EP3130704B1 - Fibre-reinforced turf support layer and method of processing thereof - Google Patents

Description

The invention relates to a support layer for turf, which has reinforcing fibers made of plastic, wherein these reinforcing fibers are not biodegradable under the environmental conditions when used as a support layer in the ground substantially. In addition, the invention also relates to a method for processing a support layer for turf. Such a support layer is made of WO2012159145A1 known.

Many popular sports, such as football, hockey or equestrian sports are preferably operated on lawns. With intensive use of natural lawns for such sports it comes quickly to a wear of the lawns. This wear can go so far that the lawns can no longer be used for sports activities. It will then require longer care and regeneration phases for the lawns, during which there is no sport can be operated. Longer downtime, due to the wear of the lawn, however, are undesirable for operators of sports surfaces.

One approach to address this problem is the use of artificial turf, which is constructed of synthetic materials and thus less quickly wears. However, even modern artificial turf does not match the behavior of a natural lawn in its behavior when performing most sports. Thus, artificial turf is in many cases unpopular with the athletes.

Another alternative for improving the wear resistance of lawns is the use of hybrid lawns. In hybrid turf, the benefits of a natural lawn are combined with the benefits of synthetic reinforcement. In such hybrid turf, a synthetic fiber-reinforced base course is first applied to the existing subfloor. The synthetic fibers in this base layer have the task of improving the shear strength of the layer by interlinking with each other. Mechanical stresses in the execution of the sports are thus better absorbed and distributed than in a soil that is not reinforced with fibers. Natural grass is then created on this base course. In this case, the reinforcing fibers of the support layer can also extend into the natural turf, which also gives the turf layer additional stability. Even such a hybrid lawn or its support layer has a finite life and must be renewed or replaced after a few years.

When disposing of used hybrid lawns then the problem arises that the synthetic fibers inseparably mixed with the mineral and organic components of lawn and base course are. Therefore, every year large amounts of material removed are incurred in the renewal of hybrid turf surfaces, which in addition to natural material also contain a large proportion of plastics. Such, kunstoffhaltiges material can not be applied in nature and must therefore be cumbersome and costly landfilled or disposed of.

The object of the present invention is therefore to simplify the disposal of used base courses of hybrid turf.

The object of the invention is achieved by a support layer having the features of claim 1. A support layer according to the invention comprises reinforcing fibers of a plastic which is substantially non-biodegradable under ambient conditions when used as a base support layer or otherwise under conditions of normal use of the hybrid lawn (eg, temperatures, moisture / water content, radiation, especially UV Radiation) is decomposed. This means that the reinforcing fibers do not or only to a very small extent change their properties during use in the base layer of a hybrid lawn. It is thus ensured that these reinforcing fibers reliably fulfill their task of mechanically supporting and strengthening the base course over a period of several years, since their mechanical properties remain substantially constant. The reinforcing fibers of a support layer according to the invention have an activation threshold, from which these fibers are then substantially completely biodegradable in particular and disappear from the support layer. At this activation threshold, from which a degradability of the reinforcing fibers given is, can be different physical effects. For example, a certain temperature can form this activation threshold. Furthermore, however, can also form a certain humidity or concentration of water or other liquids in the vicinity of the reinforcing fibers this activation threshold. In addition, other physical effects (such as irradiation with a certain wavelength of radiation, for example UV radiation) are also included as the activation threshold for the biodegradability of the reinforcing fibers of a base layer belonging to the invention.

By activating the biodegradation is initiated, in particular, a decomposition of the molecules of the plastic and then possibly the further biodegradation or other decomposition or reshaping of the plastic. Usually, the activation threshold is described by a chemical or physical parameter.

Furthermore, it is possible that the activation threshold is formed by a combination of two or more physical and / or chemical effects. For example, the Activation Threshold may consist of a combination of a given temperature with a certain water content in the vicinity of the reinforcing fibers. Exceeding such a combined activation threshold, formed from a temperature and a water content, then initially leads to an uptake of water in the reinforcing fibers. This water absorption causes a cleavage of the molecules of the plastic from which the reinforcing fibers consist. The further decomposition of the cleavage products then takes place by other mechanisms. The further decomposition can be done for example by Saprobionten. These are organisms that feed on dead material and split, reshape and shred it.

