EP0081194B1 - Bituminous pavement repair method - Google Patents

Abstract

1. A process of servicing a bituminous roadway coating layer - during a substantially continuous advance of a machine required for the performance thereof - the coating layer is heated, hoed to form a break-up material and, subsequently, new material is supplied, by dropping, to the break-up material left on the subgrade, levelled anlong with the break-up material and then compressed again, characterized in that the break-up material (21) heated to a mixed temperature and hoed by means of break-up tools (4), by a variety of mixing tools (5) reciprocating transverse of the feeding direction across the servicing width or rigidly disposed in the said area and ejecting in a mixing plane formed approximately in parallel to the subgrade and conveying material one into the other, will mix - in a uniformly mixed condition - binder (23) to be supplemented and applied within the mixing area swept by the mixing tools (5), and/or additives (24) of a predetermined grain size into the mixture in the mixing plane, and that, at the same time, the installed plank (11) - caused by the advance of the machine - moves toward the newly mixed material (25) available in an almost uniform layer thickness.

Description

The invention relates to a method for repairing a bituminous road surface layer, in which - during a substantially continuous feed of a machine required for its exercise - the surface layer heats, loosens it to a demolition material, then occasionally new pavement material is fed to the demolition material remaining on the subgrade, this is leveled together with the opening and compacted again, as well as a suitable device for carrying out the method.

The process is thus clearly characterized as a so-called “recycling-in-place process”.

Such a method is identified by DE-A-27 57 944.

The object of this method is to ensure a reduction in the expenditure on mechanical engineering for sufficient heating of the roadway.

The solution provides that the surface layer of the roadway is first preheated to a comparatively large distance in front of the tear point to just below the processing temperature and then heated to the final processing temperature directly in front of the tear point, and that, according to claim 3, behind the tear point, before Distribution and installation of the demolition material, this new ceiling material is fed.

No information is given on the mixing of this new ceiling material with the demolition material, so that a uniform mixture of the two components cannot be guaranteed.

Furthermore, various recycling processes are described in the magazine “Bitumen”, issue 6/1979, pages 173 and 174.

Section 4.3 relates to the process protected by the applicant according to German patent 25 54 710. This process provides that the existing cover layer is first re-profiled after the break-up and immediately afterwards a layer of additional mix is applied hot and together with the newly profiled old top layer is compacted in one operation, without prior mixing of break-up and new goods.

When proceeding according to section 4.4 of this article, the break-up is recorded and mixed together with additional mix.

The process cannot therefore be described as a “recycling-in-place process”, but is ultimately a process that has to be addressed primarily as a “recycling-in-plant process”.

German Patent 24 46 579 indicates a procedure similar to the procedure in accordance with section 4.4 of the magazine drawn.

Binder is added to the break-up to be recorded in a separate mobile drum dryer, whereby the drum dryer described would be called a drum mixer according to today's terminology.

Regarding DE-A-26 55 984, it should be noted that the procedure outlined here includes a method for refreshing an asphalt road surface, for example in the sense of introductory description of the object of the application, and additionally sees the mixture of the loosened surface material with liquid asphalt and / or refreshment - or rejuvenating agent, the resulting mixture being applied to the street bed.

First of all, it should be noted that the wording gives rise to misunderstandings and ambiguities, since asphalt is a mixture according to German or European terminology, which in some cases can have a liquid character - poured asphalt, mastic and at least also low-void asphalt fine concrete - but not liquid got to.

The term “freshener” is also not common here, although it can be assumed that it is low-boiling hydrocarbons that can reduce the penetration of the binder content or additives to improve the adhesive strength.

According to FIGS. 1 and 2 of the example, mixed material is additionally added in the direction of arrow 38, this addition basically speaking against the aim stated in this document, namely to be able to do without such a task in many cases (cf. page 5, last paragraph).

The mixing performance of the mixing screws shown in FIG. 2 is to be viewed critically. With the arrangement specified here, basically only a revolutionary transverse transport takes place, but not a real mixture, since a reversal of the transverse transport only takes place with advancing feed.

So it is practically only distributed and not mixed.

This document does not indicate any special training of the mixing screws.

In another embodiment according to FIG. 12 and the subsequent figures, the material to be broken is conveyed towards the center by two coaxially directed screws, so that the sprayers arranged behind in the direction of feed spray into a well-free space. The break-up led to the center is additionally fed fresh mix by a belt conveyor and the mix is "mixed" by a single-shaft mixer, which is essentially axially discharged in both directions and has paddle blades, and then later by subsequent screws, which are also coaxially assigned to each other Screed to be spread over the pave width.

