WO2007145576A2

WO2007145576A2 - Method for providing an improved road surface, use of a grinding assembly for renovating a roadway, and a tool and method fur such renovation

Info

Publication number: WO2007145576A2
Application number: PCT/SE2007/000584
Authority: WO
Inventors: Håkan THYSELL
Original assignee: Htc Sweden Ab
Priority date: 2006-06-15
Filing date: 2007-06-14
Publication date: 2007-12-21
Also published as: WO2007145576A3; SE0601337L

Abstract

The present document discloses a method for providing an improved roadway (30). The method comprises forming a wearing coat (32) of the roadway (30) by treating the roadway with a grinding and/or cutting tool.

Description

METHOD FOR PROVIDING AN IMPROVED ROAD SURFACE, USE OF A

GRINDING ASSEMBLY FOR RENOVATING A ROADWAY, AND TOOL AND

METHOD FOR SUCH RENOVATION

Field of the Invention

The present description concerns in general improvement of a roadway, but also renovation of a roadway, in which ruts extending along the roadway have formed due to road wear.

Background Art

Road wear in the form of rutting occurs relatively quickly in roadways which are exposed to much traffic, especially if the traffic comprises heavy trucks and vehicles with studded tyres. The ruts tend to grow in an accelerating manner as soon as they have exceeded a depth of about 10 millimetres, since all vehicles travelling on a roadway that has been worn in this way tend to follow the ruts more or less slavishly. This means above all that the risk of aquaplaning on such worn roadways will soon be imminent. In view of that stated above, much of the current road maintenance involves renovation work intended to eliminate rutting. Various methods are used for this work, which however for economic, logistic or technical reasons are in most cases applied so late that when the renovating action is taken, the ruts are already a serious danger to traffic.

An economic reason that supports a late action is the high cost of permanent mending since such an action results in either re-surfacing of the whole roadway (possibly after preceding face milling) or groove cutting and refilling of the cut grooves with a new coating material. As a logistic reason, which also justifies a late renovating action, mention can be made of the relatively severe traffic disturbances that are caused by all surfacing operations due to their complexity and relative slowness. Finally, a technical reason for a late action can exist, for example, when it is desired to more or less provisionally fill up the formed ruts with oil gravel since such filling-up to make the oil gravel bind requires a considerable layer thickness or, in other words, a considerable groove depth.

Additional wishes as regards road surfaces involve providing a roadway which generates a reduced noise level, reduces wear on tyres and cars, reduces the amount of generated particles, reduces damage to snow clearing tools, results in reduced fuel consumption and is safer.

Thus a general object is to provide an improved roadway.

Further objects comprise enabling quick renovation of a roadway, in which ruts extending along the roadway have formed due to road wear, at a significantly lower cost than before.

Summary

The above objects are wholly or partly achieved by methods and devices according to the independent claims. Embodiments are defined in the dependent claims and in the following description and accompanying drawings.

According to a first aspect, a method for providing an improved roadway is provided. The method comprises forming a wearing coat of the roadway by treatment with a grinding and/or cutting tool. By "roadway" is here meant roads intended for driving of vehicles, such as trucks, cars, motorcycles, bicycles etc. Floors and base plates, on which certainly vehicles are driven, are not comprised by the term "roadway".

By "wearing coat" is meant the surface which is adapted, in normal use of the roadway, to be in contact with, for example, tyres of the vehicles travelling on the roadway. "Wearing coat" thus does not involve surfaces that arise due to the fact that the roadway is milled for the purpose of coating it with a new road surface.

The method is above all intended for road surfaces comprising some kind of binder. Such road surfaces may also comprise filling materials, such as sand, gravel or stone. The invention makes it possible to use filling materials comprising larger units, or stones, than in conventional road surfaces. In one embodiment, the roadway may comprise asphalt or a similar material.

Materials similar to asphalt relate above all to road surfaces with a binder in the form of a petroleum derivative. In another embodiment, the roadway may comprise concrete, or a similar material.

Materials similar to concrete include above all road surfaces with a binder in the form of cement or the like.

The roadway can be treated with a processing element containing grinding particles located in a matrix. Such processing elements are known from, for instance, EP1661666A1 and may comprise a plastic or metal matrix, containing grinding particles, for instance of diamond, silicon carbide, aluminium oxide etc.

Alternatively, treatment can take place with a processing element comprising a cutting edge facing the roadway surface. Such processing elements are known from, for instance, DE20120137U1 and SE525802. Specifically, combination grinding elements of the type disclosed in DE20120137U1 can be used.

