PLAYING SURFACE WITH A MIXTURE OF STONES AND ELASTIC GRANULES

Abstract

Playing surface, in particular a sports floor or playing field. The playing surface comprises a substrate layer lying on top of a base layer and one or more additional layers lying on top of the substrate layer. The substrate layer is a leveled, compacted mixture of elastic granules and stones. At least one of the additional layers is an elastic layer. The substrate layer and the one or more additional layers form the playing surface.

Claims

1. A method for laying a playing surface, the playing surface being in particular a sports floor or playing field, the method comprising the steps of; providing a substrate mixture comprising elastic granules and stones; applying the substrate mixture on a base layer; leveling the applied substrate mixture; compacting the leveled substrate mixture such that a compact substrate layer is formed; and applying one or more additional layers on top of the substrate layer, at least one of the additional layers being an elastic layer, wherein the substrate layer and the one or more additional layers form the playing surface.

2. A method for laying a playing surface that provides robust protection against freeze-thaw-cycle-induced damages, the playing surface being in particular a sports floor or playing field, the method comprising the steps of: providing substrate mixture comprising elastic granules and stones; applying the substrate mixture on a base layer, the base layer being located in a geographic area subjected to multiple freeze-thaw-cycles per year. leveling the applied substrate mixture; compacting the leveled substrate mixture such that a compact substrate layer is formed; and applying one or more additional layers on top of the substrate layer, at least one of the additional layers being an elastic layer, wherein the substrate layer and the one or more additional layers form the playing surface.

3. The method according to claim 1, the base layer being a concrete, soil, sand, wood, or stone layer or a layer comprising a mixture of two or more of said materials.

4. The method according claim 1, wherein the elastic granules are rubber granules, in particular EPDM or SBR rubber granules.

5. The method according to claim 1, wherein the substrate mixture is free of a binder.

6. The method according to claim 1, wherein the substrate mixture and the substrate layer are free of any adhesive fixing the stones and rubber granules.

7. The method according to claim 1, wherein at least 5%, preferably at least 10%, e.g., at least 20% of the volume of the compacted substrate layer consists of air-filled cavities between the stones and the elastic granules.

8. The method according to claim 1, wherein the elastic layer is a PU layer.

9. The method according to claim 1, wherein the elastic layer or one of the other additional layers is an artificial turf layer or a hybrid turf layer.

10. The method according to claim 1, wherein at least one of the additional layers is a sealing layer adapted to prevent water from penetrating the playing surface and reaching the base layer.

11. The method according to claim 1, wherein the size distribution of the stones is an RRSB distribution and wherein the diameter of the stones is below 2.0 cm.

12. The method according to claim 1, wherein 40-60% of the weight of the substrate mixture consists of the stones and the rest of the weight of the substrate mixture consists of the rubber granules.

13. The method according to claim 1, wherein the size distribution of the rubber granules is an RRSB distribution and wherein the diameter of the rubber granules is below 2.0 cm.

14. The method according to claim 1, wherein the rubber granules are PU-coated granules.

15. The method according to claim 1, wherein the substrate mixture is applied such that the stones and the elastic granules are homogeneously mixed when they are applied on the base layer.

16. The method according to claim 1, wherein the compacting comprises applying pressure on the applied mixture of the stones and elastic granules such that the elastic granules become deformed and the resilience of the deformed elastic granules fixes the stones and other elastic granules in their local environment also in the absence of a binder or an adhesive.

17. The method according to claim 1, wherein the material of the base layer is susceptible to freeze-thaw-cycle-induced damages and is in particular a porous stone or a porous concrete material.

18. A playing surface, in particular a sports floor or playing field, comprising: a substrate layer lying on top of a base layer, the substrate layer being a leveled, compacted mixture of elastic granules and stones; and one or more additional layers lying on top of the substrate layer, at least one of the additional layers being an elastic layer, wherein the substrate layer and the one or more additional layers form the playing surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings:

[0065] FIG. 1 is a schematic, a cross-sectional view of a state-of-the-art playing surface.