In this case, it should be pointed out that there is no intensive mixing effect.

Especially when completing the departure Good things from an asphalt mix have the additional task that the asphalt mixture has to be "emaciated" with regard to its binder content and mortar content for a particularly long time by mixing with the demolition in order to be able to convert this material together with the demolition material into a uniform mixture.

A mere mixing between the two types of material practically leads exclusively to the stratified stratification of the different mixes, but not to an at least quasi-homogeneous mix.

Starting from this prior art, it is the task of this invention to name a method of the type described at the outset which, with minimal effort, enables the broken-up material to be evenly supplemented by additional material to a covering material largely corresponding to the original quality with the least thermal effort.

According to the invention, it is provided that the break-up material, heated to the mixing temperature and loosened by means of loosening tools, consists of several mixing tools that eject, intermeshing, and are arranged in a mixing plane that is roughly parallel to the formation, moving back and forth across the repair width or rigidly in this area uniformly mixed, in the mixture in the mixing plane within the mixing area captured by the mixing tools, to be added binder and / or aggregates of predetermined grain size, and that at the same time the screed - due to the feed of the machine - towards the newly mixed, in almost uniform layer thickness present good, moved.

Before the advantages according to the invention are discussed in detail, it should be emphasized in advance that this recycling-in-place process avoids the preparation of additional mixes in a mixing system to be provided externally to the construction site area and the separate transport of the mixes to the installation site.

Likewise, there is no longer any need for the continuous or semi-continuous carrying of a separate processing system - usually a drum mixing system - or the arrangement of a separate recording mixer in the repair unit, i.e. in the machine, whereby this receiving mixer must be provided with additional receiving and discharge devices.

The loosened demolition material heated up to the mixing temperature by the plastification is uniformly mixed by the intermixing mixing tools which eject parallel to the formation, whereby the demolition material forming a mixing plane is repeatedly exchanged in the surface of this plane pointing upwards parallel to the formation, so that a large surface presentation of the granular breakout material for the absorption or mixing of the additional components of the binder and / or the additives.

This leads to a newly prepared, practically homogeneously mixed ceiling mix that is compacted by the screed in conjunction with the machine feed in a uniform layer thickness.

The binder is also added at the usual mixing temperature, while it can be decided with the additives, depending on the amount to be added, whether they should be heated additionally.

Normally, in view of the wide temperature range of the possible incorporation and the high heat content of replastifizierten good a previous heating of the aggregates is not necessary, taking into refer in this context that without damaging the departure Good also its temperature _- turerhöhung by 15 to 20 ° C is possible.

In order to further develop the method, it should be noted that the addition of the binder takes place in the part of the mixing area immediately following the loosening tools — in some cases at several points — to the batch.

The choice of the application area enables the binder to be mixed in evenly over the entire depth of the mixing area defined by the arrangement and design of the mixing tools.

Regardless of this, it is provided that the addition of the binding agent follows the movement of these mixing tools in the case of reciprocating mixing tools or, in the case of rigidly arranged mixing tools, takes place in a reciprocating manner across the mixing region.

A device which is expedient for carrying out the method provides that the mixing tools arranged in the machine are provided with star-shaped mixing arms which are arranged parallel to the formation.

Such a design, which provides for a uniform radial ejection of the material starting from a center, supports the interlocking effect of the mixing tools and the uniform multiplication of the material.

Furthermore, it has proven to be expedient that the depth setting of the mixing tools is controlled by the depth setting of the loosening tools, so that there is a uniform distance between the level of the base of the break and the mixing tools.

In order to achieve a further comparison of the quality of the template, it is provided that the screed connected to the machine is assigned a cross-distributor, which is reciprocally moved and reciprocally moved, on the feed side.

Overall, the method and its device required for exercising fully meet the requirements of the task.

• Figur 1 zeigt im Aufriss die Strasseninstandsetzungseinrichtung, d.h. die Maschine.
• Figur 2 zeigt einen partiellen Grundriss der Maschine mit Auflockerungs- und Mischwerkzeugen, dem Querverteiler und der Einbaubohlen.

The method according to the invention is carried out by the attached schematic drawing of an example of a practical machine for practicing the method explained.

• FIG. 1 shows the road repair device, ie the machine, in elevation.
• Figure 2 shows a partial floor plan of the machine with loosening and mixing tools, the cross distributor and the screeds.

