EP3987116A1

EP3987116A1 - Road surfacing reinforcement of the cold surface dressing type and method for producing road surfacing using such a reinforcement

Info

Publication number: EP3987116A1
Application number: EP20733631.4A
Authority: EP
Inventors: Daniel Doligez
Original assignee: 6 D Solutions; Production Industrielle De Renforts Routiers Ste
Current assignee: 6 D Solutions; Production Industrielle De Renforts Routiers Ste
Priority date: 2019-06-24
Filing date: 2020-06-22
Publication date: 2022-04-27
Anticipated expiration: 2040-06-22
Also published as: ES2953333T3; EP3987116B1; FR3097572B1; WO2020260218A1; FR3097572A1; EP3987116C0

Abstract

The invention relates to a road surfacing reinforcement (10) of the cold surface dressing type comprising at least one layer of bonding binder (4) and a layer of aggregates (3), said reinforcement being intended for being deposited on said layer of bonding binder (4), characterised in that said reinforcement (10) comprises: - a web-like substrate (11) comprising non-woven polyolefin synthetic fibres; said web-like substrate being permeable to said bonding binder; and - a mat (13) consisting of high-tenacity fibres (12); said fibres (12) being intended for receiving the layer of aggregates (3); and in that said reinforcement (10) is not provided with means for bonding the mat (13) to the substrate (11).

Description

ROAD COATING REINFORCEMENT OF SURFACE A TYPE

COOLING AND ROAD COATING MANUFACTURING PROCESS

USING SUCH REINFORCEMENT

Technical area

The invention relates to the field of fiber reinforcements used in road construction and maintenance.

The invention relates in particular to a road surface reinforcement of the cold surface coating type.

The invention finds a particularly advantageous application for reinforcing road pavements, in particular for improving their resistance to the propagation of cracks.

Technological background

Conventionally, a road structure consists of a succession of layers including in particular:

- a support ground;

- earthworks made up of one or more layers of untreated material called foundation layers; and

- a coating layer made up of a succession of layers of treated materials.

There are mainly three types of bitumen surface coating layers, namely mixes and cold or hot plasters.

Asphalt mixes are a mixture of aggregates and binder, manufactured in the factory, applied in a single coat on the construction site. They are generally applied hot, that is, at temperatures between 120 and 170 ° C.

Hot surface coatings are formed directly on the site by at least two superimposed layers: a layer of fluxed bitumen and a layer of aggregates. It is also possible to repeat the operation so as to obtain a two-layer coating or three-layer ... Hot surface plasters are used at temperatures of around 160 ° C.

The cold surface coatings are also formed directly on the site by at least two superimposed layers: a layer of bonding binder, typically a bitumen emulsion or a bitumen thinned with solvent or other and a layer of aggregates. It is also possible to repeat the operation so as to obtain a two-layer or three-layer coating. Cold surface plasters are generally used at temperatures between 50 and 60 ° C.

The invention relates specifically to the latter type of coating layer.

It is common to observe cracks in the roads or the departure of material such as potholes. These degradations appear in particular with wear related to traffic, temperature variations or oxidation by UV rays. However, these degradations can lead to traffic disruption or even accidents for motorists. To fight against these phenomena of pavement cracking and material departures, it is necessary to resort to repair techniques. The same is true for certain pavements in order to improve their impermeability.

Among these techniques, one solution is to pour a new layer of cold surface plaster. However, cold surface plaster layers are often thin and subject to rapid wear, resulting in rapid reappearance of surface cracks and loosening of aggregates.

Solutions based on textile technologies are thus widely used with the aim of reinforcing the cold surface coating layer and making it more resistant to the propagation of cracks. By way of example, mention may be made of synthetic geotextiles based on polypropylene, synthetic or mineral geogrids of the type made of glass fiber or of polyester fiber, of carbon fibers or of polyvinyl acetate (PVA) fibers.

Document US Pat. No. 6,315,499 describes a geotextile consisting of a grid made from glass strands of high elastic modulus, from 6 to 28 GPa, impregnated with a PVC type resin. However, the implementation of this type of geotextile is difficult, especially on irregular supports, due to its stiffness. In addition, these geotextiles are inextensible, which complicates their installation and their unrolling on the ground, in particular on bends.