This decomposition can be done within the organisms, or by enzymes that release the organisms to the outside. Saprobionten are typical organisms in composting processes. Saprobionten in the form of thermophilic bacteria and fungi have proven to be particularly favorable for biodegradation of reinforcing fibers according to the invention. Such thermophilic organisms are particularly active at elevated temperatures, for example between 45 and 80 ° C. However, complete biodegradation of the reinforcing fibers is not limited to degradation by thermophilic organisms. It is also suitable for this purpose other microorganisms, as they are e.g. when composting finds or uses. It is clear that biodegradation as described, of course, also by exceeding an activation threshold, which is defined only by a temperature or just another physical or chemical parameter occurs.

Ultimately, after biodegradation, only organic and mineral material, which can be applied or distributed without hesitation in nature, remains behind. A support layer according to the invention thus offers the very advantageous combination of high-quality stabilization function when used in hybrid sport turfs with a significantly simplified and improved disposal after their use in hybrid turf.

Particularly advantageous is the selection or setting an activation threshold of the reinforcing fibers, which is never achieved as possible when used in the base layer of an in-use hybrid lawn. This ensures that no biodegradation of the reinforcing fibers takes place during use in the hybrid lawn. In the disposal of a used support layer is then ensured that the activation threshold is deliberately and significantly exceeded, so that the then desired biodegradation of the reinforcing fibers can take place. After a For a certain time under conditions beyond the activation threshold, the support layer then no longer contains any plastic and can be disposed of or reused as desired.

Smart way is that the activation threshold is a temperature higher than 50 ° C, 55 ° C, 60 ° C, 65 ° C or 70 ° C. According to the invention, the activation threshold, from which a biological degradation of the reinforcing fibers takes place, is formed by a temperature which is higher than 50 ° C. This activation threshold may then be, for example, 55 ° C. There are suitable plastics, such as polylactides (PLA) absorb from this temperature to a significant extent water molecules, which in turn lead to the decomposition and thus the biodegradation of plastics. In addition to exceeding the activation threshold formed here by a temperature, it should moreover be ensured that a sufficient amount of water is present in order to achieve good biodegradation of the reinforcing fibers. It is of course possible to use different plastics as a material for the reinforcing fibers, wherein the activation threshold can also be formed by higher temperatures. One way to achieve or exceed the activation threshold is the introduction of a used, worn support layer in a composting plant. In industrial composting plants, temperatures of more than 60 ° C are often used, as from this temperature germs are effectively killed. The conditions in such a composting plant are thus also ideal for the degradation of the reinforcing fibers in a support layer according to the invention. The prevailing in the composting temperature is well beyond the activation threshold for biodegradation of the reinforcing fibers and thus ensures a safe and rapid degradation of the fibers. In addition, an activation threshold can also be lower Temperatures, for example in the range of 40 ° C or 45 ° C are formed. The activation threshold depends on the material of which the reinforcing fibers are made and on the mechanisms or organisms to be used in the degradation or decomposition. Cleverly, such activation thresholds are available in applications that are not achieved in normal use as a base for a turf.

Furthermore, it is advantageously provided that the reinforcing fibers when used as a base layer in the ground, inter alia, are stable to UV radiation or water. In this embodiment, the reinforcing fibers are designed to be stable to the environmental conditions prevailing during their use in the base course. This includes that the reinforcing fibers are stable to UV radiation contained in sunlight. This is particularly favorable if parts of the reinforcing fibers stick out of the ground. If the reinforcing fibers are completely enclosed or enclosed in the ground and thus normally no UV radiation strikes the fibers, this property can be dispensed with and UV light can be used for activation, for example. This resistance to UV radiation can be achieved, for example, by using a UV-resistant, activatable plastic or by admixing pigments or by coating with a UV-absorbing coating with less stable plastics. It is also possible to color the reinforcing fibers green to make them unobtrusive within the natural grass. Furthermore, the reinforcing fibers are designed to be insensitive to water. Since lawns must be watered regularly to achieve good growth of natural grass, the reinforcing fibers are designed so that they do not absorb water under normal conditions of use in the hybrid lawn. An unwanted decomposition or swelling associated with it Change in the mechanical properties of the fibers is thus prevented.

