EP0980451A1

EP0980451A1 - Concrete surface

Info

Publication number: EP0980451A1
Application number: EP98916677A
Authority: EP
Inventors: René BRUGGEMAN
Original assignee: ECHO
Current assignee: ECHO
Priority date: 1997-05-05
Filing date: 1998-04-30
Publication date: 2000-02-23
Also published as: TR199902743T2; BE1011143A6; AU7017798A; CA2288731A1; WO1998050633A1; PL336634A1

Abstract

The invention relates to a prefabricated element (17) for the manufacturing of a road surface (1), which element is made of reinforced concrete, and in longitudinal direction is provided with a first side (8) which shows a first profile (10) over at least part of its length, and a second side (9) opposite the first side (8), which second side (9) shows over at least part of its length a second profile (11) that is complementary to said first profile (10). The invention also relates to a process for the manufacturing of a road surface comprising above described elements.

Description

CONCRETE SURFACE

This invention relates to an element for the manufacturing of a road surface according to the preamble of claim 1.

The known road surface comprises a top layer of one or more concrete layers, which are applied onto a base layer. The base layer is mostly a foundation layer marking the shape, the longitudinal profile and the transverse profile of the road. Traffic moves over the upper concrete layer of the road surface.

The known road surface is manufactured from concrete, which is cast onsite. Thereto, a layer of concrete of the desired thickness is cast on the base layer, vibrated and leveled off. This concrete layer is subsequently allowed to cure.

The known road surface has the disadvantage that the concrete shrinks during the curing, giving rise to the formation of cracks in the concrete, and a loosening of the concrete from the base layer.

It is the aim of this invention to provide an element for the manufacturing of a road surface that does not show above said disadvantages. This is achieved according to the invention in that the element is made of reinforced concrete, and the element, in longitudinal direction has a first side showing a first profile over at least part of its length, and a second side, opposite the first side, showing at least over part of its length a second profile that is complementary to said first profile.

Because the element according to the invention is manufactured previously, i.e. prior to the manufacturing of the road surface, the element has already been cured during the preceding production process, and it is possible to prevent a shrinkage of the element and thus also of the top layer during and after the manufacturing of the road surface.

The use of reinforced concrete imparts a good flexural strength to the element. According to the invention, the elements are preferably made of prestressed concrete. This allows to considerably reduce the thickness of the elements, without thereby negatively influencing the strength and flexural strength of the element. A road surface manufactured from such elements has a reduced thickness as compared to the known road surface, so that it is possible to realise a considerable saving on materials used, without thereby negatively influencing the strength of the road surface.

In a second embodiment according to the invention, the element is preferably made of concrete comprising fibrous reinforcing material.

Such an element of concrete provided with fibrous reinforcing material, has an improved tensile strength, through which the risk of the formation of cracks and fractures can be further reduced. A road surface built up of such elements will consequently be susceptible to a much lesser extent to weathering and chipping than the known road surface.

According to the invention various types of fibrous reinforcing material may be added to the concrete. Preferably, short loose fibres are used as a fibrous reinforcing material. Such fibres may be distributed uniformly in the concrete, and allow to obtain elements with an improved flexural strength and tensile strength in all directions.

According to a third embodiment of the invention, the profiled sides of the prefabricated element facing eacht other, preferably have a rounded off and/or bevelled upper edge. When two or more of such elements are placed against each other, a recess is formed along the profiled sides, between the rounded off and/or bevelled upper edges. Such a recess can serve as a drain for liquids, for example water which is on the road surface. Because the water is continuously drained from the road surface, it is possible to prevent pool formation and aquaplaning.

The invention also concerns a process for the manufacturing of a road surface, in which at least two of the above described elements are applied onto a base layer, in such a way that the elements are lying against each other with their sides in longitudinal direction, and that the profiles present at the sides engage each other.

Because the profiled sides of the elements engage each other, a road surface can be obtained that behaves as a continuous plate, with a continuous bearing face. Thereby, a load exerted on an element is at least partially tranferred to the elements which are contiguous with it. Because a locally exerted load is spread over the whole road surface, it is possible to prevent a deformation of the road surface as a result of an excessive local load.

Because the contiguous sides of two elements engage each other, it is also possible to prevent that elements conti- guous with each other are shifted in height with respect to each other, and it is possible to obtain a road surface with a better planimetry.

