EP0471978B1 - Porous surface covering element and its application - Google Patents

Abstract

The invention relates to a water-permeable surface covering element (2) for road surfaces, having a body of mineral grains (22) bonded with a binder while leaving through-pores (20) free, in particular of concrete. According to the invention, a facing layer (6) covering the body (4) is provided with pores (20) which go through to the body and the average free permeating cross-section of which is less than the average free permeating cross-section of the pores (28) of the body. In addition, the invention relates to the application of a high-pressure water jet method of flushing out the through-pores (20) of the facing layer (6) in the composite road surface of the surface covering elements (2). <IMAGE>

Description

The invention relates to a water-permeable surface fastening element for traffic surfaces according to the preambles of claim 1 or of claim 4. Such a water-permeable surface fastening element as a paving element is known from DE-A1-3 909 169.

Traffic areas are understood to mean, in particular, roads, paths, parking lots, courtyards and terraces, traffic being understood to mean both motor vehicle traffic and traffic with bicycles or people.

Surface fasteners are understood to mean, in particular, paving stones or path slabs, with or without interlocking.

It has recently been criticized that the surface fastening elements that have been customary up to now largely seal the traffic area in question impermeable to rain. The rainwater that accumulates is therefore not routed to the groundwater in the desired manner, but instead pollutes the sewage system.

Water-permeable surface fastening elements have therefore already been developed, which in turn have to be laid on a water-permeable substructure. The water permeability also requires air permeability. The invention relates to a development of such surface fastening elements.

Known surface fasteners of this type have a relatively coarse-grained structure with a rough surface and coarse pores through to the surface. Surface contaminants, including contaminants washed up by precipitation, gradually clog these coarse pores, so that water and air permeability decrease significantly over time and, in the borderline case, are no longer guaranteed. Since such contamination extends into the depth of the stone body, it is difficult or impossible to flush it out. In addition, the rough surface causes a relatively high rolling resistance and thus not only a braking effect, for example on bicycles, but also generally a relatively high traffic noise. Even pedestrians find walking on rough artificial stone surfaces uncomfortable, for example because of the risk of getting caught while walking.

It is already known from "WEGEN, Vol. 64, No. 6, June 1990, pp. 30 to 31, Ede, NL; GG VAN BOCHOVE:" Nieuw concept voor zeer open asfaltbeton ", in the case of continuously laid traffic areas made of rubber asphalt, earlier misleadingly referred to as asphalt concrete, a base layer made of coarse, single-grain (11/16 or 18/22) gravel, which is water-permeable bound with rubber bitumen, in a second step with a thin top layer of fine, very open asphalt, e.g. with ballast 4/8, For the upper layer, which is to be designed as porous as possible with a low flow resistance, a sand-free mixture with a bond by asphalt binder is provided, which is highly viscous when it is still warm. When the top layer is applied to the base layer, the grain should be in the rough texture of the base layer and thus enable a lower total thickness of the asphalt layer in comparison with the theoretical thickness value relatively large grain sizes are obviously not feared by placing the fine core of the upper layer in the coarse-grained texture of the base layer. The poroelastic two-layer asphalt obtained in this way should not only reduce noise, but also water permeability with dirt repellency, Permeability for fine dirt particles and self-cleaning due to the elastic structure due to traffic-related pressure interactions between the top layer and base layer. Cleaning techniques with pressure flushing from top to bottom through the porous asphalt layer are considered effective.

DE-A1-3 909 169, from which the preambles of claims 1 and 4 are based, relates to a water-permeable, natural-colored plaster element which, with high mechanical strength, should not fade on its natural-colored surface even after a long period of use and which is nevertheless easy to produce. For this purpose, a body made of normal concrete, i.e. of cement, aggregates and water, which is permeable to water through the incorporation of cavities, is provided with a likewise water-permeable, porous, thin facing layer made of shattered, colored natural stone. The smashed natural stone is bound by a hard plastic binder, which is pressed into the cavities of the body in the manufacture of the plaster element in a press fit to bind the facing layer to the body.

An organic binder is thus used both in the paving element of DE-Al-3 909 169 and in the rubber asphalt discussed above.

The invention has for its object to provide a water-permeable surface fastener that is less sensitive to dirt, possibly even cleanable, and has a lower rolling resistance.

This object is achieved in a water-permeable surface fastening element with the features of the preambles of claim 1 and claim 4 by their respective characterizing features.

The relatively fine, continuous pores of the facing layer have a filtering effect with regard to contaminants. Coarser contaminants are retained on the top of the surface fastening element and can be easily swept away or washed away there. Finer contaminants, which in the continuous pores of the facing layer penetrate, at least to a large extent under the effect of the rainwater, are gradually carried away into the coarser structured substructure and can seep into the substructure there together with the rainwater. This drastically reduces the risk of clogging of the entire surface fastening element. As a side effect of the more pore-shaped formation of the facing layer, even if one does not explicitly provide additional smoothing measures for the surface (cf. claim 10), a reduction in rolling resistance and thus a reduction in the other negative effects mentioned in connection with rolling resistance results.