Furthermore, it is provided that the reinforcing fibers consist of a material from the group polylactides (PLA) or the group polyhydroxyalkanoates, in particular polyhydroxybutyric acid (PHB) or the group polyvinyl alcohols (PVA). The reinforcement fibers of the support layer are formed of a material that is biodegradable beyond the activation threshold. Therefore, different biocompatible plastics are available as material for the reinforcing fibers. Particularly suitable are materials from the group of polylactides (PLA). Polylactides are synthetic polymers belonging to the polyesters. Polylactides are composed of interconnected lactic acid molecules. From polylactides thermoplastics can be produced, which can be brought into almost any shape in common processing methods (injection molding, extrusion, ...). The reinforcing fibers can thus be made in different lengths, diameters and shapes from PLA. PLA reinforcement fibers are particularly advantageous for their good mechanical properties, with high tensile strength, high modulus of elasticity and low elongation at break. These, largely due to the large molecular weight properties, provide for an effective support and networking of the support layer. In addition, PLA behaves hydrophobic under the ambient conditions prevailing in the hybrid lawn. Thus, an influence of the reinforcing fibers on the water balance of the base course is excluded. At the same time there is no risk that the fibers swell due to water absorption and change their mechanical properties, or even decompose in the soil. Below the activation threshold, PLA reinforcement fibers behave in a long-term stable and virtually rotting-free manner. Of course, the reinforcing fibers may also be made of another suitable biocompatible material, for example from the groups of polyhydroxyalkanoates, in particular polyhydroxybutyric acid (PHB) or the polyvinyl alcohols (PVA) exist. In addition, even more, under defined conditions, biodegradable plastics are associated with the invention.

Advantageously, it is provided that, in addition to the reinforcing fibers, the base layer also comprises quartz sand and / or natural sand and / or lava and / or topsoil and / or peat and / or natural cork. The reinforcing fibers serve to strengthen and improve the shear strength of the base course. The higher this shear strength, the higher the potential intensity of use of the hybrid lawn and the lower the care required and the required regeneration time.

In addition to the reinforcing fibers, the base layer contains various other materials that provide the other required properties of the base layer. For example, the base course has to be well permeable to water in order to avoid flooding the hybrid lawn during heavy rainfall. For this reason drainage systems are often installed inside the base course to remove water. Furthermore, the support layer has the task to provide a lasting flatness of the hybrid lawn, even with regular load. In one possible embodiment of the invention, the base layer contains quartz sand and / or natural sand as the largest constituent. The proportion of these sands is usually 60-80 percent by volume. Grain sizes between 0.02 mm and 4 mm have proven to be particularly favorable.

Furthermore, lava may be part of the base course. Usually, lava is added in the proportion of 0 - 18 volume percent (volume%) of the support layer.

For the proportion of lava, an interval is specified, which is described by an upper and lower limit. As an upper limit, for example, the following values are provided: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 or 25% by volume. The lower limits are, for example, the following values: 0.5, 1, 1.5, 2, 4, 6, 8, 10 or 12% by volume. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

Again, grain sizes of lava between 0.02 mm and 4 mm have been found to be particularly favorable.

For the grain size of the lava, an interval is specified, which is described by an upper and lower limit. The upper limit is, for example, the following values: 1, 1.5, 2, 2.5, 3, 3.5, 4, 5 or 6 mm. The lower limits are, for example, the following values: 0.02, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.7, 0.85, 1, 1.3, 1.5, 1.7, 2, 2.5, 3 or 4 mm. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

Another component of the base layer, in particular to a proportion of 5 to 20 percent by volume, is topsoil.