According to the invention, preferably a sealing agent is applied between the profiled sides of elements contiguous with each other. The presence of such a sealing agent on the one hand allows to have two contiguous elements fit. On the other hand, in this way a possible opening or joint which is present between two elements, may be sealed in order to prevent a seeping through of liquids, for example water, between the elements.

Since the elements which are applied according to the invention are quite thin and consequently light, they are preferably attached to the base layer by means of a bonding agent. By attaching the elements to the base layer, a solid bonding of the elements with the base layer can be obtained, and it is possible to prevent that the elements would shift as a consequence of the traffic that is moving over the road surface.

The prefabricated elements are preferably positioned diagonally with respect to the longitudinal direction of the road. The angle at which the elements are positioned with respect to the longitudinal direction of the road may be varied within broad limits. According to the invention, the angle is preferably 15 to 75 °, more preferably 30 to 45 °.

Such a diagonal positioning allows to reduce the pressure exerted on the edge of an element by a vehicle, which is moving in the longitudinal direction of the road. When manufacturing the road surface, according to the invention first a row of gutter stones contiguous with each other is preferably applied, for example on an already existing foundation layer, and subsequently the elements are applied onto the gutter stones in such a way, that the elements rest with their extremities on the edges of the gutter stones. The gutter stones then form the edge of the road surface.

According to the invention it is possible to apply such a row of gutter stones at both sides of the road surface, in longitudinal direction of the road. This will mainly be the case for narrower roads, in which the length of one prefabricated element is sufficient to cover the whole width of the road surface. It is also possible to apply, in longitudinal direction of the road several parallel rows of gutter stones. This will particularly be of importance for wide roads, in which the length of the prefabricated elements is insufficient to cover the whole width of the road surface. The use of such concealed gutters looks aesthetically beautiful.

By using gutter stones having a slot at their top side and being hollow at the inside, so that gutter stones contiguous with each other form a drain channel, it is possible to realise a draining of the water over the entire length of the road. This is in contrast to the known road surface, where the water drainage takes place through gully traps applied at well-defined distances from each other. A continuous draining of water over the entire road surface allows to prevent pool formation over the entire road surface. Because the opening has the shape of a slot, it may be avoided that erratic waste lands in the cavity inside the gutter stones and that the drain channel becomes blocked.

Such gutters may moreover be used to outline, prior to the application of the road surface, the course and the level of the road.

Because the gutter stones may be applied both in the middle and along the edge of the road, underneath the road surface, it is possible to have the road surface fall in different ways, in order to realise a good continuous draining of water. The road surface may for example have a down grade in the middle, or in the direction of the edge, or the level may remain about constant.

The road surface according to the invention preferably also comprises an intermediate layer, which is preferably built up of waste products, such as for example bituminous waste, recycled asphalt, rubber or plastic material. By means of such an intermediate layer, unevennesses present in the base layer may be smoothed away, so that a road surface with a smooth surface may be obtained. This is especially important when applying a new road surface onto damaged or milled off roads. In that case, cavities and imperfections are smoothed away by filling them up with a filling material.

The intermediate layer may or may not be elastic. An elastic intermediate layer has a vibration damping action and is capable of absorbing vibrations which for example arise as a result of heavy traffic. Because the transfer of vibrations to the base layer and/or the foundations of the road may be limited, it is possible to considerably reduce the incidence of fissures, cracks and fractures in constructions located underneath the road, such as for example the foundation and the sewer system. Because the vibrations are absorbed by the intermediate layer, it is also possible to prevent that constructions located in the vicinity of the road, suffer from the vibrations. Thus it is for example possible to considerably reduce the hindrance from the traffic, experienced by adjacent houses, water and gas lines, cables, etc. The intermediate layer may be a water impermeable or a draining layer.

The prefabricated elements are preferably provided, at their bottom side, that is the side which is resting on the intermediate layer, with a layer of a bonding agent, to effect an improved bonding of the prefabricated elements to the intermediate layer. The bonding agent is preferably a thermoplast.

Such a bonding layer allows for example to obtain, without heating, an adhesion of the prefabricated elements onto the intermediate layer. Such a boding layer also allows to prevent the presence of rising water. According to the invention it is also possible to connect the extremities of the steel reinforcement in the elements with a conductor. By applying a voltage, the steel reinforcement may be heated up. Since concrete is a comparatively good heat conductor, the heat produced in the reinforcement is transferred to the surface of the element, and the surface of the element, and thus the road surface is heated. In this way it is possible to defrost the road surface in winter, or to prevent the formation of black ice or ice on the road surface, without necessitating the use of corrosive salts. It is for example also possible to connect the reinforcement of elements contiguous with each other. In this way prefabricated elements may be drawn against each other, so that the shifting of elements with respect to each other may be prevented.

