NL1013987C2 - Sports pitch with grass playing surface and substrate stabilized by rock wool - Google Patents

Abstract

The foundation is stabilized by rock wool granules that, because of their irregular shape, are not easily displaced. Sand provides drainage. Organic materials such as humus and compost nourish the grass. The thickness of the rock wool layer is increased where wear is greatest, eg. the penalty area The foundation layer (1) of sand is at least 0.25m thick and contains drainage pipes at most 4m from each other. A further sand layer (2) is 0.08m thick. A layer of humus (3) is also 0.08m thick. A layer of clean rock wool (4) is of granules of up to 3mm size. Other layers can be triple-super-phosphate fertilizer (5 assumed), compost (6) and a mixture (7) of the previous two.

Description

STONE WOOL CONTAINING SUBSTRATE FOR A SPORTS FIELD

The present invention relates to a on a foundation layer. installed surface for a sports field that is at least partially covered with natural grass.

Such a substrate is generally known; this generally includes sand, topsoil and often 10 compost.

When a sports field provided on such a surface is heavily played, that is to say more than approximately 200 to 250 hours per year, there is firstly the danger that the grass layer 15 applied thereon will be destroyed, and subsequently that the surface in the places where the grass layer has been destroyed, wears out and potholes are created there. This is often visible at football fields in the penalty area and at the kick-off spot.

US-A-4 786 308 discloses a surface applied to a foundation layer 20 for a sports field at least partially covered with natural grass, wherein the surface consists at least partly of rock wool.

Thus, a surface is obtained with which, if the turf has been destroyed or at least damaged, the layer applied thereunder is less deepened, so that the entire sports field remains flat and even.

However, it appears that this surface is only abrasion resistant to a limited extent, so that it can be played on for a limited number of hours per year.

The object of the present invention is to provide a surface that can be played on for several hours a year.

This object is achieved in that the rock wool is formed at least in part by rock wool granulate.

The stone wool granulate stabilizes the soil, because the granulate is angular and angular, and the granulate granules are difficult to obtain 1 01 3987

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2 are movable. This leads to a stabilization of the ground, which improves the flatness of the sports field, even when the grass is overplayed.

Preferably, the substrate outside the stone wool granulate comprises sand or topsoil.

This ensures a better breeding ground for the grass plants, while also improving the hydrophysical behavior of the substrate. On the one hand, due to the different grain size of the rockwool granulate or the rockwool flakes and the sand, a certain degree of water retention is obtained, while on the other hand sufficient permeability is obtained to allow good drainage. The topsoil here serves in particular for supplying organic material to the grass plants.

(The addition of organic matter, for example in the form of compost, also improves water management.

Said advantages are enhanced when mixing between the various layers has taken place.

The invention further relates to a method for applying a substrate to a sports field at least partly covered with natural grass, wherein rock wool is one of the components and the various components are initially applied to the foundation and subsequently mixed in situ.

Since these are often large quantities, it is attractive to allow mixing in situ.

According to another method, rock wool also belongs to the components and the components are initially mixed ex situ and then applied to the foundation.

In contrast to the previous method, the mixture must be transported after the mixing process; the mixing process can take place ex situ in more controllable conditions than in situ, so that the mixture can be more homogeneous.

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Incidentally, it is possible to use combinations of the two methods mentioned above. For example, it is possible to mix a number of components ex situ and then mix them in situ after addition of additional components.

A particularly attractive method is obtained when a layer of sand is initially applied to the foundation, then a layer of topsoil is applied to the sand, after which a layer of rock wool granulate is applied to the topsoil and the layers applied are mixed.

Other attractive working methods are evident from the other sub-claims.

It is further pointed out that the substrate in vertical profile does not have to be completely homogeneous, for instance it is possible to increase the content of rock wool close to the top, since this is where the greatest mechanical loads occur. Variations are also possible in the horizontal plane. It is attractive, for example, to increase the rock wool fiber content in the vicinity of the kick-off dot.

The present invention will be elucidated hereinbelow with reference to Fig. 1a-g, in which the stages of building up a substrate according to the present invention are schematically consecutive.

A substrate 1 of sand, in particular standard sand, with a thickness of at least 0.25 m is assumed.

30 For drainage, the foundation layer must be provided with drainage pipes, preferably extending in the longitudinal direction of the field, with a mutual distance of maximum 4 m.

Then, as shown in Figure 1a, a sand layer 2 is applied with a thickness of 0.08 m. After applying this sand layer, it is leveled.

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A layer of topsoil with a thickness of at least 0.08 m is then applied.

A layer of rock wool granulate 4 is then applied to the layer of topsoil.

Preferably, use is made of stone wool granulate, the dimensions of which are between 0 and 3 mm. The rockwool granulate must of course be clean and free from contamination.

After this, the rock wool granulate is leveled and possibly fertilization is applied, consisting of triple superphosphate and slurry.

Then the applied layers are mixed by means of a milling device. Care is taken here that approximately 1 cm of the sand layer 2 is not included in the mixing process. The situation as shown in Figure 1d is then obtained.

This is again compacted and a layer of organic material, such as compost 6, is applied, as shown in figure 1e. This layer is also leveled, after which a mixing process is carried out again. The organic material is mixed with the mixture 5 already present, so that a mixture 7 is formed.

Finally, the mixture thus formed is mixed again by means of a rotary harrow, in addition, the bottom sand layer 2 is also taken along and a layer of approximately 2 cm from the ground surface is taken along. This substrate must then of course consist of miscible material, preferably sand.

Finally, the resulting mixture is compacted, leveled again, fertilized and sown.

The top layer thus formed with mineral wool granulate applied therein thus has the advantage of a high stability, a good hydrophysical behavior, whereby the generally disadvantageous effects of adjoining layers of different grain sizes are well avoided by mixing. .

It is noted here that the mixing naturally takes place such that during the mixing process only transport of the various materials takes place in the vertical direction; the top layer will thus have a relatively high content of organic material and rock wool granulate. The structure is stable after the mixing process.

Finally, it is pointed out that the mixing described above can also take place ex situ. However, it is then not possible to fit horizontal profiles. However, this is possible if the layers are mixed ex situ in portions and subsequently applied in layers.

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Claims (10)

1. Substrate 5 applied to a foundation layer for a sports field at least partly covered with natural grass, wherein the substrate consists at least partly of rock wool, characterized in that the rock wool is formed at least partly by rock wool granulate. Substrate according to claim 1, characterized in that the substrate outside the rock wool comprises sand or topsoil. Substrate according to claim 1 or 2, characterized in that the substrate outside the rock wool comprises organic material, for example compost. Substrate according to claim 2 or 3, characterized in that the rock wool is mixed with the sand, topsoil or organic material. Substrate according to any one of the preceding claims, characterized in that the substrate has a greater density of rock wool at the top than at the bottom. 6. Method for applying a foundation to a foundation for a sports field at least partly covered with natural grass, characterized in that rock wool granulate is one of the components and the components are initially applied to the foundation and then mixed in situ. 7. Method for applying a foundation to a foundation for a sports field covered at least partly with natural grass, characterized in that rock wool granulate is one of the components and the components are mixed at least partially ex situ and then on the foundation. to be applied. Method according to claim 6, characterized by the following steps: - applying a layer of sand to the foundation; 1 01 3987 • * - applying a layer of topsoil on the sand; - applying a layer of rock wool granulate to the topsoil; and 5. subsequently mixing the applied layers. Method according to claim 8, characterized in that a layer of organic material is applied to the mixed layer. A method according to claim 9, characterized in that the organic material layer is mixed with the underlying layer. f 1 01 3987