JPH06220330A - Asphalt binder for fluidity-resistant paving - Google Patents

Abstract

PURPOSE:To produce an asphalt binder excellent in fluidity resistance and the adhesiveness to aggregates, higher in heating stability compared to conventional modified asphalts, also easy to handle. CONSTITUTION:This binder can be obtained by incorporating 100 pts.wt. of a mixture of straight asphalt 40-100 in rate of penetration and blown asphalt 10-50 in rate of penetration with (B) 1.0-5.0 pts.wt. of an extract from the lubricating oil fraction of petroleum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asphalt binder used for asphalt pavement, which is the main pavement method for road pavement in Japan. More particularly, it relates to a flow-resistant pavement asphalt binder comprising a mixture of straight asphalt, blown asphalt and extract of a lubricating oil fraction of petroleum.

[0002]

2. Description of the Related Art Asphalt pavement is manufactured by mixing a mixture of crushed stone, sand, etc. having an appropriate particle size distribution with straight asphalt having a penetration of 60 to 100 as a binder in a heated state. The so-called asphalt mixture is spread and leveled, and it is rolled and rolled. However, in recent years, due to an increase in traffic volume, in particular, an increase in traffic volume of heavy vehicles, it is in a severe condition for use on an asphalt pavement. For this reason, rutting often occurs on the asphalt pavement road surface due to the flow of the mixture in the summer. Rutting of asphalt pavement not only makes the vehicle uncomfortable to ride, but also reduces the operability of the steering wheel, and water retention during rainfall in the rutting area causes slippage, which is a major traffic safety problem. ing. As a countermeasure against rutting, so-called modified asphalt obtained by adding a modifier such as rubber or thermoplastic resin to straight asphalt for road paving is increasingly used as a binder.

[0003]

As mentioned above, as a countermeasure against rutting in asphalt pavement, it is becoming common to use modified asphalt in which a modifier is mixed with asphalt, but as described below. There is a problem. Modified asphalt is roughly classified into a premix type and a plant mix type according to the method of use. As the name suggests, the premix type is a method in which straight asphalt and a modifier are mixed in advance to produce a modified asphalt before the aggregate and binder (modified asphalt) are mixed in an asphalt mix plant. And
Usually, it is stored and used in a heated state. In this type,
It is difficult to mix straight asphalt and modifier uniformly, and it is difficult to achieve the desired performance. Another drawback is that the modified material is likely to be deteriorated (thermally deteriorated) during storage. In the plant mix type, when an aggregate and a straight asphalt are mixed in an asphalt mixture plant, a modifier is also mixed at the same time. In this case, there is a problem that it is difficult to uniformly mix the modifier, and the performance as the modified asphalt is not exhibited. Further, a larger problem is that the use of rubber or a thermoplastic resin as a modifier increases the cost of asphalt as a binder.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an asphalt binder for fluid pavement for solving the above problems of modified asphalt. The asphalt binder for fluid paving according to the present invention is produced by mixing straight asphalt, blown asphalt, and an extract of a lubricating oil fraction of petroleum (hereinafter simply referred to as an extract). Blown asphalt has a higher viscosity and a lower penetration compared to general pavement straight asphalt. Therefore, if blown asphalt is mixed with pavement straight asphalt, the asphalt generally has a high viscosity and low needle penetration. Degrading,
It is inferred that the rutting resistance is improved.

However, since the blown asphalt has a low tackiness, if it is simply mixed with the straight asphalt, the adhesiveness to the aggregate is insufficient and the performance as a binder for asphalt pavement cannot be said to be sufficient. The inventors of the present invention have made the present invention as a result of earnestly examining improvement of this point. That is, when mixing blown asphalt with straight asphalt for the purpose of improving rutting resistance, the adhesiveness to the aggregate is improved by mixing 1 to 5 parts by weight of the extract with 100 parts by weight of the mixture of both. I found that I can do it.

The straight asphalt used in the present invention has a penetration of 40 or more and 100 or less. As for this, the penetration grade 40 specified in Japanese Industrial Standard (JIS standard) K22O7 is applicable.
-60, 60-80, 80-100 straight asphalt and the like. If the penetration of straight asphalt is less than 40, the adhesiveness of the asphalt binder obtained is insufficient, and if the penetration is more than 100, the rutting resistance is not improved.

