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(11) | EP 1 336 688 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Draining road surface |
| (57) The present invention relates to a road surface (1) for a road, comprising a plurality
of adjacent foundation elements (3) lying on opposite sides of and in longitudinal
direction of the road for supporting a plurality of adjacent prefabricated beam-shaped
elements (4) forming the road surface on which traffic moves, whereby each prefabricated
element (4) comprises a first (7) and second (8) edge being supported by rows of foundation
elements (3) lying opposite to each other, such that an open space (5) is formed below
the road surface (1), whereby each prefabricated element (1) is made of reinforced
concrete. |
[0002] The known road surface comprises an upper layer of concrete or asphalt applied to a foundation layer which determines the shape, the longitudinal section and the transverse section of the road. Traffic moves on the upper layer of the road surface.
[0003] From US-A-945.999 it is known that a road surface with an increased stability can be obtained on soft undergrounds by applying a plurality of concrete piles in the underground to a level where the piles are anchored in a natural firm layer. On top of the piles a support is applied on which the prefabricated concrete elements forming the road surface are positioned. Between the bottom side of the road surface and the underground a hollow space is left over serving as a drain for water seeping through via the road surface. Water falling on the road surface is drained to the underlying open space via gaps between adjacent road surface elements or via the sides of the road surface.
[0004] US-A-1.660.421 teaches to use small prefabricated concrete units instead of cobbles for paving a road surface. Opposite ends of concrete units rest with their ends on shoulders provided in thresholds. Between opposite thresholds an open space is formed. In the concrete units, spaces are provided filled with removable grout which guarantee access towards the underlying open spaces.
[0005] The known road surface has the disadvantage that the its construction is time consuming and that there is much earth moving for applying the foundation. Moreover, the road surface, made of concrete or asphalt, is not porous as a result of which rain water falling on the road surface, has to be drained via drain pipes or the sewer system. Other systems such as porous clinkers, grass tiles etc. are porous but not sufficiently stable for carrying traffic loads. There is thus a need to a road surface enabling the collection of, amongst others, water falling on the road surface, in a simple way.
[0006] It is the object of the present invention to provide a road surface with which water falling on the road surface can be collected in a simple way.
[0007] This is achieved according to the invention in that the road surface comprises, in longitudinal direction of the road, a plurality of adjacent foundation elements, whereby the foundation elements are applied on opposite sides of the road for supporting a plurality of adjacent prefabricated beam-shaped elements forming the road surface on which traffic moves, such that an underlying hollow space is formed below the road surface.
[0008] The construction out of individual elements facilitates the accessibility to the hollow space formed under the road surface. This space lying under the road surface is suitable for further use, and can be used, amongst others, for receiving ducts. The underlying space is also suited for use as a water reservoir, for instance as a reservoir for rain water, and offers as such a solution for the ever increasing demand for infiltration of water into the ground, for the provision of a buffer for large quantities of water at times of heavy rainfall, and recuperation of water. Water falling on the road surface can flow to the underlying space via grooves in between adjacent elements, where it can penetrate slowly into the ground, and/or flow in a slowed manner to the sewer system and/or be stocked for recuperation.
[0009] The road surface of the present invention is suited for the construction of roads, but can also be used for the construction of a paving for parking places, industrial grounds etc.
[0010] The elements are not intended to engage with each other as is the case with the RB-deck. To the contrary, the elements can either be positioned loosely against each other such that the rainwater can seep through adjacent elements and can penetrate into the space below the road surface. It is also possible to partly connect the adjacent elements such that a spreading of load is possible but yet rainwater can penetrate to the space under the road surface.
[0011] In case direct infiltration into the ground is not desired because of the nature of the environmental pollution, the grooves between the elements can be sealed and the rainwater can be drained and eventually be brought again under the road surface after a filtration step or another treatment for the purpose of infiltration, buffering or recuperation.
[0012] The use of prefabricated beam-shaped elements reduces the risk to shrinkage of the road surface during and after its construction.
