JPH11181716A - Spraying method of bituminous material on asphalt pavement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spraying method of bituminous material on an asphalt pavement capable of minimizing a storage tank of the bituminous material loaded on an asphalt finisher, miniaturizing a device, preventing a harmful influence in quality even when pavement is carried out immediately after spraying the bituminous material and providing large adhesive strength at low cost. SOLUTION: A first stage to spray bituminous material made of foamed asphalt foamed by adding a small amount of water in heating straight asphalt is furnished on a part N except for a part M where a travelling device of a dump truck 10 to supply asphalt mixture and a travelling device of an asphalt finisher 20 pass by a bituminous material spraying machine 11 provided on the dump truck 10 to supply the asphalt mixture. It is constituted of the first stage and a second stage to spray the bituminous material only on the part M immediately after the travelling device 28 of the asphalt finisher 20 and excluded by the first stage by a bituminous material spraying machine 27 provided on the asphalt finisher 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for spraying a bituminous agent for improving the adhesion to a lower layer when asphalt pavement is performed.

[0002]

2. Description of the Related Art Asphalt pavement is usually composed of a base layer B and a surface layer S of an asphalt mixture on a roadbed R such as crushed stone, as shown in FIG. The bituminous emulsions N-1 and N-2 are sprayed to improve the adhesion with the lower layer.

This emulsion is prepared by diluting the straight asphalt with a viscosity of about 2 times and emulsifying it with water so that it can be sprayed at room temperature. The asphalt distributor 2 mounted on a truck 1 shown in FIG. Sprayed.
In FIG. 5, 3 is an emulsion tank, 4 is a spray bar, D
Indicates a road surface.

[0004] After the emulsion is sprayed, it takes one hour until the water content evaporates.
After cultivation for about a day, the asphalt mixture is spread on the asphalt finisher, leveled, and rolled with a road roller or the like to be paved.

[0005]

However, the prior art has the following problems.

(1) When the asphalt mixture is spread and spread with an asphalt finisher after the emulsion has been sprayed, the dump truck that supplies the mixture to the finisher runs on the emulsion, and the wheel of the truck peels off the emulsion.

Further, since the asphalt finisher itself travels on the emulsion, the emulsion is peeled off by a traveling wheel or the like, and as a result, the portion becomes a pavement where the emulsion is not scattered and adhesion is poor.

Further, the emulsion adhered to the wheels of the dump truck adheres to the road surface other than the construction area and becomes dirty.

(2) When the drainage mixture having a high porosity as shown in FIG. 7 is spread over the surface layer, the contact with the lower layer becomes point contact with the crushed stone, so that the contact area is greatly reduced, and the adhesive strength is reduced. Is insufficient, and the material on the surface may be peeled off. For this reason, in the case of the drainage pavement S-1, a special material having a large bonding force of the emulsion must be used, which increases the cost.

[0010] In order to solve the above-mentioned disadvantage (1), a construction method according to Japanese Patent Publication No. 2541874 has been proposed.
In this construction method, an emulsion spraying device is mounted on an asphalt finisher, and the emulsion is sprayed immediately before the asphalt mixture is spread, which is an effective method practiced in Europe.

However, in order to carry out this method, it is necessary to mount an emulsion spraying device on the asphalt finisher. Particularly, as described above, about half of bituminous emulsion is water for dilution, so that a tank capable of storing a large amount is used. Is necessary, and the device itself becomes large.

Further, as described above, unless the bitumen emulsion is cultivated after spraying to evaporate the water content, voids are formed in the pavement mixture due to steam, which is considered to be unfavorable in quality. This is a fatal defect, especially on pavements intended for water shielding.

The present invention solves the above-mentioned conventional problems,
The storage tank of bituminous agent to be mounted on the asphalt finisher can be reduced, and the size of the device can be reduced.
Another object of the present invention is to provide a method for dispersing bitumen, which has no adverse effect on the quality even if asphalt is paved immediately after dispersing the bitumen, and can obtain a large adhesive strength at low cost.

