JP4366308B2 - Asphalt modifier, asphalt mixture containing the same, and method for producing the same - Google Patents

Description

  The present invention relates to an asphalt modifier, an asphalt mixture containing the same, and a method for producing the same.

  In general, asphalt used for asphalt pavement softens and flows at high temperatures. Therefore, particularly when the road surface in summer becomes hot, there is a problem that the surface of the pavement is plastically deformed due to the traffic load received from the tire, and rutting is caused. On the other hand, asphalt becomes hard and brittle at low temperatures, and therefore has the disadvantage that cracks occur on the surface of the pavement, especially when the road surface in winter becomes cold. In addition, problems such as aggregate scattering and pavement surface wear have arisen due to an increase in traffic and an increase in the size of vehicles, and further improvements are required for these performances.

  Therefore, as a method for solving these problems, modified I-type and modified II-type modified by adding polymer such as rubber such as SBR and thermoplastic elastomer such as SBS to the asphalt. Asphalt was developed and some effect was seen. However, in recent years, there has been a demand for longer pavement life, and there is a need to further improve the durability of conventional modified asphalt for major trunk roads with more severe traffic environments and snowy and cold regions with severe weather conditions. .

In recent years, high-value-added pavement is becoming widespread, and high-performance pavement and noise-reduction pavement use modified asphalt called high-viscosity asphalt with improved viscosity compared to the modified asphalt. It is becoming. However, even in these pavements, pavement destruction such as rutting, cracking, aggregate scattering, and wear has occurred, and further improvement in durability is still required.
The performance of these modified asphalts is known to be greatly affected by the compatibility between the asphalt and the polymer (modifier). It is necessary to uniformly disperse the polymer (modifier). However, the compatibility of asphalt and polymer (modifier) is not necessarily good, and for uniform dispersion, premixing using special equipment such as a high shear mixer for 1 hour or more, usually 2-8 It took time to stir and mix, requiring a lot of time and labor, dedicated equipment, and a lot of energy to operate the equipment.

On the other hand, when mixing asphalt and aggregate in an asphalt mixture plant, there is also a method of directly modifying the asphalt by adding a polymer (modifier) to the mixer, so-called plant mix method. It exists from the past. Since the mixing in the plant mix method is usually about 1 to 5 minutes, it is more difficult than the premix method to uniformly disperse the polymer (modifier). As a method for improving the dispersibility of a polymer (modifier), a method in which a composition in which a petroleum resin and heavy oil are blended with a polymer is prepared in advance, and this composition is added to asphalt (patent document) 1-3), a method in which a composition in which a high molecular weight polymer is mixed with asphalt in advance is prepared, and this composition is added to asphalt (Patent Document 4) has been proposed.
However, none of the above conventional methods has been sufficiently effective for shortening the mixing of the modifier and asphalt, and the uniform dispersion of the modifier and asphalt, particularly in the plant mix method, in a short time Since the dispersibility is not sufficient, the present condition is that the reforming effect by the reforming material cannot be sufficiently exhibited.

JP-A-5-295273 JP-A-9-25416 JP 2001-019852 A JP 2000-290507 A

Here, the polymer that is most difficult to melt and disperse in asphalts is pretreated in a form that is easy to melt and disperse, and because the treatment itself uses petroleum resin and heavy oil, the treatment becomes easy. The said method of patent documents 1-3 is a preferable method.
However, heavy oil is advantageous in terms of promoting melt dispersion as described above, but it is not always preferable because it tends to lower the final asphalt properties.

In view of such circumstances, an object of the present invention is to provide a plant mix type asphalt modifier excellent in compatibility with asphalt and a reforming effect.
That is, an asphalt modifier having a final asphalt physical property equivalent to or higher than that of the conventional one is provided while the melt dispersibility of the high molecular polymer is equal to or higher than that of the conventional one.

  As a result of intensive studies, the present inventors have found that an asphalt modifier having a specific property obtained by blending a high molecular weight polymer and a specific petroleum resin can solve the above problems, and has completed the present invention. .

That is, the first of the present invention is obtained by heating and mixing 50 to 200 parts by weight of a petroleum resin having a softening point of 120 ° C. or less and a weight average molecular weight (Mw) of 1800 or less with respect to 100 parts by weight of a high molecular polymer. The viscosity at 200 ° C. is 200 × 10 ^{3 to} 400 × 10 ³ mPa · s, the weight average molecular weight (Mw) is 10 × 10 ^{3 to} 150 × 10 ³ , and the melt flow rate (190 ° C., 21.2 N) is 10 to 100 g / It is related with the plant mix type asphalt modifier characterized by being 10 minutes.

The second aspect of the present invention is the first aspect of the present invention described above with respect to aggregate, asphalt in an amount of 4 to 10% by mass relative to the aggregate, and 100 parts by weight of asphalt in the asphalt mixture plant. The present invention relates to an asphalt mixture obtained by heating and mixing 3 to 40 parts by weight of the described plant mix type asphalt modifier.
Furthermore, a third aspect of the present invention is the first aspect of the present invention described above, in an asphalt mixture plant, with respect to aggregate, asphalt in an amount of 4 to 10% by mass relative to aggregate, and 100 parts by weight of asphalt. The present invention relates to a method for producing an asphalt mixture comprising heating and mixing 3 to 40 parts by weight of the described plant mix type asphalt modifier.