The invention is further elucidated by means of the attached figures and figure description.

Figure 1 shows a cross section of the road surface according to the invention, in transverse direction of the road surface.

Figure 2 shows a cross section of prefabricated elements contiguous with each other. Figures 3 and 4 show a top view of a road surface according to the invention.

Figure 5 is a cross section of figure 4.

The embodiment of the road surface 1 shown in figure 1 comprises a top layer 2, an intermediate layer 3, a base layer 4 and a foundation 24.

The top layer 2 is built up of prefabricated elements 17 contiguous with each other, which are preferably manufactured from concrete which may or may not be fibre reinforced, prestressed and reinforced. Prestressed concrete is concrete provided with a prestressed reinforcement. Because the prestressed reinforcement is anchored in the concrete, the element is compressed in the longitudinal direction. Therefore, the risk of crack forming in the concrete is consi- derably smaller. Potential cracks moreover are kept closed by the prestress forces. Such a road surface is liable to a much lesser extent to weathering and chipping.

As a reinforcement, the common materials may be applied, such as for example steel prestress wire, steel prestress strands, glass fibres, carbon fibres and other composite materials.

By the choice of the site where the reinforcement is built-in into the elements, and by varying the prestress force, it is possible to obtain elements showing the desired curvature. In this way it is for example possible to obtain prefabricated elements which have a down grade in the longitudinal direction. By means of such elements, a road surface can be obtained with a down grade in the direction of the sides.

The use of prefabricated elements allows to obtain a road surface with an improved and constant quality. A road surface manufactured from prefabricated elements immediately supports a full load upon installation, which results in much less traffic disturbance. The use of prefabricated elements moreover allows installation and repair in all weather conditions, through which the traffic disturbance becomes minimal. Through the use of prestressed concrete it is moreover possible to reduce possible deformation of the elements to a minimum.

The prefabricated elements according to the invention are mostly manufactured in an industrial process, in which the production circumstances are maintained constant as much as possible. In this way it is possible to obtain prefabricated concrete elements, and consequently a road surface, of a constant and improved quality. The quality of concrete namely widely varies with the processing circumstances. Since the manufacturing and/or repair of the known road surface often takes weeks to months, it is nearly impossible to maintain the processing circumstances constant during this period and the quality of the concrete will vary in the length of the road surface.

Besides, to obtain a good quality concrete, it is necessary to have the concrete cured for several days and/or weeks. In practice, such a period is rarely complied with, since this would involve an undesirable increase of the duration of the operations and consequently the traffic disturbance.

The road surface according to the invention on the other hand, may be installed in a relatively short time and may be fully loaded, almost immediately upon being installed, so that the traffic disturbance remains limited to a minimum. The prefabricated elements according to the invention may moreover be installed in almost any weather circumstances.

Because the elements are prefabricated, it is possible to adjust the dimensions of the elements to the dimensions of the road surface. The new road surface may then be simply manufactured in that the separate elements are put into the correct place.

Besides, the invention allows to rapidly repair damaged parts of the road surface. Thereto, damaged elements are removed from the road surface and replaced by new prefabricated elements. Such repair works may be carried out rapidly and allow to limit the traffic disturbance to a minimum.

The prefabricated elements 17 may have various shapes, in order to allow the manufacturing of a road surface adapated to a specific situation. Thus when manufacturing an essentially straight road, preferably prefabricated elements with the shape of a beam will be used. When manufacturing a roundabout, prefabricated elements 17 having essentially the shape of a beam may be used. When manufacturing a roundabout, also elements with a deviating shape may be used, so as to allow to realise the shape of the roundabout as best one can. It is for example possible to use elements of which one extremity is enlarged with respect to the other extremity, and of which the sides slope from the wide extremity to the narrower extremity.

The prefabricated elements 17 according to the invention preferably have the shape of a beam. The prefabricated elements 17 have a first side 8 which shows a first profile 10 over at least part of its length, and a second side 9 which shows a second profile 11 over at least part of its length, whereby the first profile 10 of a first element engages the second profile 11 of a second element contiguous with it. Thereto, the first side 8 may for example be convex and the second side 9 hollow, whereby the convex side 8 of a first element engages the hollow side 9 of a second element contiguous with it.