Also known are glass mats brand TruPave ^®, marketed by Owens Corning. These mats are nonwovens made of high tenacity glass and polyester fibers bonded together. Although having the capacity to slow down the propagation of cracks thanks to the bitumen which impregnates them, the fibers constituting these mats are bonded together and do not allow the fibers which constitute them to mix with the bituminous materials applied on top. In addition, these mats, by virtue of the bonding of the fibers to each other, are difficult to use in bends because they have a low elongation and poorly withstand deformations.

Document EP 1 693 517 describes a reinforcement intended for asphalt mixes. The backing consists of a waterproof backing covered with a mat of high tenacity fibers. The holder is made of a material that can be melted at temperatures in the order of 100 ° C. Thus, when laying a mix, the temperatures involved (from 120 to 170 ° C) are sufficient to allow the support to melt so that the fibers can be impregnated with the mixture of aggregates and binder. constituting the mix.

However, such a reinforcement is not suitable for the technique of cold surface coatings, which involves low temperatures, insufficient to melt the impermeable support. Thus, the support does not allow the fibers of the mat to become impregnated with the bonding binder layer of a cold surface coating. This has the effect of making the different layers of the cold surface plaster cannot be joined together. The coating is thus weakened and does not make it possible to effectively reduce the propagation of cracks and the decohesion of the aggregates.

The technical problem which the invention proposes to solve is to develop a textile reinforcement as well as an associated road reinforcement process, adapted to the technique of cold surface coatings and making it possible to facilitate the installation of the reinforcement on the ground, especially in bends.

Disclosure of the invention

In order to solve the problem set out above, the Applicant has developed a road surface reinforcement of the cold surface coating type comprising at least one layer of bonding binder and one layer of aggregates. Such reinforcement is intended to be deposited on the bonding binder layer.

Such a reinforcement is characterized in that it comprises:

- A web-type support comprising non-woven polyolefin synthetic fibers, this web-type support also being permeable to the bonding binder; and

- A mat made of high tenacity fibers, these fibers being intended to receive the layer of aggregates;

Such a reinforcement is also characterized in that it does not have any means for attaching the mast to the support.

For the purposes of the invention, a mat is defined as being a material consisting of randomly dispersed mineral fibers. The latter do not present any means of connection between them.

The veil-type backing is defined as a synthetic fabric, consisting of fibers made of polyolefin, for example polypropylene, polyester or other synthetic material which may be light, that is to say, from 2 to 30 g / m ^2. , deformable and permeable. The permeability criterion results in imbibition in a few seconds, at worst a few tens of seconds, of the web-type support when it is deposited on a layer of fluid, for example a layer of bituminous binder in the form of an emulsion.

The “high tenacity” criterion corresponds to a resistance greater than 70 GPa minimum.

In other words, the Applicant has developed a reinforcement composed of two layers which are not bonded together. The first layer forms a support for the mat which itself consists of fibers to improve the mechanical resistance of the roads.

Thus, the reinforcement obtained is more flexible than the reinforcements of the state of the art and allows an easier unrolling on the road and in the turns, without observing the formation of folds. In addition, the permeability of the backing allows the cold plaster tack coat layer to pass through the backing to impregnate the fibers and the layer of aggregate deposited on the backing. In particular, this permeability allows the different layers of the cold plaster to be bonded to each other while having an elastic character and resistant to mechanical stress and wear.

Finally, this reinforcement is also a more economical and simpler solution in terms of implementation, compared to existing solutions.

According to one characteristic of the invention, the fibers constituting the mat are selected from the group comprising carbon fibers, basalt fibers and glass fibers.

Preferably, the glass fiber is chosen because of its ease of being cut (during the manufacture of the mat) and because of its low cost price. Glass fibers are also known to have good adaptability to any climate with increased resistance to high temperatures and good stability with an elongation at break suitable for this use. Preferably, the fibers are cut. In particular, the fibers constituting the mat have a length of between 10 mm and 300 mm.

According to a first embodiment of the invention, the mat is composed of a single type of fibers of a predetermined length within the length range stated above.

According to another embodiment of the invention, the mat comprises at least two types of fibers. The fibers of the first type have a length of between 7 mm and 50 mm and the fibers of the second type have a length of between 10 and 200 mm.

