EP2236670A2 - Water-permeable paving stone and method for its production - Google Patents

Abstract

The stone has an upper layer (22) made of porous concrete and a lower layer (20) made of sealed concrete, where vertical channels (26-28, 30) are formed in the lower layer. The lower layer includes a hopper surface (48) around an opening (38), where the hopper surface is defined by a hopper edge (50). The hopper surface continuously lies from the hopper edge to the opening. The hopper edge and the adjacent opening directly adjoin each other. A hollow space (44) is formed in the upper layer above the opening and upwardly defined by a topmost point (46) of the stone.

Description

The invention relates to a water-permeable paving stone with an upper layer of porous concrete, comprising grains and a binder, wherein there are pores between the grains, the pores are interconnected and continuous, and a lower layer of dense concrete, in the vertical, continuous channels are formed, which have an upper mouth and a lower outlet.

Such a paving stone is out EP 471978 B1 known. He is essentially cuboid, in particular, he has a flat top and a flat, parallel to the top bottom. The cross section of the channels of the lower layer, seen in a plane parallel to the xy plane, is larger, in particular at least twice as large as the cross section of the pores in a sectional plane parallel thereto through the upper layer.

For further prior art is on the DE 296 15 792 U2 . DE 197 33 286 A1 and DE 10 2004 020 712 B4 directed.

Such water-permeable paving stones should fulfill as far as possible all tasks that also meet normal paving stones, which are made of only one layer of concrete. Reference is made to EN-1338 and EN-1339. The problem of the water-permeable paving stone is that due to the porosity there is less strength. This is disadvantageous. What is desired is a paving stone which, in spite of the water permeability, has a strength which is also met by a normal concrete block, in particular according to the standards specified above.

A problem of the water-permeable paving stones occurs in frost, when cavities of the paving stones are still filled with water. As you know, water expands when it freezes. This leads to a bursting and destruction of the stone. Care must therefore be taken to ensure that, in frost-prone installations, no water can accumulate in the stone itself. Water can accumulate, for example, as a result of blockage occurring within the stone or because water drainage, ie drainage, is not sufficient below the stone.

This is where the invention begins. It has set itself the task of further developing the water-permeable paving stone of the type mentioned in that it has a better water drainage and the risk of frost damage is reduced.

This object is achieved on the basis of the water-permeable paving stone of the type mentioned above in that the lower layer around each mouth has around a funnel, which is bounded by a funnel edge, that the funnel surface from the funnel edge towards the mouth continuously decreases, and that the funnel edges adjacent Close mouths directly to each other.

The water-permeable paving stone is preferably cuboid. In particular, it has a flat top and bottom. He is still at least two-ply. The upper layer is significantly thinner, seen in the z-direction, than the lower layer, it has at most 1/3, preferably at most 1/5 and in particular at most 1/7 and less thickness than the lower layer. The lower layer is responsible for the strength of the entire paving stone. It is made of a concrete, as is usually used for such, single-ply paving stones, reference is made to the standards mentioned. Although the lower layer is mechanically weakened by the channels, this is irrelevant and can be compensated for by improved quality of the concrete of the lower layer. The concrete of the lower layer is preferably compacted. The lower layer may also have a reinforcement.

The upper layer has the task to absorb superficially accumulating water over the entire top of the stone and passed through as quickly as possible to avoid that water can accumulate locally on the top and in the upper layer, the lower layer has funnel surfaces at its upper limit , These provide a sufficient, continuous slope, so that water can drain away quickly. The deepest point of the funnel surfaces is the mouth of a channel of the lower layer. Once the mouth is reached, the water flows down quickly through the relatively large channels.

As a problem, the abrupt transition in the region of the mouth between the material of the upper layer and the channel of the lower layer has now been found in the previously known paving stone. All water that is to get into the channels must flow through that part of the upper layer that is just above the mouth. The invention now proposes, in an improvement, that in the upper layer there is a cavity which directly adjoins the mouth and extends upwards. He is, for example, dome-shaped. As a result, the area through which the water must flow in order to get into one of the channels, compared to the prior art significantly increased. This in turn leads to a better drainage of water.

