EP1589149B1 - Grating stone for grass surfacings - Google Patents

Abstract

An open profile concrete block for green support surfaces especially for supporting vehicles on a grassed area, has a two layer construction. The upper layer is made of porous concrete extending to two thirds or three quarters of the thickness of the block and with a finer pored stronger concrete as the bottom support layer. The open profiles have a tapering cross section wider at the top, with the grasses area about 60 percent of the area of each block. The porous upper layer holds moisture and provides a grip for grass roots.

Description

The invention relates to an existing of a hustwerkporigen concrete lattice for plantable areas in gardening and landscaping.

Such lattice stones are used in particular where a surface is greened and at the same time should be easily accessible or passable in any weather. In terms of their basic form, they are constructed of intersecting webs with trapped, soil-filled chambers. From the chamber / web ratio results, which relative proportions of the total surface of the lattice on the one hand and the chambers on the other hand come. For a good cropability of such stones, a large chamber / web ratio is preferred. A good reasonability is also ensured by the use of concrete materials with large pore volume, which on the one hand prevents plant-damaging heating of the bricks in intense sunlight and on the other large amounts of water can be stored. Another advantage of a large pore volume is that the root ends of the plants can grow into these stones and thus be anchored in the surrounding porous concrete. Moreover, a large pore volume offers the advantage of improved air and water management and effective surface drainage. Finally, a large percentage of pores reduces the weight of the individual Lattices, making them easier to lay.

A major disadvantage of a laid grid of highly porous concrete is its low compressive strength when driving, which can even lead to the breakage of the lattice.

In order to improve the breaking strength of a lattice, is in a in the DE 94 21 282 described lattice stone for gardening and landscaping provided that the webs widen continuously from the top of the stone towards the bottom, so that the chambers of the lattice correspondingly widen to the top of the stone conical. On the one hand, this achieves a chamber / web ratio which is sufficient for a good plantability on the upper side of the lattice; on the other hand, the lattice has an improved tensile strength in the lower region which is stressed when the stone is driven through the webs widening toward the underside. However, if such gratings are made of a concrete with a particularly high pore volume, the associated lower tensile load capacity would have to be compensated by a particularly pronounced conicity of the chambers, ie by more concrete volume, in order to achieve a sufficient tensile strength of the stone. However, this leads to a greatly reduced chamber volume, which ultimately stands in the way of a good reasonability.

For the production of green areas, molded blocks are known, see for example DE 197 42 899 A1 , which consist of a concrete body and a facing layer of porous concrete. The Pores of the facing layer allow plants to root in the pores with their roots. In addition, the pores of the facing layer have a storage function for precipitation water.

In another known two-layer concrete paver ( DE 25 33 800 A1 ), the upper layer of porous material and the lower layer of solid material, wherein the upper porous layer has a much smaller height than the lower layer of solid concrete. The porous layer serves to absorb surface water and drain it over the joints between the stones. In addition, fully porous, two-layer paving stones are known ( DE 39 09 169 A1 ; DE 91 00 380 U1 ), in which the upper, comparatively thin layer has a fine porosity and the lower, much thicker layer has a higher porosity. In these concrete blocks, the finer porous layer serves either as a filter layer or as a decorative layer.

The invention is therefore an object of the invention to provide a grid for green areas in gardening and landscaping, which allows good fertility and at the same time has excellent breaking load characteristics when driving.

According to the invention, the problem is solved in the case of a lattice block consisting of a hard-grained concrete in that the lattice block is constructed from two superposed concrete layers, the lower layer having a lower porosity than the upper layer and the thickness of the lower layer one third to one quarter of the total height of the lattice.

By means of the layer structure provided according to the invention, it is achieved that the lattice stone, on the one hand, has a porosity which is sufficient for a vigorous and long-lasting growth, and at the same time, excellent breaking load properties. The upper, only under pressure load layer has such a high porosity that they can store a large volume of water and record the root ends of the growing plants in the chambers, which can survive even longer periods of drought, while the pore volume of the lower layer so low It is chosen that this layer can absorb the tensile forces acting on the underside of the stone in case of stress, but still is permeable to water. In the selected thickness ratio of the layers is taken into account that the material particularly stressful tensile forces only occur in a narrow area near the bottom of the grid. Accordingly, the thickness of the highly porous layer with about three quarters of the total thickness of the lattice stone can be made large, whereby the total weight of the lattice stone decreases and an optimal water supply of the growing growth in the chambers is ensured.

Particularly favorable conditions are the weight, the fertility and the breaking strength in a lattice block, in which the grain diameter in the grading curve for the upper layer is limited to a maximum of 5 mm and for the lower layer to a maximum of 8 mm. Thus, the porous concrete of the lower layer can follow Composition: sand 0/2 mm, chippings 2/5 mm and cement and the upper layer of the following composition: sand 0/2 mm, chippings 5/8 mm and cement. In such hard-grained concretes, although the lower layer has a larger pore volume, the number of "glue joints" between the individual grains is much greater than that of the upper layer, so that the bending tensile strength of the lower layer is higher.

According to a further advantageous embodiment of the invention, the green content in the surface of the lattice is about 60%. This achieves a visually appealing reasonableness of the surface paved with the latticed bricks according to the invention with excellent load-bearing properties of the individual latticed bricks.

Due to the layer structure of the grid according to the invention, the trapped by the webs chambers can be cuboid, without causing overloading and thus to a breaking of the grid on its underside due to excessive tensile load. However, the load behavior of the lattice blocks can be further positively influenced if the chambers widen conically towards the top of the lattice stones.

