A STRUCTURE FOR THE REINFORCEMENT OF PAVEMENTS

Abstract

The invention relates to a structure for the reinforcement of pavements. The structure is provided at predetermined positions with interruptions or with weakened zones. The invention further relates to a method of manufacturing such a structure and to a method of breaking up a pavement reinforced with such a structure.

Claims

1. A structure for the reinforcement of pavements, said structure being at predetermined positions provided with interruptions or provided with weakened zones.

2. A structure according to claim 1, wherein said structure comprises a grid or a mesh.

3. A structure according to claim 1, wherein said structure comprises elongated elements, said elongated elements being at predetermined positions along the length of said elongated elements provided with interruptions or provided with weakened zones.

4. A structure according to claim 3, wherein said elongated elements comprise elongated metal elements, elongated non-metal elements or a combination of elongated metal elements and elongated non-metal elements.

5. A structure according to claim 4, wherein said elongated metal elements comprise steel bars, steel wires or assemblies of grouped steel wires.

6. A structure according to claim 1, wherein the distance between two neighbouring interruptions or between two neighbouring weakened zones of said structure or between two neighbouring interruptions or neighbouring weakened zone of an elongated element ranges between 1 and 200 cm.

7. A structure according to claim 3, wherein said elongated elements have a tensile strength higher than 1000 MPa.

8. A structure according to claim 3, wherein said weakened zones have a tensile strength being at least 10% lower than the tensile strength of said elongated elements.

9. A structure according to claim 3, wherein said elongated elements provided with weakened zones break at said weakened zones when bent over a pulley having a diameter of 5 cm or lower.

10. A structure according to claim 1, wherein said weakened zones are obtained by a mechanical, thermal or chemical treatment.

11. A method of manufacturing a structure for the reinforcement of pavements as defined in claim 1, said method comprising the steps of manufacturing a structure for the reinforcement of pavements; providing said structure at predetermined positions with interruptions or with weakened zones.

12. A method of manufacturing a structure for the reinforcement of pavements as defined in claim 1, said method comprising the steps of providing elongated elements, for example elongated metal elements; providing said elongated elements at predetermined positions along the length of said elongated elements with weakened zones; manufacturing a structure for the reinforcement of pavements comprising said elongated elements provided with weakened zones.

13. A reinforced pavement comprising a pavement; a structure for the reinforcement of pavements as defined in claim 1; an overlay applied over said structure for the reinforcement of pavements.

14. A method of breaking up a pavement reinforced with a structure for the reinforcement of pavements as defined in claim 1, said method comprising the step of milling the surface of said pavement thereby allowing the structure for the reinforcement of pavements to break at said predetermined positions.

15. A method of breaking up a pavement according to claim 14, providing a milling machine comprising a milling drum; moving said milling machine over the surface of the reinforced pavement to be milled thereby rotating the milling drum to cut into the surface of the reinforced pavement to a desired depth as the milling machine is advanced along the reinforced pavement and allowing the structure for the reinforcement of pavements to break at said predetermined positions.

Description

BRIEF DESCRIPTION OF FIGURES IN THE DRAWINGS

[0077] The invention will now be described into more detail with reference to the accompanying drawings whereby

[0078] FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7a, FIG. 7b and FIG. 7c are schematic illustrations of embodiments of structures for the reinforcement of pavements according to the present invention;

[0079] FIG. 8 is a schematic illustration of a method of breaking up a reinforced pavement comprising a structure for the reinforcement of pavements according to the present invention.

MODE(S) FOR CARRYING OUT THE INVENTION

[0080] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0081] For the purpose of this invention “pavement” means any paved surface. The pavement is preferably intended to sustain traffic, such as vehicular or foot traffic.

Examples of pavements comprise roads, walkways, parking lots, airport runways, airport taxiways, harbour pavements, . . .

[0082] FIG. 1 is a schematic illustration of a first embodiment of a structure 100 for the reinforcement of pavements according to the present invention. The structure 100 comprises assemblies of grouped elongated metal elements 112. The assemblies of grouped elongated metal elements 112 are provided with weakened zones 113 at predetermined positions along the length of these assemblies 112. The distance between neighbouring weakened zones 113 measured along the longitudinal direction of structure 100 is for example 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm or 100 cm.