[0013] The elements comprise a side face which may be substantially flat or may be provided with a profile in such a way that profiled side faces of adjacent elements engage with each other. The use of elements comprising engaging profiled side faces results in a road surface which behaves as a continuous plate having a continuous bearing surface, in which a load applied on an element is at least partly transmitted to adjacent elements. The chance to deformation of the road surface is minimised since a locally applied load is divided over the entire road surface. At the same time the risk to moving of elements is minimised and it is possible to obtain a road surface having an improved planimetry.
[0014] Preferably, in the road surface of the present invention at least a part of the foundation elements are constructed as a hollow tube having a hollow space and an at least partly open top side. The top side is delimited in longitudinal direction by a first top edge and a second top edge, opposite to the first edge, of the foundation element. The first and second top edge of opposite foundation elements are provided for at least partly supporting (a) the edge of opposite beam-shaped elements, and (b) at least the edge of a third prefabricated covering element for covering the hollow space.
[0015] The hollow foundation elements are extremely suited for receiving ducts and form an efficient protection for these ducts. In addition, the use of the covering element will facilitate the accessibility to the ducts since in most cases the covering element has smaller dimensions than the beam-shaped concrete elements.
[0016] The hollow foundation element or hollow tube preferably has a porous side face and/or bottom, such that water ending up in the hollow space can flow via pores to the surrounding soil or open space under the road surface.
[0017] The hollow foundation element or hollow tube may also comprise filter or separation techniques which drain the water after treatment to the surrounding soil or open space under the road surface.
[0018] According to the invention, preferably means are provided for heating the road surface. Thereto, means generally known by the man skilled in the art can be used. A first possible embodiment implies that the ends of the steel reinforcement are connected by a power source. By applying an electrical voltage, the reinforcement is heated. Concrete is a relatively good heat conductor, such that the produced heat is transported to the surface of the element and the road surface gets heated. It is also possible to position a network of tubes in the upper layer of the road surface through which hot water can flow. In this way it is possible to keep the road surface free of ice in winter time. A third possibility is to apply electrical heating elements in the upper layer of the road surface element.
[0019] The use of prestressed concrete allows to substantially reduce the thickness of the elements, without thereby adversely affecting the strength and bending strength.
[0020] The concrete can also be provided with fibre-shaped reinforcement material for improving the tensile strength such that the chance to formation of cracks can further be reduced. Thereto preferably common reinforcement materials known by the man skilled in the art can be used. Preferably short loose fibres are used because they can de divided in the concrete in a uniform way and because they allow to improve the bending resistance and tensile strength in every direction.
[0021] According to the invention, between a part of the profiled side faces of adjacent elements a sealing agent can be applied to provide an improved connection between adjacent elements and to locally hinder and direct the seeping through of liquids, for instance water, between the elements.
[0022] The road surface of the present invention is preferably made by first positioning two opposite rows of adjacent supporting foundation elements, on which subsequently the beam-shaped elements are applied in such a way that the ends of the elements rest on the foundation elements. Depending on the width of the ground to be covered, a number of rows of foundation elements can be provided.
[0023] The prefabricated elements may be provided at their bottom face, i.e. the face resting on the foundation elements, with a sealing agent to bring about an improved adhesion on the foundation elements. The prefabricated elements may also be provided at their bottom side with a flexible bearing system to bring about a spreading of the load on the foundation elements and to minimise 'clicking' of the elements on the foundation. The foundation elements may comprise anchoring means for anchoring the prefabricated elements in order to minimise the risk of moving of the elements.
[0024] It is also possible to connect the reinforcement of adjacent elements allowing to pull prefabricated elements towards each other or to connect them with each other in order to prevent the moving of elements with respect to each other.
[0025] The invention is further elucidated by means of the following figures and description of the figures.
[0028] Figure 3 shows a section of an alternative embodiment of the road surface of the present invention.