Facing layers are also known per se for non-water-permeable surface fastening elements, e.g. for decorative design of the surface.

The "pore diameter" is understood to mean the largest possible diameter of a ball that just fits into the pore or can "slip" through it. "Average pore diameter" is the average of the pore diameters of all pores in the body or the facing layer. According to the literature, the "average pore diameter" for a single-grain concrete is approximately 0.14 x average grain size, which is to be understood as the mean value of the grain group used according to DIN 4226 Part 1.

With reference to this, claims 1 and 2 define pore diameter ranges which give the desired filter effect mentioned while reducing the risk of clogging but maintaining the water permeability. In the same sense, the strengths of claims 5 and 6 and the grain size of claim 3 are coordinated.

The average grain size (see e.g. Claim 3) is based on the mean value of the grain group according to DIN 4226.

The choice of materials in the context of the production of the surface fastening elements according to the invention relate to basic materials customary for concrete, so that binders based on plastics or organic binders are unnecessary. The The usual concrete binder that has not yet hardened is in accordance with DIN 1045 (concrete and reinforced concrete), no. 2.1.2, cement paste from a mixture of cement and water. Accordingly, DIN 485 (pavement slabs made of concrete) and DIN 18501 (cobblestones made of concrete) are already included in section. 1 reference to standard cements according to DIN 1164 part 1 as a binding agent of the concrete, be the respective surface fastening elements in one layer or with a facing layer. The mineral grains of the surface fastening elements according to the invention correspond to the additives of this standard.

To increase the mechanical strength, it can prove to be advantageous to provide the facing layer and / or the body with an additional incorporation of fiber material in accordance with claims 7 to 9.

In known single-layer, water-permeable surface fastening elements, individual mineral grains are bound by the binder in such a way that the continuous pores are formed everywhere between the individual grains. This can be imagined in such a way that practically the binder only partially or completely covers the surface of the grains and is not present in the space between the grains or is only present to a relatively small extent. A corresponding structure is also provided in the formation of the facing layer according to the invention.

According to claim 4, however, the surface fastener according to claim 1 is modified with respect to the body so that the mineral grains are formed by the binder to an inherently water-impermeable body in which continuous pores are formed as through channels. The then finer-pored facing layer compared to these channels distributes the absorbed liquid together with the absorbed micro-dirt particles over the individual channels, which can be provided with a lower surface density than otherwise in a body of the known type with pore formation between the individual grains.

According to claim 11, the invention also relates to the application a high-pressure water jet method for flushing out the continuous pores of the facing layer in the traffic area network of area fastening elements according to the invention. It has been shown that the unavoidable slow addition of the facing layer according to the invention can be remedied by appropriate flushing, so that the surface fastening elements according to the invention, unlike single-layer known water-permeable surface fastening elements, can also be regenerated in the application. High-pressure water jet is understood to mean a water jet in particular in a pressure range of 20 to 40 bar, ie a range that is quite common for such high-pressure water jet processes.

• Fig. 1 einen vertikalen Schnitt durch eine erste Ausführungsform eines erfindungsgemäßen Flächenbefestigungselementes und
• Fig. 2 einen vertikalen Schnitt durch eine zweite Ausführungsform eines erfindungsgemäßen Flächenbefestigungselementes.

The invention is explained in more detail below with the aid of schematic drawings using two exemplary embodiments. Show it:

• Fig. 1 shows a vertical section through a first embodiment of a surface fastening element according to the invention and
• Fig. 2 shows a vertical section through a second embodiment of a surface fastening element according to the invention.

In both embodiments of FIGS. 1 and 2, a surface fastening element 2 is composed of a body 4 located at the bottom and an upper facing layer 6 which is thinner than the body. The top 8 of the facing layer forms an element of a traffic area to be produced. The body 4 is laid on a water-permeable substructure, not shown. The body 4 and the facing layer 6 each have approximately the same thickness over the respective cross section shown, so that the top 8 of the facing layer, the underside 12 of the body 4 and the boundary layer 10 between the facing layer 6 and body 4 form essentially flat parallel surfaces. The upper side 8 is expediently designed to be smooth, while the boundary layer 10 between the facing layer 6 and the body 4 is expedient represents only an ideal surface, which in practice describes a form-fitting engagement of facing layer 6 and body 4. The underside 12 of the body 4 can also have a rough to jagged structure.

The facing layer 6 consists of mineral grains 14, the respective surface 16 of which is covered by a concrete binder, not shown, so that a structure in the manner of a single-grain pore concrete is formed. In other words, the intermediate space between the mineral grains 14 is not completely filled with the concrete binder, but the concrete binder serves essentially only for the superficial mutual bonding of the mineral grains 14 to one another, a largely coherent mesh of open pores being formed in the intermediate space. In addition to more or less horizontally extending pores 18, vertically continuous pores 20 also form in particular from the top 8 of the facing layer 6 to the boundary layer 10.

