CA1185999A

CA1185999A - Surface for sports areas

Info

Publication number: CA1185999A
Application number: CA000402020A
Authority: CA
Inventors: Egon Turba
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-05-01
Filing date: 1982-04-30
Publication date: 1985-04-23
Also published as: DE3272112D1; DK579882A; AU548363B2; IE52589B1; NO824388L; AU8399282A; EP0066099A1; ES511843A0; WO1982004081A1; IE821045L; FI824514A0; EP0066099B1; FI74758B; ES8403180A1; DK154843B; FI74758C; GR75436B; DK154843C; FI824514L

Abstract

ABSTRACT

The invention concerns a surface for sports areas particularly tennis courst, whose top layer consists of a setting compound formed essentially of brick-dust, mineral material and inorganic binding agent.

Description

3''3~3 Tlle invention conc~rns a sur.fac~ for sport~; areas, particularly tennis courts~ whose ~op layer consists o~ a settiny compound formed essen~ially of brick-dust, mineral rnaterial and inorganic binding agent.

Such a surface is ~cno~m ~rom the ~erman Pa~en~: Specii.cation 441 047. For the prepara~ion o~ a top laycr :~or ~ennis cour~s, according to this proposal, a compos.i.~ion ~.s lai.d consi.stinc3 oE
25% fine brick-dust, 20% coarser brick-~ust, 15% bindiny grit, 20% green colour, 10% black lime (a ].ump varie~y of hydraulic lime), 5% cemen~ and 5% rock salt. Furthermore, a process is known for the stabilization of tennis courts against mechanical wear, wherein the stone mixture forminy the top layer-of the tennis court surface is mixed with an aqueous dispersion of water i.nsoluble homo-or copolymers of vinyl compounds ~see DE-OS 1 g37 761). Furthermore, in order to minimize maintenance work and to adapt to changiny weather conditions, it has been proposed to insert into the top layer of a playground surface granulated si.liceous material of great strength, partly very hard and having a high water-absorbing capacity, such as hygroscopi.c .
silica~ kieselguhr, silica gel, vermiculite or siliceous fireproof clay (see DE-OS 2 122 930).

These proposals have all failed in practice. So far there has been no success in producing a surface which, on the one hand;
has the advantageous features of a typical barn floor with a surface of brick-~ust or red gravel and, on the other, possesses e~, ~ - ?
3~3 the resistance to wear and to ~lln~er that typical hard courts possess.

Tennis courts haviny a top layer of brick~dusk on a "dynamic layer" of hrick yravel, slay particles ~nd slm.i.lar substances lead to optimum playing conditiorls owing to the charac~ris~ics affecting ~oothold and slid:in~l also the elas~i.c:i.ty of the entire installati.on. Speci.al significance attclches 1o a feature.,allowing a predetermined deyree of slid:ing which ènables ~ the players momen~um ~o be absorbed by the top layer, so that a stopping action is not completel~ absorbed by the player's muscies and bones. In this way early fatigue is counteracted and the risk of injury reduced. This predetermined degree of sliding derives mainly from the fact that at a certain load indi.vidual particles of brick-dust release themselves from thei.r foundation and behaving like balls or rollers, permit the sliding movement of the shoe on the top layer. However, even when there is a certain sliding characteristic the player must be assured of a fast start.

~(~ Conslderable disadvantages accompany the good playing characteristics of a tennis court having a brick~dust surface these are, for example, very demanding maintenance, the long retention of dampness with associated diminution of foothold, the creation of dust when the brick-dust layer is insufficiently moist and, finally, low resistance to wear which leads to the known irregularities in the heavily used areas. Other .i.

