EP0509877A1 - Device for resurfacing a road by successive spreading of an adhesive layer and a hot asphalt layer on the road surface - Google Patents

Abstract

The device consists of a motorised mobile unit (1) comprising, from the front towards the rear in its direction of travel on the road surface, a means (8) for receiving hot bituminous mixtures, a device for transferring the hot bituminous mixtures towards the rear of the mobile unit (1), a device (16) for spreading the bituminous mixtures and a compacting and smoothing table (17) as well as a spraybar (18) for spraying bitumen emulsion, which can extend in the transverse direction. The extensible spraybar (18), consisting of two spraybar elements (18a, 18b) which can move relative to each other in the transverse direction, is placed at the rear part of the mobile unit (1), in front of the device (16) for spreading the bituminous mixtures, with a spacing of less than one metre. The spraybar comprises an additional means for spraying and measuring out bituminous liquid in the interface zone between the two spraybar elements (18a, 18b). <IMAGE>

Description

The invention relates to a device for producing a road surface by successive spreading on the road surface to be covered, of a bonding layer constituted by a liquid bituminous product such as a bitumen emulsion and a layer of hot bituminous material. incorporating aggregates, such as a mix, the spreading width of the two products can be adjusted continuously between two extreme positions.

A process is known for producing a road surface consisting of bituminous mixes produced hot or cold, the adhesion of the coating layer on the road surface being ensured by a layer of a liquid bituminous binder which is generally constituted with a bitumen emulsion.

In the case where the coating consists of a hot bituminous product such as a mix containing aggregates (in particular pebbles of different particle sizes), bitumen, a pulverulent material as well as any other additives, the mix can be spread on the road previously coated with the bonding layer, at a temperature of approximately 150 ° C.

Conventionally, the liquid bituminous binder constituting the bonding layer is spread on the road before spreading the hot mixes, sufficiently in advance so that the bitumen of the bonding layer can be separated from the solvent or possibly from water in the case of the use of an emulsion, by evaporation of the solvent or of the water in the open air.

The liquid bituminous binder is spread on the road by a spreader completely independent of the device used to spread the asphalt, then compact it and smooth it out.

In European patent 0.049.260 filed by the Swedish company AB SKANSKA CEMENT GUTIERIT, it has been proposed to spread the granular bituminous product such as a mix, on the bonding layer, immediately after the spreading of this bonding layer. on the road. Unexpectedly and, in particular in the case where the bonding layer consists of an aqueous bitumen emulsion, drying and breaking of the emulsion under the effect of the heat of the hot mixes results in an improvement in the qualities of the bonding layer and therefore of the coating produced.

In addition, this avoids, to a large extent, deteriorating the bonding layer by the passage of gear on this still liquid or broken layer in the case of use of bitumen emulsion spread well before spreading the hot coated.

Various devices have been proposed making it possible to apply this process, in the case of a coating layer constituted by asphalt or other road surfacing products incorporating aggregates and pulverulent materials bound by a bituminous material.

In particular, it has been proposed to use a device for spreading, compacting and smoothing asphalt for road surfacing, generally called a paver, for simultaneously carrying out the spreading of the liquid bituminous binder of the bonding layer. .

The finishers known in the prior art generally consist of a motorized mobile assembly comprising, from front to rear of the mobile assembly in its direction of movement on the road surface, a means for receiving granular bituminous materials, a bituminous material transfer device towards the rear of the mobile assembly, a device for spreading with granular bituminous material and a table for compacting and smoothing the layer of material spread on the road.

When a bituminous binder spreading ramp intended to constitute the bonding layer is integrated into the paver, this ramp is arranged in front of the paver, so that the wheels or tracks of the mobile assembly are caused to circulate on the freshly spread bituminous binder layer. It is therefore necessary to provide additional ramps arranged at the rear of the wheels or tracks of the mobile assembly to reconstitute a substantially homogeneous bonding layer.

