EP0066099B1 - Method of establishing a surfacing for sports grounds, in particular for tennis courts - Google Patents

Description

The invention relates to a method according to the preamble of patent claim 1.

The post-published DE-A-31 11 128 dated March 20, 1981 claims a covering for sports facilities, in particular tennis courts, and its manufacture, and is based on the preamble of claim 1. The covering layer of that covering is formed from a setting mass consisting essentially of brick powder, mineral material and inorganic binder. That setting mass is a dough-like, aqueous slurry which contains as a binder a tile adhesive, namely a hydraulically hardening thin-bed mortar in accordance with DIN 18 156. In accordance with the process for producing that covering, a dough-like slurry of tile adhesive, brick powder, mineral material, preferably quartz sand, is applied to water on a prepared substructure with an essentially flat surface.

The invention according to that DE-A-31 11 128 also goes back to the inventor named for the present application. With reference to DE-A-31 11 128, its content is also to be made part of the present application insofar as this is necessary for understanding and further explaining the present invention.

According to that older proposal, the covering components are applied in the form of an aqueous slurry to the prepared substructure and set there. The finished slurry should have a pulp-like consistency with a relatively low water content, so that after the setting a good water permeability of the covering is guaranteed. The preparation of a usable slurry presents some difficulties, since lump formation can occur when the tile adhesive comes into contact with moist brick powder and the high viscosity of the slurry which forms requires high gravitational forces in order to achieve an even distribution of all components. When transporting the prefabricated aqueous slurry onto the prepared substructure, there is a risk that the previously leveled substructure surface will become uneven due to wheel impressions or the like. After setting, the covering formed from the aqueous slurry has a smooth, dense surface, comparable to the surface of set concrete, which must be mechanically roughened in a separate operation before using the covering as a tennis court or the like.

• a) Ziegelmehl, mineralisches Material und dieser Fliesenkleber in Form eines trocken-vermischten Teilchengemisches auf dem Unterbau aufgebracht werden;
• b) das trockene Teilchengemisch dort eben planiert und verdichtet wird; und
• c) das verdichtete Teilchengemisch mit Wasser besprüht wird, um die Teilchengemisch-Schicht gleichmäßig zu befeuchten.

The object of the present invention is to provide a method for producing a covering for sports facilities, in particular tennis courts, which covering has the advantages set out in German DE-A-31 11 128, but the manufacture of which involves the preparation and application of an aqueous one Avoid slurry of the covering components associated disadvantages. In particular, the application to the prepared substructure should be facilitated, the water permeability of the finished covering increased and / or mechanical roughening of the surface of the set covering should be avoided. Starting from a process for producing a covering for sports facilities, in particular tennis courts, in which process brick powder, mineral material and tile adhesive, namely hydraulically hardening thin-bed mortar according to DIN 18 156, are applied to a prepared substructure, the solution according to the invention of the above object is that

• a) Brick flour, mineral material and this tile adhesive in the form of a dry-mixed particle mixture are applied to the substructure;
• b) the dry particle mixture is leveled and compacted there; and
• c) the compressed particle mixture is sprayed with water in order to uniformly moisten the particle mixture layer.

Advantageous embodiments of the method according to the invention relate to the selection of the tile adhesive, the mineral material, the composition of the dry-mixed particle mixture, the sequence of adding the components during the preparation of the particle mixture, the application of the particle mixture to the substructure surface and the preferably repeated spraying of the compressed particle mixture with quite fine water droplets, as indicated in the subclaims.

According to the method according to the invention, a covering for sports facilities, in particular tennis courts, is thus obtained which has a top layer containing brick flour on a mostly customary substructure, for example on a substructure with the typical layer sequence of a tennis surface in accordance with DIN 18 035 sheet 5; in such a case the dry premixed particle mixture is applied to the dynamic layer of such a substructure to form the tennis surface.

In addition to brick flour, the covering must contain hard, preferably rounded, particles made of an inert material, for example quartz sand particles. Another, particularly important difference to conventional brick meal cover layers is the fact that a bonded covering is obtained by the process according to the invention, with tile adhesive serving as a special and additional binder. Surprisingly, it has been shown that the formation of a hard, screed-like or concrete-like top layer is avoided when working by the process according to the invention, and instead a loosely bound mass after the targeted addition of water from the dry-mixed and compressed particle mixture after the setting reaction has been carried out is obtained. The clay minerals in the brick powder obviously also take part in the setting process caused by the tile adhesive.

