Description

Technical Field

[0001 ] The invention relates to a fabric for the reinforcement of roads or

pavements. The invention also relates to a road or pavement reinforced with such a fabric and to a method of reinforcing a pavement or a road.

Background Art

[0002] Fabrics for reinforcement of roads or pavements are known in the art.

Fabrics for the reinforcement of an overlay, for example an asphalt overlay, are also known in the art.

[0003] WO-A1 -2014/161930 and WO-A1 -2014/161931 disclose a fabric to prevent reflective cracking. Reflective cracking is the process by which an existing crack, discontinuity or joint propagates towards the surface through an overlying layer of asphalt. Once a reflective crack reaches the surface, an open path is created allowing the penetration of water into the lower layers of the pavement. Left untreated, this situation will lead to further deterioration of the pavement structure and to a reduction in overall serviceability.

[0004] The fabric disclosed in WO-A1 -2014/161930 discloses a fabric with a

series of substantially parallel elongated metal elements which are bound to a substrate.

[0005] The fabric WO-A1 -2014/161931 discloses a fabric with also a serious of substantially parallel elongated metal elements which are kept parallel by means of yarns.

[0006] Both above fabrics are flexible and can be wound in a roll for

transportation and unwound or unrolled over their entire length at the time of installation. However, in almost all cases these fabrics have a width that is smaller than the width of the road to be renovated. So various fabrics have to be unrolled one adjacent to another to cover the entire width of the road. Disclosure of Invention

[0007] It is an object of the present invention to facilitate the installation of various road reinforcing fabrics.

[0008] It is another object of the present invention to guarantee an optimal

transfer of forces between adjacent reinforcing fabrics.

[0009] It is yet another object of the present invention to make to provide a

practical way of reinforcing an overlay on an existing road.

[0010] According to a first aspect of the present invention, there is provided a fabric adapted for the reinforcement of roads or pavements, such as an overlay on existing roads or pavements. The fabric has a length in a longitudinal direction and a width in a transverse direction. The fabric has in longitudinal direction a left zone extending along the length at the left border and a right zone extending along the length at the right side.

Between the left zone and the right zone, there is a middle or centre zone. The left zone or the right zone or both are intended to overlap with a right or left zone of an adjacent fabric in order to optimally transfer the forces between adjacent fabrics in transverse direction of the formed composite fabric-asphalt or fabric-concrete. Either the left zone or the right zone or both are marked.

[001 1 ] The marking avoids that the overlapping is not neglected and that

installation is done in a proper way.

[0012] In a preferable way of marking, the left zone or the right zone or both are marked by a colour differing from the colour of the rest of the fabric.

[0013] Preferably, in the fabric elongated longitudinal reinforcing elements are running substantially parallel in longitudinal direction and elongated transverse reinforcing elements are running substantially parallel in transverse direction. The elongated longitudinal and transverse

reinforcement elements may be metal wires, metal bundles or metal cords, carbon fibers, synthetic fibers or glass fibers or yarns made therefrom. Preference is given to steel cords since steel cords both have a high strength and flexibility due to its twisting of thin wires or filaments.

[0014] Usually the elongated longitudinal reinforcement elements and the

elongated transverse reinforcement elements have a spacing in-between ranging from 15 mm to 75 mm, e.g. from 20 mm to 70 mm, e.g. from 25 mm to 65 mm.

[0015] In a preferable embodiment of the invention, the left zone or the right zone or both comprise two to six elongated longitudinal reinforcement elements.

[0016] From a more general point of view, the width of the overlapping and thus the width of the left zone and the right zone, may vary depending upon to the distance between two adjacent elongated longitudinal reinforcing elements. Whatever the width, however, it is highly preferable that the width of the overlap is constant over the whole length.

[0017] In another preferable embodiment of the invention, the fabric further

comprises a substrate. A substrate has the advantage that the asphalt which is deposited on the fabric with the substrate does not penetrate between the reinforcing elements and thus flattens the fabric, in other words, undulation of the fabric is avoided. The elongated longitudinal reinforcement elements are bound to the substrate. This bounding can be realized in various ways, e.g. by means of a glue or by means of a yarn. The elongated transverse reinforcement elements may or may not be bound to the substrate. The binding the elongated transverse reinforcing elements may be done by means of an extra stitch at the points where elongated transverse reinforcing elements cross with elongated

longitudinal reinforcing elements or by means of a glue.

In case the elongated transverse reinforcement elements are not bound to the substrate, they preferably lie under the elongated longitudinal reinforcement elements. In this case the elongated transverse

reinforcement elements are not surrounded by a yarn and are less fixed: To a certain extent some movement is possible. This case is also the most economical way of using a yarn, since only the elongated

longitudinal reinforcing elements need to be fixed. [0018] The embodiment of a fabric with a substrate where only the elongated transverse reinforcing elements lie under the elongated longitudinal reinforcing elements and where only the elongated longitudinal reinforcing elements are bound to the substrate either by means of an adhesive or by means of a yarn, can be used independently without the marking feature. As mentioned, this embodiment has the advantage of an economical way of manufacturing, since only the elongated longitudinal reinforcement elements need to be bound. The elongated transverse reinforcing elements are less fixed and have some freedom of movement.