In addition, the pavers are intended to produce pavements on pavements of variable width, so that it is necessary to provide ramps made up of separate mobile elements whose relative position in the transverse direction is adjustable.

This results in a complex arrangement of the ramps and delicate adjustment conditions of the elements constituting these ramps, in order to produce a bonding layer as homogeneous as possible. The homogeneity of the bonding layer is generally defective, in the areas of overlap of the ramp elements and in the areas of passage of the wheels or tracks of the pavers.

In addition, the emulsion reserve which can be transported by the paver is limited, so that the autonomy of the paver on site is insufficient.

These problems have been at least partially resolved, in the case of more complex assemblies intended in particular for producing thin-layer coatings of special types as described in the application. Patent 89-09893 dated July 21, 1989 filed by the company SCREG ROUTES ET TRAVAUX PUBLICS.

In the case of pavers comprising a smoothing table with lateral extension, it has also been proposed, in patent application 89-12132 filed on July 31, 1989 by the company SCREG ROUTES ET TRAVAUX PUBLICS, to combine the extensible ramp elements with the adjustable elements of the smoothing table. The device which is the subject of this patent application also comprises means making it possible to obtain a substantially homogeneous bonding layer in the areas of overlap of the various ramp elements.

However, in the case of a conventional type finisher with adjustable working width, hitherto no device has been known for spreading a bituminous binder such as an emulsion, integrated into the finisher, which makes it possible to remedy all the drawbacks linked to the use of integrated ramp finishers known from the prior art.

The object of the invention is therefore to propose a device for producing a road surface by successive spreading over the road surface to be covered, with a bonding layer constituted by a liquid bituminous product, such as a bitumen emulsion. , and a layer of hot bituminous material incorporating aggregates such as a mix, constituted by a mobile motorized assembly comprising, from front to rear in its direction of movement on the road surface, a means for receiving the granular bituminous material, a device for transferring bituminous material to the rear of the mobile assembly, a device for spreading bituminous material and a table for compacting and smoothing the layer of bituminous granular material as well as a spreading ramp of bituminous product extending in the transverse direction, supplied by a liquid reservoir of sufficient capacity containing a liquid such as an emulsion, this device making it possible to produce a completely homogeneous bonding layer over a width of road surface identical to the width of spreading of the coated materials and to avoid any deterioration of this bonding layer before spreading the granular bituminous material such as a mix.

For this purpose, the extendable ramp made up of two ramp elements with relative movement in the transverse direction is arranged, at the rear part of the mobile assembly, in front of the device for spreading bituminous products with a spacing of less than one meter relative to to this spreading device, and comprises an additional means for spreading and metering bituminous liquid in the interface zone between the two ramp elements, in order to allow continuous adjustment of the working width.

In order to clearly understand the invention, a description will now be given, by way of nonlimiting examples, with reference to the appended figures, several embodiments of a device according to the invention.

Figure 1 is a side elevational view of a device according to the invention, of the finisher type with adjustable working width.

FIG. 2 is a perspective view of the rear part of the finisher shown in FIG. 1.

Figure 3 is a schematic top view along 3 of Figure 2, of the rear part of the finisher.

Figure 4 is an enlarged sectional view along 4-4 of Figure 3, of an additional means for spreading and metering bituminous liquid in the interface zone between the two ramp elements, according to a first embodiment.

Figure 5 is a perspective view of an additional means for spreading and metering bituminous liquid in the interface area between the two ramp elements, according to a second embodiment.

In FIG. 1, a device for producing a road surface of the finisher type with integrated ramp is generally designated by the reference 1. The finisher 1 which is produced in the form of a mobile assembly moves, in progress operating on site, in the direction of arrow 3, by means of tracks 4 driven by a heat engine 5, by means of a transmission assembly 6.

