DK154843B - PROCEDURE FOR PREPARING A COAT FOR USE IN SPORT PLACES, INSIDE TENNIS COURSES - Google Patents

Description

DK 154843 B

The present invention relates to a method of producing a coating of the kind specified in the preamble of the claim for use in sports fields, especially tennis courts.

German Patent Application No. P 31 11 128.9 relates to a surface-3 coating for use in sports centers, in particular tennis courts, and a method for making such a coating. The upper layer of the present surface is formed of a bonding mass consisting essentially of brick dust, a mineral material and an inorganic binder. The bonding mass is a doughy aqueous slurry which contains as a binder a tile binder, ie. a hydraulic hardening thin mortar according to German standards DIN 18 156. In accordance with the process for making said surface 15, a doughy slurry consisting of the tile binder, tile dust and mineral material, preferably quartz sand, is applied in water on a formed foundation with a substantially planar surface.

According to the aforementioned German patent application, the 20 surface components are applied in the form of an aqueous slurry to the manufactured foundation on which the slurry is cured.

The slurry prepared should have a porridge-like consistency with a relatively low water content, so as to ensure that the surface after curing is permeable to water. The preparation of a usable slurry involves some difficulties, as the contact between the binder and the moist brick dust can cause clump formation, and the high viscosity of the slurry formed requires great effort to achieve uniform mixing of all the components. When the prepared aqueous slurry is transported to the produced foundation, there is a danger that the pre-planned surface of the foundation will be dislodged due to wheel pressure or 2

DK 154843 B

similar loads. Following the bonding, the layer formed by the aqueous slurry has a smooth and dense surface comparable to the surface of hardened concrete. This surface must be mechanically roughened in a special operation step before the surface can be used as a coating on tennis courts.

It is the object of the present invention to provide a method of producing a surface coating for use in sports centers, in particular 10 tennis courts, which has the surface coating of the parts disclosed in the above-mentioned German patent application No. P 31 11 128.9 at the same time as avoiding the disadvantages associated with the preparation and application of an aqueous slurry of the surface components. The present invention provides for facilitating the application of the coating to the produced foundation, to increase the water permeability of the finished surface and / or to eliminate the need to roughen the surface mechanically after curing.

In order to achieve this, the process according to the invention is characterized in that: a) the substrate is applied to brick dust, mineral material and binder in the form of a dry mixture; b) the dry mixture is planed, smoothed and compressed, 25 and c) the compressed mixture is sprayed with water until uniform wetting of the layer is achieved.

In addition to brick dust, the surface must contain hard, preferably rounded particles of an inert material, for example particles of quartz sand. Another and especially 3

DK 154843 B

A significant difference from the conventional brick dust-containing cover layers is that in the process according to the invention a "bonded" layer is obtained, in which the tile adhesive serves as a specialized extra binder.

Surprisingly, it has been found that in carrying out the process according to the invention, hard, paving-like or concrete-like covering layers are avoided, and, after the above-mentioned addition of water, a loosely bonded mass is obtained from the compressed aggregate mixture after the curing reaction has taken place. It is clear that the clay dust of the brick dust participates in the bonding process produced by the tile adhesive.

In the method according to the invention, on the one hand, the compactness of the brick dust layer can be significantly increased, so as to obtain a greater abrasion resistance, while on the other hand the sliding characteristics of the coating can be adjusted (for example, as the static or sliding friction of the surface under a specific load -20 ning) over a wide range by carefully selecting the quantities of the components contained in the surface layer. Despite the increased strength, it is possible to maintain to a large extent the slip conditions which characterize the known surface layers of brick dust. These 25 slip characteristics can also be set to certain values according to the selected requirements.

Finally, by selecting specific thicknesses, the degree of softness of the overlay for a given composition can be affected.

