacent shaped blocks 1 of the surface covering 10, joints 6 are formed, which are filled with a joint material 7 and form a percolation path for discharging precipitation water from a surface of the surface covering 10 facing away from the bedding layer 4.

To produce the surface covering 10, a plurality of molded bricks 1 are laid on the bedding layer 4 in a composite, wherein the underlay layer 4 is a conventional bedding layer 4, which consists essentially of a material mixture having a particle size of 0.1 mm to 5 mm consists. After laying the blocks 1, the joint material 7 is placed on the blocks 1 and dry rubbed into the joints 6. Subsequently, the surface covering 10 is shaken off and finally re-grouted. This process can after a certain time, z. B. be repeated at a distance of 2 weeks.

The joint material 7 of the illustrated example consists of a mixture of a sand content, a fines content and your artificial molecular sieve and also forms a filter layer for the removal of pollutants from the rainwater. The artificial molecular sieve has a grain size of 1.8 mm to 2.3 mm and is between 4% and 6% of the mixture of the joint material 7. A pore width of the artificial molecular sieve is based on the size of the pollutants to be absorbed and is between 3 Å and 10 Å. For example, the artificial molecular sieve may be a commercially available material designated 4A or 5A or 13X.

To illustrate the taking place on the surface covering 10 water cycle is in the FIGS. 3a and 3b in each case a section of a surface covering 10 is shown in a vertical section, wherein in FIG. 3a the infiltration and absorption route for rainwater and in FIG. 3b the evaporation path for cached precipitation water is indicated.

Precipitation water impinges on the surface of the surface covering 10 on the water-impermeable, first layer 1.1 of the conglomerates 1 and seeps into the grout material 7 via the joints 6. From there, at least part of the water flowing in the direction of the bedding layer 4, infiltrating water enters the second layer 1.2 of the stones 1 and that on the adjacent to the joint material 7 peripheral sides 5, 5 ', 5 ", 5"'. The infiltration or transport path of the rainwater is in FIG. 3a indicated by black arrows.

The cached in the second layer 1.2 of the bricks 1 water under appropriate conditions, for example, when heating the surface covering 10 by sunlight, evaporate and escape back into the environment. The evaporating water passes in the form of water vapor from the second layer 1.2 of the shaped brick 1 via the circumferential sides 5, 5 ', 5 ", 5 ''' adjoining the joint material 7 back into the joint material 7 and from there to the surface where it is In order to improve the steam discharge or vapor discharge, the shaped bricks 1 of the illustrated example additionally have openings 8 in their impermeable first layer 1.1, which allow the escape of water vapor FIG. 3b indicated by white filled double arrows. However, the additional openings 8 are only optionally formed in the first layer 1.1 of the molded blocks, the evaporation of the cached water is carried out without the additional openings 8 in sufficient effectiveness.

Water can advantageously be intermediately stored via the present sheet material 10 and returned to the atmosphere at a later time by evaporation. On the one hand, evaporation can counteract, for example, the urban heat island effect caused by the resulting evaporation cold, and on the other hand it supports the natural water cycle and thus improves the urban water balance. The sheet material 10 is particularly suitable for making an effective contribution to achieving the goal of drainage planning to be used in Germany in order to achieve evapotranspiration between 34% and 92% of the rainwater.

LIST OF REFERENCE NUMBERS

1

cast stone

1.1

first shift

1.2

second layer

1.3

third layer

2

bottom

3

top

4

underlayment

5, 5 ' , 5 '' , 5 '''

pages

6

Put

7

grout

8th

opening

9

spacer

10

surface covering

d ₁

Layer thickness of the first layer

d ₂

Layer thickness of the second layer

d ₃

Layer thickness of the third layer

H

Total height of the form stone

Claims (14)

