EP0168504B1 - Mastic asphalt and embedded refrigerant pipes for the construction of ice rinks and ice surfaces, and for the simultaneous use as sports and play grounds - Google Patents

Abstract

1. Process for the production of an artificially frozen ice rink structure consisting of the mineral, statically loadbearing base onto which a layer of material is placed lor the embedding of the pipes carrying the refrigerant are embedded consists of mastic asphalt, the bitumen content of pumped which is formed by primary bitumen which has a penetration (100g, 5s, 258C- of not less than 35 to 50 m**-1, a ring and ball softening point of max. 54 to 598C and a Fraas brittle temperature of a least -68C.

Description

The invention relates to a method for producing an artificial ice rink structure according to the preamble of claim 1.

When building artificial ice rinks, the procedure is generally such that the pipes carrying the refrigerant are either embedded directly in concrete or in a chemically setting mineral screed, the pipes being as close as possible to the surface of the potting compound sprayed with ice-forming water (concrete, mineral screed, etc .) come to rest in order to obtain a uniformly thick natural ice surface that forms in the shortest possible time.

When using metal pipes (iron pipes) for the coolant carriers, which are preferably meandering or serpentine for the return and return flow of the refrigerant, it has been shown that they are subject to considerable corrosion even after a relatively short use. This is caused by the porous, water and oxygen permeable structure of the concrete or mineral screed, which cannot prevent the penetration of ice water in the long run, so that the pipe surface is directly exposed to the corrosive action of water and. Is exposed to atmospheric oxygen.

It is therefore necessary from time to time to renew or repair the structure of the concrete or screed foundation supporting the artificial ice rink together with the embedded support tubes for the refrigerant, in particular the iron tubes for the refrigerant often having to be replaced altogether.

It goes without saying that such repairs, repairs, etc. are not only associated with considerable costs, they also shut down the operation of the respective ice rink for longer periods, these periods resulting from tearing open the existing system and relocating a new structure assemble additively, can be increased by the time required to set the new structure.

Plastic pipes, which may be a substitute for metal pipes because they are far less subject to the corrosive effects of water and oxygen, are ruled out for the construction of artificial ice rinks because they do not withstand the high loads caused by vibration when pumping through the refrigerant brine (pump impacts) , on the other hand, are not able to cope with the given temperature fluctuations, especially at the low operating temperatures of the brine, and eventually become brittle and brittle due to the aggressive effect of the saline refrigerant brine. This means that plastic pipes are also subject to the destructive influence of other corrosive conditions, even if not the oxide and therefore rust-forming corrosion caused by the action of water and oxygen.

For the above reason, plastic materials for the production of the pipes carrying the refrigerant in the construction of ice rinks, after they were briefly proposed and also tried, were soon replaced by metal pipes, in particular iron pipes, since these at least offer greater resistance to the influence of pressure and vibration phenomena. In the absence of any other option, the time schedule for repairing the overall structure, combined with renewal of the iron pipes - or vice versa - is accepted.

Another and not to be underestimated disadvantage of artificial ice rinks on the basis of concrete and partly also on the basis of mineral screed, which serve as an investment for the refrigerant-carrying metal pipes, can be seen in the fact that the building materials mentioned can only be laid in joints.

In addition to the fact that such joints offer a particular target for penetrating, corrosive water, the pipes carrying the refrigerant are directly exposed to the atmosphere at their interfaces and are therefore particularly at risk at these points.

Finally, such joints prevent the temporary use of the surface, for example in summer as a roller skating rink or for other types of sport and exercise that cannot be carried out on grooved surfaces.

It has now been found that the disadvantages derived above in the construction of artificial ice rinks from pipes or pipes carrying refrigerant laid in concrete or screed can be remedied if, according to the measure of the invention, the pipes carrying the refrigerant are laid in poured asphalt of a very specific construction .