The dimensions of the prefabricated elements 17 may be varied within broad limits. The length may for example vary from 1 to 30 m, the width from 0.3 to 1.2 m or more, the thickness from 8 to

25 cm, preferably from 8 to 18 cm. The prefabricated elements according to the invention have a smaller thickness as compared to the known concrete elements.

If desired, the prefabricated elements may be pro- vided at their top side with a texture 18 so as to obtain a road surface with an improved grip of the tyres and a decreased rolling resistance and rolling noise.

When manufacturing the road surface, the elements are applied onto a base layer 4 in such a way that the sides 8, 9 of elements contiguous with each other, engage each other. Because their sides engage each other, a force exerted on a first element can be transferred to the second element. Such elements which fit together, behave as one continuous plate, in which a good transfer of a locally exerted force to the rest of the plate is possible, so that wear by strong local forces can be considerably diminished.

The sides 8, 9 of the prefabricated elements 17 are preferably provided at their top side with a bevelling and/or rounding off 14 so as to create a drain 15 between two contiguous elements.

When manufacturing the road surface, a sealing agent 12 may be applied between the profiled sides 8, 9 of two elements engaging each other. The presence of such a sealing agent 12 prevents water from seeping through between the elements 17 to the layers underneath. If no sealing agent is applied, water may seep through between the elements, and the road surface is draining. Such a sealing agent can also have a shock absorbing action, and consequently prevent wear along the sides of the elements.

The sealing agent ensures that the joint remains elastic, and allows the elements, for example under the influence of heat, to expand without thereby influencing the planimetry of the road surface or damaging the sides of the elements.

The sealing agent can also absorb deviations if the profiles at the sides do not engage each other well.

The presence of such a sealing agent is not necessary. If no sealing agent is present between contiguous elements, the road surface may be drained for example through the joint.

The sealing agent may be applied previously to the sides, or after having installed two or more elements side by side.

The prefabricated elements 17 may comprise at their bottom side an adhesive layer 16, to improve the adhesion on the intermediate layer 3. The base layer 4 may for example be formed by an existing road surface, or by the foundations of a new road to be constructed. Such a base layer 4 may be built up of for example a hardened mixture of pebbles and sand, lean concrete or asphalt. In case the base layer 4 is formed by an existing road surface, often underneath the base layer 4 will also be a foundation layer 24.

The intermediate layer 3 is between the base layer 4 and the top layer 2 and may for example be built up of industrial waste products, such as for example bituminous waste, recycled asphalt, rubber or plastic material.

When manufacturing the road surface according to the invention, preferably a row of gutter stones 5 contiguous with each other is applied along the edge of the road, onto the base layer 4. The gutter stones 5 may be applied along both edges of the road, parallel to the longitudinal direction 6 of the road.

Subsequently, the required number of prefabricated elements 17 is laid on the gutter stones, in such a way that they are resting with their extremities on the gutter stones 5 and that they are lying diagonally with respect to the longitudinal direction of the road. If desired, the elements 17 may be laid to form various patterns, for example a herringbone design or other designs if the width and/or the course of the road require or allow this (see figure 3).

The elements 17 are laid against each other in such a way that their sides 8, 9 engage each other. In case the road surface is very wide, several, preferably parallel rows of gutter stones 5 may be installed underneath the road surface. The prefabricated elements 17 then always rest with their extremities on the gutter stones.

Previously, a bonding agent may be applied onto the bottom side of the elements, so as to realise a good bonding of the elements with the base layer 4. Previously, also a sealing agent 12 may be applied to the sides of the elements. It is also possible to apply the sealing agent afterwards.

When manufacturing a road surface for a common road with an essentially straight longitudinal profile, preferably prefabricated elements 17 are used of which the length is geared to the width of the road. Depending on the width of the road, one or more profiles may be laid in their longitudinal direction against each other, so as to cover the whole width of the road. When manufacturing for example roundabouts or crossings, the length and width of the prefabricated elements 17 can be adapted such that the road surface is following the shape of the crossing or roundabout as well as one can.

In the preferred embodiment shown in figure 2, the gutter stones at their top side comprise a slot 19, and the gutter stones are hollow at the inside. They comprise in longitudinal direction 6 of the road two open walls facing each other. By laying two or more gutter stones in the longitudinal direction of the road against each other, a drain channel 22 is created underneath the road surface, for example to drain water.