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disadvantages are the comparativel.y ~ ort life arld the nece.,sity of an annual spring service.
Some of these disadvantages lo not occur wi-th hard courts having a top layer of asphalt or concrete. ~lowever, such hard courts frequently fail to satisfy from a player's point oE
view because the characteristic s].iding feature oE the brick-dus-t court is missing. Thi.s increases premature Ea-tigue and aLso the risk of injury; in addition, the consi.de:rable hardncs-; and minimal elasticity of such courts leads -to heavy ball wear and balls which are too fast in the case of a hard drive.
According to one aspect of the present invention, there is provided a surface for sports areas, having a top layer consisting of a setting compound formed essentially of brick-dust~
mineral material and tile cement, that is a hydraulic-settiny thin-bed mortar in accordance with DIN 18 156. Preferably, fine~
grained quar-t~ sand serves as the mineral material. Advantageous embodiments of the invention pertain to the proportions of brick-dust, tile cement and quartz sand in thé mixture used for preparing the surface, the grain size of the quartz sand and the thickness of the top layer, as stated in the sub claims. The covering layer provided in the invention can form the barn floor surface of the customary barn floor surface construction, as is kno~n from DIM 18 035, page 5. In addition~ the surface according to the invention can be laid on a bitumen-or cement bound base, pervious to water. A special base consists essentially 185~99 of a step-dampening layer of aerated cement blocks on a foundation of reinforced fine concrete.
According to a second aspect of the invention there is provided a process for the manufacture of a surface for a sports area, comprising the steps of:
a) preparing an intimate dry powder mixture of the components brick-dust, mineral material and tile cement;
b) spreading said dry powder mixture on a prepared, essentially level foundation;
c) compacting said layer of powder mixture; and d) applying the necessary amount of water.
Within the framework of the invention it has been established surprisingly, that by the selected addition of tile cement and quartz sand to the well-known brick-dust, the strength of the brick-dust layer is considerably increased, so that greater resistance to wear is achieved, and by the selected choice of the proportions:of these components, the value of the sliding characteristic determined~ for example, as static or sliding ;::.csm/~
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, friction under a given load can be adjus~ed over a ~.ide range.
In spite of the increased strencyth, the sliding characteri.stlc i.n particular of the well-knowrl ~ric]c-clus~ top layers can be maintained~ In addition, the slidiny charactcr;.stic can be adjusted to deIinite va].ues for selec~ed requireln~nts. Fina].ly/
by selecting certain layer thicknesses, the degree of softlless, of ~he top layer can be inEluerlcecl for a givcrl cornpo~:it-ion.

The mixture of tile cement, brick-dust and quartz sand provided by the invention produces a top layer of unusually high resistance to wear, so that after many hours of tennis playing practically no maintenance work and/or service are required.
The top layer is frost proof, so that when combined with a winter-proof foundation no special renovation work is needed after the winter break.

The top layer, made in accordance with the invention, ic shown to be resistant to water, but it is water penneable to the rec~uired degree; i.e. after a fall of rain superfluous quantities of water are conducted rapidly, i.e. within abollt 10.
minutes, through the porous top layer to the founclation, from where the~ flow away~ Even during considerable, prolonged drought, the top-layer particles do not become loose, so that any noticeable accumulation of dust does not occur.

In this way the surface according to the invention permits playing, largely independent of the weather, without additional ~ 3 measures, such as sweepincl, rolliny and/or ~,/a~er;in~J.
~, ~inally, the top layer in accordance wi~h the inverltion can bc j-~
very easily repaired by simply app1~rincJ frcshly prrpared paste at worn places. r~his se~s and adheres securely, etJen in very thin layers, to the exis~ln~ Inaterial, ~i-thout additional steps~
Because of this property it is a very ;irnple ma-tter to make the boundary lines; at these lines yrooves are cu~ Otlt O:~ ~h~` top layer, which is red because of the red br:ick-dust, and in~o these grooves is poured paste made of ~he sarne components, which has been dyed white.

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In the following the invention is explained in detail with the help of preferred appIications. Brick-dust, tile cement~ quartz sand and water are taken as initial components for such top layers.

The brick-dust used is the well-known, commercially-available product as widely used for the preparation of the top layer of known tennls courts~

Tile cement also represents a known, commercially-available product which is de~ined by the technical world as hydraulic-setting thin-bed mortar (see DIN 18 156 ?art 1 and 2). Such hydraulic hardening thin-bed mortars are powdery mixtures of hydraulic binding agents, mineral additives (at the most 0.5 mm grain size) and organic supplements. The powdery thin-bed mortar is prepared by mixing with water and ~ 3~

is ready for use after a bri.~ ripeni.n~ time. 7~1i.thin the frame~ork of this invention it :i.s pr~ferab]~ ~o use tile celnents which fulfil the conditions ~or thin~}~ed rnor~ar DIN l8 1.56~M (see DIN 18 156, part 2).