[0066] FIG. 2 is a flow chart of a method of manufacturing a playing surface.

[0067] FIG. 3 is a schematic, cross-sectional view of a playable structure comprising a leveled, compacted mixture of stones and elastic granules.

[0068] FIG. 4 is a schematic, cross-sectional view of a pavement structure at several moments during the manufacturing of the playing surface.

[0069] FIG. 5 is a schematic, cross-sectional view of a playable structure comprising an artificial turf layer.

[0070] FIG. 6 is a schematic, cross-sectional view of a playable structure comprising a sealing layer.

DETAILED DESCRIPTION

[0071] Like-numbered elements in these figures either are equivalent elements or perform the same function. Elements that have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

[0072] FIG. 1 is a schematic, a cross-sectional view of a state-of-the-art playing surface as it may look after several years of use in an area with frequent freeze-thaw cycles. An elastic layer 102 has been placed on top of a base layer 104, e.g., a concrete base. The base layer may originally have had a plain, level surface that provided mechanical support for the elastic layer 102 over its full extent. However, after many years in a region with many freeze-thaw cycles, the surface of the base layer may comprise multiple depressions and cracks. As a consequence, some regions of the elastic layer are not mechanically supported by the base layer and will be stretched strongly if a heavy object hits the elastic layer in said regions. This stretching may soon result in material fatigue and a significantly shortened life expectancy of the sports floor. In particular, if the stretching of the elastic layer 102 results in the elastic layer becoming brittle and water-permeable, the decay of the elastic layer may be accelerated because even more water may reach and further damage the base layer.

[0073] FIG. 2 is a flow chart of a method of manufacturing a playing surface 300, 400, 500, 600, e.g., a sports field or playground as depicted, for example, in FIGS. 3, 4, 5, and 6. The playing surface generated with this method may be particularly robust against freeze-thaw-cycle-induced damages. In the following, the method of FIG. 2 will be described by making reference also to elements of FIGS. 3 and 4.

[0074] The method comprises a first step 202 of providing a substrate mixture 402. The substrate mixture comprises elastic granules 304 and stones 306 as depicted, for example, in FIGS. 3 and 4. The provision of the mixture can imply, for example, that an installer in the immediate vicinity of the place where the sports floor is to be installed mixes stones and elastic granulate in the desired ratio. Mixing can be done manually. Preferably, however, mixing is done in a rotating drum, which can take larger volumes of stones and elastic granulate and mix them homogeneously. For example, mortar mixers or construction vehicles and/or equipment of different sizes can be used to produce a homogeneous mixture of elastic granulate and stones. The amount of the mixture to be produced depends on the size of the area onto which the mixture is to be applied and on the desired thickness of the substrate layer 302. The choice of a suitable mixing device depends on the mixing capacity required in view of the quantity of mixture required. Since the mixture preferably does not contain any binding agents or adhesives but rather is a loose composition of particles, smaller mixing containers can in principle also be used to gradually provide the desired quantity of the mixture. There is no particular time pressure with regard to the processing and application of the mixture on the base layer 310, as the mixture preferably does not contain any binder or adhesive with a limited time window for processing until curing that would have to be taken into account.

[0075] Alternatively, the mixture 402 can also be produced in a factory and then transported in sacks or loose on a truck to where the new sports floor is to be created.

[0076] Next, in step 204, the substrate mixture is applied on a base layer 310. This step can be performed manually, automatically, or semi-automatically. For example, a mortar mixer can tip the finished, homogeneous mixture onto the area specified above. Alternatively, a technician can also apply the mixture from a bucket.

[0077] Next, in step 206 of the method, the applied mixture is leveled. For example, a person with a long rod or a rake can smooth out the mixture that has been applied to the base layer and thus make it flat and level. It is also possible for a machine, such as a mortar mixer, to travel in several lanes over the base layer, thereby applying a defined amount of the mixture to the base layer, whereby an elongated object (rod, rake, knife) in tow smooths and levels the applied mixture.