The chassis 7 of the finisher mounted on the tracks 4 carries, at its front part, a hopper 8 for receiving granular bituminous products such as hot mixes which are poured into the hopper 8, during the progress of the finisher 1 on the site. , by a dump truck which can be connected to the paver 1, by means of a coupling device 10 placed at the front end of the paver 1. The tilting of the truck's skip then makes it possible to carry out filling of the hopper 8 with hot mixes, without interrupting the advance on the site of the paver 1.

Cylinders such as 11 fixed between the chassis 7 of the paver and the arm 15 secured to the smoothing table are intended for adjusting the table incidence.

The chassis 7 of the paver also carries, along its length, a continuous conveyor with bars 12, the front end of which is situated under the hopper 8. The conveyor with bars 12 makes it possible to transport the hot mixes introduced into the reception hopper 8, direction of the rear end of the finisher.

A large-capacity liquid reservoir 13 is also fixed to the chassis 7, between the receiving hopper 8 and the heat engine 5, above the bar conveyor 12.

The bar conveyor 12 is driven by the heat engine 5, by means of a transmission assembly comprising a chain 14.

Two suspension arms such as 15 are fixed to the chassis 7 on each of the sides of the chassis, so as to comprise a rear part 15a, outside the chassis ensuring the suspension and the fixing of the device 16 for spreading bituminous coated materials and of the table 17 for compacting and smoothing the mixes spread on the road surface by the device 16.

The rear end of the bar conveyor 12 constituting its outlet end is disposed slightly at the front and above the device 16 constituted by a screw having two successive parts with reverse pitch, as can be seen in FIG. 2.

In this way, the hot mixes brought to the rear of the chassis by the conveyor 12 are evacuated so as to be supported by the screw 16 which ensures the spreading of these mixes along the entire width of the road surface to be coated. and following a layer of constant thickness.

A bituminous emulsion spreading ramp 18 comprising two ramp elements 18a and 18b movable in the transverse direction relative to each other is arranged immediately in front of the spreading device 16 for hot mixes.

When the finisher is in operation on the site, the ramp elements 18a and 18b comprising spray nozzles distributed along their length are supplied with bituminous emulsion from the storage tank 13.

The distance between the ramp 18 and the spreading device 16, along the length of the chassis is small, this length can be of the order of 400 to 500 mm. In all cases, this length is less than 1 meter.

In addition, the ramp 18 is located entirely behind the tracks 4 for moving the paver 1, so that these tracks 4 are not likely to pass over the layer of bituminous emulsion freshly spread on the road surface, during the finisher operation 1.

The ramp elements 18 a and 18b are arranged below a protective cover 19 fixed to the chassis 7, below the rear part of the bar conveyor 12 and comprising extensions which follow the ramp in its lateral extension .

The relative arrangement of the bituminous emulsion spreading ramp 18, the hot mix spreading device 16 and the compacting and smoothing table 17 makes it possible to carry out successively and with very short time intervals between the various operations. spreading the bituminous emulsion, spreading the hot mixes and compacting and smoothing the coating constituted by the hot mixes spread on the bituminous emulsion layer.

The general structure of the finisher shown in FIG. 1 makes it possible to limit the total length of the machine, by virtue of an arrangement in height and vertically above the bar conveyor, of elements such as the emulsion tank 13, the heat engine 5 and the transmission device 6.

The cockpit 20 is arranged at the top of the finisher, so as to improve the visibility conditions of the driver 21 ensuring the control of the machine.

In the transport position, the upper part of the driving position can be folded down, so as to limit the height of the finisher.

In FIG. 2, we can see the rear part of the paver 1 comprising the compacting and smoothing table 17, the distribution and spreading screw 16 for the hot mixes and the elements 18a and 18b of the ramp 18.

The finishing table 17 comprises a central element or base table 17a and two lateral elements 17b and 17c constituting lateral extensions of the base table 17a making it possible to vary the working width of the finisher.

The base table 17a has lateral fittings 21 and 21 ′ which make it possible to suspend the finishing table from the end parts 15a of the suspension arms 15 of the finisher.