Advantageously, the length of the first type of fibers is between 7 mm and 50 mm, preferably between 10 mm and 40 mm and the length of the second type of fibers is between 20 and 150 mm, preferably close to 100 mm.

The shorter fibers deform more easily and penetrate better inside the layer of aggregate deposited on the mat, especially during compaction. They ensure a hold between the aggregates and thus strengthen the layer of aggregates.

The longer fibers remain at the interface between the tie layer and the aggregate layer and help strengthen the bond between layers. In addition, the long fibers also make it possible to avoid any discontinuity in the transmission of stresses, which contributes to better fatigue resistance of road structures.

In order to facilitate the flow of the bonding binder through the reinforcement, the support is presented as an open fabric, having a perforated and light structure. In particular, the web-type support has a basis weight of at most 20 g / m ² . Likewise, the mat has a basis weight of between 40 and 300 g / m ² , advantageously between 50 and 200 g / m ² , preferably between 50 and 120 g / m ² .

Indeed, like the veil-type support, the mat forms a very perforated structure, allowing the passage of aggregates in certain places.

Advantageously, the glass fibers have a diameter of between 12 and 50mth, preferably between 15 and 30mth; and have a length of between 10 and 500mm, preferably between 20 and 200mm.

In practice, such a reinforcement is packaged in the form of rolls. These are then unrolled on a road structure to be repaired or built. When installing the reinforcement, the openings in the mat and the fineness of the support, combined with its permeability, ensure direct contact between the bonding binder layer and the aggregate layer. Thus, the reinforcement is positioned at the interface between the layers of the plaster and allows the forces to be transmitted to the structure without causing cracks.

The invention thus relates to a method of manufacturing a road surface of the cold coated type. The process comprises the following steps:

- application of a bonding bond coat over an existing pavement;

- unwinding of at least one reinforcing roll according to the invention, and depositing the reinforcement on the tie binder layer so that the reinforcement is impregnated with the binder layer;

- deposit on the reinforcement of a layer of aggregates;

application of pressure on the layer of aggregates so as to deform the surface of the reinforcement. According to one embodiment of the method, at least two reinforcing rolls are staggered to be unwound, in order to preserve a minimum space, ideally zero, or even a slight overlap between two adjacent reinforcing bands, in order to create continuity. reinforcement across the width of the road.

In practice, the reinforcement rollers have a width of 0.50 m to 4 m. The staggered unwinding thus allows the reinforcement to be placed in bends without creating folds.

In practice, an unwinder is adapted to a spreader. The rolls are attached to unwinding bars. The spreader can thus simultaneously apply the bonding binder and the reinforcement, object of the invention.

According to another embodiment, the method further comprises the following steps:

- application of a second layer of bonding binder; and

- application of a second layer of aggregates on said second layer of bonding binder.

Such an embodiment is called a multi-layered cold plaster and allows the thickness of the cold plaster to be increased and hence its wear resistance.

- application of an additional layer of bonding binder; and

- on top, application of at least one layer of cold or hot bonded materials.

In other words, the coating may consist of one or more layers incorporating the fibrous reinforcement according to the invention, and include additional layers of various materials, either identical to that of the lower layers, or different, or a combination of the two. Brief description of Wear

The manner of carrying out the invention, as well as the advantages which result therefrom, will emerge clearly from the description of the embodiments which follow, in support of the appended figures in which:

Figure 1 is a schematic representation in top view of a reinforcement according to a first embodiment of the invention;

Figure 2a is a schematic sectional view of a single-layer cold surface coating before compaction comprising a reinforcement of Figure 1;

Figure 2b is a schematic sectional view of a cold surface coating comprising a reinforcement of Figure 1 and an upper layer, after compaction;

FIG. 3 is a schematic representation of the method of manufacturing the reinforcement according to one embodiment of the invention; and

FIG. 4 is a schematic representation of the implementation of the process for applying the emulsion and unwinding of the product of FIG. 1 during the manufacture of a road paving of the cold surface coating type, according to a method of realization of the invention.

detailed description

Referring to Figure 1, the reinforcement 10 is composed of a web-type support 11, on which is deposited a mat 13.

More precisely, the support 11 of the synthetic nonwoven veil type consists of polyolefin fibers, for example polypropylene. By way of example, the web can have a basis weight of 12 g / m ² .