[0078] Next, in step 208, the leveled substrate mixture 402 is compacted. The compacting is performed such that the leveled substrate mixture 402 forms a compact substrate layer 302. Compaction is a process that reduces the pore space of a surface layer filled with air or other volatile materials. This gives the substrate layer a desired property; it becomes more resistant to mechanical stresses and has increased stability and ability to keep all objects contained in this layer at a constant position due to the resilience of the elastic granules in this layer. For example, compaction of the mixture 402 can be performed with vibratory or oscillating rollers, whereby the interaction of vibrations of the roller drum and the weight of the roller transform the loose stone/elastic granule mixture 402 into a compacted substrate layer 302. The intensity of compaction can be controlled, e.g., by the deflection of the drum; i.e., the amplitude of the vibration, the frequency of the vibration; i.e. the frequency and the impact time; i.e. the travel speed. For example, a single-drum compactor with padfoot drums for large amplitudes can be used.

[0079] The leveling step can in some embodiments be performed together or in combination with step 204, 208, or both.

[0080] For example, a first vehicle may comprise a rotatable container in which the mixture 402 is homogeneously mixed. While the first vehicle moves over the base layer 310, a defined amount of the mixture 402 is released and applied to the ground and an elongated object in tow of the first vehicle immediately levels the applied mixture. The first vehicle is followed by a second vehicle comprising vibratory or oscillating rollers that compact the leveled mixture.

[0081] According to another example, a first vehicle or a person may apply the mixture on the base layer while moving over the base layer. The applied mixture is not leveled at first. Then, a compaction machine or a compaction device is used for compacting the mixture. The compaction can be performed in lanes, whereby the compacted lanes overlap in order to ensure that the compacted mixture is level. In this case, the compaction step may inherently comprise a leveling step, because the applied mixture is compacted and leveled in a single operation.

[0082] Next in step 210, one or more additional layers 502, 308, and 602 are applied on top of the substrate layer. At least one of the additional layers is an elastic layer 308 that is sufficiently elastic to protect the players from injuries. Depending on the embodiment, multiple elastic layers may be applied. The additional layers may comprise various types of structurally and functionally diverse layers, depending on the particular use case scenario. For example, one of the additional layers can be an artificial turf layer, a sealing layer, a pigmented coating layer for providing a desired color impression, an adhesive layer in between two of the additional layers, barrier layers, and the like.

[0083] Any one of the additional layers, for example, may be simply placed on top of the existing layers without applying an adhesive layer. Alternatively, the additional layer can be glued to or mechanically fixed to the existing layers.

[0084] When all desired additional layers have been applied, the substrate layer in combination with one or more additional layers forms the playing surface.

[0085] FIG. 3 is a schematic, cross-sectional view of a playable structure 300 comprising a leveled, compacted mixture of stones 306 and elastic granules 304 that provides the substrate layer 310. FIG. 3 shows that the compacted mixture compensates for irregularities and depressions in the base layer 310. On the one hand, this may be due to the fact that these irregularities may already have existed when the mixture of stone and elastic granules was applied to the base layer and then compacted. On the other hand, this effect can also be the result of the compacted substrate layer in some designs losing some of the stones and the elastic granules at the points where the base layer shows damage and gaps so that these can fill the cavities created in the base layer. Hence, the substrate layer may be adapted to repair itself and the base layer automatically.

[0086] FIG. 4 is a schematic, cross-sectional view of a surface structure at three different moments during the manufacturing of the playing surface 400.

[0087] FIG. 4A shows a first state 410 of a surface structure after a loose mixture 402 of stones 306 and elastic granules 304 has been applied to a base layer 310. The surface of the base layer has holes and depressions, but these are completely filled by the stones and the elastic granules. FIG. 4A shows an essentially level but not-yet-compacted layer.

[0088] FIG. 4B shows a second state 420 of the surface structure depicted in FIG. 4A after the mixture 402 has been compacted, for example, by a roller. The stones and elastic granules are now visibly more densely packed and form the substrate layer 302. However, the substrate layer still contains air-filled cavities.