[0014]

According to the present invention, in a method for dispersing bitumen on asphalt pavement, a traveling device of a dump truck for supplying an asphalt mixture and a traveling device of an asphalt finisher are supplied by a bitumen disperser. A first step in which a small amount of water is added to the heated straight asphalt to a portion excluding the passing portion, and a bitumen consisting of foamed foam door asphalt is sprayed, and a first step immediately after the asphalt finisher traveling device. A second step of spraying the bituminous agent only on the portions removed in the step.

[0015] The bitumen sprayer is mounted on an improved sprayer and asphalt finisher, which is an ordinary asphalt emulsion sprayer.

Since the bitumen to be sprayed with the asphalt finisher only needs to be in the area where the wheels pass, the capacity of the tank for storing the bitumen can be small, and further, the bitumen is converted to foamed asphalt to form an asphalt emulsion. Approximately half the volume of the storage tank, further reducing the size of the storage tank.

Further, by using foam door asphalt as an adhesive, since the water content is very small, even if paving is performed immediately after spraying, there is no adverse effect on the quality and the construction period can be shortened.

In addition, foam door asphalt has a higher adhesive strength than conventional emulsions, and can provide stronger adhesive strength than special emulsions which have particularly enhanced adhesive strength for drainage pavement.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
Has an asphalt tank 12, a water tank 13, and a spray bar 14.

First, as a first step, a bitumen sprayer 11 is used.
As a result, foam asphalt is sprayed on the road surface prior to asphalt pavement. At this time, the width and position of spraying are determined by the dump truck 10 that supplies the asphalt mixture.
And a certain distance, for example, 50 to 60 m, except for a portion M through which the traveling device of the asphalt finisher 20 described later passes. N indicates a scattered portion.

In FIG. 2, an asphalt finisher 20 includes a hopper 21, a bar feeder 22, a screw 2
3, a screed 24, an asphalt tank 25, a water tank 26, and a spray bar 27 are provided. The traveling device may be of a tire type.

The dump truck 10 has an undispersed portion M
And the asphalt mixture is supplied to the hopper 21 of the asphalt finisher 20, as shown in FIG.

The asphalt finisher 20 also travels on the unspread portion M, and sprays the foam door asphalt only on the unspread portion M on the road surface P by the spray bar 27 immediately after the traveling device 28 passes. This means that foam door asphalt has been spread over the entire surface of the pavement.

On the other hand, the asphalt mixture supplied to the hopper 21 is conveyed to the rear part of the vehicle body by the bar feeder 22, and is poured into the center of the screw 23 after the foam door asphalt has been sprayed on the entire surface and spread. Is laid flat with a screed 24 as in the case of the pavement.

Therefore, the portion where the foam door asphalt is sprayed by the spray bar 27 is immediately spread with the asphalt mixture. However, since the foam door asphalt contains only 1 to 2% of water, the pavement is Does not affect the quality of the.

Furthermore, in the case of a drainage mixture produced only from crushed stone without fine particles, as shown in FIG. 7, the contact area with the lower layer is greatly reduced, so that the adhesive strength becomes a problem. It was confirmed that when door asphalt was used, higher adhesive strength was obtained as compared with conventionally used emulsions.

FIG. 4 shows an example of the result of a comparison experiment of the adhesive strength between foam door asphalt and a conventional emulsion.

(1) is a rubber-containing emulsion used for ordinary drainage pavement, and (2) is a highly adherent emulsion improved for thin-layer drainage pavement. (3) is the case of foam door asphalt, and the active ingredient excluding water etc. is (2)
A comparative experiment (Kenken formula) was performed by adjusting the coating amount so as to be the same as the high adhesiveness of the sample.

From these results, it was confirmed that the foam door asphalt (3) had the highest adhesive strength and was not peeled off at the bonding surface but was broken inside the drainage pavement. Further, the application amount is only 70% of (2).

