EP0506538B1 - Roadlane usually without traffic such as a hardshoulder - Google Patents

Abstract

The hard shoulder or other road lane, which is usually not subjected to traffic, comprises a draining main surfacing made of draining surfacing material or porous concrete; the said surfacing is covered by a secondary layer made of a material which is impervious to the residual matter, which material is intended to protect the said lane so that its main surfacing does not become clogged up by the residual matter which settles thereon.

Description

The present invention relates particularly to emergency stop lanes, which are provided, for example, on the lateral edges of multi-lane roads or motorways and more generally to the road lanes usually not subject to vehicle traffic. .

More particularly still, the invention relates to pavement strips of this type, which are produced in a draining coating, such as a draining asphalt.

A draining mix is an aggregate-bitumen mixture that has a void percentage generally greater than 20%. Draining asphalts are experiencing a strong development as a wearing course on high traffic roads, in particular on motorways, urban bypasses, complementary development links of the motorway network.

• le confort et la sécurité de conduite par temps de pluie, en supprimant notamment les projections d'eau à l'arrière des véhicules et en améliorant la visibilité du marquage routier,
• la réduction des bruits de roulement,
• l'adhérence à forte vitesse.

The advantage of such an open coating is threefold. He rocks:

• driving comfort and safety in rainy weather, in particular by eliminating water splashes at the rear of vehicles and improving the visibility of road markings,
• reducing road noise,
• grip at high speed.

When a roadway is coated with draining asphalt, to allow the transverse flow of water from the tracks to the outlets, the emergency stop strip is also coated in the same way.

After commissioning, many non-native materials (atmospheric dust, cigarettes, metallic debris, tire rubber, pavement treatment residue, etc.) are deposited on the pavement.

These residues are gradually displaced by traffic, particularly to the emergency lane. Since this is not or very little subject to traffic, the residues which deposit there, remain there, and, little by little, penetrate by gravity in the body of the draining covering, thus clogging the effective voids.

After a while, the first few centimeters of the emergency stop strip are completely blocked. The water coming from the traffic lanes can no longer be evacuated and it flows out at the edge of the emergency lane. To date, mechanical attempts at in situ treatment, without milling the clogged coating, have failed. We can cite, for example, the use of sweeper-vacuum cleaner type materials which are now recognized for their preventive and not curative interest. On the other hand, the use of such devices near heavy traffic flows is dangerous.

In an article entitled “Nieuw concept voor zeer open asfaltbeton”, published in the journal Wegen vol. 64, No. 6, June 1990, pages 30/31, is described a coating of a roadway subjected to traffic. This coating is composed of a first layer of a fairly coarse structure covered with a second layer of fine structure. The structure of the coating is chosen in such a way that the life of this coating is greatly improved and that, at the same time, a self-cleaning effect by circulation is ensured. However, this document provides little information on the composition of the coating.

Document FR-2.615.520 relates to a bituminous composition for cold-cast mixes. This document discusses the use of cold-cast mixes for the maintenance of worn pavements of all kinds. The document also indicates that the phase bituminous makes it possible to bind the aggregates to the support and to ensure the tightness of the whole.

However, this document does not disclose anything on the constitution of a strip usually not subject to traffic, nor on the drainage of the coating, or even on specific measures to prevent surface clogging of the strips of roadway usually not subject to traffic.

• pas de modification des qualités drainantes des enrobés de la bande d'arrêt d'urgence,
• possibilité de circuler occasionnellement sur la bande d'arrêt d'urgence en toute sécurité (adhérence au support et rugosité de surface),
• pas de diminution de la qualité structurelle de la bande d'arrêt d'urgence,
• pas de surépaisseur préjudiciable à la sécurité des usagers.

The object of the present invention is to provide a more effective and safer solution for preventing the surface clogging of emergency stop strips in draining mixes. According to the invention, a secondary layer of a material is applied to said strips, the formulation of which exactly meets the specifications set by the managers of high traffic roads, in particular:

• no change in the drainage qualities of the mixes of the emergency stop strip,
• possibility of driving on the emergency lane occasionally in complete safety (adhesion to the support and surface roughness),
• no reduction in the structural quality of the emergency lane,
• no excess thickness detrimental to user safety.

The subject of the present invention is therefore an emergency stop strip or other strip of roadway usually not subject to traffic, comprising a main coating draining in asphalt draining or porous concrete. Said coating is covered by a layer secondary in a material impervious to residues of a reconstituted particle size, intended to protect said strip against clogging of its main coating by the residues which deposit therein according to the characteristics of claim 1.

The aggregates can be of reconstituted particle size of size 0/4, 0/5 or 0/6. A bitumen emulsion can be produced from a bitumen of grade greater than or equal to 40/50, the bitumen content of which is greater than 55%. The thickness of this secondary layer can vary between 0.4 and 1.5 cm approximately. The setting regulating additives may include thickeners, shear thinners or viscosants, or any other similar product.

The setting regulator additives may also include an accelerator.

• granulats    100%
• émulsion de bitume    12 à 14% du poids sec de granulats
• eau de mouillage    8 à 15% du poids de granulats et, de préférence,
• épaississant    0,1 à 1,5% par rapport au poids de l'émulsion
• accélérateur    0,1 à 1,5% en poids sec de granulats

The bituminous concrete layer, with which it is at least partially covered, is cold cast and has the following composition by weight:

• 100% aggregates
• bitumen emulsion 12 to 14% of the dry weight of aggregates
• dampening water 8 to 15% of the weight of aggregates and, preferably,
• thickener 0.1 to 1.5% based on the weight of the emulsion
• 0.1 to 1.5% dry weight accelerator of aggregates

The secondary layer is advantageously applied with a density of 12 to 20 kg / m ² .