The central base table 17a and the extendable side tables 17b and 17c comprise, in known manner, eccentric vibration devices, reciprocating tamping devices and heating means making it possible to compact and smooth the bituminous mixes. spread over the road surface.

Each of the fittings 21, 21 ′ carries telescopic columns such as 22a and 22b having a movable part slidably mounted in a fixed part integral with the corresponding fitting 21 or 21 ′ which is connected at its end to a fitting 23b (or 23c) constituting the end side wall of one of the extendable tables 17b and 17c.

The fittings 21 and 21 ′ secured to the base central table are fixed on arms 24b and 24c, themselves connected to the frame of the finisher by the cylinders 11 (Figure 1) for adjusting the incidence and the like to the arms 15 (Figure 1).

The extension of the finishing table 17 is carried out by the cylinder rods 25 and 25 ′.

The side doors 28b and 28c integral with the table 17 each drive an element of the ramp 18a or 18b to adjust the spreading width identical to that of the mixes.

The spreading screw 16 comprises two successive parts with reverse pitch 16a and 16b ensuring the distribution and spreading of the hot mixes over the entire width of the base central table 17a, as can be seen in particular in FIG. 3.

In FIG. 3, the finishing table 17 has been shown in its position of maximum extension, the lateral extensions 17b and 17c being in the extension of the central table 17a. In addition, extensions 26b and 26c have been placed in the extension of the extensions 17b and 17c respectively, towards the outside.

Corresponding extensions 27b and 27c of the screw 16 having reverse pitches make it possible to spread the hot mixes over the maximum total working width of the finishing table.

As can be seen in FIGS. 2 and 3, the ramp elements 18a and 18b constituting the extendable ramp 18 fixed respectively at their ends to the side doors 28b and 28c in positions slightly offset in the longitudinal direction make it possible to adapt the width spreading the bituminous emulsion to the working width of the paver, which is adjusted by moving the doors 28b and 28c, as indicated above.

Each of the ramp elements 18a and 18b comprises nozzles 29a (or 29b) regularly distributed along the length of the corresponding ramp and placed at a distance from each other.

The ramp element 18a has, at its free end opposite to the support arm 24b, an extension 30 slightly offset in the longitudinal direction relative to the ramp element 18a and carrying a nozzle 31.

As can be seen in FIG. 2, when the paver is in an extension position below its maximum extension, part of the ramps 18a and 18b is placed opposite the central part of the working area finisher. All the nozzles of the boom 18a are then open; the nozzles of the ramp 18b, in position interference with those of the ramp 18a are closed.

The variable width zone 35 linked to the extension of the table is treated by the nozzle 31.

The nozzles 29a and 29b of the ramp elements 18a and 18b are flat jet nozzles having a defined diffusion angle.

The height of the ramps above the ground of the site is adjusted by hydraulic jacks so that the successive jets 33a and 33b intersect exactly at the ground of the site. In this way, each of the jets 33a and each of the jets 33b ensure the spreading of the bituminous emulsion over a strip of constant width, the different juxtaposed strips ensuring the formation of a homogeneous layer over the entire working width of the machine.

Each of the ramp elements 18a and 18b is supplied with bituminous emulsion by a positive displacement pump, from the bituminous emulsion tank 13 which is insulated and which is provided with a beam of temperature maintenance in which a heat transfer fluid circulates.

The ramp pressure and feed rate are adjusted, depending on the width and spreading speed of the paver, by a computer controlling and managing the main functions of the paver. Depending on the pressure information in the boom, its height is automatically adjusted by the on-board computer.

In addition, the computer provides control of the emulsion spreading ramps so that the amount of emulsion spread per unit area is constant, regardless of the speed of advancement of the device and the spreading width.

The flat jet nozzles 29a and 29b are equipped for their opening and closing with electropneumatic valves.

In order to obtain a perfectly homogeneous and regular layer over the entire working width, it is necessary to ensure the closing of certain flat jet nozzles when the two ramp elements come into covering position over part of their length, during finisher width settings, as shown in Figure 2.