In the method, the roadway can be processed with a grinding assembly, which has a planetary disc, which is arranged to rotate about a substantially vertical axis of rotation, and grinding heads mounted on the planetary disc, which are arranged to rotate about axes that are parallel to said axis of rotation.

The method may comprise renovation of a roadway, in which ruts extending along the roadway have formed due to road wear, by grinding down the surface of the roadway to a depth corresponding to at least said ruts.

The method may also comprise treatment of a roadway which has no, or very little, wear, to provide a more even wearing coat. The method may also comprise treatment of a roadway, whose condition is comparable to a newly-produced roadway, to provide a more even wearing coat. The above method of treatment can result in a very smooth roadway surface, which can be expected to reduce the level of the tyre noise that occurs as vehicles travel on the roadway by about 25%. Moreover, a lighter roadway can be provided by stones present in the roadway appearing more distinctly. Due to the reduced vibrations between tyre and roadway, a reduction of the particles that form in wear on the roadway is provided. This reduction of the vibrations is also advantageous from the view point of wear on tyres and vehicles.

Moreover, the risk of snow clearing vehicles being damaged, for instance the risk of the scraper cutting into the road surface, is reduced.

A smoother roadway surface also results in reduced fuel consumption since the rolling friction is reduced.

According to a second aspect, use of a grinding assembly is provided, which has a planetary disc, which is arranged to rotate about a substantially vertical axis of rotation, and grinding heads mounted on the planetary disc, which are arranged to rotate about axes that are parallel to said axis of rotation, for renovating a roadway, in which ruts extending along the roadway have formed due to road wear, by grinding down the surface of the roadway to a depth corresponding to at least said ruts. By using a per se known grinding assembly of a type that is normally used above all for grinding of concrete floors, it will be possible in an extremely quick, easy and cost-effective manner to completely eliminate ruts even at a very early stage when they have not yet developed into a real danger to traffic and become so deep that vehicles tend to follow them and thus in an accelerating manner make them deeper. In contrast to face milling which is known in the context and in which horizontally arranged rolls tear off parts of the road surface including stone material included in the same, there is formed, in spite of the very limited removal of material during grinding, a smooth surface which offers tyres rolling on it a large contact surface and, thus, a good grip. In addition, the grinding action effectively reduces tyre noise, which is positive from the environmental point of view and, since parts of stone material included in the road surface are uncovered (and thus not torn away), a ground roadway will in most cases be considerably lighter, which is highly important in terms of traffic safety.

According to yet another aspect, the object is achieved by a tool for renovating a roadway, in which ruts extending along the roadway have formed due to road wear, said tool being characterised in that it is adapted to be mounted on a road vehicle, and that it comprises at least two, preferably at least three, grinding assemblies, which are arranged in a manner overlappingly covering at least the width of the road vehicle and which each have a planetary disc, which is arranged to rotate about an axis of rotation which is substantially vertical to the roadway, and grinding heads mounted on the planetary disc, which are arranged to rotate about axes which are parallel to said axis of rotation.

It will be appreciated that such a tool makes it possible to achieve the advantages resulting from using a grinding assembly as stated above in an effective way, preferably covering an entire traffic lane. It will also be appreciated that this solution makes it possible for a person responsible for a road to use a road vehicle, such as a truck, which is probably already available for anti-skid treatment in the winter months.

Preferably, the grinding assemblies have hydraulic motors, which are arranged to be driven by a hydraulic pump on board the road vehicle. Also this solution thus advantageously comprises use of existing resources.

Preferably, the grinding assemblies have a suction socket, which, for sucking off grinding dust, is connectable to a suction assembly on board the vehicle. Such a solution is suitable since in grinding of the road very large amounts of grinding dust form, which must be taken care of in an effective manner, preferably using a large storage tank on board a platform of the road vehicle.

According to yet another aspect, a method for renovating a roadway is provided, in which ruts extending along the roadway have formed due to road wear, the method being characterised in that the roadway is levelled by at least one grinding assembly, which has a planetary disc, which is arranged to rotate about a substantially vertical axis of rotation, and grinding heads mounted on the planetary disc, which are arranged to rotate about axes which are parallel to said axis of rotation, by grinding down to a depth corresponding to at least said ruts.

The advantage of this method compared to prior art methods for renovating roadways is obvious in the light of that stated above, and the method can be used for road maintenance at close intervals and at a relatively low cost and, consequently, for significantly improved traffic safety.

Brief Description of the Drawings

An embodiment of a grinding assembly for use according to the present description, a tool and a method will be described in more detail in the following with reference to the accompanying schematic drawings, in which

Fig. 1 is a side view of the grinding assembly with three grinding heads; Fig. 2 is a bottom view of the grinding assembly; and

Fig. 3 is a front view of a road vehicle with a tool mounted on the same.