In order not to jeopardize the strength of the paving stone, at least one layer of 5 mm thickness is located above an uppermost point of such a cavity. The cavity itself has a height of, for example, 2 to 10 mm in the z-direction.

The upper layer is produced without fines, it has grains with at least 0.25 mm dimensions and no smaller components of the surcharge. The pores of the upper layer are contiguous, in particular they go through from the top to the cavity. The funnel surfaces drain the water quickly, they offer a slope everywhere. Their angle is adapted to achieve a rapid discharge of the water, even with slightly oblique arrangement of the paving stone in a laid surface. The funnel surfaces prevent local accumulation of water and prevent frost damage.

The diameter of the channels is preferably between 10 and 15 mm. They are preferably conical. They extend from the mouth down to the outlet.

In a preferred embodiment, the surface of the channels and / or the angle at which the channels extend downwardly are selected so that the angle of self-locking between the concrete and ice is exceeded. This has the consequence that when freezing a plug located in the channel of ice is pressed down, but not blow it up. So the plug may lift the paving stone, but the cobblestone is not destroyed by him. The surface of the channels is preferably smooth.

If the paving stone is laid, then there is a sufficiently permeable layer below it, for example a gravel layer. The water drainage must be so large that in the paving stone itself no water stops.

The advantage of water-permeable paving stones is that laid surfaces are no longer sealed, as is the case with normal, impermeable paving stones, but rather the water can seep into the soil underneath the stone.

In tests, it has been found that the splitting force of the water-permeable paving stone according to the invention is about 3 N / mm ² . A normal stone has values of about 3.6 N / mm ² . If one chooses solid material such as granite, basalt or porphyry for the grains, then one also achieves values for the water-permeable paving stone, as they are achieved for the normal stone. The tests have shown that the break line passes through the grains but holds the binder. It thus depends essentially on the strength of the grains.

Preferably, two channels are not in a plane that is parallel to a narrow surface of the paving stone. The channels lie in planes defined by their center lines, these planes have a cut surface with the paving stone. This cut surface has a surface area. The surface area of this cut surface should be larger than the surface area of a narrow surface. In other words, the channels are staggered. This ensures that a fault line runs parallel to a narrow surface through at most one channel. The fracture surfaces in which there are at least 2 channels have a larger surface area than the narrow surface, so that a break parallel to the narrow surface requires less energy than a break through two channels.

For the production of water-permeable paving stones several methods are proposed. During production, make sure that the upper layer is intimately connected to the lower layer. The upper layer represents a certain wear layer there. The pores are sufficiently large so that usual soiling can happen and no puddles remain on the top. Preferably, the pores are formed so that the narrowest point is at the top. As a result, there is too much dirt above the top and dirt that has passed can not get stuck anywhere in the stone.

Preferably, the lower layer is first prepared. For this purpose, normal concrete is given in a corresponding form. The funnel surfaces are either at the bottom of the mold or at the top. After making this lower layer, the funnel surfaces are smooth. The upper layer is now added, their grains combine with the upper surface of the lower layer. The addition of the upper layer takes place at a time at which the lower layer has not yet cured, preferably the curing has not yet begun.

The bottom layer can be made in a standard block making machine currently used for the production of impermeable paving stones. Here normal filling systems can be used. The mold has either towering punches that leave the channels open or the bottom layer is first made continuously, without releasing the channels and these are subsequently formed before the material hardens, for example, they are drilled.

The lower layer is compacted using the usual methods such as pressure, shaking or the like.

Fig. 1:

eine Draufsicht auf die Oberseite eines Pflastersteins,

Fig. 2:

eine Untersicht des Pflastersteins,

Fig. 3:

einen Schnitt entlang der Schnittlinie III-III in Figur 1,

Fig. 4:

eine Draufsicht auf die Oberfläche einer unteren Lage, eine obere Lage ist nicht dargestellt,

Fig. 5:

ein Schnittbild durch eine Form für die Herstellung des Pflaster- steins, jedoch eines Pflastersteins ähnlich demjenigen nach den Fi- guren 1 bis 4, die Schnittlinie entspricht der Schnittlinie I-I in Figur 2,

Fig. 6:

die Form nach Figur 5, jedoch nunmehr gefüllt mit Betonbrei für die Herstellung der unteren Lage,

Fig. 7:

die gefüllte Form gemäß Fig. 6, jedoch ist nunmehr ein Stempel in die Oberfläche des Betonbreis eingedrückt und findet eine Form- gebung statt,

Fig. 8:

die Form gemäß Figur 7, jedoch ist nunmehr der Stempel entfernt und ist eine obere Lage in die Form eingebracht worden, und

Fig. 9:

ein Schnittbild entsprechend Figur 5 für eine andere Ausbildung der Form, nunmehr ist der Stempel beweglich.