Surprisingly, it has been shown that mastic asphalt - with appropriate construction and processing - not only can be laid seamlessly, as is known, so that the overall complex of disadvantageous joints mentioned is eliminated, but it also provides flawless, tight pipe covering, which does not allow corrosive media such as water and oxygen to attack the pipe material (metal or iron pipes).

In addition, the mastic asphalt has the flexibility that is required to absorb and neutralize the shock-like vibrations that occur when pumping around the refrigerant brine.

In principle, there are two ways of building artificial ice rinks in the sense of the invention.

Either the mastic asphalt embedding the pipes carrying the refrigerant is applied directly or by means of a thin layer of raw glass fleece and / or bitumen paper to the substrate, for example made of concrete (Solid ceiling or sole concrete), or it is spread and glued on a substructure made of bitumen gravel on the mastic asphalt. In particular, the last-mentioned structure has already proven itself to be relatively optimal in practical use, since bitumen gravel (round grain mixtures, in particular for asphalt base courses) has an expansion coefficient which corresponds approximately to that of the mastic asphalt.

It is already known to use mastic asphalt modified with plastics such as ethylene-vinyl ester copolymer or styrene-butadiene copolymer as an investment material for pipes carrying heat. For example, DE-A 2 937 057 describes a mastic asphalt screed for the production of underfloor heating in which high-vacuum bitumen, in particular HVB 85/95 or 95/105 (DIN), is used, if not exclusively, as bitumen.

Apart from the fact that the state of the art according to DE-A-2 937 057 is based on a completely different task, the finding of which is to be sought in particular in the high stability and flexibility of mastic asphalt in relation to the surfaces of heating pipes at relatively high heating medium temperatures , for which practically only bitumens of the high vacuum types (HVB) with breaking points in the positive range and the unavoidable additions of copolymers up to 4.5% by weight. in relation to bitumen, the copolymers in particular having the task of regulating penetration, the invention can only be realized with those types of bitumen that are commercially available as so-called primary bitumens (DIN 1995) and are defined as street bitumens.

These have according to DIN 1995 under the designation B 45, B 65 and (if applicable) B 80 Fraass breaking points of at most - 6 to - 10 (B 80) ° C. The ring and ball softening points are 54-59 ° C for B 45, 49-54 ° C for B 65 and 44-49 ° C for B 80. The penetrations (100g, 5 s., 25 ° C in 1/10 mm) are 35-50 for B 45, 50-70 for B 65 and 70 to 100 for B 80. Only these bitumens can be used for the purposes of the invention, it having been shown that B 45 as such, i.e. H. can be used without any modifying additions to copolymers, while the varieties B 65 and B 80 should expediently be modified by certain copolymers, which are defined later.

Bitumen B 45 (according to DIN 1995) has proven to be particularly advantageous in the sense of the invention, its softening point in particular being of crucial importance. Only through this, d. H. when using non-modified bitumen B 45, the surface of the mastic asphalt structure can also be used with ice loads (e.g. roller skating etc.) or for walking and driving during ice-free periods (summer), while the bitumen types B 65 and - in particular - B 80 require modification by polymeric substances in order to provide usable asphalt surfaces that can be used for the same purpose.

Bitumen B 45 can therefore be used to build a poured asphalt without any modifying additives due to the given breaking point of -6 ° C, which is equally suitable for embedding refrigerant-carrying pipes, but at the same time also absorbs the loads that the surface has in excellent conditions in ice-free periods Make way as suitable for other types of sports or loads.

Bitumens with a low refractive index than B 45, i.e. the types B 65 and - with restrictions - B 80, can in principle also be used in the sense of the invention, but it has been shown in the endurance test that a modification, albeit a minor one, is expedient here , in particular copolymers or block copolymers. which contain styrene and conjugated diene groups and have average molecular weights between 25,000 and 250,000, in particular from 50,000 to 200,000 (e.g. styrene-butadiene copolymers or block copolymers) and polyolefins such as polybutene, polyisobutylene and - in particular - copolymers of ethylene and a vinyl and / or acrylic ester, if appropriate in combination with a pure polyolefin and / or a styrene-diene copolymer or block copolymer, are suitable.