As can be seen in FIG. 2, the nozzles 29b of the ramp element 18b located in the part of this ramp element 18b placed opposite the ramp element 18a are closed while the assembly nozzles 29a of the ramp element 18a are open so as to allow the formation of flat jets 33a juxtaposed over the entire length of the ramp 18a. The adjustment of the working width of the paver being continuous, the relative position of the ramp elements 18a and 18b can be arbitrary at any given time. There is therefore generally between the last throw flat 33′a situated at the end of the ramp 18a and the last flat jet 33b dispensed by the ramp element 18b, a longitudinal space 35 whose width can be between 0 and d , d being the length of the step, that is to say the longitudinal distance between any two nozzles of the ramp elements 18a and 18b.

In order to obtain a spreading of a completely homogeneous and regular layer of bituminous emulsion over the entire working width of the paver, it is necessary to ensure additional spreading and metering of bitumen in zone 35.

For this, use is made of the nozzle 31 located on the extension 30 placed at the end of the ramp element 18a, this extension 30 of the ramp element 18a being supplied with bituminous emulsion at the same pressure and at the same flow rate as the ramp 18a.

In Figure 4, there is shown in section and on a large scale the nozzle 31 disposed at the end of the ramp element 18a and used to ensure the spreading and metering of bitumen in the interface zone between the elements ramp 18a and 18b.

The nozzle 31 of cylindrical shape comprises a chamber 32 communicating with the extension 30 of the ramp element 18a, having a cross section of suitable shape; an adjustment cam 36 is rotatably mounted in the chamber 32, as indicated by the arrow 37.

The cam 36 is movable between a fully closed position of the chamber 32, this position corresponding to the outline in solid lines of the chamber 32 shown in FIG. 4 and an adjustable open position shown in broken lines.

The open position of the cam 36 which is adjusted and managed by the finisher's on-board computer, as a function of the relative position of the ramp 18a and 18b makes it possible to adjust the flow rate and the angle of diffusion of a flat jet 38 ensuring the spreading and the metering of the bituminous emulsion in the interface zone between the ramp elements 18a and 18b.

This adjustment of the cam 36 ensures spreading by the flat jet 38 of a layer of bituminous emulsion, along a strip of desired width, so as to ensure complete continuity of the layer of bituminous emulsion, according to all the working width, while the paver is moving.

In Figure 5, there is shown an alternative embodiment of the means for ensuring the continuity of the emulsion layer, in the interface zone between the ramp elements 18a and 18b.

According to this variant, a pneumatically controlled piston 40 is fixed to the end of the ramp element 18a so as to ensure the displacement of a flat jet nozzle 42 in the interface zone 35. The nozzle 42 is fixed at the end of a conduit 41 connected to the rod of the pneumatic cylinder 40 and supplied with bituminous emulsion via the ramp element 18a.

The nozzle 42 ensures the formation of a flat jet 43 along a plane perpendicular to the direction of the ramps 18a and 18b which corresponds to the direction of movement of the rod of the jack 40, of the conduit 41 and of the nozzle 42, as shown by the double arrow 44.

The pneumatic cylinder 40 ensures the displacement of the nozzle 42 in the zone 35 corresponding to the interface zone between the ramp elements 18a and 18b situated between the last jet 33′a of the ramp 18a and the last jet 33b of the ramp 18b.

The nozzle 42 is supplied with bituminous emulsion, via the conduit 41, intermittently, during the movement of the nozzle 42 in one way or the other, as shown by the double arrow 44.

The intermittent supply of the nozzle 42 makes it possible to produce strip by strip, in the interface zone 35, a layer of bituminous emulsion which is perfectly continuous and perfectly homogeneous with respect to the layers spread by the nozzles 29a and 29b of the ramp elements 18a and 18b respectively.