Strapazierfähigkeit erhalten wird;

kann durch gezielte Auswahl der Mengenanteile der Belagbestandteile der Wert des Rutschverhaltens, beispielsweise bestimmt als Haft- oder Gleitreibung an der Belagoberfläche unter bestimmter Belastung in einem weiten Bereich eingestellt werden. Insbesondere kann tro" der gesteigerten Festigkeit weitgehend das

der bekannten Ziegelmehl-Deckschicht erhalten werden. Daneben kann das Rutschverhalten auf bestimmte Werte für gezielte Anforderungen eingestellt werden. Schließlich kann bei gegebener Zusammensetzung der Deckschicht deren Weichheit durch Auswahl bestimmter Schichtdicken beeinflußt werden.According to the inventive method on the one hand, the strength of the brick powder layer can be increased significantly, so that a

Durability is maintained;

the value of the slip behavior, for example determined as static or sliding friction on the surface of the covering under certain loads, can be set within a wide range by targeted selection of the proportions of the covering components. In particular, the increased strength can largely do that

the well-known brick powder top layer can be obtained. In addition, the slip behavior can be set to specific values for specific requirements. Finally, given the composition of the cover layer, its softness can be influenced by selecting certain layer thicknesses.

The method according to the invention results in a cover layer of extremely high durability, so that practically no care and / or maintenance work is required even after playing tennis for several hours. The surface layer proves to be frost-proof, so that no special renovation work is required even after the winter break when used with a winter-proof substructure.

The covering produced according to the invention proves to be waterproof and is permeable to the extent necessary; i.e. after a rain, excess water quickly, i.e. within a few minutes, through the porous cover layer to the substructure and derived from it. Even when there is considerable dryness in the tangan, the surface covering layer particles do not detach, so that no significant dust formation occurs. The topping produced according to the invention thus permits largely weather-independent playability without additional measures such as the known removal, rolling and / or watering. Since the formation of dust is considerably reduced, the covering produced according to the invention can also be provided as a floor covering in tennis halls and the like.

Finally, the covering produced according to the invention can be repaired particularly easily, since the dry premixed particle mixture is simply applied again to worn areas and is then carefully sprayed with water. The newly applied material binds securely to the existing covering material even in a very thin layer thickness without additional measures.

The method according to the invention is explained in detail below on the basis of the production of a cover layer for tennis courts. Brick powder, tile adhesive and quartz sand are used as essential components for creating such a covering layer.

The well-known, commercially available product is used as brick flour, which is widely used to form the top layer in known tennis courts. Brick flour of grain size 0/3 is preferably used, i.e. a material whose average particle size should not significantly exceed 3 mm.

Tile adhesive is also a well-known, commercially available product, which experts call hydraulic thin-bed mortar (cf. DIN 18156, Parts 1 and 2). Such hydraulically hardening thin-bed mortars are powdery mixtures of hydraulic binders, mineral aggregates (usually 0.5 mm grain size) and organic additives. In the context of this invention, tile adhesives which meet the conditions for thin-bed mortar DIN 18156-M (cf. DIN 18 156, Part 2) are preferably used. Deviating from the usual processing of tile adhesive, the dry tile adhesive powder is carefully mixed with other solids in the present case, and the mixture obtained is moistened uniformly with water.

The composition of such tile adhesives is known. For example, German Patent 1,158,430 discloses the use of a mortar that dry 24.8 to 89.9% by weight Portland cement, 0.2 to 6.5% by weight methyl cellulose with a viscosity between 10 and 7000 cP, measured in a 2% aqueous solution, and contains about 10 to 75% additives such as sand or ground limestone and about 10 to 40% water are added to the use, so that the viscosity of the water phase of the mixture is at least 500 cP to Laying tiles and tiles, covering the surface to be tiled with a layer of mortar and pressing the tiles dry into it. There, as well as in US Pat. No. 2,934,932, a number of exemplary tile adhesive compositions which can be used for the present purpose are given. A laying mortar is known from German patent specification 1 646 493 which, in addition to cement and graded sand, contains 0.1 to 1.5% by weight of methyl cellulose and 1.0 to 10% by weight of a copolymer of 20 to 80% by weight. Contains vinyl chloride and 80 to 20 wt .-% vinyl propionate. In addition, this laying mortar can also contain 5 to 25% by weight of tress. Furthermore, German Auslegeschrift 2 146 709 describes the use of a mortar mixture for laying tiles and tiles in the thin bed method, consisting of 25 to 85% by weight of cement, 0.05 to 0.15% by weight of methyl cellulose with a viscosity of 1000 to 3000 cP, measured in a 2% aqueous solution, melamine-formaldehyde condensation products containing 1.5 to 6% by weight sulfonic acid groups and having a viscosity of 40 to 500 cP, measured in 20% aqueous solution, 0.02 to 0 , 1% by weight of water-soluble, nonionic polyacrylamide, each based on the total weight of the dry mixture, the rest of sand and / or ground limestone. This mortar mixture can additionally contain 0.5 to 5% by weight of asbestos fibers.