[0019] Different ways of colour marking may be applied.

[0020] One way of colour marking is that the two to six elongated longitudinal reinforcement elements in the right or left zone or in both right and left zone have a colour different from the colour of the other elongated longitudinal reinforcement elements. This different colour may be obtained by painting or by applying a different coating with a differing colour, for example a brass or copper coating versus a zinc or a zinc aluminium coating. As a matter of another example, a polymer coating may be applied by means of emulsion or extrusion and the polymer may have a different colour.

[0021 ] Another way of colour marking is as follows: the fabric further comprises yarns for stitching the elongated longitudinal reinforcement elements to the substrate. The yarns that are located in the left zone or the right zone or both have a colour different from the colour of the yarns in the middle zone. For example, the yarns in the left and right zone may have a red colour while the yarns in the middle zone have a white colour.

[0022] Yet another way of colour marking is by marking the substrate: the fabric further comprises a substrate and this substrate has in the left zone or in the right zone or in both a colour different from the colour of the substrate in the middle zone. Instead of a different colour another visually differing marking may also be applied.

[0023] According to a second aspect of the invention, there is provided a road or pavement reinforced by means of a fabric according to the first aspect of the invention.

According to a third aspect of the invention, there is provided a method of reinforcing a road or pavement with a fabric according to the first aspect of the invention.

This method comprises following steps:

a) depositing a first adhesion layer, such as a tack coat (i.e. bitumen emulsion) or a bitumen layer (i.e. pure or polymer modified bitumen). The adhesion layer is sprayed in exactly the same dimensions (or slightly broader) than the reinforcing product

b) unrolling a first fabric according to one of the claims 1 to 9 over the first adhesion layer adjacent or close to the one side of the pavement or road; c) depositing a second adhesion layer over a width at least equal to the width of the fabric starting from the left or right zone of the first fabric, whichever is more remote from the one side of the road;

d) unrolling a second fabric according to one of the claims 1 to 9 to cover the second adhesion layer and overlapping with the left or right zone of the first fabric, whichever is more remote from the one side of the road.

Brief Description of Figures in the Drawings

[0024] Figure 1 is a perspective view of one example of a fabric according to the first aspect of the invention;

[0025] Figure 2 is an enlarged upper view of part of a fabric according to the first aspect of the invention;

[0026] Figure 3a is a cross-section according to plane IIIA-IIIA in Figure 2 and

Figure 3b is a cross-section according to plane IIIB-IIIB in Figure 2.

[0027] Figures 4a, 4b, 4c, 4d illustrate various steps in the installation of an

overlay reinforced by means of a fabric according to the invention;

[0028] Figure 5 is a perspective view of another example of a fabric according to the first aspect of the invention. Mode(s) for Carrying Out the Invention

[0029] Figure 1 shows a perspective view of partially unrolled fabric 100. The fabric 100 has a left zone 102 and a right zone 104 and a middle zone in- between the left zone 102 and the right zone 104. The fabric 100 has elongated longitudinal reinforcement elements 106 in the middle zone, five elongated longitudinal reinforcement elements 108 in the left zone 102 and five elongated longitudinal reinforcement elements 1 10 in the right zone 104.

[0030] The elongated longitudinal reinforcement elements 108 in the left zone

102 and the elongated longitudinal reinforcement elements 1 10 in the right zone 104 have a different colour, which is indicated by thicker lines in Figure 1 .

[0031 ] The fabric 100 further comprises elongated transverse reinforcement

elements 1 12.

[0032] Although non-metal reinforcement elements are not excluded, preference is given to metal reinforcement elements and more particularly to steel elements because of the strength of steel. Steel cords are preferred because of their flexibility and ability to be wound in a roll.

[0033] The steel cords may have any construction such as a 3x1 , a 4x1 , a 1 +6, a 2+2, ...

[0034] The steel filaments in the steel cords are preferably coated with a

corrosion resistant layer such as a zinc or zinc alloy coating or such a such as a polymer coating. The steel filaments have a diameter which may range from 0.10 mm to 0.50 mm, e.g. from 0.20 mm to 0.40 mm. The steel filaments individually or the steel cords as a whole may be provided with a plastic coating.

[0035] The steel composition may be a plain high carbon steel composition,

which may be along following lines: a minimum carbon content of 0.40%, a manganese content ranging from 0.40% to 0.70%, a silicon content ranging from 0.15% to 0.30%, a maximum sulfur content of 0.03%, a maximum phosphorus content of 0.30%, all percentages being

percentages by weight. [0036] The distance between two adjacent longitudinal steel cords 106, 108 or 1 10 can be 40 mm or 50 mm. The distance between two adjacent transverse steel cords may be 30 mm or 50 mm.