The gutter stones 5 have a first side 20 on which the prefabricated elements 17 are resting and a second side 21 which may form the edge of the road. The second side 21 may for example be elevated with respect to the first side so as to form a clear demarcation between the road surface and the surroundings. The second side 21 may also comprise a bevelling 25 so as to obtain a progressive transition between the road surface 1 and the surroundings. The drain channel 22 may be connected to the sewer system 27 located underneath the road. In case the road surface comprises several rows of contiguous prefabricated elements 17, the extremities of a first row of elements may be applied on the first sides 20 of a row of gutter stones 5 contiguous with each other, and the extremities of a second row of elements may be applied on the second sides 21 of the gutter stones 5.

In that case, both sides 20 and 21 have preferably the same height. In that case it is possible to construct the sides of the road with a row of contiguous gutter stones 26 which do not form a drain channel at the inside. By constructing the sides (edges) of the road with above described gutter stones, it is possible to install the road surface with a fall in different directions. Thus it is for example possible to have the road surface slope down in the direction of the sides, by laying the gutter stones 5 with their upper side at a lower level than the level of the middle of the road. In that case, water on the road surface will preferably be drained towards the sides of the road.

It is also possible to have the road surface slope down in the direction of the middle of the road. In that case, the upper side of the gutter stones 5 is laid at a lower level than the level of the sides of the road.

The road surface according to the invention may be used for both the manufacturing of new roads and the application of a new road surface on existing roads.

List of used references.

1 road surface

2 top layer

3 intermediate layer foundation

5 gutter stone

6 longitudinal direction of road surface

7 steel reinforcement

8 first side

9 second side

10 first profile

11 second profile

12 sealing agent

13 bonding layer

14 rounding off/bevelled edge

15 draining profile 6 adhesive layer 7 prefabricated element 8 texture 9 slot 0 first side 1 second side 2 drain channel 3 concrete 4 levelling layer 5 bevelled edge 6 border stone 7 sewerage and gully trap

Claims

1. Prefabricated element for the manufacturing of a road surface, characterised in that said element is made of reinforced concrete, and said element has in longitudinal direction a first side which shows a first profile over at least part of its length, and a second side opposite the first side, which second side shows over at least part of its length a second profile which is complementary to said first profile.

2. Element according to claim 1 , characterised in that the element is manufactured from prestressed concrete.

3. Element according to any one of claims 1 or 2, characterised in that the concrete is provided with a fibrous reinforcing material.

4. Element according to any one of claims 1 to 3, characterised in that said first and second sides have a bevelled and/or rounded off upper side.

5. Process for the manufacturing of a road surface, characterised in that at least two elements according to any one of claims 1 to 4 are applied on a base layer, in such a way that their sides are lying against each other in longitudinal direction, and the first profile of a first element engages the second profile of a second element.

6. Process according to claim 5, characterised in that a sealing agent is applied between the sides of elements contiguous with each other.

7. Process according to claim 5 or 6, charac- terised in that a bonding agent is applied between the elements and the base layer.

8. Process according to any one of claims 5 to 7, characterised in that the road surface has a longitudinal direction and that the prefabricated elements are applied diagonally, preferably at an angle of 15 to 75 ┬░, more preferably 30 to 45 ┬░, with respect to the longi- tudinal direction of the road.

9. Process according to any one of claims 5 to 8, characterised in that a row of gutter stones contiguous with each other, is applied in longitudinal direction of the road surface, whereafter the prefabricated elements are applied onto the gutter stones, in such a way that said elements rest with their extremities on said gutter stones.

10. Process according to claim 9, characterised in that said gutter stones at their upper side, parallel to the longitudinal direction of the road, comprise a slot, which gutter stones are hollow at the inside and have at least two open walls facing each other, in such a way that contiguous gutter stones form a drain channel in longitudinal direction of the road surface.

11. Process according to claim 9 or 10, whereby the road surface comprises two side edges facing each other, charac- terised in that each of said side edges is formed by a row of gutter stones contiguous with each other.

12. Process according to any one of claims 9 to 11 , characterised in that between the side edges facing each other, an additional row of gutter stones contiguous with each other, is applied.

13. Gutter stone for use in the process for the manufacturing of a road surface according to any one of claims 9 to 12.