The composition o~ such t~.le cements i.5 we~.l kno~m. ~or e~:ample, the German Pa-tent specifi.cation l l58 ~30 d.isc].os~s the application of a mortar which! ~ihen dr~, contains 2~.8 to 89~9%
by wei.ght Portland cernent, 0.2 to 6.5 ~ by weight methyl cellulose having a viscosity between lO and 7000 cP, measured in a 2%
aqueous solution, also approximately lO to 75 ~ additives, such as sand or ground limestone. To use, approximately lO to 40 %
water is mixed-in, so that the viscosity of the water phase of the mixture , for laying flagstone an~ tiles is at least 500 cP.
~e surface to be tiled is covered with a layer of mortar and the dry tiles are ~ressed into thisO Xn the US Patent specifica-tion

2 934 932 a number of typical tile cement compositions suitable for the present purpose are given. From the German Patent specification l 646 493 a bedding mortar is known which, in addition to cement and graded sand, contains O.l to l.5 % by weight me-thyl cellulose and l.0 to lO ~ by weight of an interpolymer of 30 to 80~ by weight vinyl chloride and 80 to 20 %
by weight vinyl propionateO In addition, this beddiny mortar can also contain 5 to 25 % by weight trass. Moreover, the German Auslegeschrift 2 146 709 describes the application of a mortar mixture for laying flagstones and tiles according to the thin-bcd process, consisting of 25 to 85 % by wei~ht cement, 0.05 .

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to O.lS ~ by weight methyl cellulo-ie haviny a viscosity of 1000 to 3000 cP, measured in a 2% ayueous solution, 1.5 to 6 ~ by weight sulfonic acid group-containiny rnelarnine oxmaldehyde condensation pr~duct having a viscosi-ty o~ 40 to 50b cP
measured in a 20 ~ aqueous solution, 0.02 to 0.1 ~ by weigllt ~ater-soluble non-ionic polyacry]amide, based .i.n eve~y cas~ on the total ~ei.yht of the dry mix~ure, remclin-~er .;ancl arld/or ground limestone. Additionally, this mortar mi.~ture c~n cont.ain 0.5 to 5 % by weight asbestos fibre.

The contents of these printed works are also to be regarded as part o~ the present specificationt insofar as they concern the composition o~ tile cement, that is, 'nydraulic-setting thin-bed mortar in the sense of DIN 18 156, part 1 and part 2.

~ccording to these printed works such tile cements consist .ssentially of approximately 24.8 to 89.8 ~ by weight cement, approx;.mately 10 to 75 % by weight additives such as sand and/or c3round l.imestone and approximately 0.2 to 6.5 % by ~eight methyl cellulose and can, in addition, contain further components, according to choice, i.e. up to 10 ~ by weight interpolymer of vinyl chloride and vinyl propionate, up to 6 ~ by weight melamin ~ormaldehyde condensation product, up to 0.1 % by ~eight polyacrylamide, up to 25 % by ~eight trass and/or up to 5% by eight fibrous material, pre~erably asbestos. As e~amples, the following cements may be mentioned: .Port~and cement, Portland slag cement, lime slag cement, iron-ore cement, Puzzolan cement .

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and the like. The follo~ing cornpos~l:i,ons have p~oved ther~c;c]ves particulary suitable'for t~e present pu~pose: ~

Ti]e cement I wi-th , ~, 48% by weight Portland cement PZ 55 F
45% by weicjht washed, fire--dried Quartæ sand 0.1 - 0.6 rnrn

4.2% by weight dispersible pc~wdered polymeride on the bas;s o vinyl - chloride/vinyl propionate 2.5% by weight methyl cellulose (degree of substi~ution 30%
- methoxyl; viscosity 10 000 mPas or a 20%
aqueous solution accorai~g to Brookield at ;-20C and 20 rpm~. I
0.3% by ~eight calcium oxalate.