Such modifying copolymers, which are not themselves the subject of the invention, z. B. mentioned in AT-A-371 139, DE-A-3 202 480 or DE-A-2 937 057 and there as suitable for the construction and modification of bituminous binders, for polyethylene sealing compounds and membranes , as well as for mastic asphalt screed compositions, in the latter case these mastic asphalt screeds are proven to be suitable for the production of floor structures with pipes embedded in the mastic asphalt for liquid and vaporous heat transfer media (heating medium).

For the purposes of the invention, the addition of copolymers or related substances to bitumens with penetrations of 50-70 or 70-100 mm- ¹ (B 65 and B 80) serves primarily for the penetration and the respective softening point for the values of the bitumen B 45 to adapt.

Naturally, this presupposes that the additive is kept within those limits which lower or increase the penetration (ideal: 35-50 mm- ') and the softening point (ideal: 54-59 ° C RuK), but on the other hand the breaking point Hold or set in the required negative temperature range (ideal according to B 45: ―6 ° C).

If the bitumen used for the mastic asphalt in the sense of the invention is modified by polymeric substances, the additional amounts, depending on the bitumen used (road or primary bitumen), are over 0 to about 4.0% by weight, in particular 0; 6 up to 2.6% by weight and especially 0.8 to 1.4% by weight, based on the bitumen in mastic asphalt.

As mastic asphalt, which in the sense of the invention for the construction of ice rinks, d. H. Suitable as investment material for the pipes carrying the refrigerant can be both high-chip and low-chip mastic asphalt, the transitions from high-grit to low-chip mastic asphalt are generally fluid. Bituminous compositions containing voids, which require subsequent compaction and as are used, for example, for hot rolled asphalt cover layers in hot paving, are only suitable to a limited extent as an investment material for the pipes carrying the refrigerant according to the invention, because they require the aforementioned compression and the other cannot guarantee adequate corrosion protection on the surfaces of metal pipes.

The grain gradation of the mastic asphalt can vary in the ranges 2/5 to 8/12.

• Füller wie Kalksteinmehl usw. : zwischen etwa 20 und 34 Gew.-%
• Splitt : zwischen etwa 35 und 55 Gew.-%
• Rest, insbes. Natur und/oder Edelbrechsand : zwischen etwa 11 und 45 Gew.-%
• Dazu Bitumen, mit oder ohne Modifizierungsmittel : zwischen etwa 6,1 und 8,9 Gew.-%, insbesondere 7,1 bis 8,2 Gew.-% und bevorzugt 7,2 bis 7,6 Gew.-%.

Overall, a mastic asphalt suitable for the purposes of the invention is composed as follows:

• Fillers such as limestone flour etc.: between about 20 and 34% by weight
• Grit: between about 35 and 55% by weight
• Rest, especially natural and / or fine crushed sand: between about 11 and 45% by weight
• In addition bitumen, with or without modifying agent: between about 6.1 and 8.9% by weight, in particular 7.1 to 8.2% by weight and preferably 7.2 to 7.6% by weight.

It has been shown in further development of the invention and in its practical use that an additional improvement in the stability of the pipes carrying the refrigerant, in particular their corrosion resistance, but also their resistance to naturally occurring vibrations caused by the pumping work can be improved if the pipes carrying the refrigerant are laid on so-called spacers made of strips of asphalt mastic so that they are not directly connected to the substructure. Such strips of asphalt mastic, which are not themselves the subject of the invention, have a thickness or thickness of approximately 5-12 mm, in particular 10 mm, and can be laid in any widths and lengths. During processing, the mastic layer (mastic strips) is first applied to the substrate, for example concrete, according to the invention, then the pipes are laid on these strips and finally the mastic asphalt is spread out in one or two stages. The use of the strip-shaped spacers made of asphalt mastic initially leads to a kind of insulation between the metal pipes and the substrate, so that there is no risk of the pipes rusting. In addition, the pipes are not stiff or rigid on the concrete, but they can counter all vibrations that occur; so they are elastic.

example

• 37 bis 38 Gew.% Splitt variabler Kornabstufung, beispielsweise zu zweidrittel aus 2/5 mm und eindrittel 8/12 mm ;
• 28 bis 30 Gew.-% Füller ;
• Rest für 100 % Mineralstoffe : Natur und/oder Edelbrechsand, beispielsweise 14 Gew.-% Natursand und 21 Gew.-% Edelbrechsand.