The fabric 100 further comprises a substrate 114. This substrate 114 can be a non-woven or a plastic grid. The nonwoven may be of polyethylene, polypropylene, polyethyleneterephtalaat, polylactic acid, polyamide, ... or combinations thereof. The nonwoven may be spunbond, needle-punched, spunlaced, The plastic grid may be made of polyethylene, polypropylene, polyethyleneterephtalate, polylactic acid, polyamide, ... or combinations thereof. The plastic grid may be woven, extruded, thermobonded, ... The advantage of a substrate is dimensional stability together with a lightweight open structure.. The non-woven version has the advantage that the tack coat which is applied as first layer above the road to be renovated, may penetrate in the substrate 114 and thus assures a good adhesion during installation. The plastic grid has the advantage that it is widely available and is cheap.

[0037] Figure 2 gives an enlarged and upper view of part 1 16 in Figure 1 .

Figure 3a is a cross-section according to plane IIIA-IIIA of Figure 2 and Figure 3b is a cross-section according to plane IIIB-IIIB of Figure 2.

[0038] One or more synthetic yarns 202 bind the longitudinal steel cords 106 in the middle zone to the substrate 1 14 and one or more synthetic yarns 204 bind the longitudinal steel cords 108 in the left zone 102 to the substrate 1 14. Transverse steel cords 1 12 are not directly bound by means of the yarns 202 and 204. As further shown in Figure 3a and in Figure 3b, the transverse steel cords 1 12 lie under the longitudinal steel cords 106, 108 (and 1 10) and are thus held together. The colour marking is realized by giving the yarns 202 in the middle zone a colour different from the colour of the yarns 204 in the left zone. This is made clear by showing the yarns 204 somewhat thicker than the yarns 202 in Figure 2 and by showing the yarns 204 as a rhomb and the yarns 202 as a circle in Figure 3a and Figure 3b.

[0039] Renovating a road or pavement 400 according to the invention may be done as follows:

As illustrated in Figure 4a, a first bitumen layer 402 is laid on the left side of an existing road 400 over a width which is at least equal to the width of a fabric 100.

Figure 4b illustrates the next step: a first reinforcing fabric 100 with a left zone 102 and a right zone 104 is unrolled over its total length at the left side of the road 400 over the first adhesive bitumen layer 402.

A second adhesive bitumen layer 402' is applied starting from the right zone 104 of the first fabric 100, see Figure 4c.

Further on, a second fabric 100' is unrolled over its whole lengthover the second adhesive bitumen layer 402'. This realizes an overlap of its left zone 102' with the right zone 104 of the first fabric, see Figure 4d. This assures an anchoring between the two fabrics 100 and 100' and results in an optimal transfer of the forces in traverse direction.

Once the whole surface of the road 400 has been covered with adhesive bitumen layers 402, 402', ... and fabrics 100, 100', ... one or more asphalt layers may be applied.

Another alternative way of renovating a road is that after application of a first bitumen layer 402 and a first fabric 100, i.e. at the stage of Figure 4b, an asphalt layer is applied, however, thereby leaving uncoated the right zone 104.

Anyway, colour marking makes sure that the overlapping of the left and right zones 104, 102' is paid attention to.

Additionally, the colour marking greatly facilitates the aligning of the subsequent second adhesion layers 404, 406 and avoids adhesion problems in the zones of overlap. Figure 5 illustrates another example of a fabric 500 according to the invention. The difference with the example of Figures 1 , Figure 2, Figure 3a and Figure 3b is as follows: Substrate 1 14 has in the left zone 102 and in the right zone 104 a visual marking 502, 504 that is different from the visual aspect of the middle zone. [0041 ] Examples

[0042] First Example

- distance between two adjacent longitudinal steel cords: 40 mm

- distance between two adjacent transverse steel cords: 30 mm

- non-woven substrate

- weight 335 g/m ²

- tensile strength: 38 x 50 kN/m

- stiffness: 3100 x 4400 kN/m

- four longitudinal steel cords in left zone and four longitudinal steel cords in right zone

[0043] Second Example

- distance between two adjacent longitudinal steel cords: 50 mm

- distance between two adjacent transverse steel cords: 50 mm

- plastic grid as substrate

- weight 240 g/m ²

- tensile strength: 30 x 30 kN/m

- stiffness: 2500 x 2500 kN/m

- four longitudinal steel cords in left zone and four longitudinal steel cords in right zone

[0044] List of reference numbers

100 first example of (first) fabric according to the invention

102 left zone

104 right zone

100' second fabric

102' left zone of second fabric

104' right zone of second fabric

106 longitudinal steel cords in middle zone

108 longitudinal steel cords in left zone

1 10 longitudinal steel cords in right zone

1 12 transverse steel cords

1 14 substrate

1 16 part of fabric to be enlarged in Figure 2 yarn in middle zone

yarn in left zone

road to be renovated

first adhesion layer

' second adhesion layer

second example of fabric according to the invention visual marking in left zone

visual marking in right zone