The blown asphalt used in the present invention has a penetration of 10 or more and 50 or less. The blown asphalt may be produced by any production method, but the one produced by air blowing treatment using straight asphalt as a raw material and a catalyst such as polyphosphoric acid is particularly preferable because the brittleness at low temperature is improved. Further, if the penetration degree of blown asphalt is less than 10, the resulting asphalt binder has insufficient adhesion, and if the penetration degree exceeds 50, the effect of improving rutting resistance cannot be seen.

The extract used in the present invention is
For the purpose of producing a lubricating base oil, it means an extraction component obtained by subjecting a petroleum fraction to an extraction treatment with a solvent such as furfural, which has a selective solubility for aromatic compounds. The asphalt binder of the present invention is obtained by adding 1.0 to 5.0 parts by weight of extract to 100 parts by weight of a mixture of straight asphalt and blown asphalt. If the amount of the extract added is less than 1.0 part by weight, the effect of improving the adhesiveness is not obtained, and if it exceeds 5.0 parts by weight, the asphalt binder is softened and rutting resistance is reduced.

[0009]

【Example】

(Example 1) Penetration 70 (unit: 1/10 mm, measuring method is J
According to IS K2207. same as below. ) 50 parts by weight of straight asphalt and 50 parts by weight of blown asphalt having a penetration of 35 (manufactured by air blowing treatment using polyphosphoric acid as a catalyst) to 100 parts by weight of the extract (at 25 ° C.). A viscosity of 48 poise) 4.0 parts by weight was sufficiently mixed in a heat-melted state to obtain a uniform mixture (hereinafter referred to as binder A).

Using the binder A, a wheel tracking test, which is a flow resistance (rubbing resistance) test, was conducted on a dense-grained ascon (asphalt concrete) mixture having a crushed stone top of 13 mm. As a result, the dynamic stability (DS) was 3500 cycles / mm. The dynamic stability by the wheel tracking test is the number of times the wheel travels per 1mm of sinkage by reciprocally moving the test wheels on the Ascon test piece under prescribed load conditions and measuring the time variation of the wheel sinkage. Appears. Therefore, it is generally considered that the larger this value is, the higher the flow resistance is.

Further, in order to examine the adhesiveness of the binder A to the aggregate, a peel resistance test was conducted according to the Japan Petroleum Institute Test Method J.
It carried out according to PI-5S-27 "Peeling resistance test method of coarse aggregate". That is, a specified amount of binder and fully dried aggregate (grain size 9.5 to 13 mm) are mixed at a predetermined temperature,
Twenty grains of the aggregate were collected on a glass plate, left for 30 minutes in high-temperature water at 80 ° C., and the peeled state of asphalt was visually observed. As a result, the peeled area ratio was 0% (pattern number I).

Comparative Example 1 For comparison, a wheel tracking test was conducted under the same conditions as in Example 1 using the straight asphalt as a binder. The dynamic stability in this case was 800 times / mm, which was the result of inferior flow resistance as compared with Example 1.

(Comparative Example 2) A mixture test of 50 parts by weight of straight asphalt and 50 parts by weight of blown asphalt used in Comparative Example 1 was subjected to an adhesion test on aggregate in the same manner as in Example 1. The result is a peeled area ratio of 5%
In the case of (Pattern No. II), the adhesion was inferior to that of Example 1.

[0014]

The asphalt binder according to the present invention is excellent in flow resistance and adhesiveness to aggregates, and
As compared with the conventional modified asphalt using a thermoplastic resin as a modifier, it has excellent heating stability and is easy to handle.

Claims (2)

[Claims] 1. An extract of a lubricating oil fraction of petroleum is added to 100 parts by weight of a mixture of straight asphalt having a penetration of 40 or more and 100 or less and blown asphalt having a penetration of 10 or more and 50 or less. An asphalt binder for fluid pavement obtained by mixing up to 5.0 parts by weight. 2. The asphalt binder for fluid pavement, wherein the blown asphalt according to claim 1 is produced by an air blowing process using a straight asphalt as a raw material and a catalyst.