The method of the invention provides a surface layer with an exceptionally high abrasion resistance which is substantially better than the abrasion resistance of an ordinary sand web. The surface layer is frost resistant so that 4

DK 154843 B

where, when combined with a winter-resistant foundation, no special renovation work is required after the winter break.

The surface layer produced by the method of the invention has been found to be water resistant while being permeable to water at least equal to the permeability of conventional sand webs. Thus, after a rainfall, the excess water will quickly, ie. over 10 of a few minutes, it passes through the porous surface layer and down to the foundation, which then carries the water away. Even during significant and sustained periods of drought, the surface layer particles do not loosen, ensuring that no significant dust formation occurs. In this way, the surface coating made according to the invention allows the sports ground to be used largely independently of the weather without requiring further measures such as the known sweeping, drumming and / or watering. Thus, since dust formation 20 is substantially reduced, the surface coating made according to the invention can also be used as flooring on indoor tennis courts.

Finally, it is very easy to repair over the surface layer made by the method of the invention, simply applying new amounts of the dry aggregate mixture to the worn areas, and then carefully spraying these areas with water. The newly applied material will thereby bond and adhere to the existing surface material, even in very thin layers, without the need for additional measures.

The method according to the invention is described below in more detail in relation to the preparation of a surface layer for tennis courts. The significant com- 5

DK 154843 B

components for making such a surface layer are brick dust, tile adhesive and quartz sand.

The tile dust used is a well-known, commercially available product widely used in the manufacture of surface layers for known tennis courts.

Preferably, a brick dust with a granulometry of 0/3 is used, i.e. a material whose average particle diameter does not substantially exceed 3 mm.

The tile adhesive is also a known and commercially available product, which is commercially referred to as a hydraulically bonding thin mortar (see standard DIN 18 156, parts 1 and 2). Hydraulic hardening thin mortar materials of this type are powdery mixtures of hydraulic binders, mineral additives (whose particle size does not exceed 0.5 mm) and organic additives.

Preferably, such tile adhesives are used which satisfy the requirements for thin mortar set forth in standard DIN 18 156-M (as compared to DIN 18 156, part 2). In contrast to this ordinary work-up of the tile adhesive, a careful mixing of the dry binder powder with the other solids is carried out in the present case, after which the obtained mixture is uniformly wetted with water.

The composition of such tile adhesives is well known.

Such tile adhesives consist essentially of about 24.8 - 89.8 wt. Of cement, about 10 - 75 wt. Additives such as sand and / or ground limestone, and about 0.2 - 6.5 wt. methyl cellulose, and they may additionally contain other selected components, in particular 30 up to 10 wt. Si of a vinyl chloride and vinyl propionate blend polymer, up to 6 wt. of a melamine-formaldehyde condensation product, up to 0.1. wt% polyacrylamide,

DK 154843B

6 up to 25 wt.% Of a mineral material in the form of volcanic tufts and / or up to 5 wt. K fibrous material, preferably asbestos. Examples of cement include the following types of cement: Portland cement, Port-5 land slag cement, limestone slag cement, iron ore cement and puzzolan cement. For the present purpose, the following compositions have been found to be particularly suitable:

Tile Adhesive I with

48.0 weight in Portland cement PZ 55 F

45.0 wt-Si. washed, flame-dried quartz sand 0.1 - 0.6 mm 4.2% by weight dispersible powdered polymer based on vinyl chloride / vinyl propionate weight o methylcellulose (degree of substitution 30 ° in methoxyl viscosity 10,000 mPa for a 2¾ aqueous solution according to Brookfield at 20 ° C and 20 rpm 20 wt% calcium oxalate

Tile adhesive II with 47.0 wt .- 0 Blast furnace 48.0 wt .- 0 washed flame-dried quartz sand. . P .2 0.6 mm 2.5 wt.% Methyl hydroxyethyl cellulose (degree of substitution 25¾ methoxyl. 10¾ ethylene glycol ether; viscosity: 20 · ΟΟΌ mPa for a 2¾ aqueous solution according to Brookfield at 20 ° C and 20 rpm) 2.0 weight in cellulose fibers, diameter: approx. 30 µm, length: approx. 300 µm 0.5 weight in calcium chloride 7

DK 154843 B

The quartz sand used is of the type commonly used in the building industry with the quality designation "rough"; this quartz sand has an average particle size of up to 0.7 mm. In addition to finely formulated silica, the term "quartz sand" includes other fine-grained, inert mineral substances as well as mixtures of silica with such mineral substances.