The height between the upper surface of the secondary layer and the upper surface of the coating of the circulating part is preferably less than 1 cm.

The surface of the secondary layer can be at the same level on the surface of the coating of the circulated part of the roadway.

Another subject of the invention is the use of a cold bituminous grout to produce, on an emergency stop strip or any other strip not usually subjected to the circulation of a roadway, a layer protection against clogging by residues deposited there.

The following description of several embodiments of the invention is purely illustrative and not limiting.

The basic road surfacing used according to the invention is produced conventionally in a draining mix or porous concrete. The composition of such a draining mix or porous concrete is perfectly known to those skilled in the art. It is the same for the means to be used for the production of pavements from these materials. One can refer in this respect to the information note of SETRA dated December 13, 1990.

According to the invention, the emergency stop strip made from such a draining coating is coated with a secondary layer of poured bituminous concrete. This poured bituminous concrete is a cold bituminous grout.

• gravillons concassés    10%
• sable    60%
• filler    30%
• bitume polymère   15%

A composition of a hot-poured bituminous mortar is for example:

• crushed gravel 10%
• sand 60%
• filler 30%
• 15% polymer bitumen

However, a cold bituminous grout is used. Such a cold bituminous grout is a homogeneous mixture of fillerized sand, gravel, emulsion, water and setting regulating additives.

It is applied in a thin layer of 12 to 20 kg / m ² . The dosage chosen depends on the caliber selected and the traffic.

• granulats    100% de matériaux secs
• émulsion   13% par rapport au poids sec de granulats
• eau de mouillage   10% par rapport au poids sec de granulats
• épaississant    1% par rapport à l'émulsion
• accélérateur    0,5% par rapport au granulats

An example of weight composition is as follows:

• aggregates 100% dry materials
• emulsion 13% based on the dry weight of aggregates
• dampening water 10% relative to the dry weight of aggregates
• thickener 1% compared to the emulsion
• 0.5% accelerator compared to aggregates

The aggregates are successively introduced first, then the supply water and finally the emulsion. The mineral additions are made in the aggregates and the liquid additions in the feed water.

Such a sealant has limited penetration into the draining mix (5 mm). Its applied surface finish is quite rough. This sealing product also has good adhesion to the support.

In still other examples, the dosage of the emulsion varies between 12 and 14% by dry weight of aggregates, the wetting water varies between 8 and 15% by dry weight of aggregates, the setting accelerator varies from 0 , 1 to 1.5% by dry weight of aggregates, the thickener between 0.1 and 1.5% by weight of emulsion.

This thickener is essentially in liquid form. It is intended to freeze the grout but does not thicken the emulsion. It is added either in the filler water or in the emulsion. It is also advantageous to use rheofluidifiers or viscosants to replace it.

The emulsion can be of several types. It can be a bitumen emulsion produced from an 80/100 bitumen with a content greater than 60%. It can also be an emulsion elastomer obtained by incorporating a latex into the aqueous phase of the emulsion.

The accelerator can be in solid form (cement, slaked lime, quicklime) or in liquid form.

The reconstituted aggregates are preferably of size 0/4, 0/5 or 0/6. For a 0/4 bituminous grout, the particle size components will be between 95% and 100% at 4 mm, 35% at 40% at 2 mm and 6% at 9% for 0.08 mm.

The grout is implemented by means of a specific compact machine which includes the aggregate hoppers, the emulsion tank, the water tanks and various additives, a continuous mixer and the applicator sled.

Claims (11)

1. A roadlane usually without traffic, comprising a main draining coating made of a draining coating material or of porous concrete, whereas the said coating is covered by a secondary layer designed for preventing the main coating of the said roadlane against choking, characterised in that the material out of which the secondary layer is made is a cold bituminous slurry comprising a mixture of granulates, a bitumen emulsion representing 12 to 14% of the dry weight of the granulates, make-up water accounting for 8 to 15% of the weight of the granulates and setting regulating additives.
2. A roadlane according to claim 1, characterised in that the granulates exhibit a reconstituted granulometry of calibre 0/4, 0/5 or 0/6.
3. A roadlane according to claim 2, characterised in that the thickness of a secondary layer ranges between 0.4 and 1.5 cm.
4. A roadlane according to any of the claims 1 to 3, characterised in that the bitumen emulsion is made out of a bitumen of a grade equal to or greater than 40/50, whose bitumen content lies above 55%.
5. A roadlane according to any of the claims 1 to 4, characterised in that the setting regulating additives comprise thickeners, rheoliquefiers or viscosifiers.
6. A roadlane according to any of the claims 1 to 5, characterised in that the setting regulating additives comprise an accelerator.
7. A roadlane according to any of the claims 5 or 6, characterised in that the setting regulating additives exhibit the following weight composition :

   - thickener    0.1 to 1.5 % in relation to the weight of the emulsion

   - accelerator    0.1 to 1.5 in dry weight of the granulates.
8. A roadlane according to any of the claims 1 to 7, characterised in that the secondary layer is applied with a density of 12 to 20 kg/m².
9. A combination of a roadlane according to any of the preceding claims with a section of the road exposed to traffic, characterised in that the height between the upper surface of the secondary layer and the upper surface of the coating of the section exposed to traffic is smaller than 1 cm.
10. A combination according to claim 9, characterised in that the upper surface of the secondary layer is at the same level as the upper surface of the coating of the section of the road exposed to traffic.
11. A use of a cold bitumen slurry comprising a mixture of granulates, a bitumen emulsion representing 12 to 14% of the dry weight of the granulates, make-up water accounting for 8 to 15% of the weight of the granulates and setting regulating additives, in order to produce on a roadlane usually without traffic, of a road comprising a main draining coating, a protective coating against choking of its main coating.