For the portion of the topsoil an interval is given, which is described by an upper and lower limit. As an upper limit, for example, the following values are provided: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28 or 30% by volume. The lower limits are, for example, the following values: 0.5, 1, 1.5, 2, 4, 6, 8, 10 or 12% by volume. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

Suitable topsoil for a base course is defined in the standard DIN 18300 as soil class 1 as topsoil or topsoil and contains inorganic material as well as humus and soil organisms. Also suitable are flowing soil types, as classified in the standard DIN 18915 as floor group 2.

As a further suitable constituent of the support layer, peat, ideally to a proportion of 3 - 11 volume percent (volume%) resulted. Experience shows that Hochmoortorf or Weißfeintorf can be used well.

For the proportion of peat, an interval is specified, which is described by an upper and lower limit. For example, the following values are provided as the upper limit: 2, 4, 6, 8, 10, 11, 12 or 13% by volume. The lower limits are, for example, the following values: 0.5, 1, 1.5, 2, 4, 6 or 8% by volume. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

Furthermore, a base layer of natural cork, in particular in a grain size between 0.5 mm and 20 mm, preferably between 3 mm and 7 mm are used.

For the grain size of the natural cork, an interval is specified, which is described by an upper and lower limit. The upper limit is, for example, the following values: 3, 5, 7, 10, 12, 15, 17 or 20 mm. The lower limits are, for example, the following values: 0.5, 1, 2, 3, 4, 5, 7, 10, 12 or 15 mm. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

Depending on the desired properties of the hybrid lawn, the proportion of natural cork may be in the range of 0 - 13 volume percent (volume%).

For the proportion of natural cork, an interval is specified, which is described by an upper and lower limit. The upper limit is, for example, the following values: 2, 4, 6, 8, 10, 12 or 13% by volume. The lower limits are, for example, the following values: 0.5, 1, 1.5, 2, 4 or 6% by volume. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

The constituents of a base layer listed here have proven to be particularly favorable in practice. Of course, however, other and further components may be contained in the support layer. In addition, other particle sizes or volume fractions than the stated sizes or proportions of the constituents in a support layer are also part of the invention and disclosed.

Furthermore, it is advantageously provided that the layer thickness of the support layer is between 30 mm and 300 mm, in particular between 60 mm and 200 mm. The base layer may be designed differently thick depending on the location and desired properties of the hybrid lawn. Thicknesses between 60 mm and 200 mm have proven to be particularly favorable. Also suitable are thicknesses between 30 mm and 300 mm. In addition, however, thinner or thicker support layer are also covered by the invention. For the layer thickness, an interval is specified, which is described by an upper and lower limit. The upper limit is, for example, the following values: 150 mm, 200 mm, 250 mm and 300 mm. The lower limits are, for example, the following values: 30 mm, 45 mm, 75 mm, 60 mm and 90 mm. The disclosure of this application includes the set of all intervals which consists of all possible combinations of the aforementioned upper and lower limits.

Furthermore, the invention provides that the proportion of reinforcing fibers on the support layer is between 0.1 and 4% by weight. The proportion of reinforcing fibers in the base layer is relevant to the achieved shear strength of the base layer. A proportion between 0.1 and 4% by weight of the reinforcing fibers on the base layer has proven to be particularly favorable for the shear strength.

The percentage of reinforcing fibers is given as an interval, which is described by an upper and lower limit. The upper limit is, for example, the following values: 2, 4, 6, 8 or 10% by weight. The lower limits are, for example, the following values: 0.05, 0.1, 0.5, 1, 1.5, 2 and 4% by weight. The disclosure of this application includes the amount of all intervals which consists of all possible technically correct combinations of the aforementioned upper and lower limits.