On this web 11, a mat 13 is formed by a stack of glass strands 12 with a count of 2400 tex cut and randomly distributed over a thickness of 0.2 and 5 mm. Each fiber of the mast is about 17mth in diameter. For example, the length of the cut fibers 12 can be 50 or 100 mm for a surface weight of 90 g / m ² . Referring to Figure 2a, a bonding binder layer 4 is deposited on a floor to be repaired or more generally where it is necessary to improve the surface layer 2. The floor 2 generally consists of granular materials bonded to bitumen or cement. or else granular materials not linked to each other. The floor 2 also has an irregular appearance with cracks or potholes on the surface. Alternatively, the bonding binder layer 4 is deposited on an earthwork or a track to form a new roadway. In this case, the ground 2 to be covered can also include the normal irregularities of unbound earthmoving materials.

The reinforcement 10 is deposited on the bonding binder layer 4. The reinforcement 10 is thus pressed against the ground 2 and does not fly away. A layer of aggregates 3 is then applied to the reinforcement 10.

With reference to FIG. 2b, the permeability of the web-type support allows the reinforcement 10 to adopt a three-dimensional configuration and to be impregnated in a few seconds to a few tens of seconds with the layer of bonding binder 4. The reinforcement 10 then becomes transparent and the bonding binder layer 4 rises by capillary action at the level of the upper face of the reinforcement 10, in particular during compaction. The reinforcement 10 and the layer of aggregates 3 are partly embedded in the layer of bonding binder 4.

An upper layer 5 is then applied to the aggregates 3. This upper layer 5 may correspond to a second layer of bonding binder and aggregates or to an asphalt layer or any other upper layer of road surfacing.

With reference to FIG. 3, a method for producing the reinforcement can be implemented in the factory or directly in situ, during the repair of the road.

In the first case, the reinforcement 10 is produced by scrolling the web 11 on a conveyor 16, directly above which is a cutting unit 17, formed for example facing cylinders, at least one of which is equipped with cutting members. This cutting unit is fed by one or more wire (s) of glass and generates segments of wires 12, which fall randomly on the web 11. These segments 12 have a length determined by the configuration of said cylinders, the speed of which makes it possible to adjust the quantity and thickness of wires 12 making up the mat 13.

Alternatively and not shown in Figure 3, several cutting units 17 configured to produce each of the wires 12 of a predetermined length can be juxtaposed to produce a mat 13 composed of wires 12 of different lengths.

The cutting methods are known to those skilled in the art. The web 11 on which the mat 13 rests has no means of catching the mat 13. The web 11 is then returned to form rollers 18. In this way, the mat 13 is clamped between two portions of the web 11 and the webs. wires 12 are not liable to fly off or fall during storage or transport.

The rolls thus formed have a length of between 10 and 500 m and a width which may vary between 30 cm and 4 m depending on the application for which they are intended. For example, in the case of a straight road without bends, a single roller the width of the road can be used. On the contrary, if the road has many bends, the juxtaposition of several rollers of smaller width makes it possible to better understand the homogeneous distribution of the fibers in the cold plaster layer.

Once produced, the rolls are then transported and unrolled on the site of the roadway to be repaired or covered.

Referring to Figure 4, a process for manufacturing a road surface can be implemented on a new roadway or a pre-existing roadway.

A first bonding binder layer is deposited by means of an emulsion spreader 40 projecting the binder via a ramp of spray nozzles 41. A bonding binder is typically a bitumen emulsion composed of 65% to 69% bitumen for 31 to 35% water and also contains additives. The binder layer is deposited so as to obtain a basis weight of approximately 1100 g / m ² .

The rear of the spreader 40 is fitted with a frame comprising reels on which reinforcing rollers 18 are installed. The number and position of the reels is determined to allow the placement of several reinforcements, over the total width of the road, in parallel side-by-side or with an overlap between the rollers 18. The frame can adopt two positions: one position low allowing the reinforcement to be unrolled and an upper part allowing other tasks to be performed such as moving the spreader 40 from its storage location to the site.

Preferably, the reels are mounted in staggered rows, so that the adjacent reinforcements overlap to ensure continuity of coverage. The reels are preferably independent, so as to allow a differential in length deposited in the turns, between the inside and the outside of the curve.