In addition to the essential components indicated, 10 additives such as dyes, fungicides, bactericidal or herbicidal agents and other known additives can be used.

The hardness and strength of the surface coating obtained by the method of the invention, as well as the slip conditions in the surface of the coating, can be adjusted within wide limits by appropriate selection of the amounts of the constituent components. The desired slip conditions cannot be achieved without the presence of a minimal amount of quartz sand, especially under wet conditions. With the prescribed amounts of brick dust and quartz sand, an increase in the amount of tile adhesive will lead to an increase in the hardness and an increase in the coefficients for the static friction and the friction friction. These coefficients of friction can be used as a criterion for the slip conditions. To determine these 25 coefficients of friction, a test blank (length 10 cm, width 5 cm, thickness 0.5 cm) of smooth rubber for shoe soles is used, and this blank is passed over surfaces to be tested under a load of 150 N with a speed that starts at 0 and reaches up to 3 cm / sec. The 30 required tensile forces are measured with a dynamometer and the coefficient of friction is determined by the formula:. . i_ T row power t

Coefficient of friction = --r—;

Load.

DK 154843B

8

The coefficient of static friction is related to the force needed to move the test piece. The coefficient of the slip friction corresponds to the required force at a speed of 3 cm / 5 sec. Under these conditions, the coefficients of friction (static and slip friction) of known brick dust surfaces were determined to be about 2.7 - 3.0. Friction coefficients in this range can also be obtained for surface coatings made by the method of the invention by appropriately selecting the amounts of the various components. With the prescribed amounts of brick dust and tile adhesive, an increase in the amount of quartz sand will lead to a reduction of these 15 coefficients of friction, which will increase the slip on the surface.

In order to produce a surface coating especially suitable for use on a tennis court, one can mix 100 parts by volume of brick dust with 10 - 90 parts by volume of quartz-20 sand and 20 - 60 parts by volume of tile adhesive (in practice it has proved appropriate to work with parts by volume, since the effects of the often varying moisture content of the brick dust, which in practice is difficult to determine, are largely eliminated). To prepare a dry mixture, preferably 100 parts by volume of brick dust is mixed with 20 - 60 parts by volume of quartz sand and 35 - 55 parts by volume of tile adhesive. The tile adhesive used in this case has the composition listed above as "tile adhesive I" or "tile adhesive II" and this does not lead to any appreciable differences in the properties of the surface layer.

The minimum layer thickness of the finished and cured surface should be 10 mm, or at least 5 mm. A maximum value for the thickness of the surface layer appears 9

DK 154843 B

considering that the surface layer becomes softer as the thickness increases. For this reason, the thickness of the layer should not exceed 30 mm, and the layer should under no circumstances be more than 35 mm thick. With higher 5 layer thicknesses, one must expect the possibility of cracking and a reduction of water permeability. Layer thicknesses of between 15 and 25 mm have been found to be suitable and a layer thickness of about 20 mm is particularly preferred. In the method according to the invention, the pre-prepared mixture is applied in a dry state to the produced substrate, after which the mixture is smoothed and compressed.

In compression, the thickness of the layer is reduced, which means that the loose dry aggregate must be applied with a greater layer thickness in order to provide a surface of the layer thicknesses specified above after compression and curing. In general, the thickness of the loose unbonded layer is of the order of 15-20% due to the compression and curing, so that the dry loose mixture must be applied to the substrate in a correspondingly thicker layer to obtain the above layer thicknesses. in the finished surface.