Advantageously, it is provided that the length of the reinforcing fibers is between 15 mm and 700 mm, in particular between 30 mm and 500 mm. The length of the reinforcing fibers also has an influence on the achieved shear strength of the base course. When selecting a length for the reinforcing fibers, it plays a role in how the fibers are introduced into the support layer. If the fibers are mixed into the base layer before application of the hybrid turf, other fiber lengths may be optimal than with subsequent introduction of the reinforcing fibers into an already laid turf or already laid base course. Particularly favorable results can be achieved with reinforcing fibers achieve a length between 30 mm and 500 mm. Good shear strength is also achieved in the range between 15 mm and 700 mm. In addition, however, larger or smaller lengths of the reinforcing fibers are associated with the invention. For the length of the reinforcement fibers, an interval is specified, which is described by an upper and lower limit. The upper limits are, for example, the following values: 90 mm, 100 mm, 150 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, 650 mm and 700 mm. The lower limits are, for example, the following values: 15 mm, 30 mm, 45 mm, 60 mm, 75 mm and 100 mm. The disclosure of this application encompasses the set of all intervals, which consists of all possible, technically meaningful combinations of the aforementioned upper and lower limits.

In a preferred embodiment of the proposal, it is provided that the thickness of the reinforcing fibers is between 0.05 mm and 2 mm, in particular between 0.1 mm and 1 mm. The thickness of the reinforcing fibers also has an influence on the mechanical strength of the base layer and thus of the hybrid turf. Particularly favorable results have been found in a thickness of the reinforcing fibers between 0.1 mm and 1 mm. However, also in the range between 0.05 mm and 2 mm for the thickness of the reinforcing fibers show very good results. In addition, larger or smaller thicknesses of the reinforcing fibers are disclosed with the invention. For the thickness of the reinforcing fibers an interval is given, which is described by an upper and lower limit. The upper limit is, for example, the following values: 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm. The lower limits are, for example, the following values: 0.05 mm, 0.1 mm, 0.2 mm, 0.4 mm and 0.6 mm. The disclosure of this application encompasses the set of all intervals, which consists of all possible, technically meaningful combinations of the aforementioned upper and lower limits.

According to the invention it is provided that the reinforcing fibers within the support layer in different directions, distributed randomly and at least partially there is a toothing between the individual reinforcing fibers. In this embodiment of the invention, the reinforcing fibers are disordered within the support layer. This means that there is no preferred or conscious direction in which the fibers run. Between the individual randomly distributed present fibers occurs at least partially to a toothing of the individual reinforcing fibers with each other. The fibers touch each other, hook into each other or are partially wrapped around each other. This creates an interaction between the individual fibers, which corresponds to a kind of networking. This networking or gearing ensures the desired improvement in the shear strength of the base layer. Thanks to the improved shear strength, the hybrid turf can be used much more intensively without heavy wear and requires less regeneration times. Such a disordered presence of the reinforcing fibers in the support layer can be produced, for example, by mixing the reinforcing fibers with the other constituents of the support layer before the application of the base support layer. The base layer thus mixed with reinforcing fibers is then applied to the floor of the sports facility and applied as the topmost layer of natural grass. The randomly present reinforcing fibers in the base layer have proven to be particularly favorable for stabilizing the root zone of the natural grass. Of course, it is also part of the invention that reinforcing fibers are introduced into an already created turf structure subsequently in a disordered direction.

Also possible is a combination of different arrangements of the reinforcing fibers within the base layer. Thus, for example, randomly present in the support layer reinforcing fibers can be used with an ordered present layer of fibers in combination to produce special properties of the hybrid lawn. Clever way is provided that the reinforcing fibers are net-like or fabric-like in the support layer. In this embodiment, reinforcing fibers in ordered form are net-like or fabric-like in the support layer. Such an ordered shape provides a particularly good improvement in the shear strength of the backing layer along the direction of the reinforcing fibers. It is possible here to arrange different net-like or fabric-like arrangements one above the other, wherein the direction of the fiber progressions is in each case slightly offset from one another. This in turn allows excellent shear strengths to be generated in different directions. Such mesh-like or fabric-like executed reinforcing fibers can be introduced, for example, characterized in that a portion of the support layer is first distributed on the ground, then the net-like reinforcing fibers are placed and then further support layer material is filled. The reinforcing fibers are designed, for example, as roll goods or web goods and are opened a pad rolled out. This stratified application of the support layer can of course also be done with multiple layers of reinforcing fibers.