Further advantages and features of the invention will become apparent from the other claims and the following description of non-limiting embodiments of the invention, which are explained in more detail with reference to the drawings below:
In this drawing show:

Fig. 1:

a top view of the top of a paving stone,

Fig. 2:

a bottom view of the paving stone,

3:

a section along the section line III-III in FIG. 1 .

4:

a top view of the surface of a lower layer, an upper layer is not shown,

Fig. 5:

a sectional view through a mold for the production of the paving stone, but a paving stone similar to that according to the figures 1 to 4, the section line corresponds to the section line II in FIG. 2 .

Fig. 6:

the shape after FIG. 5 but now filled with concrete slurry for the production of the lower layer,

Fig. 7:

the filled form according to Fig. 6 , but now a stamp has been pressed into the surface of the concrete slurry and a shaping takes place,

Fig. 8:

the form according to FIG. 7 However, now the punch is removed and an upper layer has been introduced into the mold, and

Fig. 9:

a sectional view accordingly FIG. 5 for another embodiment of the mold, now the stamp is movable.

As a rule, the paving stone consists of two layers 20, 22, as shown in the figures, but it may also have three or more layers. In each case, it has a lower layer 20. It occupies at least 70%, preferably at least 80% to 90% of the volume of the paving stone. It is made of a normal compacted concrete commonly known for its good quality. In particular, a concrete is used, as it is known from the standards and as it is currently used for paving stones. Advantageously, the concrete is reinforced, as will be discussed later.

With the lower layer 20, an upper layer 22 is firmly connected. This upper layer 22 is made of cement, water and a supplement, which has no fines. The supplement is grainy. The granulation band is between 0.25 mm and 7 mm, in particular between 0.5 and 3 mm. This releases pores between the grains. The pores are interconnected. Porous passages are provided from an upper surface 24 of the paving stone to an intermediate surface 42, in which intermediate surface 42 the lower layer 20 and the upper layer 22 touch. It is important that the upper layer 22 be porous and durable in use also remains porous.

The lower layer 20 is provided with vertical, continuous channels 26-30. These have a slightly conical shape 62, so are truncated cones. They have a round cross section. Other cross sections are possible. It's important, that the cross-section of the intermediate surface 42 to a bottom 32 of the paving stone steadily expanded. In other words, a molded part 64, which in the manufacture of the lower layer 20 keeps the space for a channel 26 free, must be removed downwards, in the negative z-direction. The conical shape 62 prevents dirt from settling and blockages. The conical shape 62 is also advantageously designed in such a way that freezing water in a channel 26 is pressed down somewhat by the increase in volume occurring during freezing. The forces occurring during freezing have a sufficiently large component down, in the negative z-direction. The angle of self-locking between ice and the concrete surface is smaller than the angle of inclination of the extension, in particular in the conical shape 62. The inner surface of the channels 26 to 30 is sufficiently smooth so that there can be no positive connection between ice and concrete.

The channels 26-30 mean a weakening of the lower layer 20 and thus of the paving stone. As FIG. 3 shows, the channels 26 to 30 offset from each other. Thus, the channels 26 and 28 lie in a plane 34. This plane 34 encloses with an end face, ie an outer surface of the paving stone running parallel to the yz plane, an angle ≥ 15 °. As a result, the sectional area of this plane 34 with the paving stone has a surface area which is greater than the surface area of the end face 36. If the plane 34 were parallel to the yz plane, a break of the paving stone along such a plane could be preferred. By obliquely displacing the channels 26 to 30, the strength of the paving stone is increased.