[0089] FIG. 4C shows a simple example of a complete playing surface structure 400 after an elastic layer 308 has been applied to the substrate layer 302. The playing surface 400 can be, for example, a sports floor, a playground floor, or a floor of a recreational facility.

[0090] Optionally, there may be an adhesive layer between the substrate layer and the elastic layer 308 (not shown), but this adhesive layer preferably does not penetrate the substrate layer 302 at all or only very slightly.

[0091] The base layer can be, for example, soil, sand, concrete, stones, or mixtures thereof. The base layer can likewise be wood or an existing floor pavement. The base layer is preferably an outdoor base layer.

[0092] The height of the e-layer 308 depends on the intended use. Typically, the height of the e-layer is in the range of 8 mm-40 mm.

[0093] The e-layer can be applied in situ (e.g., by generating a liquid PU reaction mixture optionally comprising elastic granules before the liquid mixture is applied on the substrate layer. The liquid mixture has self-leveling capabilities and may optionally be leveled actively with the help of a leveling device. The liquid reaction mixture has a viscosity and/or reaction speed that ensures that the liquid PU reaction mixture will not, or at least will not deeply, penetrate the substrate layer. For example, the PU reaction mixture may be adapted to harden before the mixture penetrates the upper 0.8 cm of the substrate layer, preferably before it penetrates the upper 0.2 cm of the substrate layer.

[0094] Alternatively, the e-layer is manufactured at a manufacturing plant (e.g., in the form of e-layer rolls or tiles). The rolls or tiles are transported to the use site and laid on the substrate layer of that use site. Optionally, the e-layer tracks generated by the e-layer rolls and/or the e-layer tiles are attached to the substrate layer. For example, the e-layer roll or the e-layer tiles are glued, tacked, nailed, or otherwise fixed to the base layer, thereby preventing the filling of the air cavities of the substrate layer.

[0095] Preferably, the additional layer that is applied directly on top of the substrate layer is applied without any adhesive layer in between the substrate layer and said additional layer. Alternatively, said additional layer can comprise an adhesive layer or coating on its lower side that contacts the substrate layer. In this case, however, the adhesive layer or coating is highly viscous such that it does not penetrate the compacted substrate layer deeper than a maximum penetration depth. The maximum penetration depth is, according to embodiments, 0.8 cm, preferably 0.4 cm. This may ensure that the substrate layer remains basically free of any binder or adhesive that can prevent the granules and stones from sliding into depressions in the soil that may later develop as a result of the weather.

[0096] FIG. 5 is a schematic, cross-sectional view of a playable structure 500 comprising an artificial turf layer 502. The playable structure 500 is an example for a playable structure according to embodiments of the invention that comprises more than one additional layer. Any of the one or more additional layers can simply be put onto the respective lower layer without any fixation means. Alternatively, any of the one or more additional layers is glued, nailed, tacked, or otherwise fixed onto the respective lower layer.

[0097] FIG. 6 is a schematic, cross-sectional view of a playable structure 600 comprising a sealing layer 602. The playable structure 600 is an example for a playable structure according to embodiments of the invention that comprises more than one additional layer. In this case, the structure 600 comprises the elastic layer 308 as a first additional layer and the sealing layer 602 as a second additional layer.

LIST OF REFERENCE NUMERALS

[0098] 102 sports floor [0099] 104 ground, base layer [0100] 106 cavity (cracks, depressions of base layer) [0101] 202-210 steps [0102] 300 playing surface [0103] 302 compacted mixture of stones and elastic granules [0104] 304 elastic granules [0105] 306 stones [0106] 308 elastic layer [0107] 310 base layer [0108] 400 playing surface [0109] 402 (non-compacted) stone/elastic granules mixture [0110] 410 surface structure comprising a leveled stone/elastic granules mixture [0111] 420 surface structure comprising a compressed stone/elastic granules mixture [0112] 500 playing surface [0113] 502 artificial turf [0114] 600 playing surface [0115] 602 sealing layer