The object of the invention is also achieved by methods for preparing a base layer according to one of the embodiments described, comprising the method steps: activation of the reinforcing fibers, in particular composting of the base layer. With the aid of the method according to the invention, a used support layer of a hybrid lawn is processed. In this case, the activation threshold of the reinforcing fibers is exceeded, whereby then a biodegradability of the reinforcing fibers is given. The reinforcing fibers that behave stably when used in the hybrid lawn are now completely degraded after activation, ie after the activation threshold has been exceeded, so that after a certain time they are no longer present in the base course. As a particularly favorable for activation or for exceeding the activation threshold, a composting of the used support layer has been found. In one, especially industrial composting environmental conditions are present, which can lead to the exceeding of the activation threshold and thus to the biodegradation of the reinforcing fibers in the support layer.

Clever way is provided that the activation, in particular composting with temperatures higher than 50 ° C takes place. In this embodiment of a method according to the invention, the activation of the reinforcing fibers by temperatures of greater than 50 ° C, 55 ° C, 60 ° C, 65 ° C or 70 ° C. These temperatures will be achieved particularly easily in the context of an industrial composting, in which temperatures at this level or even above are common and common. Due to this ease of activation temperatures in industrial composting plants, opportunities for activation and thus degradation of the reinforcing fibers are easily and inexpensively accessible.

Furthermore, it is provided that the support layer is removed from the soil before activation / composting. In this embodiment of the method, the support layer is first removed from the floor of the sports venue and then fed to the activation or composting, where then the degradation of the reinforcing fibers takes place. This has the advantage that the removed base course can be replaced immediately by a new base course to build a new hybrid lawn and thus no downtime in the sports facilities arise.

Advantageously, it is provided that after activation / composting the base layer is used as biomaterial / earth, in particular for the construction of a base layer according to one of the already described embodiments. In this embodiment of the method, the material of the used support layer is used after the degradation of the reinforcing fibers for the construction of a new support layer. This has the advantage that the materials of the old base course are already mixed in a favorable ratio with each other and thus little to no effort in the mixing creates a new base course. New reinforcing fibers can then be added according to the desired shear strength of the new support layer in the appropriate amount shape and shape as needed. In addition to the use of the material of the used base course after the complete removal of the reinforcement fibers for new base course, however, the treated material can also be used for other applications, for example in agriculture, horticulture or the like, since it now free of plastics. Due to the complete freedom of the material from plastic remnants, it can also be used in nature, for example for the creation of biotopes or the like.

In this context, it is pointed out in particular that all features and properties described in relation to the device as well as methods are mutatis mutandis applicable also with respect to the formulation of the method according to the invention and applicable in the context of the invention and as co-disclosed. The same also applies in the opposite direction, that is to say, structural features which are in accordance with the invention are therefore also taken into account and claimed within the scope of the device claims and likewise belong to the disclosure.

• Fig. 1 eine dreidimensionale, geschnittene Ansicht einer ersten Ausführungsform einer Tragschicht in einem Sportboden,
• Fig. 2 eine dreidimensionale, geschnittene Ansicht einer zweiten Ausführungsform einer erfindungsgemäßen Tragschicht in einem Sportboden und
• Fig. 3 eine dreidimensionale, geschnittene Ansicht einer dritten Ausführungsform einer Tragschicht in einem Sportboden.

In the drawing, the invention is shown schematically in particular in one embodiment. Show it:

• Fig. 1 a three-dimensional, sectional view of a first embodiment of a support layer in a sports floor,
• Fig. 2 a three-dimensional, sectional view of a second embodiment of a support layer according to the invention in a sports floor and
• Fig. 3 a three-dimensional, sectional view of a third embodiment of a support layer in a sports floor.

In the figures, the same or corresponding elements are denoted by the same reference numerals and therefore, if not appropriate, will not be described again. The disclosures contained in the entire description are mutatis mutandis to the same parts with the same reference numerals or identical component names transferable. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to the new situation mutatis mutandis when a change in position. Furthermore, individual features or combinations of features from the illustrated and described different embodiments may represent for themselves, inventive or inventive solutions.