With reference to these publications, their content, insofar as it relates to the composition of tile adhesive, namely hydraulically hardening thin-bed mortar within the meaning of DIN 18 156, part 1 and part 2, is also to be made part of the present application.

According to these publications, such tile adhesives essentially consist of approximately 24.8 to 89.8% by weight of cement, approximately 10 to 75% by weight of aggregates such as sand and / or ground limestone and approximately 0.2 to 6.5% by weight. -% methyl cellulose, and can optionally contain other components, namely up to 10 wt .-% copolymer of vinyl chloride and vinyl propionate, up to 6 wt .-% melamine-formaldehyde K-ondensationsprodukt, up to 0.1 wt .-% polyacrylamide, to 25% by weight of tress and / or up to 5% by weight of fibrous material, preferably asbestos. As cement, for example, Portland cement, Portland slag cement, lime slag cement, iron ore cement, pozzolana cement and the like come into consideration. The following compositions have proven particularly useful for the present purpose:

Tile adhesive 1 with

• 48.0% by weight of Portland cement PZ 55 F
• 45.0% by weight of washed, fire-dried quartz sand 0.1-0.6 mm
• 4.2% by weight dispersion powder polymer based on vinyl chloride / vinyl propionate
• 2.5% by weight methyl cellulose (degree of substitution) 30% methoxyl; Viscosity 10,000 mPas for a 2% aqueous solution according to Brookfield at 20 ° and 20 rpm)
• 0.3% by weight calcium oxalate

Tile adhesive 11 with

• 47.0% by weight blast furnace cement HOZ 35 L 48.0% by weight washed, fire-dried quartz sand 0.2 - 0.6 mm
• 2.5% by weight of methylhydroxyethyl cellulose (degree of substitution 25% methoxyl, 10% ethylene glycol ether; viscosity: 20,000 mPas for a 2% aqueous solution according to Brookfield at 20 ° C. and 20 rpm)
• 2.0% by weight of cellulose fibers, diameter: approx. 30 µm, length: approx. 3oo µm
• 0.5% by weight calcium chloride

The product of the "coarse" quality level usually used in the construction industry serves as quartz sand, such quartz sand has an average particle size of up to about 0.7 mm. The term "quartz sand" is intended to include not only finely ground silicon dioxide but also other finely divided, inert minerals and mixtures include from silica with such minerals.

If this is desired, other additives can be provided in addition to the specified essential components, such as dyes, fungicidal, bactericidal or herbicidal agents and other known additives.

• Reibbeiwert = Zugkraft / Belastung

The hardness and strength of the cover layer obtained by the process according to the invention and the slip behavior on the surface of this cover layer can be adjusted to a large extent by appropriate selection of the proportions of the components mentioned. The desired slip behavior cannot be achieved without a minimum proportion of quartz sand, especially when it is wet. With given proportions of brick powder and quartz sand, an increase in the proportion of tile adhesive leads to an increase in hardness and an increase in the coefficient of friction of adhesion or sliding friction. Such coefficients of friction can be used as a guide for the slip behavior. To determine these coefficients of friction, a test specimen (10 cm long, 5 cm wide, 0.5 cm high) made of smooth shoe sole rubber is passed over the test surface under a load of 150 N at a speed of initially 0 to finally 3 cm / sec. The required tensile forces are measured with a power box, and the coefficient of friction according to the formula:

• Coefficient of friction = tensile force / load

determined. The coefficient of friction of adhesion refers to the force required to set the test specimen in motion; the coefficient of friction of the sliding friction corresponds to the force required at a speed of 3 cm / sec. Under these conditions, friction coefficients of adhesion and sliding friction in the range from approximately 2.7 to 3.0 were determined for known brick dust coverings. By suitable selection of the proportions and the various components, friction coefficients in this area can also be achieved on the cover layers produced according to the invention. With given proportions of brick powder and tile adhesive, an increase in the quartz sand content leads to a decrease in these coefficients of friction, which as a result promotes slipping on the surface of the surface layer.