While the two exemplary embodiments of FIGS. 1 and 2 are the same in this respect, they differ in the following:

1, the structure of the body 4 is basically the same as that of the facing layer 6 with the only exception that the mineral grains 22 of the body 4 have a substantially larger grain size than the mineral grains 14 of the facing layer 6. However, there is agreement in particular in a basic structure in the manner of a single-grain pore concrete, in which the mineral grains 22 are bonded to one another on their respective surface 24 by the concrete binder, not shown. Again, however, only such a quantity of concrete binder is used that, as in the case of the facing layer, it essentially only acts as a surface and results in an open pore network with more or less horizontally extending pores 26 and more or less vertically extending pores 28, the latter of the interface 10 between facing layer 6 and body 4 in vertical Pass through towards the bottom 12 of the body 4.

The continuous or open pore mesh of the facing layer and the continuous or open pore mesh of the body must communicate at least in the vertical direction; therefore, even when connecting the facing layer and body in the interface 10, the concrete binder should only be used sparingly, insofar as it also connects the facing layer 6 and body 4. In particular, the vertical pores 20 of the facing layer 6 must communicate with the vertical pores 28 of the body 4. Due to the larger grain size of the mineral grains 22 in the body, the mean free passage cross section of the vertically continuous pores 28 of the body is also larger than that of the vertically continuous pores 20 of the facing layer 6.

In the second embodiment of FIG. 2, mineral grains that are still used are instead formed by the concrete binder to form an otherwise dense body 30, in which instead of the vertically continuous pores 28 of the embodiment of FIG. 1, vertical vertically running from top to bottom Channels 32 are preformed, which have a significantly larger passage cross section than the vertical pores 20 of the facing layer 6 and can also have a larger passage cross section than the vertical pores 28 of the body 4 of the embodiment according to FIG. 1. In this case, a substantially smaller number of vertical channels 32 in the embodiment of FIG. 2 than in the case of vertical pores 28 in the embodiment of FIG. 1 are sufficient. There is no need to provide a preformed channel analog to the horizontal pores 26 of the exemplary embodiment according to FIG. 1. The vertical channels 32 are distributed over the horizontal cross-sectional area of the surface fastening element so that the water entering the body 4 through the pore mesh in the facing layer 6 is discharged as evenly and as completely as possible to the underside 12 of the body 4, even in the second exemplary embodiment in FIG. 2 becomes.

Claims (11)

1. Water-permeable surface paving element (2) for traffic surfaces with a concrete body (4) in which mineral grains (22) are bound by the concrete binder leaving open through-passing pores (28), and with a thinner facing layer (6) which covers the body (4) and in which the mineral grains (14) are bound by a binder leaving open pores (20) passing through to the body (4), characterized in that the binder of the facing layer (6) is also the concrete binder such that the entire surface paving element (2) is composed of concrete, and in that the average pore diameter of the facing layer (6) is at most half the average pore diameter of the body (4).
2. Surface paving element according to Claim 1, characterized in that the average pore diameter of the facing layer (6) is at most a third of the average pore diameter of the body (4).
3. Surface paving element according to Claim 1 or 2, characterized in that the average grain size of the facing layer (6) is at most half, preferably a third, of the average grain size of the body (4).
4. Water-permeable surface paving element (2) for traffic surfaces with a concrete body (4) in which through-passing pores are left open, and with a thinner facing layer (6) which covers the body (4) and in which mineral grains (14) are bound by a binder leaving open pores (20) passing through to the body (4), characterized in that the binder of the facing layer (6) is also the concrete binder such that the entire surface paving element (2) is composed of concrete, in that the through-passing pores of the body (4) are vertical channels (32) preformed in an otherwise impermeable body (30), and in that the average passage cross-section of the pores in the facing layer (6) is smaller than the average passage cross-section of the channels (32) based on the same base area.
5. Surface paving element according to one of Claims 1 to 4, characterized in that the thickness of the facing layer (6) is at most a quarter, preferably at most a sixth, of the thickness of the body (4).
6. Surface paving element according to one of Claims 1 to 5, characterized in that the thickness of the facing layer (6) is at least a twentieth, preferably at least a tenth, of the thickness of the body (4).
7. Surface paving element according to one of Claims 1 to 6, characterized in that fibres are distributed over the facing layer (6) and/or the body (4).
8. Surface paving element according to Claim 7, characterized in that the fibres are mineral fibres, preferably glass fibres.
9. Surface paving element according to Claim 7 or 8, characterized in that the fibres are plastic fibres.
10. Surface paving element according to one of Claims 1 to 9, characterized in that the top side (8) of the facing layer (6) is formed so as to be smooth with fine pores.
11. Use of a high-pressure water jet process for washing clear the through-passing pores (20) of the facing layer (6) in the composite traffic surface comprising surface paving elements (2) according to one of Claims 1 to 10.

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