T~le _ ment II with ~7% by weight blast-furnace cement ~OZ 35 L .
~3% by weiyht washed, fire-dried quartz sand 0.2 to 0.6 mm _ ~.5% by weight rnethyl hydroxyethyl cellulose (degree of substitution 25 % methoxyl, 0 Q~ ethylene glycol ether; viscosity:
20 000 mPas for a 2% aqueous solution according to Brookfield at 20C an,d 20 rpm) 2~0% by weight cellulose fibres, diameter: approximately 30 ~m, length approximately 300 ~m 0.5% by weiyht calcium chloride.

The quartz sand used ls that: comrnonly used in the building industry, hav:iny the quali.ty yrade "finec;t": ~uartz sand such as this has a mean grain slze of O.OL to 0.4mm. The designation quartz sand shall include other f:ine-grain, i.nert mineral substances, and mixtures of si.l:icon di.ox:ide with such mineral substances, as well as f:inely mill.ed silicon d:ioxide. The named components brick-dust, thln-bed mortar powdèr as tile cement and quartz sand are mixed :in-tima-tely in a rota-tirlg drum or the like.
In addition to the named, necessary componen1s needed for the mixture further additions can be provided in so far as these are desired, such as dyes, fungicidal, bactericidal or herbicidal agents and other desired additivesO
The hardness and strength of the top layer provided according -to -the invention, as well as the sliding behaviour at the surface of this top layer can be adjusted over a wide range by the appropriate selection of the components provided. Without a minimum proportlon of quartz sand it is not possible to realize the desired sliding behaviour, particularly when it is wet. With the prescribed proportions of brick-dust and quartz dust, an increase in the proportion of tile cement leads to an increase in the hardness and of the coefficients of static and sliding csm/~

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fr;ction. Such coefEici.ents of Fri.cti.on can be evaJua-ted as an indication of the slidi.ng behaviollr. To determine these coefficients of friction a test piece oE smooth shoe-sole rubber (10 cm long, 5cm wide and 0.5 cm -th:i.ck) exposed to a load of 15 kp is moved with a speed of initi.ally 0 and finally 3 crn/sec across the test surface. The necessary trac-tion is determined with a dynamometer and the coe~ficient oE fric-tion :is establ:Lshed according to the formula: coefficient oE frictLon = tractiorl/
load. The coefficient of static fricti.on relates to the force required to overcome inertia; the coefficient of sliding friction relates to the force necessary for a speed of 3 cm/sec.
Under these conditions, coefficients of friction, static and sliding, were determined in the range 2.7 to 3.0 for known brick-dust surfaces. With the prescribed proportions of brick-dust and tile cementl an increase in the.proportion of quartz sand leads to a lowering of these friction coefficients which promotes sliding on the surface of the top layer.
In order to make the top layer of the surface according to the invention the intimate dry powder mixture of the components brick-dust, mineral material~ preferably fine-grained quartz sand and tile cement is spread on a prepared, essentially levél foundation. The layer of powder mixture is compacted and the necessary amount of water in the form of a very fine water spray is applied. For preparing the dry powder mixture it is recommended, at first to add the mineral material preferably quartz sand into the mixing device, subsequently to add the powdery tile `~csm/~

r3~3 cemen-t ancl f:i,na]ly to a('ld the ~rick dl,l3l.
The compact:ing of' the 'Layer oi' powder m:ixture can be done by means of a rol]er or the L:ike as is convent:ional in preparing and compactlng the layers of known tennis col1rts having a top layer made essen-tially Erom br-;ck-dust.
The necessary amoun-t of water is -that amount which J.S
easily absorbed by the layer of compacted powder m:ixture withou-t noticeable amounts of water remaining on the surfac~e of the layer oE compacted powder mix-ture. Dur:iny the who:Le ~pr~ying stage the forminy of a con-tinuous water layer on the surface of the layer of the compac-ted powder mixture should be avoided, because such a great amoun-t of water at a given moment would lead to an undesirable reaction of the powder mixture limited to the surface zone thereof.
This alternative method for preparing the inventive top layer of sports areas, particularly tennis courts, can be performed using conventional equipment and avoids the transportation of the highly viscous aqueous paste over large distances.
The surface according to the invention can be installed in the widest variety of sports centres. The surface according to the invention is particularly suitable for tennis courts. The surface according to the invention can be provided for indoor as well as outdoor cour-ts because when used for tennis courts there is neither an excessive genera-tion of dust nor is there any need for watering as there is in the case of conventional csm/~