Description of Embodiments

In the drawings, the same reference numerals are used throughout in the figures to designate equivalent parts. For the sake of clarity, not all reference numerals are, however, repeated in all figures and, thus, for a complete description all figures must be taken into consideration.

The grinding assembly 1 can be of a type that is normally used for grinding of concrete floors. It comprises a body 2, a driving motor 3, a circular planetary disc 4, which is mounted in bearings in the body 2, and a number of, for instance three or four, grinding heads 5-7, which are mounted in bearings on the planetary disc 4 and have an underside with a grinding tool that will be described below. The planetary disc 4 is rotatable by means of the motor 2 clockwise in Fig. 2 about a central, substantially vertical axis of rotation r, and the grinding heads 5-7 are, relative to the planetary disc, rotatable counter-clockwise in Fig. 2 about substantially vertical planetary axes p1-p3, which are equidistantly spaced about said axis of rotation r. For power transmission between the driving motor 3 and the planetary disc 4 and the grinding heads 5-7, respectively, prior art technique is used, such as drive belts which are not to be seen in the views in Figs 1 and 3, since they are concealed by the body 2 in the form of a casing, and in Fig. 2 since they are concealed by the planetary disc 4.

Examples of grinding assemblies as stated above are disclosed, for instance, in Applicant's EP1358043A1 and EP0700327A1.

For the actual grinding, use is made of grinding tools, such as easily exchangeable grinding blocks 8, for example comprising diamond. Of the grinding blocks 8, a suitable number are in prior art manner mounted on the underside of the grinding heads 5-7, but for the sake of clarity only one is illustrated in the figures.

The driving motor 3 is usually electric in grinding assemblies that are used for floor grinding. When used for road grinding, such a solution can be considered to be less convenient since it would require access to a powerful, mobile high voltage generator. Therefore the driving motor 3 can in one embodiment be a hydraulic motor, which, as shown in Fig. 3, is connected by tubes 11 and a hydraulic output 12 to a hydraulic pump 13, which is frequently already available on road vehicles 14, such as the truck shown in Fig. 3.

In addition to said road vehicles 14, Fig. 3 illustrates a vehicle-mounted tool 10, which comprises three hydraulically operated grinding assemblies 1. The three grinding assemblies 1 are arranged at the front of the road vehicle 14 so that in an overlapping manner they fully cover the entire width w of the road vehicle 14, the central grinding assembly 1 being arranged slightly in front of the other two grinding assemblies 1.

The tool 10 comprises link arms 15, which in the form of parallel struts are articulated to vehicle mountings 16 and tool mountings 17 and, by associated hydraulic pistons 18, are vertically adjustable relative to the road vehicle 14 to allow transport and grinding respectively.

As is evident from Fig. 3 and in this the right grinding assembly 1 , the grinding assemblies 1 included in the tool 10 suitably comprise a suction socket 19, which is connected to the space under the body 2 in the form of a cover. The purpose of the suction socket 19 and corresponding suction sockets (not shown) on the other grinding assemblies 1 is to enable in prior art manner connection of a suction device (here symbolised by the arrow 20) for sucking away grinding dust. This is particularly important in connection with road grinding due to the large amount of grinding dust formed.

The above described grinding assembly 1 and the tool 10 are used, as is clearly evident from Fig. 3, to grind a roadway 30 in which ruts 31 have formed due to road wear. When the grinding action is applied, the ruts 31 suitably have a depth of only about a few or possibly ten millimetres and have thus not yet reached such a depth that the tendency to accelerated deepening as described by way of introduction has appeared. The grinding of the roadway 30 occurs down to a depth substantially corresponding to the depth of the ruts 31 and results in a very even roadway 30 with uncovered, ground-down stone material in the asphalt. The evenness of the roadway 30 results in good drainage, reduced noise of tyre and a maximum tyre contact surface, and the uncovered, ground-down stone material results in most cases in a considerably lighter roadway than before.

A person skilled in the art realises that the above described grinding assembly 1 , the tool 10 and the method can be varied in different ways within the scope of the claims. Thus, for instance the number of grinding heads 5-7 in the grinding assembly can be different, the number of grinding assemblies

1 included in the tool 10 can be different, and the tool 10 can instead be designed as a tool 10 mounted under or at the rear end of a road vehicle 14.