Preferably, the reels are positioned and unwound as close to the ground as possible, typically against the ground, to allow the reinforcement not to be deformed under the effect of gravity and the wind, and also to allow the reinforcement to soak up. quickly of the tack coat layer before it breaks or dries. Alternatively, the rolls can be unwound by hand by applying the same precautions as those mentioned above. In some cases, the reinforcement can be unwound, with the fibers 12 below and the support 11 above. This makes it possible to create an interface rich in bitumen reinforced by mat 13.

A layer of aggregates is then deposited on the reinforcement, generally by a gravel spreader. The aggregates are generally stone and have a diameter of between 2 and 15 mm. They are distributed so as to obtain a layer with a surface density of approximately 2 kg / m ² to 15 kg / m ² . The layers are then compacted by a compactor, to allow the bonding binder to impregnate the upper layers and the reinforcement to deform to adopt the topology of the road. A second emulsion layer is then deposited on the layer of aggregates.

The process can then be repeated so as to form bilayer or tri-layer cold plasters therefore including several fibrous reinforcements. It is also possible to deposit other layers of material (without fibrous reinforcement) on top of the layer (s) including the fibrous reinforcement (s).

In conclusion, this reinforcement makes it possible to transmit the stresses to which the road structure is subjected and to obtain better resistance to cracking and the disintegration of aggregates. Such reinforcement also constitutes a durable, economical alternative that is simpler to implement than the existing solutions for reinforcing the coating of road pavements.

Claims

1. Road surfacing reinforcement (10) of the cold surface coating type comprising at least one layer of bonding agent (4) and one layer of aggregates (3), said reinforcement being intended to be deposited on said layer of binder. 'hooking (4), characterized in that said reinforcement (10) comprises:

- a web-type support (11) comprising synthetic fibers of non-woven polyolefins; said web-like support being permeable to said bonding binder; and

- a mat (13) made of fibers (12) with high tenacity; said fibers (12) being intended to receive the layer of aggregates (3);

and in that said reinforcement (10) is devoid of means for attaching the mast (13) to the support (11).

2. Road paving reinforcement according to claim 1, characterized in that the fibers (12) constituting the mat (13) are selected from the group comprising carbon fibers, basalt fibers, glass fibers.

3. Road surface reinforcement according to one of claims 1 or 2, characterized in that the fibers (12) constituting the mat (13) have a length of between 10 mm and 300 mm.

4. Road surface reinforcement according to one of claims 1 to 3, characterized in that the mat (13) comprises at least two types of types of fibers (12); the fibers of the first type having a length of between 7mm and 50mm and in that the fibers of the second type have a length of between 10 and 200mm.

5. Road pavement reinforcement according to one of claims 1 to 4, characterized in that the web-type support (11) has a basis weight of at most 20 g / m ² .

6. Road surfacing reinforcement according to one of claims 1 to 5, characterized in that the weight per unit area of the mat (13) is between 40 and 300 g / m ² .

7. Road surfacing reinforcement according to one of claims 1 to 6, characterized in that the glass fibers (12) have a diameter of between 12 and 50 µm and an average length of between 10 and 500mm.

8. Road surfacing reinforcement according to one of claims 1 to 7, characterized in that said reinforcement (10) is packaged in the form of rolls (18).

9. A method of manufacturing a road paving of the cold surface coating type, characterized in that said method comprises the following steps:

- application of a bonding bonding layer (4) over an existing roadway (2);

- unwinding of at least one roll (18) of reinforcement (10) according to claim 8, and depositing of said reinforcement (10) on said layer of tie binder (4) so that said reinforcement (10) s 'impregnated with said binder layer (4);

- depositing a layer of aggregates (3) on said reinforcement (10);

- application of pressure on the layer of aggregates (3) so as to deform the surface of said reinforcement (10).

10. A method of manufacturing a road surface according to claim 9, characterized in that at least two rollers (18) of reinforcements (10) are unrolled in staggered rows.

11. A method of manufacturing a road surface according to claim 9, characterized in that said method further comprises the following steps:

- application of an additional layer of bonding binder on said layer of aggregates; and

- application of a layer of aggregates or bonded materials on said second layer of bonding binder.