The displacement of the nozzle 42 by virtue of the pneumatic jack 40 and the command to open and close the nozzle 42 at determined times making it possible to define successive spreading phases separated by phases where the nozzle 42 is not in use , are provided by the finisher's on-board computer, depending on the relative position of the ramp elements 18a and 18b.

In FIG. 3, the ramp 18 for spreading bituminous emulsion has been shown in its position of maximum extension, the ramp elements 18a and 18b then not having opposite zones.

The device according to the invention constituting a paver for road surfacing with an integrated ramp could be produced so that it has dimensions and characteristics making it possible to facilitate its conditions of transport from one site to another and its conditions of use. on a road or motorway site.

The paver has a width of 2.50 m, an overall length of 6.90 m and a height, when transferred, of 3 m.

The capacity of the hot asphalt receiving hopper 8 is 6.5 m ³ and the capacity of the emulsion reserve is 3000 liters.

The finishing table with which the emulsion spreading ramps and the screws are associated spreading hot mixes allows to obtain a continuously variable working width between 2.50 m and 4.80 m. The use of extensions, as shown in Figure 3, allows to obtain a working width varying continuously between 3.70 and 6 meters.

In all cases, the bituminous emulsion layer spread over the road surface to be coated is perfectly homogeneous and the hot mixes are spread over this bituminous emulsion layer as soon as it is spread over the road surface, so that it no deterioration of the bituminous emulsion layer can be caused by an external agent.

All of the operations are managed by the on-board computer, as a function of input data relating to the characteristics of the bonding layer and of the coating layer for which the spreading and the finishing are ensured.

The device according to the invention therefore makes it possible to obtain a bonding layer and a coating layer of perfect quality and the operation of the machine is reduced to simple visual piloting operations which are facilitated by the position of the station. to the upper part of the finisher.

The invention is not limited to the embodiments which have been described.

This is how an emulsion spreading ramp can be used, the movable elements of which are mounted on the finisher in a manner different from that which has been described and, for example, entirely independent of the finishing table.

The spreading ramp can be produced in a form different from that which has been described and equipped with different nozzles from flat jet nozzles.

Likewise, the means for metering and spreading bituminous emulsion in the interface zone of the ramp can be produced in a form different from the two embodiments which have been described.

In all cases, however, the emulsion spreading ramp must be placed immediately in front of the hot mix spreading device, which can be made in a different form from a screw comprising two parts with opposite pitch.

Generally, the spreading of emulsion is carried out in an area located a few centimeters from the area where the hot mixes are spread.

In order to keep the advantages of the device according to the invention with regard to its longitudinal dimensions and the quality of production of the coating, the distance between the spreading ramp and the device for spreading hot mixes, in the longitudinal direction, should not exceed one meter.

The feed speed of the paver in operation on the road construction site can generally be adjusted to a value between 0 and 30 m / min.

Finally, the device according to the invention can be used for the production of any road surface consisting of bituminous products incorporating a granular material used hot and spread over a bonding layer consisting of a liquid bituminous product.

Claims (13)