[0029] The embodiment of the road surface shown in figure 1 comprises a base 2 on which a plurality of supporting foundation elements 3 are positioned. The rows of foundation elements may be positioned parallel to each other or not, for example depending on the shape of the surface to be covered. The foundation elements 3 extend in height direction with respect to the base 2 and form a support for beam-shaped elements 4 forming the road surface. The beam-shaped elements rest with their ends on the top side of the foundation elements 3. Between the bottom side of the of the beam-shaped elements 4 and the base 2 a hollow space 5 is present suited for receiving ducts 6 and which can for instance be used as a water reservoir for rain water or water originating from adjacent buildings.
[0030] In the embodiment shown in figure 3 a part or all of the foundation elements 13 are constructed as hollow tubes. Each hollow tube 13 has a hollow space 15 and an at least partly open top side 11. The hollow tubes can have various shapes known by the man skilled in the art, and can for instance by U-shaped, with a round or flat bottom 14. The hollow tube 13 has two opposite upright side faces 12 having a first and a second top edge 17, 18. The edges 7, 8 of the prefabricated beam-shaped elements rest at least partly on the first and second top edge 17, 18 of opposite foundation elements 13.
[0031] It is preferred that the edges 7, 8 of the prefabricated elements only rest on a part of the first and second top edge 17, 18 of the tubular foundation element such that sufficient space is left over on this first and second top edge for supporting a third covering element 10 for the hollow space 15 in the tube 13. In this way a continuous road surface is formed.
[0032] The hollow space is extremely well suited for receiving ducts 6, whereby the tube 13 forms a protection for the ducts. The use of a separate covering element 10 for covering the hollow space 15 facilitates the accessibility of the ducts 6.
[0033] By providing the hollow tube 15 with a porous side face 12 and/or a porous bottom 14, water ending up in the hollow tube 15 can infiltrate into the ground. This infiltration is also possible by positioning the hollow tubes in longitudinal direction 'cold' against each other. On the other hand it is possible to apply filter- or separation techniques in or round the hollow tube 15 such that an optimal purification of the water is obtained before the water contacts the soil.
[0034] The invention provides a solution for the ever increasing problem that companies must be able to find a solution for the rain water falling on the company ground. This road surface is suited, amongst others, for building parking places, private or public roadways and for covering larger or smaller surfaces in general. The storage reservoir and/or water drainage possibility being provided with the present invention efficiently uses an existing surface, is space-saving and prevents the need to building specific reservoir basins which often take too much space.
[0035] The foundation elements 3 can be made of any suitable material known by the man skilled in the art. They can for instance be made of concrete, brickwork. The foundation elements 3 may be solid or may comprise openings or canals 9 allowing the ducts 6 applied below the road surface to pass in all directions. The ducts 6 and/or canals 9 are suited for transporting a heated liquid, for instance hot water in case it is the purpose to heat the road surface.
[0036] The road surface is constructed of a plurality of adjacent prefabricated elements 4 which are preferably made of fibre reinforced or not, prestressed or common reinforced concrete. As reinforcement common used materials can be used such as steel bars, steel prestressed cable, steel prestressed strands, glass fibres, carbon fibres and other composite materials.
[0037] By varying the choice of the position where the reinforcement is built in the elements 4 and by varying the prestressing force, the curvature of the elements 4 can be varied depending on the conditions. In this way it is for instance possible to obtain prefabricated elements 4 which incline downwardly in longitudinal direction such that the road surface inclines downwardly in the direction of the side face of the road.
[0038] The shape of the prefabricated elements 4 can be adapted to the specific situation of the road surface to be constructed. When constructing a substantially straight road, preferably prefabricated elements 4 having the shape of a beam will be used. When constructing a roundabout, elements will be used of which the shape allows to approach the shape of the roundabout as close as possible. It is for instance possible to use elements having one end which is broadened with respect to the other end and having side faces which slant from the broad end towards the smaller end.
[0039] The use of prefabricated elements 4 allows to obtain a road surface 1 with an improved and constant quality and which allows an immediate complete load almost immediately after the building of the road, resulting in less traffic hinder. In addition, the use of prefabricated elements allows a quick building and repair in all weather conditions, thereby minimising traffic hinder. The use of prestressed concrete minimises the risk to deformation.