The asphalt modifier of the present invention is suitable as a plant mix type asphalt modifier because of its excellent compatibility with asphalt and its modification effect.
That is, an asphalt modifier excellent in melt dispersibility of the polymer and final physical properties of the asphalt can be obtained as compared with conventional modifiers in which the polymer is treated with petroleum resin and heavy oil. .

Hereinafter, the present invention will be described in detail.
(Composition of asphalt modifier)
The asphalt modifier of the present invention is obtained by blending 50 to 200 parts by weight of a petroleum resin having a predetermined property with respect to 100 parts by weight of a polymer. When the amount of the petroleum resin is less than 50 parts by weight based on 100 parts by weight of the high molecular polymer, the compatibility of the high molecular polymer cannot be sufficiently improved and can be quickly and uniformly mixed in the asphalt. Not preferable. On the other hand, when the blending amount of the petroleum resin exceeds 200 parts by weight, the blending ratio of the polymer polymer in the asphalt modifier becomes small, so that the asphalt reforming effect is reduced, and the role as the asphalt modifier is reduced. It is not preferable because it cannot be completed.

(Polymer polymer)
As the polymer polymer to be blended in the asphalt modifier of the present invention, any polymer polymer can be used as long as it is used for the asphalt modifier. Preferably, a thermoplastic elastomer such as styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS) is used. These thermoplastic elastomers can be suitably used, and one or more of these thermoplastic elastomers can be combined appropriately. Of these, a styrene-butadiene-styrene block copolymer (SBS) is more preferably used.
As a more preferable styrene-butadiene-styrene block copolymer, those having a styrene content of 5 to 40% by mass and a weight average molecular weight (Mw) of 50,000 to 400,000 are preferable. The lower limit of the styrene content is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of preventing the asphalt modifier from causing sticky blocking, preventing the modification effect of the added asphalt from being expected, and the like. More preferably, it is 15% by mass or more. On the other hand, the upper limit is preferably 40% by mass or less, more preferably 30% by mass in order to improve the difficulty of forming the asphalt modifier due to the high melting temperature. Hereinafter, it is more preferably 25% by mass or less. Further, the lower limit of the weight average molecular weight is preferably 50,000 or more, more preferably 100,000 or more, and more preferably 150,000 or more in order to exert the modification effect of the asphalt modifier. On the other hand, the upper limit is preferably 400,000 or less, more preferably 300,000 or less, and even more preferably 200,000 or less in order to prevent the melting temperature from becoming high and making it difficult to form the asphalt modifier.

(Petroleum resin)
The softening point of the petroleum resin used for the asphalt modifier of the present invention needs to be 120 ° C. or less, preferably 100 ° C. or less, more preferably 90 ° C. or less. When the softening point exceeds 120 ° C., the asphalt modifier obtained by blending the polymer is not only high in softening point but also becomes a viscous composition under melting. It is difficult and unfavorable to mix quickly and uniformly in asphalt.
Moreover, the molecular weight of the petroleum resin used for the asphalt modifier of the present invention needs to be 1800 or less, preferably 1500 or less. When the molecular weight of the petroleum resin is increased, there is a concern that the compatibility with the high molecular weight polymer may be lowered. Therefore, it is not preferable that the molecular weight exceeds 1800.
The lower limit values of the softening point and molecular weight are not particularly limited, but are within a range that is naturally defined from the point of being obtained as a petroleum resin and the point of securing the viscosity of the final asphalt mixture.
In addition, the petroleum resin used for the asphalt modifier of the present invention is not particularly limited as long as it has the above-mentioned properties, but it is not limited to aromatic (C9) petroleum resin, aliphatic (C5) petroleum resin, C5-C9 copolymer petroleum resin, DCPD petroleum resin, and modified products of these petroleum resins can be used alone or in combination of two or more. Among these, particularly preferred petroleum resins include C9-based petroleum resins because the compatibility of the asphalt modifier with asphalt is enhanced.
In addition, the said physical property petroleum resin is available as a commercial item as shown in the below-mentioned Example etc.

(Properties of asphalt modifier)
The viscosity of the asphalt modifier of the present invention at 150 ° C. needs to be in the range of 200 × 10 ^{3 to} 400 × 10 ³ mPa · s. The lower limit of the viscosity at 150 ° C. is preferably 220 × 10 ³ or more, more preferably 240 × 10 ³ or more, from the viewpoint of improving the dynamic stability of the asphalt mixture. On the other hand, the upper limit is preferably 370 × 10 ³ or less, more preferably 350 × 10 ³ or less, from the viewpoint of improving the melt dispersion of the modifying material in the asphalt mixture plant.
The viscosity at 150 ° C. here refers to a value measured according to JIS K7117 “Method of measuring viscosity with a rotational viscometer”.

