WO1982004081A1 - Method for the preparation of a coating of a sport ground,particularly tennis courts - Google Patents

Abstract

The covering layer of the covering consists of brick dust and finely divided mineral aggregates, in particular coarse silica, which are bound by a hydraulic mortar, as it is used in particular in laying slabs. For the preparation, the brick dust, the mineral aggregates and the solid components of this mortar are dry mixed and the dry mixture is applied to the prepared base, is leveled and is compressed, for example by means of rollers. Then, sprinkle with water to evenly moisten the compressed layer of mixture. The mortar contains cement, sand and / or limestone, methylcellulose and, as desired, the copolymer of vinyl chloride and vinyl propionate, polycondensate of melamineformaldehyde, polyacrylic amide, trass and / or a fibrous material, preferably asbestos.

Description

 Process for producing a covering for sports facilities, in particular tennis courts

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

German patent application P 31 11 128.9 dated 2o. March 1981 claims a covering for sports facilities, especially tennis courts, and its manufacture. 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. According to the method 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 base with an essentially flat surface.

The invention according to that patent application P 31 11 128.9 also goes back to the inventor named for the present application. With reference to the application P 31 11 128.9, its content is also to be made part of the present application documents, 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 a good water permeability of the covering is guaranteed after setting. The preparation of a useful 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.

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 the German patent application P 31 11 128.9, but in the manufacture of which the preparation and application of an aqueous slurry of Avoid disadvantages associated with covering components. 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 method for producing a covering for sports facilities, in particular tennis courts, in which method 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 of the above object is that

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

Advantageous refinements 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 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 meal on a mostly conventional 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 of an inert material, for example quartz sand particles. A further, particularly important difference to conventional brick meal cover layers can be seen in the fact that a bonded covering is obtained by the process according to the invention, tile adhesive being used as a special and additional binder. Surprisingly, it was found that when working according to the process according to the invention the formation of a hard, screed-like or concrete-like top layer is avoided, and instead, after the targeted addition of water, a loosely bound mass is obtained from the dry-mixed and compressed particle mixture after the setting reaction has been carried out.

The clay minerals in the brick powder obviously also take part in the setting process caused by the tile adhesive.

According to the method according to the invention, on the one hand, the strength of the brick powder layer can be increased considerably, so that greater durability is obtained; on the other hand, 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 specifically selecting the proportions of the covering components. In particular, despite the increased strength, the slip behavior of the known brick powder top layer can be largely maintained. 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 top 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 required extent; i.e. after a rain, excess water is quickly within a few minutes, through the porous cover layer to the substructure and derived from it. Even in the case of considerable, long-lasting dryness, the surface covering layer particles do not detach, so that no appreciable dust formation occurs. Thus, the covering produced according to the invention permits largely weather-independent playability without additional measures such as the known removal, rolling and / or watering. Since the formation of bars is reduced considerably, 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 18 156, 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 18 156-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 which 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% for use Water are added so that the viscosity of the water phase of the mixture is at least 500 cP, for laying tiles and tiles, whereby the surface to be tiled is covered with a layer of mortar and the tiles are pressed 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 made from 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 7o9 describes the use of a mortar mixture for laying tiles and tiles in a thin bed method, consisting of 25 to 85 wt .-% cement, 0.05 to 0.15. % By weight of methyl cellulose with a viscosity of 1000 to 3000 cP, measured in a 2% strength aqueous solution, 1.5 to 6% by weight melamine-formaldehyde condensation products containing sulfonic acid groups and a viscosity of 40 to 500 cP, measured in 20% aqueous solution, 0.02 to 0.1% by weight water-soluble, nonionic polyacrylamide, in each case based on the total weight of the dry mixture, the rest being sand and / or ground limestone. This mortar mixture can additionally contain 0.5 to 5% by weight of asbestos fibers.

With reference to these documents, 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 documents. 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 may also optionally contain other components, namely up to 10% by weight of copolymer of vinyl chloride and vinyl propionate, up to 6% by weight of melamine-formaldehyde condensation product, up to 0.1% by weight of polyacrylamide, up to 25% by weight .-% Traß and / or up to 5 wt .-% fibrous material, preferably asbestos. Portland cement, Fortland slag cement, lime slag cement, iron ore cement, pozzolana cement and the like are suitable as cement. The following compositions have proven particularly useful for the present purpose:

Tile adhesive I 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 of polymer dispersion powder

Base vinyl chloride / vinyl propionate

2.5% by weight of methyl cellulose (degree of substitution)

30% methoxyl; Viscosity 10,000 mPas for a 2% aqueous solution according to Brookfield at 20 ^o C and 20 rpm)

0.3% by weight calcium oxalate

Tile adhesive II 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 cellulose fibers, diameter: approx. 30 μm, length: approx. 300 μm

0.5% by weight calcium chloride

The product of the "rough" quality level commonly 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, in addition to finely ground silicon dioxide, other finely divided, inert minerals, and mixtures of silicon dioxide 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.