For many applications, a satisfactory surface layer can be obtained if the surface coating made according to the invention is provided on a flat, solid, dry and water-derived substrate. Such a substrate may be the available soil itself, or it may be specially made. The typical layer sequence for 30 tennis courts, consisting of a filter layer, a carrier layer and a dynamic layer in accordance with DIN standard 18 035 page 5, is considered particularly suitable as a substrate, and the coating produced by the method according to the invention then serves as a final surface. .

DK 154843 B

ID

Furthermore, the method according to the invention makes it possible to prepare the surface coating on top of a water-permeable, bituminous or cement bonded base, for example on a base in the form of a known hard web. If a given asphalt or concrete pavement is to serve as a base and the water permeability of that base is insufficient, a number of holes can be drilled through this sub-pavement and into the water-absorbing underlying soil.

The dry mixture prepared from the aforementioned tea components is placed in the dry state on the substantially plane surface of the soil or the foundation produced. The mixing of ingredients takes place in a conventional manner.

The resulting dry mixture is applied to the surface of the substrate in the prescribed layer thickness, after which it is leveled and compressed in the dry state. The compression can be carried out with the aid of various devices. A manually drawn drum and 20 commonly used for the planning of tennis courts has proved suitable. The compression should not be carried out to an excessive extent as this will result in unsatisfactory moisture penetration into the compressed material upon subsequent irrigation. Preferably, the drum is terminated when the thickness of the loosely applied and leveled layer is reduced by about 15 - 20¾.

The applied compressed layer, which is still dry, is then subjected to a spray with water. During the application of the spraying, uniform moisture absorption should be ensured throughout the total thickness of the layer of the compressed material. It is advantageous to perform the irrigation with as fine water drops as possible and 11

DK 154843 B

to avoid significant local excess water. If the surface of the compressed layer is applied to too much water, the curing reaction will take place relatively quickly in the areas of the layer which are close to the surface, 5 which prevents the moisture from penetrating into the deeper layers. In this way, there is a risk that the surface homogeneity over the total thickness will be reduced.

For example, good results are obtained by spraying the compressed surface as finely as possible until the water 10 remains briefly on the surface before absorbing. This spray is repeated after a few minutes, until the water remains briefly on. ·. surface, and this procedure is repeated again.

In a practical experiment carried out under these conditions 15 with a compressed layer, the thickness of which was 25 mm, about 4 to 6 liters of water was applied. m.

After the compressed layer is wetted as uniformly as possible, the layer cures over the total layer thickness over about 12 hours. The course can be used for 20 tennis games after about 2-3 days in dry weather. After bonding the layer, the surface may, if necessary, be applied to a layer of very fine brick dust to accelerate the appearance of the typical slip conditions which characterize conventional brick dust webs.

The surface coating prepared by the method of the invention can be applied to a wide variety of sports pitches. The surface coating in question is particularly suitable and intended for use on tennis courts. When the surface coating is used as a tennis court, there is no unnecessary development of dust, nor should the water be irrigated, as is usually the case with conventional brick dust courts, and therefore, the surface coating in question can also be used on indoor sports grounds. Among • t 12

DK 154843 B

The other applications include hard courses for other ball games, long jump courses and courses for running and sprinting.

Claims (1)

GB 154843 B P_a tentk r_a v: Process for the preparation of a coating for use in sports fields, especially tennis courts, whereby a mixture of brick dust, mineral material and a tile adhesive is applied, more specifically a hydraulically bonded thin-layer mortar in accordance with with the standards applicable in Germany, DIN 18 156, characterized by: a) applying the substrate the mixture of brick dust, mineral material and tile adhesive in the dry state; 10 b) planing, smoothing and compressing the dry mixture on the substrate, and c) spray the compressed mixture with water until uniform wetting of the layer is achieved.