For the purpose of investigating the effect of the treatment method on the noise level of a newly-produced asphalt road, a newly coated road portion with a length of 30 m and a width of 2.5 m was tested, located in a fenced test area. Grinding of a portion of a roadway surface was performed by means of an HTC 950RX, which is sold by the applicant, provided with metal-bound diamond tools of the type HTC C3 grey, which are sold by the applicant. The grinding of the entire road portion took about 1 hour, and resulted in the tips of the stones appearing in the road surface being ground off so that a smoother surface was provided. In testing, two different cars were used, a BMW 730 and a Volvo XC90. For measurements, a sound level meter of the type B&K 2231 was used, which during measurements was mounted on a stand, at a distance of about 2.3 m from the roadway and 0.7 m above the roadway. The background noise was measured to be about 50 dBA. The speed of the cars during measuring was 50 km/h. The result is shown in Table 1 below. Table 1 : test results

As is evident from Table 1 , a ground roadway, in normal driving at 50 km/h, reaches on average a reduction of the noise level by about 4 dBA, and in driving with the engine disengaged, on average a reduction by about 2 dBA. Grinding of the roadway according to the present description could thus be expected to result in a reduction of the noise level by about 25%.

It will be appreciated that in practical application of the methods described here, the tool illustrated in Fig. 3 is used with optional equipment of cutting and/or grinding tools. Also other types of grinding and/or cutting tools can be used in the here described methods for improving and renovating roadways.

Claims

1. A method for providing an even wearing coat of a roadway (30), c h a r a c t e r i s e d by forming the wearing coat (32) of the roadway (30) by treating the roadway with a grinding and/or cutting tool.

2. A method as claimed in claim 1 , wherein the roadway is provided with a road surface comprising a binder.

3. A method as claimed in claim 1 , wherein the road surface comprises asphalt or a similar material.

4. A method as claimed in claim 2, wherein the road surface comprises concrete or a similar material.

5. A method as claimed in any one of the preceding claims, wherein the roadway (30) is treated with a processing element containing grinding particles located in a matrix.

6. A method as claimed in any one of the preceding claims, wherein the roadway (30) is processed with a grinding assembly (1), which has a planetary disc (4), which is arranged to rotate about a substantially vertical axis of rotation (r), and grinding heads (5-7) mounted on the planetary disc, which are arranged to rotate about axes (p1-p3) which are parallel to said axis of rotation (r).

7. A method as claimed in any one of the preceding claims, wherein the method comprises renovation of a roadway (30), in which ruts (31) extending along the roadway (30) have formed due to road wear, by grinding down the surface of the roadway (30) to a depth corresponding to at least said ruts (31).

8. A method as claimed in any one of the preceding claims, wherein the method comprises treatment of a roadway (30), which has no, or very little, wear, to provide a more even wearing coat (32).

9. A method as claimed in claim 8, wherein the method comprises treatment of a roadway, whose condition is comparable to a newly-produced roadway, to provide a more even wearing coat (32).

10. Use of a grinding assembly (1), which has a planetary disc (4), which is arranged to rotate about a substantially vertical axis of rotation (r), and grinding heads (5-7) mounted on the planetary disc, which are arranged to rotate about axes (p1-p3), which are parallel to said axis of rotation (r), for renovating a roadway (30), in which ruts (31) extending along the roadway (30) have formed due to road wear, by grinding down the surface of the roadway (30) to a depth corresponding to at least said ruts (31).

11. A tool (10) for renovating a roadway (30), in which ruts (31 ) extending along the roadway (30) have formed due to road wear, c h a r a c t e r i s e d in that the tool (10) is adapted to be mounted on a road vehicle (14), and that it comprises at least two grinding assemblies (1), which are arranged in a manner overlappingly covering at least the width (w) of the road vehicle (14) and which each have a planetary disc (4), which is arranged to rotate about an axis of rotation (r) which is substantially vertical to the roadway (30), and grinding heads (5-7) mounted on the planetary disc (4), which arranged to rotate about axes (p1-p3) which are parallel to said axis of rotation (r).

12. A tool (10) as claimed in claim 11 , in which the grinding assemblies (1) have hydraulic motors (3) which are arranged to be driven by a hydraulic pump (13) on board the road vehicle (14).

13. A tool (10) as claimed in claim 11 or 12, in which the grinding assemblies (1) have a suction socket (19), which, for sucking off grinding dust, is connectable to a suction assembly (20) on board the road vehicle (14).

14. A method for renovating a roadway (A), in which ruts (31) extending along the roadway (30) have formed due to road wear, c h a r a c t e r i s e d in that the roadway (30) is levelled by at least one grinding assembly (1), which has a planetary disc (4), which is arranged to rotate about a substantially vertical axis of rotation (r), and grinding heads (5-7) mounted on the planetary disc (4), which are arranged to rotate about axes (p1-p3) which are parallel to said axis of rotation (r), by grinding down to a depth corresponding to at least said ruts (31).