The channels 36 to 30 extend from an upper mouth 38 to a lower spout 40. The upper mouth 38 of all channels 26-30 lies in a plane parallel to the xy plane and is also located in the intermediate surface 42. Above This intermediate surface 42, the channels 26 to 30 continued through a cavity 44 upwards. The cavity 44 is located in the upper layer 22. It connects to the upper mouth 38 and is, for example dome-shaped. He has a top point 46. Above this top point 46 is still at least one layer of the top layer 22 of 5 mm thickness, preferably more. The height of the cavity 44 measured in the z-direction is at least 2, preferably at least 5 mm and can reach up to about 10 mm. There are one to ten channels 26 to 30 per 100 cm ² provided. The thickness of the upper layer 22 is between 7 and 25 mm, preferably about 15 mm.

In the following, the intermediate surface 42 will be discussed. In this are the upper mouths 38 of the channels, in the FIGS. 1 to 4 a total of 4 channels 26 to 30 are provided. Around each one of the upper orifices 38 is a funnel, it has a funnel surface 48 and is bounded by a funnel edge. From the edge of the funnel 50 to the mouth 38, the funnel surface 48 drops steadily, so there is an incline everywhere for the discharge of water. The funnel edges 50 of adjacent funnels are linearly adjacent to each other, they are immediately adjacent to each other. In the embodiment shown, the funnel edges 50 are all in an upper plane 54 that is parallel to the xy plane. Partly fall the funnel edges 50 with the side surfaces of the paving stone together. All bevels are inward, there is no outward slope of a funnel area. Thus, the entire incident on the top 24 of the paving stone water is passed through the channels 26 - 30. A lateral overflow should not take place.

It is intended that the paving stone is always dry. It should be avoided that moss and other plants can settle in the stone and clog the pores.

The paving stone can have any external dimensions. Preferably, the top 24 is parallel to the x-y plane, the same applies to the bottom 32. The side surfaces can be made arbitrarily, preferably the paving stone is cuboid.

The funnel surfaces 48 have an angle of inclination with respect to an x-y plane which is greater than 3 °, in particular greater than 5 °, preferably greater than 7 °, and may for example also go up to 15 °. The funnel surfaces 48 are formed so that each channel 26 to 30 has approximately the same feed surface. The funnel edges 50 can be straight, as in the example shown, but they can also have any other shape.

In order to obtain an intimate connection between the two layers 20, 22, it is advantageous to additionally apply cement in the region of the intermediate surface 42 before after the production of one layer 20, the other layer 22 is applied. As a result, a higher concrete quality in the area of the intermediate surface 42 is achieved. Preferably, the topsheet 22 is made of two individual layers, thereby forming a lower, second layer of grains which are coarser than the grains of the overlying first layer. The coarser grains should have the highest possible own strength. They are intimately related to the lower layer 20. It is thus created a sufficiently large area for the discharge of water in the region of the intermediate surface 42.

In the production of a mold 62 is used, it is preferably first the lower layer 20 is made. The channels 26 to 30 can be formed in that corresponding mold parts 64 are provided in the mold 62 for the production of the paving stone. These moldings 64 can be used as moving parts (see Fig. 9 ), they can allow movement in the z-direction. The channels 26 to 30 can also be introduced later, for example, by drilling or cutting out before curing of the concrete, eg before the application of the upper layer 22nd

For the production, the normal method for the production of non-water-permeable paving stones can be used as a starting method. As with the known method, normal concrete slurry 52 is introduced into the mold 62 and distributed in it. The added amount is exactly measured. Preferably, the lower layer 20 is started. Preferably, the lower layer 20 is oriented so that the later interface 42 is at the top, see Fig. 6 , But it can also be down, then the mold 62 has a corresponding profiling in its bottom, which is adapted to the funnel surfaces 48 and is essentially a negative image to Fig. 4 , If the later intermediate surface 42 above, a punch 60 is used, which then has a shape corresponding to the funnel surfaces 48 instead of the bottom. The punch 60 is pressed into the concrete slurry 52 and causes a shaping of the upper surface of the lower layer 20, as it is later also in the interior of the finished paving stone, and a compression. The mold parts 64 are preferably not only designed to mold a channel 26 to 30, but also the overlying cavity 44. They therefore protrude beyond the upper surface of the lower layer 20. Either the punch 60 has recesses for them, which receive the upper portions of the punch 60 (see Fig. 7 ), or the molded parts 64 can around the Measure, which makes up the height of the cavity 44, are elastically pressed down as soon as the punch 60 rests (see Fig. 9 ). With application of the punch 70 at the same time a shaking or compaction takes place via other steps, for example, higher-frequency shaking.