The assemblies of grouped elongated metal elements 112 may comprise steel cords. A preferred steel cord comprises between 2 and 12 filaments, for example a cord having one core filament having a diameter of 0.37 mm and 6 filaments having a diameter of 0.33 mm around this core filament (0.37 +6×0.33).
In an alternative embodiments the assemblies of grouped elongated metal elements 112 comprise bundles of parallel or substantially parallel elongated metal elements, for example bundles of 12 parallel or substantially parallel elongated metal elements.
The assemblies of grouped elongated metal elements 112 are all oriented parallel or substantially parallel to each other. The orientation of these assemblies 112 corresponds with the longitudinal direction 105 of structure 100.
The assemblies of grouped elongated metal elements can be coupled to or integrated to a substrate 110. In the embodiment shown in FIG. 1 the assemblies 112 are glued to substrate 110.
The substrate 110 may for example comprise a polymer material, glass, carbon or any combination thereof. The substrate 110 is for example a grid or foil obtained by extrusion. Alternatively, the substrate 110 comprises a woven or non-woven structure, for example a woven or non-woven polymer structure. Examples of non-woven structures comprise a needle-punched or spunbond non-woven substrate, for example in polyamide, polyester (for example polyethylene terephthalate (PET)), polyethylene or polypropylene.
In a preferred embodiment the assemblies of grouped elongated metal elements 112 comprise steel cords twisted elongated metal filaments glued to a polymer substrate 110 for example a non-woven polyether sulphone substrate or an extruded polypropylene grid (35 g/m2 having a 6×6 mm mesh).
In another preferred embodiment the assemblies of grouped elongated metal elements 112 comprise steel cords glued to a substrate 110 made of glass fibers or glass rovings or to a substrate comprising carbon filaments.

[0083] FIG. 2 is an illustration of a second embodiment of a structure 200 for the reinforcement of pavements according to the present invention. The structure 200 comprises a group of assemblies of grouped elongated metal elements 212. The assemblies 212 are provided with weakened zones 213 at predetermined positions along the length of these assemblies 212.

The assemblies of grouped elongated metal elements 212 may comprise steel cords. The assemblies of grouped elongated metal elements comprise for example steel cord comprising 3 filaments having a diameter of 0.48 mm twisted together (3×0.48 mm).
In alternative embodiments the assemblies of grouped elongated metal elements 212 comprise parallel or substantially parallel filaments, for example a bundle of 12 parallel or substantially parallel filaments.
The assemblies of grouped elongated metal elements 212 are all oriented parallel of substantially parallel to each other. The orientation of these assemblies 212 corresponds with the longitudinal direction 205 of structure 200.
The assemblies 212 are coupled to a substrate 210 by means of stitches 214. The stitches 214 are preferably formed by a yarn. The yarn comprises for example a multifilament yarn, preferably a polyamide, a polyester (for example polyethylene terephthalate (PET)), a polyvinyl alcohol or a polypropylene yarn.
The yarn may be provided with weakened zones. Alternatively, the yarn is not provided with weakened zones.
The substrate 210 comprises for example a woven or non-woven structure, for example a woven or non-woven polymer structure. Examples of non-woven structures comprise a needle-punched or spunbond non-woven substrate, for example in polyamide, polyester (for example polyethylene terephthalate (PET)), polyethylene or polypropylene.
In a preferred embodiment the assemblies of grouped elongated metal elements 212 comprise steel cords comprising twisted steel filaments. The steel cords are stitched to a polymer substrate 210 for example a non-woven polyether sulphone substrate by means of a polyester yarn 214 (for example polyethylene terephthalate).

[0084] FIG. 3 is a further illustration of a structure 300 for the reinforcement of pavements. The structure 300 comprises a first group of assemblies of grouped elongated metal elements 312 and a second group of assemblies of grouped elongated metal elements 314. The first group of assemblies 312 comprises steel cords oriented substantially parallel to each other in a first direction. The first group of assemblies 312 is provided with weakened zones 313 at predetermined positions along the length of the assemblies 312. In the embodiment shown in FIG. 3, the weakened zones 313 are zones of the assemblies 312 provided with indentations or zones having a reduced diameter.

The second group of assemblies 314 comprises steel cords oriented substantially parallel to each other in a second direction. The second group of assemblies 314 is provided with weakened zones 315 at predetermined positions along the length of the assemblies 314. The weakened zones 315 are zones of the assemblies 314 provided with indentations or zones having a reduced diameter.
The first direction is different from the second direction. The included angle between the first direction and the longitudinal direction 305 of the structure 300 is 45 degrees. The included angle between the first direction and the section direction is indicated by α. The included angle α is 90 degrees.
The assemblies of the first group 312 and the assemblies of the second group 314 are stitched to a substrate 310 along lines 316 by at least one yarn. The substrate 310 comprises for example a woven or non-woven structure.
Either the assemblies 312 of the first group or the assemblies 314 of the second group are provided with weakened zones 313, 315 along the length of the assemblies 312, 314. In a preferred embodiment both the assemblies 312 of the first group and the assemblies 314 of the second group are provided with weakened zones 313, 315.
For a person skilled in the art it is clear that it is also possible to provide either the first group of assemblies 312 or the second group of assemblies with weakened zones 313, 315.

[0085] FIG. 4 shows a schematic illustration of a structure 400 for the reinforcement of pavements. The structure 400 is a knitted structure. The knitted structure 400 comprises a number of assemblies of grouped elongated metal elements 402 in parallel or mutual substantially parallel position. The assemblies of grouped elongated metal elements 402 are provided with weakened zones 403 at predetermined positions along the length of these assemblies 402.