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 slipping 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 of the various components, friction coefficients can also be achieved in this area on the cover layers produced according to the invention. With given proportions of brick powder and tile adhesive, an increase in the quartz sand proportion 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 flour can be mixed with 10 to 90 parts by volume of quartz sand and 2 to 6 parts by volume of tile adhesive. (Working with vol. Parts has proven itself well in practice, since here the effects of the frequently strongly changing and in practice difficult to check moisture content of the brick powder are largely eliminated). Preferably, the preparation of the dry-mixed particle mixture 100 parts by volume of brick powder mixed with 20 to 60 parts by volume of quartz sand and 35 to 55 parts by volume of brick powder. In this case, the composition "Tile Adhesive I" or "Tile Adhesive II" 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 30 mm, in particular not more than 35 mm. With thicker layers, crack formation 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 process according to the invention, the dry premixed particle mixture is applied in the dry state to the prepared substructure, leveled there and compacted. During the compression, 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 the 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 in a corresponding higher layer thickness must be applied to the prepared substructure.

For many applications, a satisfactory covering is obtained if the covering is produced according to the method according to the invention on a flat, solid, dry and water-draining surface. Such a surface can be the naturally present 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 surfaces, is suitable as a substructure, the top layer produced according to the invention then serving as the tennis surface. With reference to DIN 18 035, page 5, the content, insofar as it is required 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 documents. 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 is used as a base and the 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 that promote 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 flour 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 with the mixture of quartz sand and brick powder. After adding the tile adhesive, mix for 5 minutes to ensure an even distribution.

The dry-mixed particle mixture obtained is applied in the intended layer thickness to 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 part mixture has decreased by approximately 15 to 20%.

Thereupon the still dry, compacted part sprayed with water mixture. With this

Spraying should achieve uniform moisture absorption across the entire layer thickness of the compressed 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. 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 after about 2 to 3 days in dry weather. 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 one produced by the process according to the invention Rubber can be used as a rubber in a wide variety of sports facilities. This surface is particularly suitable and intended for tennis courts. Since there is neither excessive dust formation when used as a tennis court nor 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

Claims: 1. Process for the production of a covering for sports facilities, in particular tennis courts, in which brick powder, mineral material and tile adhesive, namely hydraulically hardening thin-bed mortar in accordance with DIN 18 156, are applied to a prepared substructure, characterized in that a) brick powder, mineral material and these tiles glue be applied to the substructure in the form of a dry-mixed particle mixture; b) the dry particle mixture is leveled and compacted there; and c) the compacted particle mixture is sprayed with water to uniformly moisten the particle mixture layer. 2. The method according to claim 1, characterized in that a tile adhesive is used as the hydraulically hardening thin-bed mortar according to DIN 18156, which from about 24.8 to 89.8 wt .-% cement, about lo to 75 wt .-% aggregates such as sand and / or ground limestone and about 0.2 to 6.5 wt .-% methyl cellulose, and optionally other components, namely up to 10 wt .-% copolymer of vinyl chloride and vinyl propionate, up to 6%. -% Kelamine-formaldehyde condensation product, up to 0.1 wt .-% polyacrylic amide, up to 25 wt .-% bottoms and / or up to 5 wt .-% fibrous material, preferably contains asbestos. 3. The method according to claim 1 or 2, characterized in that the mineral material is finely divided quartz sand with an average particle size of 0.01 to 0.7 mm. 4. The method according to any one of claims 1 to 3, characterized in that for the preparation of the particle mixture 100 vol. Parts of brick flour 10 to 90 parts of mineral material, preferably Quartz sand, and dry mixed with 20 to 60 parts by volume of tile adhesive. 5. The method according to claim 4, characterized in that for the preparation of the particle mixtures. 100 vol 20 to 60 vol. Parts of mineral material, preferably quartz sand, and with 35 to 55 parts by volume of tile adhesive can be mixed dry. 6. The method according to any one of claims 1 to 5, characterized in that first brick flour and mineral material are dry mixed in a rotating mixing drum or the like. Then the dry, powdery tile adhesive is added and evenly distributed by further mixing in the previously generated mixture becomes 7. The method according to any one of claims 1 to 6, characterized in that the dry particle mixture is applied in a layer thickness of about 15 to 50 mm on the surface of the substructure. 8. The method according to any one of claims 1 to 7, characterized in that the dry particle mixture layer is compressed by rolling. 9. The method according to any one of claims 1 to 8, characterized in that the compressed textile mixture layer is sprayed with fine water droplets until liquid water remains visibly on the surface of the particle mixture layer. 10. The method according to claim 9, characterized in that the spraying with fine water droplets is repeated several times.