Fig. 1 shows a three-dimensional, sectional view of a first embodiment of a support layer in a sports floor. Under a sports floor here is to understand the totality of all layers that form the background for the practice of sports. As a particularly favorable hybrid lawn has been found as a sports floor. A sports floor formed by a hybrid lawn contains artificial fibers in at least one of its layers and is otherwise naturally constructed. The base of the shown sports floor is a floor 4. Under a floor 4 is here to understand any surface that naturally prevails or already exists at the place where the sports floor should be created. This floor 4 is leveled before the construction of the sports floor and possibly otherwise pretreated as needed, for example, compressed, so that it forms a good surface for the subsequent supporting layer 1.

The base layer 1 is located as in Fig. 1 On the floor 4 above the support layer is again the lawn 3. The lawn 3 is usually formed by a natural turf. However, it would also be possible, the shown sports floor with a turf 3, the turf 3 being formed by an artificial turf. Lawn 3 is thus to be understood as the area in which the blades of a natural or artificial turf project out of the base layer 1. The roots of a lawn 3 formed by a natural turf are located, at least for the most part, within the base layer 1. In the area of the turf 3, the athletes directly contact the sports floor. Essential for the function of the shown sports floor and the base layer 1 are the reinforcing fibers 2, which in the Fig. 1 illustrated embodiment of a support layer extend substantially vertically. In this case, the ends of the reinforcing fibers 2 from the support layer 1 upwards into or through the lawn 3. This standing of the reinforcing fibers 2 into or through the lawn 3 provides additional solidification and thus more intensive usability of the lawn 3. Within the support layer 1, the reinforcing fibers 2 also provide consolidation, resulting in improved shear strength of the entire sports floor. In the illustrated embodiment, the reinforcing fibers were 2 after the application of the support layer 1 and the lawn 3 on the bottom 4 subsequently implanted from above into the support layer 1. This can be done by hand or with the aid of a device or machine. In the case shown, the reinforcing fibers 2 were taken approximately in the middle of their length by a tool and then pushed in the vertical direction through the turf 3 into the base layer 1. Of course, it is also possible to push the reinforcing fibers 2 first into the base course and then apply the turf 3. In addition, the reinforcing fibers 2 can also be introduced into the base layer 1 by other methods or with other aids in such a way that, as in the case shown, they extend essentially in the vertical direction.

Fig. 2 shows a three-dimensional, sectional view of a second embodiment of a support layer according to the invention in one Sports ground. The construction of the sports ground in Fig. 2 is shown, consists of the same layers as those in Fig. 1 already described. The reinforcing fibers 2 are in the Fig. 2 illustrated embodiment of the support layer 1 disordered and extending in different directions before. Due to the fact that the reinforcing fibers run in a disordered manner and along the course of the fibers changing spatial directions, there is a mutual entanglement or a mutual toothing of the reinforcing fibers 2. Exactly this interlocking between the individual reinforcing fibers 2 ensures a solidification of the support layer 1, which in turn increased Shear strength of the base layer 1 and thus of the entire sports floor leads. Furthermore, randomly propagating reinforcing fibers 2 stabilize the root zone of the turf 3 and thereby also provide increased wear resistance of the sports floor. Also in the in Fig. 2 In the illustrated embodiment, the ends of the reinforcing fibers 2 may protrude upward from the base course 1 into or through the turf 3. This in turn leads to increased wear resistance and better playability of the turf 3, which is formed by both natural blades of grass and synthetic reinforcing fibers 2, which is often referred to as hybrid turf. For a more pleasing appearance, the reinforcing fibers 2 can be dyed green so that they are barely distinguishable from the appearance of the natural blades of grass. The introduction of the reinforcing fibers in the in Fig. 2 illustrated embodiment of a support layer is advantageously already before the application of the support layer 1. The reinforcing fibers 2 can even before the construction of the sports floor evenly mixed with the other materials of the support layer 1. This saves time when building the sports ground at the sports venue. Of course, it is also possible to apply the reinforcing fibers 2 during the application of the base layer 1 on the floor 4 or mix. In addition, the reinforcing fibers 2 can also be introduced after the application of the lawn 3 in the support layer 1.