In the knitted structure 400 shown in FIG. 4 the assemblies of grouped elongated metal elements are worked in to the loop of stitches 420 at the stitch line 440. The stitches 420 are formed by a yarn, for example a single or multifilament yarn, preferably a polyamide, a polyester (for example polyethylene terephthalate (PET)), a polypropylene yarn or a metal yarn such as a steel yarn. The yarn of the stitches 420 may or may not be provided with weakened zones.
The textile stitches shown in this example are in a tricot configuration. Preferred assemblies of grouped elongated metal elements 402 comprise steel cords.

[0086] FIG. 5 is a schematic illustration of a structure 500 for the reinforcement of pavements. The structure 500 comprises a woven structure having in warp direction 502 a number of assemblies 504 of grouped elongated metal filaments, for example a number of steel cords. The assemblies of 504 are provided with interruptions 503 along their length. The warp direction 502 may further comprise a yarn (a binding warp filament) 505, for example between two assemblies of grouped metal filaments 502. The yarn 505 may or may not be provided with weakened zones or with interruptions.

The weft direction 506 comprises yarns, for example polyamide monofilaments (70 tex) 508. The structure 500 has for example a plain weave pattern. The elements of the weft direction may or may not be provided with weakened zones or with interruptions.

[0087] FIG. 6 is a schematic illustration of a structure 600 for the reinforcement of pavements. The structure 600 comprises a polyester grid, for example a polyethylene terephthalate (PET) grid. The structure 600 is at predetermined positions provided with weakened zones 602.

[0088] FIGS. 7a, 7b and 7c illustrate a preferable embodiment of the a structure 700 for the reinforcement of pavements. FIG. 7a is a schematic illustration, FIG. 7b shows a cross-section according to plane B-B and FIG. 7c shows a cross-section according to plane C-C.

Structure 700 comprises a substrate 710 as carrier in the form of a plastic grid or a non-woven. The structure 700 further comprises steel cords 712 substantially parallel to each other in the longitudinal direction. The transversal distance between two neighbouring steel cords 712 may range between 25 cm and 60 cm. These steel cords 712 are provided with weakened spots 714 , e.g. at distances ranging between 40 cm and 60 cm. The structure 700 also comprises steel cords 716 substantially parallel to each other in the transverse direction. The longitudinal distance between two neighbouring steel cords 716 ranges between 25 cm and 60 cm. The transversal steel cords 716 may also be provided with weakened spots or interruptions (not shown). Synthetic yarns 718 hold the substrate 710, the steel cords 712 and the steel cords 716 together in a way that is best seen on FIG. 7b and FIG. 7c. The substrate 710 forms the basis.

[0089] The transverse steel cords 716 are positioned upon the substrate 710. The longitudinal steel cords 712 are positioned upon the transverse steel cords 716. The yarns 718 are stitched along the longitudinal steel cords 712 and and stitch the longitudinal steel cords 712 to the substrate 710.

In principle, no additional yarns or alternative adhesive means are needed for the transverse steel cords 716, since these steel cords 716 lie under the longitudinal steel cords 712.
However, additional stitches by means of additional yarns may fix the transverse steel cords 716 separately. Alternatively additional stitching may be provided at the cross-over points of the longitudinal steel cords 712 and the transverse steel cords 716.

[0090] FIG. 8 is a schematic illustration of a method of breaking up a pavement 802 reinforced with a reinforcement structure 804 according to the present invention. The pavement 802 is milled using a milling machine 800. The milling machine 800 comprises a milling drum 806 provided with cutting teeth 808. As the milling machine 800 is advancing over the surface of the reinforced pavement 802, the milling drum 806 is rotating over the surface of the reinforced pavement 802 and the milling drum 806 is cutting material from the surface of the reinforced pavement 802 to a desired depth. By the milling process the pavement 802 comprising the reinforcement structure 804 is ground or broken up into small pieces. As the reinforcement structure 804 is provided at predetermined positions with weakened zones, the reinforcement structure 804 will break at these predetermined positions during the milling process. Consequently, the length of the broken pieces of the reinforcement structure 804 is limited so that entanglement of broken pieces of the reinforcement structure 804 for example around the milling drum 806 of the milling machine 800 is avoided.

[0091] Generally, the milling machine 800 includes a conveyor system 810 designed to carry the milled material and to move the material for example to a truck. The material can be incorporated into new pavement or can be recycled.

In case the reinforcement structure comprises steel, it may be advantageous to provide the conveyor system 810 with magnets (not shown). The magnets allow to separate the steel from the milled material resulting in a higher purity of the milled pavement material.
Also the breaking unit or breaking units can be provided with magnets, instead of or in addition to the magnets of the conveyor system 810.