1. A mastic asphalt which is particularly suitable for the construction of an artificial ice rink in the sense of the invention has the following composition:

• 37 to 38% by weight grit of variable grain gradation, for example two thirds from 2/5 mm and one third 8/12 mm;
• 28 to 30 wt% filler;
• Remainder for 100% minerals: natural and / or fine crushed sand, for example 14% by weight natural sand and 21% by weight fine crushed sand.

In addition there are approx. 7.5% by weight - based on the total mass - of primary bitumen with a penetration (100 g, 5 s, 25 ° C.) of 35 to 50 mm- ', a ring and a softening point. Sphere from 54 to 59 ° C and a Fraass breaking point of at most - 6 ° C.

This mastic asphalt is applied to a suitable substrate, which will be defined later, in a layer thickness of 45 to 55 mm in hot construction and serves as an investment for the metal pipes carrying the refrigerant. The application is seamless, whereby a successive two-stage embedding of the mastic asphalt is particularly recommended, in which after filling a first mastic asphalt layer of approx. 20 to 25 mm thickness, the refrigerant pipes are fixed and then the cover is closed off by the second mastic asphalt layer.

As already mentioned, the primary support of asphalt mastic strips of 5 to 12 mm, in particular 10 mm, on the mineral substrate, for example concrete, is particularly advantageous. The mastic strips are spread out on the base by gluing or some other type of fastening in accordance with the later arrangement of the pipes. This is followed by the second mastic asphalt layer, which functions homogeneously with the first as a complete unit.

• a) Ein Bitumen der Penetration 50 bis 70 mm-¹ und einem Brechpunkt von max. - 8°C wird mit ca. 0,8 bis 1,4 insbesondere 0,65 Gew.-% - bezogen auf das Bitumen - eines Äthylmen-Vinylacetat-Copolymerisat mit einem Komponentenverhältnis von 0,8-1,2 : 1,2-0,8 modifiziert, wobei Eigenschaften erhalten werden, die dem nicht modifizierten Bitumen nach 1. nahe kommen, so daß es direkt als den Gußasphalt im Sinne der Erfindung aufbauendes Bitumen eingesetzt werden kann.
• b) Bei den höheren Penetrationswerten, etwa 70 bis 100 mm-¹ und Brechpunkten bis - 10 °C sind größere Anteile an Modifizierungsmittel erforderlich. In diesem speziellen Falle kann beispielsweise ein Styrol-Butadien-Copolymerisat bzw. Blockcopolymerisat oder ein Polyolefin wie Polyisobutylen, beide mit Molmassen im Bereich von ca. 200 000, in einer Menge von 0,6 bis 2,6, insbesondere bei Styrol-Butadien-Block-copolymerisaten in einer Menge von ca. 0,8 bis 1,2, eingesetzt werden. Die Mengenangaben sind wiederum Gew.-%, bezogen auf das Bitumen.