Subsequently, the punch 60 is removed, the mold parts 64 are above the upper surface of the lower layer 20 upwards. Now, the upper layer 22 is applied and evenly distributed in the mold 62, so that a flat top 24 is achieved.

The mold 62 may be made of any material, preferably plastic molds.

FIG. 9 shows an alternative for the mold 62. The moldings 64 are now movable in the z-direction. For each molding 64, the mold 62 has a through hole in its bottom. The mold parts 64 are no longer, as in the previous embodiment, firmly connected to the bottom of the mold 62, but movable relative to this floor. They also run longer, they always protrude, even in the normal position, the FIG. 9 shows, below the ground. The normal position is the position in which the mold parts 64 are located in the previous embodiment.

Below the molding is a spring 66, which biases the molding 64 in the illustrated normal position, wherein it is pressed against a stop. In this state concrete slurry 52 is filled for the lower layer 20. The illustrated normal position is secured downwardly by a slider 68 which engages in a notch of the molding 64 or alternatively under the bottom 32 of this molding 64. This slider 68 is biased by a slider spring 66 in the position shown. He is guided in a guided tour.

After the concrete slurry 52 in the mold 62 according to FIG. 9 was filled and a state like in FIG. 6 is present, a stamp 60 as in FIG. 7 applied, but this has no recess as the punch 70 after FIG. 7 for each molding 64, but a closed, bottom surface. Before the punch 70 is pressed onto the concrete slurry 52, the slider 68 is pulled free. The punch 70 pushes the molding 64 to a certain extent, namely the height of the Cavity 44, down. Once the slider 68 is removed again, the spring 66 pushes the molding 64 back up to the position shown in FIG FIG. 9 so that the further steps, as in FIG. 8 illustrated for the other embodiment, can be performed.

Claims (9)

A water-permeable paving stone having a porous concrete upper layer (22) comprising grains and a binder, with pores between the grains, the pores interconnected and continuous, and a lower layer (20) of dense concrete, in the vertical, continuous channels (26-30) are formed having an upper mouth (38) and a lower mouth (40), characterized in that the lower layer (20) has a funnel surface (48) around each mouth (38), which is delimited by a hopper edge (50), that the funnel surface (48) from the hopper edge (50) to the mouth (38) falls down, and that the funnel edges (50) of adjacent mouths (38) directly adjacent to each other. Water-permeable paving stone according to claim 1, characterized in that an upper side (24) of the lower layer (20) is formed exclusively by funnel surfaces (48). Water-permeable paving stone according to claim 1 or 2, characterized in that above at least one mouth (38) in the upper layer is a cavity (44) which opens down into the channel (26, 30) and upwards through an uppermost point (46) is limited. A water-permeable paving stone according to claim 3, characterized in that the uppermost point (46) lies below an upper level (54) defined by the hopper edges (50). Water-permeable paving stone according to one of the preceding claims, characterized in that the uppermost point (46) is at least 5 mm below a top (24) of the paving stone, and that this upper side (24) is substantially planar. Water-permeable paving stone according to one of the preceding claims 3-5, characterized in that the uppermost point (46) is between about 2 and about 10 mm above the mouth (38). Water-permeable paving stone according to one of the preceding claims 3-5, characterized in that the channels (26-30) continuously widen from the mouth (38) to the outlet (40), in particular that they have a surface and an angle such that that in the channel (26, 30) befindliches, freezing water is pushed out automatically downwards. A water-permeable paving stone according to any one of the preceding claims, characterized in that the top layer (22) comprises a first layer forming the top (24) of the paving stone and a second layer located between the first layer and the bottom layer (20) , and that the second layer has a larger pore volume than the first layer. Water-permeable paving stone according to one of the preceding claims, characterized in that the upper layer (22) is made of a concrete consisting of water, cement and grains with a grain size between 0.25 and 7 mm, preferably between 0.5 and 3 mm is made, in particular that the upper layer (22) has no fines less than 0.25 mm.

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