The two arrows assigned to FIGS. 1 and 2 indicate the feed or working direction.

The machine for repair is based on a partially modified paver in its basic device 1, with the use of a wheel paver being provided in the case of this example.

Of course, a tracked paver is also suitable as the basic device in the same way.

A front carriage 3 ′ carrying the gas tank 3 is connected to the device front pointing in the feed direction.

The gas tank 3 is used to supply energy to the multipart replastification device 2 which is articulated to the front end 3 '.

The basic device 1 is further assigned the binder tank 6 with the binder metering 7 and the binder feed device 8 and the leveling bars 12 are articulated.

The supports of the loosening tools 4 and the movable mixing device 5 are arranged under the leveling bars 12. Furthermore, a rake-shaped transverse distributor 10 and the screed 11 are provided on the leveling beam 12.

The movable mixing device 5 is connected to the feed device 8 for the hot liquid binder 23. In addition, a feed chute 9 opens into the space laterally delimited by the formation downwards and the two leveling beams 12 for occasionally required absorption of the mineral additives 24, which supplement the batch 22 in accordance with the prescribed recipe.

• Die Deckschicht 20 wird durch das Replastifiziergerät 2 auf die erforderlichen Temperatur - die im allgemeinen zwischen 170 und 190° liegt - in der erforderlichen Tiefe durchgehend erwärmt.

To summarize the process sequence:

• The cover layer 20 is continuously heated to the required temperature - which is generally between 170 and 190 ° - at the required depth by the replastification device 2.

In the interest of avoiding surface cracking of the binder in the top layer, the heat is applied in a graded setting.

As the device advances, the loosening tools 4 penetrate the cover layer 20 at a preset depth, lift it off and convert it into agglomerates of different sizes into the break-up material 21.

The mixing tools 5 even out the distribution of the agglomerates of different sizes over the repair width and thus convert the breakup material 21 into a uniform batch 22.

The binding agent 23, which is to be supplemented according to the recipe, and the mineral additives in the required amount are added to the mixture 22 and further processed by the mixing tools to a quasi-homogeneous mixture, which is a new mixture in a layer of almost uniform thickness on the subgrade distributed.

This layer is further evened out by the cross distributor 10, which is supplemented in the manner of a computation, and then passes under the screed 11 (vibrating screed).

The further treatment of the new top layer 26 pre-compacted in this way is carried out in the usual way.

Claims (6)

1. A process of servicing a bituminous roadway coating layer - during a substantially continuous advance of a machine required for the performance thereof - the coating layer is heated, hoed to form a break-up material and, subsequently, new material is supplied, by dropping, to the break-up material left on the subgrade, levelled anlong with the break-up material and then compressed again, characterized in that the break-up material (21 ) heated to a mixed temperature and hoed by means of break-up tools (4), by a variety of mixing tools (5) reciprocating transverse of the feeding direction across the servicing width or rigidly disposed in the said area and ejecting in a mixing plane formed approximately in parallel to the subgrade and conveying material one into the other, will mix - in a uniformly mixed condition - binder (23) to be supplemented and applied within the mixing area swept by the mixing tools (5), and/or additives (24) of a predetermined grain size into the mixture in the mixing plane, and that, at the same time, the installed plank (11)- caused by the advance of the machine - moves toward the newly mixed material (25) available in an almost uniform layer thickness.

2. Process of servicing a bituminous roadway coating layer according to claim 1, characterized in that the addition of binder (23), in the part of the mixing area directly following the break-up tools (4), to the mixture is effected by dropping at several points.

3. A process of servicing a bituminous roadway coating layer according to claims 1 or 2, characterized in that the addition of binder (23), with reciprocating mixing tools (5), follows the movement of the said mixing tools (5) and, with rigidly disposed mixing tools, is rigidly effected in a manner reciprocating across the mixing area.

4. An apparatus for carrying into effect the process according to claims 1 to 3, characterized in that the mixing tools (5) disposed in the machine are provided with radially distributed mixing arms disposed in parallel to the subgrade.

5. An apparatus for carrying into effect the process according to claims 1 to 4, characterized in that the depth adjustment of the mixing tools (5) are controlled by the depth adjustment of the break-up tools (4).

6. An apparatus for carrying into effect the process of claim 1, characterized in that associated to the inlet side of the integrated plank (11) connected to the machine is a transverse distributor (10) reciprocating transverse of the feeder menas and supplementarily formed as a rake.

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