2. The same or little different structure with regard to their composition of fillers, grit and sand are also found in mastic asphalt investment materials whose bitumen has higher penetration and lower breaking point values. An adjustment can be achieved here by adding the modifiers already mentioned and defined:

• a) A bitumen with a penetration of 50 to 70 mm- ¹ and a breaking point of max. - 8 ° C with about 0.8 to 1.4, in particular 0.65 wt .-% - based on the bitumen - of an ethylmen-vinyl acetate copolymer with a component ratio of 0.8-1.2: 1.2 -0.8 modified, whereby properties are obtained which come close to the unmodified bitumen according to 1., so that it can be used directly as bitumen building up the mastic asphalt according to the invention.
• b) At the higher penetration values, about 70 to 100 mm- ¹ and breaking points down to - 10 ° C larger amounts of modifiers are required. In this special case, for example, a styrene-butadiene copolymer or block copolymer or a polyolefin such as polyisobutylene, both with molecular weights in the range of approximately 200,000, in an amount of 0.6 to 2.6, in particular in the case of styrene-butadiene Block copolymers are used in an amount of about 0.8 to 1.2. The quantities are again% by weight, based on the bitumen.

It is understood that the respectively optimal amount of modifying agent differs from case to case and as a function of the poured asphalt structure, the flow temperatures of the refrigerant, the quality and quality of the bitumen, in particular its characteristic data and other criteria determining the structure of the ice rink, before Use must be determined. This methodology is familiar to the person skilled in the art and therefore does not go beyond the scope of the invention.

But as already said, when using a primary bitumen with a Fraass breaking point of at most - 6 ° C, a penetration of 35 to 50 mm- 'and a softening point Ring u. Sphere of 54 to 59 ° C without any modifying agent.

The basic structure of an ice rink in the sense of the invention is described by way of example with reference to FIGS. 1, 2 and 3.

1, the overall structure initially consists of the mineral base layer (5), which of course is not subject to any downward limitation. It follows in the order upwards a sub-floor (4), for example made of concrete (solid ceiling) with a thickness of (a) = 100 to 250 mm, reference being made to the fact that these dimensions are only given as examples and are only subject to the requirements of sufficient load-bearing capacity .

In the order of further construction, the concrete layer (4) is covered in one or more layers with a separating layer and / or sliding layer (3) (bitumen paper, etc.), whereby an optimal separation of the mastic asphalt layer (2) from the concrete base (4) is achieved . As a result of this, the mastic asphalt (2) can follow lengthwise extensions without bracing itself against the substructure, for example made of concrete.

The metal pipes (1) through which the refrigerant is pumped are embedded in the mastic asphalt (2) of (b) = 35 to 60 mm, in particular 45 to 55 mm thick. The tubes (1) generally have an outer diameter of 15 to 25 mm. To support them, prefabricated documents (supports) (12) made of metal or plastic at intervals of 150 to 200 mm and a thickness of 8 to 15 mm, for example, on the separating or sliding material (3) - or also directly on the substrate ( 4) be provided. However, it is more appropriate. as shown in Fig. 3, to lay the pipes on a support of asphalt mastic.

The surface of the bituminous investment material (mastic asphalt) (2), i.e. the surface that forms the actual ice surface after the applied water has iced, can finally be covered with a relatively thin layer (13) of a suitable for roller skating, curling or another sport ( Plastic) covering mass to be occupied. Such a covering generally has a thickness of approximately 2.0 to 3.0 mm.

Figure 2 shows a slightly different structure of the substructure for ice rinks in the sense of the invention. Here, the separating or sliding layer (3) is dispensed with and the mastic asphalt (2), which receives the refrigerant pipes (1), possibly with the interposition of a layer (6) of asphalt concrete (cover layer mixture can be installed at low temperatures; low-viscosity binder) applied and glued directly to a substructure (7) made of bitumen gravel (asphalt base course) with a round grain mixture as filler). This ensures that any stresses that may occur in the overall package of mastic asphalt (2), asphalt concrete (6) and bitumen gravel (7) - based on the less important mineral base layer (9) - are quickly reduced.

This is important because bituminous gravel has approximately the same expansion coefficient as mastic asphalt, so that a «thermoplastic bond - with and without asphalt concrete (6) - takes place through the entire structure of the underground for the artificial ice rink.