In addition, the in Fig. 1 and Fig. 2 embodiments of a support layer shown are also combined with each other, so that both unordered as well as ordered introduced reinforcing fibers 2 are present in a support layer 1.

Fig. 3 shows a three-dimensional, sectional view of a third embodiment of a support layer in a sports floor. Also in this, in Fig. 3 shown embodiment of a support layer 1, the layer structure is identical to Fig. 1 and Fig. 2 , The reinforcing fibers 2 are in the illustrated embodiment in a kind of fabric or mesh. This means that the fibers are regularly arranged in a certain way. In the illustrated case, the fibers are substantially horizontal and either parallel to each other or they take a 90 ° angle to each other. This arrangement of the reinforcing fibers provides for a particularly good solidification of the support layer in the direction of the reinforcing fibers 2. Since the reinforcing fibers 2 in the in Fig. 3 illustrated embodiment substantially only in two horizontal directions, which are 90 ° to each other, run, the strength of the support layer 1 in these directions is particularly large, in contrast, lower in other directions. Therefore, a plurality of fabrics or nets of reinforcing fibers 2, which are twisted relative to each other with respect to the fiber direction, can be introduced into the base layer 1. Thus, the support layer 1 is solidified in other directions. The introduction of a network or fabric of reinforcing fibers 2 can be carried out particularly favorable during the application of the support layer 1 on the floor 4. It is also possible parallel to that Fig. 3 shown to provide a network or fabric of reinforcing fibers 2 more such networks or fabric, of which a layer may also be provided at the boundary between the base layer 1 and 3 lawn. Through a network or fabric of reinforcing fibers 2 directly on the border to the turf 3, a solidification of the root zone of the turf 3 is achieved, which in turn increases the wear resistance of the sports floor. Also the in Fig. 3 illustrated embodiment of a support layer 1 can with one or both embodiments, in Fig. 1 and Fig. 2 shown are used in combination.

Claims (9)

1. Support layer for turf with reinforcing fibres (2) of plastic, wherein these reinforcing fibres (2) are essentially not biodegradable under environmental conditions when used as support layer in the soil, characterized in that within the support layer (1) the reinforcing fibres (2) are distributed disorderly in different directions, and there is at least a partial interlocking of the single reinforcing fibres (2), wherein the amount of the reinforcing fibres (2) in the support layer is between 0.1 and 4 % by weight, and these reinforcing fibres (2) have an activation threshold above which the reinforcing fibres (2) are essentially completely biodegradable, wherein the activation threshold is a temperature above 50° C.
2. The support layer according to claim 1, characterized in that the reinforcing fibres (2) are resistant, among others, to UV radiation or water when used as support layer in the soil.
3. The support layer according to any one of the preceding claims, characterized in that the reinforcing fibres (2) consist of a material of the group polyactides (PLA) or the group polyhydroxyalcanoates, in particular polyhydroxy butanoic acid (PHB), or the group polyvinyl alcohols.
4. The support layer according to any one of the preceding claims, characterized in that the support layer is provided, besides the reinforcing fibres (2), also with quartz sand and/or natural sand and/or lava and/or topsoil and/or peat and/or natural cork.
5. The support layer according to any one of the preceding claims, characterized in that the layer thickness of the support layer is between 30 mm and 300 mm, in particular between 60 mm and 200 mm.
6. The support layer according to any one of the preceding claims, characterized in that the length of the reinforcing fibres (2) is between 15 mm and 700 mm, in particular between 30 mm and 500 mm.
7. The support layer according to any one of the preceding claims, characterized in that the thickness of the reinforcing fibres (2) is between 0.05 mm and 2 mm, in particular between 0.1 and 1 mm.
8. Method for treating a supply layer according to any one of the preceding claims, comprising the method steps

   - Removal of the supply layer (1) from the soil (4),

   - Activation of the reinforcing fibres (2), in particular composting the supply layer (1),

   wherein the activation, in particular composting is carried out with a temperature higher than 50°C.
9. The method according to claim 8, characterized in that after the activation/composting the supply layer (1) is used as bio material/soil, in particular for the construction of a supply layer (1) according to any one of the claims 1 to 7.

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