To prepare a top layer that is particularly suitable as a tennis court covering, 100 parts by volume of brick powder can be mixed with 10 to 90 parts by volume of quartz sand and 20 to 60 parts by volume of tile adhesive. (Working with vol. Parts has proven itself well in practice, since here the effects of the frequently changing and, in practice, difficult to check moisture content of the brick powder are largely eliminated). Preferably, to prepare the dry-mixed particle mixture, 100 parts by volume of brick flour with 20 to 60 parts by volume of quartz sand and 35 to 55 parts by volume of brick flour mixed. In this case, the composition "Tile Adhesive I" or "Tile Adhesive 11" given above was occasionally used as the tile adhesive, without this leading to any noteworthy differences in the properties of the top layer.

Thanks to the high strength of the covering produced according to the invention, it can be produced in a relatively small layer thickness on the prepared substructure. The minimum layer thickness is determined by the intended service life of the covering. In this regard, the minimum layer thickness of the finished, set covering should be 10 mm, but at least 5 mm. A maximum layer thickness results from the observation that when the layer thickness of the cover layer increases, its softness increases; the layer thickness should therefore not be more than 35 mm, in particular not more than 30 mm. With larger layer thicknesses, cracking and a decrease in water permeability must also be expected. Layer thicknesses between 15 and 25 mm have proven successful, a layer thickness of approximately 20 mm being particularly preferred. In the method according to the invention, the dry premixed particle mixture is applied in a dry state to the prepared substructure, leveled there and compacted. During the compaction, the layer thickness decreases, so that the loose, dry particle mixture must be applied in a larger layer thickness in order to obtain a covering with the layer thicknesses specified above after compression and setting. In general, the layer thickness of the loose, loose particle mixture decreases by the compression and setting by about 15 to 20%, so that to ensure the above-mentioned layer thicknesses of the finished covering, the dry, loose particle mixture is applied in a correspondingly higher layer thickness to the prepared substructure got to.

For many applications, a satisfactory covering is obtained when the covering is produced on a flat, firm, dry and water-draining surface using the process according to the invention. Such a subsoil can be the naturally existing floor or a prepared substructure. In particular, the layer sequence with filter layer, base layer and dynamic layer according to DIN 18 035, sheet 5, which is typical for tennis courts, is suitable as the substructure, the top layer produced according to the invention then serving as the tennis surface. With reference to DIN 18 035, sheet 5, the content thereof, insofar as it is necessary for further explanation of the substrate, filter layer, base layer and dynamic layer including their materials, grain sizes and requirements, should also be made part of the present application. Furthermore, according to the method according to the invention, the covering can be produced on a water-permeable, bituminous or cement-bound base, for example on a base in the form of a known hard court. If a given asphalt or concrete layer serves as a base and its water permeability is insufficient, a number of holes can be drilled through this layer into the water-draining surface.

The dry premixed particle mixture of the constituents mentioned is applied in a dry form to the essentially flat surface of the prepared substrate or substructure. The components can be mixed in conventional devices, for example in rotating drums with drum inserts which promote the mixing. The devices which are customary for producing concrete, for example the known vehicles for simultaneously mixing and transporting ready-to-use concrete, have proven successful. Preferably, the brick powder and the quartz sand are first put into the mixing drum or the like. These two components are roughly mixed together by rotating the drum a few times. The powdered, dry tile adhesive is then added and distributed uniformly in the other components. When adding the tile adhesive, it is advisable to avoid a local excess of tile adhesive. As far as possible, the tile adhesive should be placed in the rotating mixing drum to the mixture of quartz sand and brick powder. After adding the tile adhesive, the mixture should be mixed for at least 5 minutes to ensure an even distribution.

The dry-mixed particle mixture obtained is applied in the intended layer thickness on the surface of the substructure, leveled there largely and then compressed in the dry state. The compression can be done with different devices. A hand-drawn roller, as is usually used for compacting tennis courts, has proven to be suitable. The compression should not be carried out too far, since otherwise the moisture does not penetrate sufficiently into the compacted material during subsequent watering. Rolling is preferably ended when the layer thickness of the loosely applied and leveled particle mixture has decreased by approximately 15 to 20%.