1. A concrete paving stone (1) for use in a surface covering (10) which can be produced by paving, the paving stone (1) having at least one bottom (2) provided for laying on a bedding layer (4) of a subsurface and a top (3) opposite the bottom (2), and the paving stone (1) having a multi-layered construction and at least one water-impermeable first layer (1.1), which is arranged along the top (3), and at least one water-permeable second layer (1.2),
   characterised in that
   the paving stone (1) comprises at least one third layer (1.3) adjoining the second layer (1.2), and in that the third layer (1.3) is designed in the form of a water-impermeable layer and is arranged on the bottom (2), provided for laying on the bedding layer (4), of the paving stone (1), wherein the second layer (1.2), arranged between the first and third layers (1.1, 1.3), is designed to receive and store water.
2. The paving stone (1) according to Claim 1,
   characterised in that
   the water-impermeable first layer (1.1) consists of a dense facing concrete forming the top (3) of the paving stone (1).
3. The paving stone (1) according to Claim 1 or 2,
   characterised in that
   the water-permeable second layer (1.2) consists of a porous light-weight concrete.
4. The paving stone (1) according to any one of Claims 1 to 3,
   characterised in that
   the water-impermeable third layer (1.3) consists of a sealing material.
5. The paving stone (1) according to any one of the preceding claims,
   characterised in that
   the water-impermeable third layer (1.3) is designed, when the paving stone (1) is installed in the surface covering (10), to prevent water migrating via the bottom (2) out of the second layer (1.2) of the paving stone (1) and into the bedding layer (4).
6. The paving stone (1) according to any one of the preceding claims,
   characterised in that
   a layer thickness (d₂) of the water-permeable second layer (1.2) is between 70% and 90% of a total height (h) of the paving stone (1), preferably between 75% and 85% of the total height (h) of the paving stone (1) and particularly preferably around 80% of the total height (h) of the paving stone (1).
7. The paving stone (1) according to any one of the preceding claims,
   characterised in that
   the paving stone (1) has at least three adjoining peripheral sides (5, 5', 5"), wherein the peripheral sides (5, 5', 5") are permeable to water and water vapour, at least in the region of the second layer (1.2) of the paving stone (1).
8. The paving stone (1) according to any one of the preceding claims,
   characterised in that
   openings (8) to allow water vapour to exit are provided in the water-impermeable first layer (1.1).
9. The paving stone (1) according to any one of the preceding claims,
   characterised in that
   the paving stone (1) has at least one further layer between the first and third layers (1.1, 1.3).
10. A surface covering (10) comprising a plurality of multi-layered paving stones (1) according to any one of Claims 1 to 9, laid together by paving on a bedding layer (4) of a subsurface, wherein each paving stone (1) has at least one water-impermeable first layer (1.1), one water-permeable second layer (1.2) and one water-impermeable third layer (1.3), wherein joints (6) are formed between adjacent paving stones (1) of the surface covering (10), and wherein the joints (6) are filled with a substantially gravel- or sand-like joint material (7) and form a path for rain water to run away from a surface of the surface covering (10).
11. The surface covering (10) according to Claim 10,
    characterised in that
    respective peripheral sides (5, 5', 5'', 5''') of the plurality of paving stones (1) form an inlet path for the rain water running in the joints (6) filled with joint material (7) to run into the water-permeable second layer (1.2) of the paving stones (1).
12. The surface covering (10) according to Claim 10 or 11,
    characterised in that
    the peripheral sides (5, 5', 5") of the plurality of paving stones (1) form an outlet path for evaporating water to exit from the water-permeable second layer (1.2) of the paving stones (1) into the joints (6) filled with joint material (7).
13. The surface covering (10) according to any one of Claims 10 to 12,
    characterised by
    a specified water absorption capacity, wherein the surface covering (10) is designed to absorb and temporarily store a specified amount of precipitation water per unit area of the surface covering (10).
14. The surface covering (10) according to any one of Claims 10 to 13,
    characterised in that
    the joint material (7) forms a filter layer for removing pollutants from the rain water drains and consists of a mixture of a gravel- and/or sand-like fraction, a fine fraction and an artificial molecular sieve.

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