After laying the grids, the area paved in this way is usually compacted by means of a vibrator ("shaking off"). It can easily lead to edge breakage on the surface of the marginal lattice especially because of the here particularly porous concrete, which is the optical Appearance of the area affected. For this purpose, according to an advantageous embodiment of the invention, it is provided that the surface of the lattice stones is lowered in the edge region towards the outer edge, so that this edge region susceptible to breakage no longer comes into contact with the Rüttelfläche of the vibrator, whereby an edge breakage is effectively prevented.

To lattice stones, which have laterally open half chambers on the peripheral edge to summarize after production to a package with improved stability and in particular in the mechanical laying of the lattice to move them to avoid crosshatch against each other, is according to an embodiment of the invention provided that a portion of the half chambers are closed in the lower region, such that half open chambers and half closed in the lower region chambers are located opposite the abutting edges of adjacent lattice stones respectively. With such trained lattice stones, it can not come to mutual hooking of the web ends on the peripheral edge.

Fig. 1

einen erfindungsgemäßen Gitterstein in perspektivischer Ansicht,

Fig. 2

den Gitterstein der Fig. 1 in Draufsicht,

Fig. 3

den Gitterstein der Fig. 1 in einer Seitenansicht und

Fig. 4

zwei benachbart stehende Gittersteine gemäß Fig. 1 in seitlicher Schnittansicht gemäß der Linie IV-IV der Fig. 1.

In the following the invention will be explained in more detail with reference to a drawing illustrating an embodiment. Show it:

Fig. 1

a lattice stone according to the invention in a perspective view,

Fig. 2

the lattice of the Fig. 1 in plan view,

Fig. 3

the lattice of the Fig. 1 in a side view and

Fig. 4

two adjacent grids according to Fig. 1 in a side sectional view along the line IV-IV of Fig. 1 ,

The lattice brick 1 according to the invention consists according to Fig. 2 from twice four crossing at right angles webs of equal length 2, 3 and thus has a square cross-section. The webs 2, 3 include a total of 9 chambers 4, also square in cross-section, which receive soil or a substrate for green vegetation. As in particular in Fig. 2 recognizable, the edge of the grid 1 is formed by the ends 2a, 3a of the webs 2, 3, which form short projections with respect to the respective outer transverse web. As Fig. 2 shows further, the web ends of each adjacent bricks meet the front side against each other.

The lattice block 1 consists of a concrete with a high particle size and is composed of two superimposed concrete layers S1, S2 of different porosity, the lower layer S2 having a lower porosity than the upper layer S1 (see FIG. Fig. 4 ). It is thereby achieved that the lattice brick 1 with the upper layer S1 has a porosity which is sufficient for a vigorous and long-lasting growth and at the same time is distinguished by excellent breaking load properties due to the comparatively low porosity of the lower layer S2. In the present case, the thickness d of the lower layer corresponds to approximately one quarter to one third of the total thickness D of the lattice 1. Accordingly, the thickness of the upper layer S2 extends over approximately three quarters of the total thickness of the lattice. This reduces the total weight of the Grid, and optimal water supply of growing in the chambers growth is ensured.

As in particular in the side view of Fig. 3 can be seen, the webs 2, 3 widened from the top of the lattice block 1 to its underside, so that expand the chambers 4 from the bottom to the top of the lattice 1 accordingly. As a result, the tensile strength of the lower portion of the grid is additionally strengthened and thus the strength of the grid against breakage further improved.

As the 3 and 4 show, the surfaces of the web ends 2a, 3a, which form the edge of the lattice 1, lowered by a slight bevel to the outside. This is particularly important when the web ends 2a, 3a form the outer edge of a paved with a plurality of lattice stones 1 surface. In this case, the lowered surfaces of the web ends 2a, 3a can not come into contact with a vibrator and be broken by this.

In the figures, a part of the otherwise open half chambers is closed at the peripheral edge of the lattice in the lower region, with concrete poured out, which is pulled up to the walls of the webs 2. The lowest height h of the closed area should be at least 20% of the total height of the stone, which need not be congruent with the thickness d of the lower layer S1. The distribution between completely open and half-closed half chambers is made so that arise at the peripheral edge chambers, one half of the chamber is half closed and the other half of the chamber is completely closed. It results Then there is a mutual continuous contact surface, which allows the laid lattice stones to move against each other without the ends of their webs 3a can interlock with each other.

Claims (7)

1. Grating stone (1) consisting of a hollow concrete for plantable areas in horticulture and landscaping, characterised in that the grating stone (1) is built up from two concrete layers (S1, S2) lying one above the other, the lower layer (S2) in the installed state having a lower porosity than the upper layer (1), and the thickness of the lower layer (S2) corresponding to a third to a quarter of the total height (D) of the grating stone (1).
2. Grating stone according to claim 1, characterised in that the maximum particle diameter of the porous lower layer is 5mm and that of the upper porous layer is 8 mm.
3. Grating stone according to claim 2, characterised in that the hollow concrete of the porous lower layer (S2) has a composition of sand 0/2 mm, stone chips 2/5 mm and cement and the hollow concrete of the upper layer (S1) has a composition of sand 0/2 mm, stone chips 5/8 mm and cement.
4. Grating stone according to any one of claims 1 to 3, characterised in that the green content in the surface of the grating stone (1) is 50 to 60%, in particular 60%.
5. Grating stone according to any one of claims 1 to 4, characterised in that the chambers (4) of the grating stone (1) enclosed by webs (2, 3), in the installed state, widen conically toward the upper side of the grating stone (1).
6. Grating stone according to any one of claims 1 to 5, characterised in that the surface of the grating stone (1) is lowered in the edge region toward the outer edge.
7. Grating stone according to any one of claims 1 to 6, characterised in that the grating stone (1), at its peripheral edge, has laterally open, half chambers, some of the half chambers being closed in the lower region in such a way that half open chambers and half closed chambers in the lower region oppose one another in each case at the abutting edges of adjacent grating stones (1) .

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