[0040] The prefabricated elements 4 applied in the road surface of the present invention are made with an industrial process in which the production conditions are kept constant as much as possible, resulting in a road surface with a constant and improved quality. Indeed, the quality of concrete strongly varies depending on the processing conditions. To obtain concrete with a good quality it is moreover necessary to allow the concrete to harden for a number of days and/or weeks. In practice such a resting period is seldom respected since in this way the time span of the works, and thereby traffic hinder, is undesirably increased. The dimensions of the prefabricated elements 4 can be adapted to the dimensions of the road surface 1 in advance, which simplifies the construction of the road surface. Moreover, by using prefabricated elements 4 it is further possible to repair damaged parts of the road surface in a fast way by removing the damaged elements and replacing them by new ones.
[0041] The dimensions of the prefabricated elements 4 can be varied between broad limits. The length can for instance vary between 1 to 30 m, the width can vary between 0.3 and 1.2 m or more, the thickness can vary between 8 and 40 cm, preferably between 8 to 20 cm. If desired, the prefabricated elements 4 can be provided at their top side with a texture to improve the grip of ties on the road surface and to minimise the rolling resistance and rolling noise.
[0042] Between the side faces of two adjacent elements 4 a sealing agent can be applied for hindering the local seeping through of water. In the case no sealing agent is applied, water can seep between the elements and the road surface is a draining road surface.
[0043] The road surface of the present invention is preferably made by applying a first row of foundation elements 3, 13 along the edge on the base 2. A second row is positioned on the opposite side of the road. The first and second row of foundation elements 3, 13 can have the same or different heights, depending on the relief of the underground and the relief of the road surface 1 to be constructed. The prefabricated elements 4 are positioned with their ends on the foundation elements 3, 13. The prefabricated elements 4 can extend in longitudinal direction or in transverse direction of the road, or can extend diagonally with respect to the longitudinal direction of the road. If desired, the prefabricated elements 4 can lie in a predetermined pattern if requested or allowed by the width and/or direction of the road surface.
1. A road surface (1) for a road, comprising a plurality of adjacent foundation elements
(3, 13) lying on opposite sides and in longitudinal direction of the road for supporting
a plurality of adjacent prefabricated beam-shaped elements (4) forming the road surface
on which traffic moves, each prefabricated element (4) comprising a first (7) and
second (8) edge being supported by rows of foundation elements (3) lying opposite
to each other, such that an open space (5) is formed below the road surface (1), each
prefabricated element (1) being made of reinforced or prestressed concrete.
2. A road surface according to claim 1, characterized in that at least a part of the foundation elements (13) is constructed as a hollow tube comprising
a hollow space (15) and an at least partly open top side (11), the top side being
delimited in longitudinal direction by a first and second top edge, opposite to the
first top edge, the first and second top edge of opposite foundation elements being
provided for at least partly supporting respectively a first and second edge (7, 8)
of a first and second beam-shaped element (4), and for supporting a third prefabricated
covering element (10) for covering the hollow space.
3. A road surface according to any one of claims 1-2, characterized in that ducts are provided in the hollow space (15).
4. A road surface according to claim 2 or 3, characterized in that the hollow tube has a porous side face (12) and/or bottom (14).
5. A road surface according to any one of claims 1-4, characterized in that ducts (6) are provided in the open space (5).
6. A road surface according to any one of claims 1-5, characterized in that means (2) are provided for heating the road surface (1).
7. A road surface according to claim 6, characterized in that the means for heating (2) comprise canals through which a heated liquid is directed.
8. A road surface according to claim 6, characterized in that a part of the reinforcement of the prefabricated elements (4) is connected with an
electrical source for heating the elements (4).
9. A road surface according to any one of claims 1-8, characterized in that the prefabricated elements (4) are made of prestressed concrete, preferably of prestressed
concrete provided with a fibre-shaped reinforcement material.
10. A road surface according to any one of claims 1-9, characterized in that a sealing agent is applied between the side faces of at least a part of the adjacent
prefabricated elements (4).