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brick-dust courts. Further application examples involve, among others, hard courts for other ball games, lony-jump tracks and tracks for running and sprinting.
As is known and previously described the surface may be prepared by mixing the dry componen-ts wi-th wa-ter prior to spreading. In this instance the componen-ts are mixed and wa-ter is added to form a paste.
To obtain a readily workable, dough-like paste approximately 25 to 50 par-ts by vol. water, preferably 30 to 40 parts by vol~ water are added to 100 parts by vol. powder mixture. The paste is desirably prepared in a con-tainer e~uipped with a mechanical agitator. The paste is ready for use after an agitation period of approximately 5 minutes and a following ripening period lasting a few minutes.
To prepare a paste suitable for the purposes of the prior invention 100 parts by vol. brick-dust can be mixed with 20 to 250 parts by vol. tile cement in powder form and 10 to 400 parts by vol. quartz sand. (Working with parts by volume has proved itself well in practice because in this way the effect of the widely-fluctuating moisture conten-t, which is difficult to establish, is eliminated to a large extent). Preferably, for the preparation of a paste 50 to 150 parts by vol. tile cement and 150 to 350 parts by vol. Quartz sand are added to 100 parts by vol. brick-dust. Particularly preferred is a ratio of 70 to 120 parts by vol. tile cement and 250 to 350 parts by vol. quartz sand to 100 parts by vol. brick-dust.

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A number of recipes are lis-ted he]ow for the preparation oF usable pastes N~o. Brick-dust Tile cement Quartz sand Water Comrnent conc.resultparts by vol. parts by vol. parts by vol. parts by vol. Iop layer 1 3 1 1 1 5 go~d 2 4 1 1 1.7 usable 3 5 1 1 2 usable 4 2 1 2 105 yoGd 1 1 3 1.5 very good 6 1 2 2 2 hard 7 1 3 1 2 ~ery hard 8 2 0.5 2.5 105 very elastic Depending upon the case, the compount Tile Cement I or Tile Cement II was used without leading -to any noteworthy differences in the properties of the top layer.
Because of -the great strength of the reaction product obtained from the paste of brick-dust, tile cement and quartz sand in water after reaction by setting and substantial removal of water, it can be applied in a relatively thin layer -to the prepared base. The minimum layer thickness is determined by the length o~ life envisaged for the surface; in this regard the minimum layer thickness should be 10 mm, at least, however, 5 mm. A maximum layer thickness derives from the observation that the softness of the top layer increases with increasing layer thickness; for ` ~- csm/~

