JP2956870B2 - Modified asphalt mixture - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asphalt pavement mixture composed of asphalt and various types of aggregates, and more particularly to a plant mix type pavement mixture.

[0002]

2. Description of the Prior Art Asphalt pavement has advantages such as uniform distribution of traffic load due to good flexibility, various construction methods and shortening of construction period, and self-healing cracks. Have been. In general, the asphalt pavement composite material construction method consists of a mixture of the best combination of asphalt and aggregate, and is directly affected by changes in the weather environment and traffic vehicles. Is done. In particular, with the recent development of high-speed and heavy-load traffic roads, these requirements have become even more severe, and several asphalt improvement technologies have already been developed.

[0003] Modified asphalts in the future include those in which a polymer material such as rubber or resin is added to asphalt, improvement of low-temperature brittleness, improvement of durability, impact resistance, high-temperature stability, etc., and abrasion resistance. There are several salient features such as decline. Styrene-based elastomers such as SBS (styrene-butadiene block copolymer) and SIS (styrene-isoprene block copolymer) are used as rubber materials, and polyethylene, polypropylene, ethylene-vinyl acetate copolymer are used as resin materials. Alternatively, an olefin resin such as an amorphous polyolefin is used.

However, these high-molecular materials, including amorphous polyolefin, are sufficiently stirred and mixed with molten asphalt, and even if apparently dissolved, they do not actually dissolve uniformly with asphalt, but slightly dissolve. It only dissolves with low molecular weight substances in asphalt. From the micro observation of the mixture at this time, it can be seen that a so-called “sea-island structure” is formed. In other words, when a small amount of polymer material is added to asphalt,
The polymer material becomes island portions having a diameter of about 1 to 100 microns.

[0005] Another important task imposed on asphalt road pavement is prevention of separation of asphalt from aggregates such as crushed stone, gravel or sand. It is said that the phenomenon of asphalt peeling from aggregates is affected not only by the material properties of the aggregates, but also by environmental conditions such as temperature and traffic load.In particular, since many of the aggregates are hydrophilic,
It becomes remarkable when moisture enters between the aggregate and the asphalt. A mixture in which only asphalt is covered with an aggregate is easily peeled because the asphalt has low adhesive strength and cohesive strength. Modified asphalt obtained by adding 1 to 5% by weight of a polymer material such as the above rubber or resin to asphalt forms an "sea-island structure". Durability is not significantly improved.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned drawbacks. As a result, the above-mentioned aggregate was mixed with asphalt by mixing the aggregate with an amorphous polyolefin resin. Solved the shortcomings. INDUSTRIAL APPLICABILITY The asphalt pavement mixture of the present invention exerts a great effect in preventing separation and separation of aggregate and asphalt without impairing the characteristics of asphalt and modified asphalt.

The asphalt in the present invention is straight asphalt by-produced during oil refining and blown asphalt obtained by blowing air into the straight asphalt at a high temperature.
0 dmm or more, and the ethane trichloride soluble matter is 99% or more. As the aggregate in the present invention, crushed stone, gravel,
Sand, steelmaking slag, artificial lightweight aggregate, and the like may be used in combination.

The amorphous polyolefin resin in the present invention is obtained by copolymerizing propylene with ethylene and / or butene-1 using a special catalyst, and has a number average molecular weight in the range of 1,000 to 20,000. With an ethylene content of less than 2 to 20% by weight or a butene-1 content of 10
７０70% by weight, preferably 30-50% by weight. When the number average molecular weight is less than 1,000, the cohesive strength is too low and the effect of modifying asphalt is small, and the number average molecular weight is 20,000.
If it is larger than the above, the melt viscosity is too high, and it is difficult to uniformly coat the aggregate. If the ethylene content is greater than 20% by weight or the butene-1 content is greater than 70% by weight, the surface tackiness of the amorphous polyolefin resin will increase, and handling with stirring and mixing with the aggregate will be complicated. If the ethylene content is 2% by weight or less or the butene-1 content is 10% by weight or less, the adhesion to the aggregate is reduced, and the purpose of preventing the separation and separation of the asphalt from the asphalt cannot be achieved. The apparent viscosity of the amorphous polyolefin resin is from room temperature to about 6
It is 10 ³ to 10 ¹⁰ centipoise at 0 ° C., preferably 10 ⁶ to 10 ⁷ centipoise. As the amorphous polyolefin resin, those modified with an unsaturated acid, a metal salt thereof, an unsaturated silane compound, or the like can also be used. Since the amorphous polyolefin resin used in the present invention has a lower melt viscosity than a conventional asphalt modifying polymer material, it is possible to form a uniform film on the aggregate.