The positioning of the previously mentioned asphalt mastic strips as a corrosion-preventing base - and support - for the pipes (1) carrying the refrigerant is shown in FIG. 3. The overall structure remains unaffected. The poured asphalt (2, 2a) is introduced in two stages after the mastic strips (15) have been laid (and glued) and the pipes (1) have assumed their intended position on these strips. The first mastic asphalt layer (2) is introduced up to the height of the diameter of the pipes (1), and as soon as these have reached their fixed position in the layer (2), the second mastic asphalt layer (2a) is introduced.

It is naturally possible for the mastic asphalts for layers (2) and (2a) to have different or the same composition. Mastic asphalt with a modifier can also be used on the one hand, and mastic asphalt without a modifier on the other. Both layers (2, 2a) can also consist of modified mastic asphalt.

In addition to the comments on the overall scope of the invention, it should also be said that with two-stage (or multi-stage) construction of the mastic asphalt (2, 2a), a different mastic asphalt composition is particularly important if the surface of the mastic asphalt is ice-free other sports than ice skating should serve. However, such variations are within the discretion of those of ordinary skill in the art and are part of the general idea of the invention.

Claims (12)

1. Process for the production of an artificially frozen ice rink structure consisting of the mineral, statically loadbearing base onto which a layer of material is placed for the embedding of the pipes carrying the pumped refrigerants, characterised in that the compound in which the pipes carrying the refrigerant are embedded consists of mastic asphalt, the bitumen content of which is formed by primary bitumen which has a penetration (100g, 5 s, 25 °C) of not less than 35 to 50 mm^―1, a ring and ball softening point of max. 54 to 59 °C and a Fraas brittle temperature of a least - 6 °C.

2. Process in accordance with Claim 1, characterised in that a solid floor(4) in concrete is first placed on a mineral base course (5), and on this a separation and/or sliding course (3) is placed in one or more layers, and on top of this the mastic asphalt course (2) is applied in one or more stages with the pipes carrying the refrigerant embedded in it.

3. Process in accordance with one of Claims 1-3, characterised in that for the structure of the mastic asphalt (2), a bitumen is used which has a penetration of more than 50 mm-¹, a ring and ball softening point of less than 54 °C and a Fraas brittle temperature lower than - °C but a maximum of ―10 °C, and which is modified with a copolymer.

4. Process in accordance with Claim 3, characterised in that the volume of modification agent is a maximum of 4.0 % by weight related to the bitumen.

5. Process in accordance with Claim 4, characterised in that a copolymer or block-copolymer from the group polyolefines, styrene-diene, ethylene-vinyl and/or acrylester copolymers is used as modification agent.

6. Process in accordance with one of Claims 1-5, characterised in that the mastic asphalt used has the following overall structure :

20 to 34 % by weight fillers such as limestone etc.,

35 to 55 % by weight chippings of variable grading,

11 to 45% by weight natural and/or artificial stone sand, 6.1 to 8.9, in particular 7.1-8.2 % by weight bitumen (primary bitumen) with a penetration of not less than 35 to 50 mm-¹, a ring and ball softening point of max. 54 to 59 °C and a Fraas brittle temperature of at least - 6 °C.

7. Process in accordance with Claim 6, characterised in that the bitumen contains between 0.6 and 2.6, in particular between 0.8 and 1.4 % by weight modification agent in relation to the bitumen.

8. Process in accordance with Claim 7, characterised in that the pipes (1) carrying the refrigerant are laid on spacers in mastic asphalt.

9. Process in accordance with Claim 8, characterised in that the mastic asphalt is laid in strips and the strips are 5-12 mm thick.

10. Process in accordance with one of Claims 1-9, characterised in that the surface of the mastic asphalt (2) is provided with an appropriate surfacing material (13) for sporting disciplines not dependent on ice. -

11. Process in accordance with Claim 9, characterised in that the mastic asphalt course is placed in two stages, whereby first the mastic strips (15) are placed on the loadbearing base (4), possibly with an interim layer of a separation and/or sliding course (3), then the pipes (1) are laid on these strips parallel to them, after which a first mastic asphalt course (2) is filled in up to about the middle of the pipes, and finally the second course of mastic asphalt (2a) is spread.

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