This foam door asphalt has a volume of 10% by adding water to heated straight asphalt by adding 1 to 2%.
It is foamed up to 15 times and has very good adhesion and is used as a roadbed material improver. This foam disappears in about 10 to 20 seconds and returns to the original straight asphalt. In this experiment, however, the drainage mixture was covered with the foam and bonded in accordance with the actual construction method. It is considered that this foam quickly permeates and adheres between the crushed stones of the mixture, thereby eliminating voids between the crushed stones and obtaining high adhesive strength. In other words, it has been found that such a mixture is more effective for a mixture having a large gap and insufficient adhesive force, such as a drainage mixture.

From the results of this experiment, it was proved that foam door asphalt is most effective as an adhesive and that it is also effective in terms of cost since a small amount of spray is required. Regarding the method and apparatus for producing foamed asphalt, the technique of Japanese Patent Application No. 8-261793 filed earlier by the present applicant can be used, and description thereof is omitted here.

When foamed asphalt is used, since the water content is extremely low as compared with the conventional asphalt emulsion as described above, no training time is required, and the whole surface is sprayed immediately before paving with an asphalt finisher. Is also possible.

[0033]

The present invention has the following excellent effects.

(1) In the second stage, the bitumen sprayed with the asphalt finisher is applied to the 50
Since only a range of ６０60 cm is required, the volume of the spraying device, especially the tank for storing bitumen, may be small. Further, by making the bitumen into foam door asphalt, about half the amount of the asphalt emulsion is required, and as a result, the capacity of the storage tank can be 15 to 20% and the size of the apparatus can be reduced.

(2) The use of foam door asphalt as an adhesive has a very small water content of 1 to 2%, so that there is no adverse effect on the quality even when paving immediately after spraying. That is, unlike the asphalt emulsion, no training time is required after spraying, and the construction period can be shortened.

(3) Foam door asphalt has a higher adhesive strength than conventional emulsions, and can provide even stronger adhesive strength than special emulsions which have particularly enhanced adhesive strength for drainage pavement.

With the above effects, it is possible to reduce the size of the bitumen sprayer, to shorten the construction period of pavement work and to improve the quality.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment in which a bitumen is sprayed by a bitumin sprayer.

FIG. 2 is a plan view showing a mode in which bitumen is sprayed by a bitumin sprayer provided in an asphalt finisher.

FIG. 3 is a side view showing knitting of the construction machine.

FIG. 4 is a table showing the results of a comparative experiment on the adhesive strength between foam door asphalt and a conventional emulsion.

FIG. 5 is a side view showing a mode of spraying a conventional bitumen using a truck.

FIG. 6 is a cross-sectional view of an asphalt pavement on which a bitumen has been sprayed.

FIG. 7 is a cross-sectional view of drainage pavement.

[Description of Signs] 10 ・ ・ ・ Dump truck 11 ・ ・ ・ Bitumin sprayer 12 ・ ・ ・ Asphalt tank 13 ・ ・ ・ Water tank 14 ・ ・ ・ Spray bar 20 ・ ・ ・ Asphalt finisher 21 ・ ・ ・ Hopper 22 ・..Bar feeder 23 ・ ・ ・ Screw 24 ・ ・ ・ Screed 25 ・ ・ ・ Asphalt tank 26 ・ ・ ・ Water tank 27 ・ ・ ・ Spray bar 28 ・ ・ ・ Crawler type traveling device N ・ ・ ・ Bitumen spraying part M: unsprayed part

Claims (1)

[Claims] 1. A small amount of water is added to heated straight asphalt by means of a bitumen spreader to a portion excluding a portion where a traveling device of a dump truck supplying an asphalt mixture and a traveling device of an asphalt finisher pass. A first step of spraying a bitumen consisting of shaped foam asphalt, and a second step of spraying the bitumen only on a portion of the asphalt finisher immediately after the traveling device and removed in the first step. Method of spraying bitumen on asphalt pavement.