1.- Device for producing a road surface by successive spreading on the road surface (2) to be covered, with a bonding layer consisting of a liquid bituminous product, such as a bitumen emulsion, and a layer of hot bituminous material incorporating aggregates such as a mix, constituted by a mobile motorized assembly (1) comprising, from front to rear in its direction of movement on the road surface, a receiving means (8) of the granular bituminous material, a device (12) for transferring the granular bituminous material towards the rear of the mobile assembly (1), a device (16) for spreading the granular bituminous material and a compacting and smoothing table (17 ) of the layer of granular bituminous material as well as a spreading ramp (18) of bituminous product extending in the transverse direction, supplied by a reservoir (13) of sufficient capacity containing a liquid such as an emuls ion, characterized in that the extendable spreading ramp (18) consisting of two ramp elements (18a, 18b) with relative movement in the transverse direction is arranged, at the rear part of the mobile assembly (1), in front the bituminous product spreading device (16), with a spacing of less than one meter relative to the spreading device (16), and that it comprises a complementary means (30, 31, 40, 41, 42) for spreading and for metering bituminous liquid in the interface zone (35) between the two ramp elements (18a, 18b) in order to allow continuous adjustment of the working width. 2. - Device according to claim 1, characterized in that each of the elements (18a, 18b) of the extendable ramp (18) is fixed to a side door (28b, 28c) integral with an extension table lateral (17b, 17c) of the compacting and finishing table (17) and that the lateral extension can be carried out continuously. 3.- Device according to any one of claims 1 and 2, characterized in that each of the ramp elements (18a, 18b) comprises a plurality of spreading nozzles (29a, 29b) with flat jet distributed along the length of the ramp elements (18a, 18b) with constant spacing ( d ). 4.- Device according to claim 3, characterized in that each of the flat jet nozzles (29a, 29b) comprises an opening and closing means pneumatically controlled. 5.- Device according to any one of claims 1 to 4, characterized in that the additional means for spreading and metering bituminous liquid in the interface zone (35) between the two ramp elements (18a, 18b ) is constituted by a conduit (30) connected to the end of one of the ramp elements (18a, 18b) directed towards the interior of the paver, on which is placed a spreading nozzle (31) comprising a chamber (32 ) communicating with the duct (30), in which is rotatably mounted a cam (36) for adjusting the flow rate and the angle of dispersion of the jet of bituminous liquid (38) leaving the chamber (32) of the nozzle (31). 6.- Device according to any one of claims 1 to 4, characterized in that the additional means for spreading and metering bituminous liquid in the interface zone (35) between the two ramp elements (18a, 18b ) is constituted by a jack (40) fixed to the end of one of the ramp elements (18a, 18b) directed towards the interior of the finisher, by a conduit (41) communicating with the corresponding ramp element ( 18a, 18b) for its liquid supply bituminous and fixed on the cylinder rod (40) and by a nozzle (42) fixed on the duct (41) and supplied with bituminous liquid by this duct (41), the nozzle (42) being a flat jet nozzle (43 ) directed along a plane perpendicular to the longitudinal direction of the ramp elements (18a, 18b) and to the direction of movement (44) of the cylinder rod (40) making it possible to move the nozzle (42) in the interface zone (35) between the two ramp elements (18a, 18b). 7.- Device according to claim 6, characterized in that the nozzle (42) comprises an opening and closing means allowing the constitution or the intermittent interruption of the flat jet (43), during movements of the nozzle (42) in the interface area (35). 8.- Device according to any one of claims 5, 6 and 7, characterized in that the additional means for spreading and metering bituminous liquid (30, 31, 40, 41, 42) is connected, for its control , depending on the relative arrangement of the ramp elements (18a, 18b), to a control computer of the device. 9.- Device according to any one of claims 1 to 8, characterized in that the device (16) for spreading granular bituminous material is constituted by a screw comprising at least two parts (16a, 16b) having reverse pitch . 10.- Device according to any one of claims 1 to 9, characterized in that the bituminous liquid reservoir (13) ensuring the supply of the ramp (18) is placed in a vertical position, above the device bituminous material transfer (12), at the rear of the bituminous material receiving means (8). 11.- Device according to any one of claims 1 to 10, characterized in that the spreading ramp (18) is disposed at the rear of displacement means (4) of the mobile assembly on the road surface ( 2), below the rear part of the bituminous material transfer device (12). 12.- Device according to any one of claims 1 to 11, characterized in that it comprises means for adjusting the flow rate of the ramp (18) making it possible to keep constant the quantity of liquid bituminous product spread per unit area , whatever the speed of advancement of the device and the width of the spread. 13.- Device according to any one of claims 1 to 12, characterized in that it comprises automatic means for adjusting the height of the spreading ramp (18) above the road surface (2) allowing to maintain constant the thickness of the bonding layer over the entire working width regardless of the ramp supply pressure.

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