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this reason therefore the layer thickness should not exceed 30 mm and in any event it should not be more -than 35 mm. With greater layer thicknesses thc- formation oE cracks must be reckoned with.
I.ayer -thicknesses of between 15 and 25 mm have proved -themselves wel]; a layer thic]cness of approximately 20 mm is specially preferred.
In many cases a satisfactory surface layer is ob-tained if the named paste is applied in the given thickness on a level, firm, dry and water-pervious foundation. A foundation such as this could be provided by the natural, available ground, or a prepared foundation could be involved. ~s a foundation, the typical layer sequence for barn floors with filter- load-bearing-- and dynamic layers according to DIN 18 035 page 5, is particularly suitable and the top layer as provided according to the invention serves as the top surface. With reference to the contents of DIN 18 035, page 5, these shall also be regarded as a part of the present specification in so far as they are necessary for the explanation of foundation, filter layer, load-bearing layer and dynamic layer including their materials and requirements.
Furthermore, the surface provided according to the invention can be applied to a bituminous- or cement-bound base, pervious to water, for example, on a base in the form of a known hard court. If an existing asphalt or concrete layer whose permeability is inadequate is to serve as a base, a number of holes can be drilled through this layer, down to the subsoil, where water will be conveyed away. Quite special requirements are met by a substructure for whose preparation a primary layer of reinforced :~ - 15 -'' 'c sm/i's fine concrete is laid, over the entire area, on a suhsoil which is essen-tially level and pervious to water; on this primary layer of reinforced fine concre-te aerated cement blocks are placed in rows, join-tlessly, and finally the paste provicled according to the invention is applied on the surface of the aerated cemen-t blocksO
The layer of aerated cement blocks serves as a step-dampening layer and carries an approximately 2 cm thick -top layer which is obtained from a dough-like paste of 1 part by vol. tile cemen-t, 1 part by vol. brick-dust and 3 parts by vol. quartz sand in 1.5 par~s by vol. water. This top layer sets within approximately 12 hours. In dry weather the court is ready for playing after approximately 4 to 5 days. If required an adhesive layer of paste, prepared as prescribed, with tile cement in water can be provided between the top layer and the immediately ad~oining underlayer.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the manufacture of a surface for a sports area, comprising the steps of:
a) preparing an intimate dry powder mixture of the components brick-dust, mineral material and tile cement;
b) spreading said dry powder mixture on a prepared, essentially level foundation;
c) compacting said layer of powder mixture, and d) applying the necessary amount of water.

2. A process according to claim 1, characterized in that a foundation is provided with a layer sequence typical of a barn floor area in accordance with DIN 18 035 page 5, upon whose dynamic layer the dry powder mixture is applied in order to form the barn floor surface according to the sequence of steps a) to d).

3. A process according to claim 1, characterized in that the powder mixture is applied to a bituminous-bound or cement-bound base which is previous to water.

4. A process according to claim 3, characterized in that in order to ensure permeability in a given asphalt or concrete layer forming the base, a number of holes are drilled, down as far as the subsoil.

5. A.process according to claim 1, characterized in that on an essentially level subsoil, pervious to water, a primary layer of reinforced fine concrete is poured over the entire area, on this are laid aerated cement blocks, lined up jointlessly and on the surface of the layer of aerated cement blocks is laid the powder mixture, in order to form the top layer according to the sequence of steps a) to d).

6. A process according to any one of the claims l to 3, characterized in that the necessary amount of water is applied in form of a very fine water spray in such a way that, the formation of a continuous water layer on the surface of the layer of the compacted powder mixture is avoided.

7. A process according to any one of the claims l to 3, characterized in that the necessary amount of water is said amount which is easily absorbed by the layer of compacted powder mixture without noticeable water amounts remaining on the surface of the layer of powder mixture.

8. A process according to claim l, characterized in that the tile cement is a water-hardening thin-bed mortar according to DIN 18 156 consisting of approximately 24,8 to 89,8% by weight of cement, about l0 to 75% by weight of additives such as sand and/or ground limestone, about 0,2 to 6,5% by weight of methyl-cellulose and, selectively, of additional components, namely up to 10% by weight of a co-polymer made of vinyl-chloride and vinyl-propionate, up to 6% by weight of a 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.

9. A process according to claim l or 8, characterized in that the mineral material used is finely divided quartz sand having an average particle size of 0,01 to 0,7 mm.

10. A process according to claim 1, characterized in that for the purpose of preparing the mixture of particles, 100 parts by volume of brick-dust are mixed dry with 10 to 90 parts of mineral material, preferably quartz sand, and with 20 to 60 parts by volume of tile-adhesive.

11. A process according to claim 10, characterized in that for the purpose of preparing the mixture of particles, 100 parts by volume of brick-dust are mixed dry with 20 to 60 parts by volume of mineral material, preferably quartz sand, and with 35 to 55 parts by volume of tile-adhesive.

12. A process according to claim 1, characterized in that the brick-dust and mineral material are first mixed dry in a rotary mixing drum or the like, after which the dry, powdered tile-adhesive is added and is uniformly distributed, by further mixing, in the mixture previously produced.

13. A process according to claim 1, characterized in that the dry mixture of particles is applied to the surface of the base in a layer of about 15 to 50 mm in thickness.

14. A surface for a sports area having a top layer consisting of a setting component formed by the process of claim 1.