The proportion of the amorphous polyolefin resin is 0.01 to 1 part by weight, preferably 0.03 to 0.3 part by weight, based on 100 parts by weight of the aggregate. . Asphalt is preferably used in an amount of 3 to 10 parts by weight. If the amount of the amorphous polyolefin resin is less than 0.01 part by weight, the original purpose of preventing separation or separation of the asphalt from the asphalt cannot be achieved, and if the amount is more than 1 part by weight, no improvement in performance is observed. It becomes economy. When the amount of asphalt is less than 3 parts by weight, the adhesiveness for fixing the aggregate is insufficient, and when the amount is more than 10 parts by weight, stability against temperature change is lacking. The asphalt pavement mixture was mixed for about 2 hours using a heating mixer installed in a normal asphalt plant.
Aggregate heated to 00 ° C and amorphous polyolefin resin
Mix for about one minute, then add asphalt and add one more
It can be manufactured by mixing and stirring for about a minute.

[0010]

According to the present invention, by mixing an aggregate obtained by coating an aggregate with an amorphous polyolefin resin and asphalt, the aggregate and the asphalt can be mixed without impairing the characteristics of the asphalt and the modified asphalt. It has a great effect on preventing peeling and separation from the substrate.

[0011]

Examples and Comparative Examples Hereinafter, the present invention will be described specifically.

(1) Preparation of asphalt pavement mixture (materials to be mixed) Aggregate: Road crushed stone (for asphalt mixture, JIS A
5001) Amorphous polyolefin ("UT358" manufactured by Ube Lexen)
5 ”or less, abbreviated as APAO) Asphalt (Showa Shell Sekiyu Sekiyu Straight Asphalt 60/80) Polypropylene (Ube Industries, Ltd.“ B301H ”or less, PP
Abbreviation) SBS rubber (Shell Chemical's "TR1101" or lower, SB
Abbreviated as S)

(2) Performance Evaluation Test The composite material obtained from the above materials was subjected to a coarse aggregate peeling resistance test in accordance with the Japan Petroleum Institute regulations (JPI-5S27). Immediately after immersing the coated aggregate in a constant temperature water bath maintained at 80 ° C. for 30 minutes, the aggregate is immediately transferred to a container containing water at room temperature, and 20 aggregates are taken out. I do.

Examples 1 and 2 A predetermined amount of A melted in a stainless beaker at 190 ° C.
PAO was added, and then 100 g of aggregate (heated and dried at 190 ° C. and under a 9.5 mm sieve and 13.2 mm sieve) was added.
The aggregate was uniformly coated with APAO by mixing with a spatula for 1 minute. Next, a predetermined amount of asphalt melted at 190 ° C. was added and mixed for 1 minute to completely cover the aggregate,
Cooled to room temperature. The performance evaluation test was performed using the coated aggregate. Table 1 shows the mixing ratios and the results.

[0015]

[Table 1]

Comparative Example 1 The procedure of Example 1 was repeated, except that APAO was not used. Comparative Example 2 The same procedure as in Example 1 was carried out except that APAO was previously dissolved in asphalt and then aggregate was mixed. Comparative Example 3 In Comparative Example 2, SBS (0.25) was used instead of APAO.
(Parts by weight) except that Comparative Example 2 was used. Comparative Example 4 The procedure of Example 1 was repeated, except that PP (0.25 parts by weight) was used instead of APAO. Comparative Example 5 In Example 1, SBS (0.25) was used instead of APAO.
(Parts by weight) was performed in the same manner as in Example 1.

Continuation of the front page (56) References JP-A-59-126804 (JP, A) JP-A-61-14255 (JP, A) JP-A-51-129 (JP, A) JP-A-62-281 (JP) , A) JP-A-7-18620 (JP, A) JP-B-42-16416 (JP, B1) Patent 72410 (JP, C1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 95 / 00 C08K 9/04 C08L 23/02-23/24 E01C 7/30

Claims (1)

(57) [Claims] 1. An asphalt pavement mixture comprising an aggregate coated with an amorphous polyolefin resin.