Then the still dry, compressed particle mixture layer is sprayed with water. With this spraying, uniform moisture absorption should be achieved over the entire layer thickness of the compacted layer. For this purpose it is expedient to work with water droplets which are as fine as possible and to avoid a considerable local excess of water. Unless you are on the If too much water is applied to the surface of the compacted layer, the setting reaction takes place relatively quickly in the areas of the cover layer near the surface, which prevents moisture from penetrating into deeper areas. This can impair the homogeneity of the covering over its entire layer thickness. Good results were achieved, for example, by spraying the compacted surface with a spray which was as fine as possible until the water stopped briefly on the surface of the layer. This spraying was repeated after a few minutes until the water stopped again briefly on the surface of the layer and then repeated again under these conditions. In a practical experiment, approximately 4 to 6 liters of water were applied per m ^{2 of} an approximately 25 mm thick, compressed layer.

After the compacted particle layer has been moistened as evenly as possible, this layer sets over the entire layer thickness within approx. 12 hours. The playability of the course is then given in dry weather after about 2 to 3 days. After the layer has set, the surface can be sprinkled with very fine brick flour if necessary to accelerate the formation of the slipping behavior typical of conventional brick flour places.

The covering produced by the method according to the invention can be used as a covering in a wide variety of sports facilities. This surface is particularly suitable and intended for tennis courts. Since there is no excessive dust formation when used as a tennis court, nor is the water required for conventional brick flour courts, this surface can also be provided in sports halls. Other application examples include Hard courts for other ball games, the run-in section of long jump facilities as well as running and sprint tracks.

Claims (10)

1. Method of establishing a surfacing for playing areas of sports grounds, in particular for tennis courts, which comprises applying brick dust, mineral material and tile cement, namely hydraulic-setting thin-bed mortar according to DIN 18156, - part 1 in its version of April 1977, part 2 in its version of March 1978 onto a prepared foundation, characterised in that

a) brick dust, mineral material and this tile cement are applied onto the foundation in the form of a dry-mixed aggregate;

b) said dry aggregate is there levelled and compacted; and

c) said compacted aggregate is sprayed with water so as to uniformly moisten the layer of aggregate.

2. Method according to claim 1, characterised in that the tile cement used as hydraulic-setting thin-bed mortar according to DIN 18156, is consisting of about 24.8 to 89.8% by weight of cement, about 10 to 75% by weight of additives such as sand and/or milled limestone, and about 0.2 to 6.5 % by weight of methyl cellulose, and optionally contains further components, viz. up to 10% by weight of vinyl chloride/vinyl propionate interpolymer, up to 6% by weight melamine formaldehyde condensation product, up to 0.1% by weight of polyacrylamide, up to 25% by weight of trass and/or up to 5% by weight of fibrous material, preferably asbestos.

3. Method according to claim 1 or 2, characterised in that said mineral material is finely divided quartz sand having a mean particle size from 0.01 to 0.7 mm.

4. Method according to any one of claims 1 to 3, characterised in that said aggregate is prepared by dry-mixing 100 parts by volume of brick dust with 10 to 90 parts by volume of mineral material, preferably quartz sand, and with 20 to 60 parts by volume of tile cement.

5. Method according to claim 4, characterised in that said aggregate is prepared by dry-mixing 100 parts by volume of brick dust with 20 to 60 parts by volume mineral material, preferably quartz sand, and with 35 to 55 parts by volume of tile cement.

6. Method according to any one of claims 1 to 5, characterised in that brick dust and mineral material are first dry-mixed in a rotating mixing drum or the like, and then the dry powdery tile cement is added and uniformly distributed in the previously produced mixture by further mixing.

7. Method according to any one of claims 1 to 6, characterised in that said dry aggregate is applied to the surface of said foundation in a layer of a thickness of about 15 to 50 mm.

8. Method according to any one of claims 1 to 7, characterised in that said dry layer of aggregate is compacted by rolling.

9. Method according to any one of claims 1 to 8, characterised in that said compacted layer of aggregate is sprayed with fine water droplets until liquid water remains visible on the surface of the aggregate layer.

10. Method according to claim 9, characterised in that said spraying with fine water droplets is repeated several times.