The weight average molecular weight (Mw) of the asphalt modifier of the present invention needs to be 10 × 10 ^{3 to} 150 × 10 ³ . The lower limit of the weight average molecular weight is preferably 30 × 10 ³ or more, more preferably 50 × 10 ³ or more, from the viewpoint of improving the dynamic stability of the asphalt mixture. On the other hand, the upper limit is preferably 130 × 10 ³ or less, and more preferably 120 × 10 ³ or less, from the viewpoint of improving the melt dispersion of the modifying material in the asphalt mixture plant.
In addition, the weight average molecular weight here refers to the value of the weight average molecular weight (MW) calculated | required by the gel permeation chromatograph method (GPC).

The melt flow rate (190 ° C., 21.2 N) of the asphalt modifier of the present invention needs to be 10 to 100 g / 10 minutes. The lower limit of the melt flow rate is preferably 20 g / 10 min or more, and more preferably 30 g / 10 min or more, from the viewpoint of improving the dynamic stability of the asphalt mixture. On the other hand, the upper limit is preferably 90 g / 10 min or less, and more preferably 80 g / 10 min or less, from the viewpoint of improving the melt dispersion of the modifying material in the asphalt mixture plant.
Here, the melt flow rate (190 ° C., 21.2 N) means a value at a test temperature of 190 ° C. and a load of 21.2 N measured by ASTM D1238 “Test Method for Flow Rates of Thermoplastics by Extraction Plasometer”. . In other words, the flow rate for 10 minutes when extruding an asphalt modifier melted at a constant temperature of 190 ° C. from a circular die having a specified length and diameter at a constant load of 21.2 N is a numerical value expressed in grams.

(Manufacturing method of asphalt modifier)
The production method of the asphalt modifier of the present invention is not particularly limited as long as the blending ratio, properties, and the like satisfy the above ranges. Usually, polymer polymers and petroleum resins are mixed using a mixer such as a heat melting kettle, high shear mixer, Banbury mixer, Hensyl mixer, etc., then pelletizer, extrusion molding machine, processing molding machine, press molding machine, etc. Can be formed into an appropriate shape.
In addition, the shape of the asphalt modifier of the present invention is not particularly limited, and can be used in any shape. For example, a pellet shape, a plate shape, a string shape, a block shape and the like can be mentioned, but in consideration of the mixing operability in the plant, a pellet shape is preferable. Pelletization of asphalt modifier is performed by, for example, heating and mixing a polymer and petroleum resin at 150 to 180 ° C. for 3 to 10 minutes, and then extruding into a string using an extruder and then cutting with a pelletizer or the like. Is possible. If the size of the pellet as a preferable pellet is 1 to 50 mm, preferably 1 to 20 mm, more preferably 1 to 10 mm, it is advantageous because it can be rapidly melted and dispersed even in plant mixing.

(Method for producing asphalt mixture)
The asphalt modifying material of the present invention is blended and mixed with asphalt together with aggregates, if necessary, and used for road pavement in the form of an asphalt mixture.
The asphalt mixture of the present invention to be used for the above use is preferably produced by the following method.
That is, in road pavement, asphalt and aggregate are mixed in an asphalt mixture plant, and the resulting asphalt mixture is applied to road pavement. The asphalt mixture plant has a short mixing time because of on-site construction, but the asphalt modifier of the present invention sufficiently melts and disperses even in a mixed state in such a mixture plant.
Specifically, such mixing is performed in the asphalt mixture plant in the amount of asphalt corresponding to 4 to 10% by mass of the aggregate, input aggregate, and 100 parts by weight of input asphalt. An asphalt mixture can be produced by adding 3 to 40 parts by weight of the asphalt modifier of the invention and heating and mixing.
More specifically, the aggregate heated to 160 to 200 ° C is charged into the mixer, and then asphalt heated to 150 to 190 ° C is charged in an amount corresponding to 4 to 10% by mass of the aggregate. Mix. Thereafter, 3 to 40 parts by weight of the above-mentioned asphalt modifier is added to 100 parts by weight of the input asphalts and mixed.

  Here, when the addition amount of the asphalt modifier with respect to 100 parts by weight of the input asphalt is less than 3 parts by weight, a satisfactory modification effect cannot be obtained even if the asphalt modifier is added. Preferably, 10 parts by weight or more is more preferable. On the other hand, when the added amount of the asphalt modifier exceeds 40 parts by weight, mixing in the plant becomes difficult and only a non-uniform asphalt mixture can be produced. Therefore, preferably 40 parts by weight or less, more preferably 30 parts by weight or less, More preferably, it is 20 parts by weight or less.

The aggregate used in the asphalt mixture of the present invention is not particularly limited as long as it is used for paving, but granular materials such as crushed stone, sand, gravel and similar steel slag can be used.
In the asphalt mixture of the present invention, an amount of asphalt corresponding to 4 to 10% by mass of the aggregate is used. If the asphalt is less than 4% by mass, the asphalt construction work is difficult, and if it exceeds 10% by mass, the strength as a paving material is insufficient.

  Moreover, the asphalt used for the asphalt mixture of the present invention is not particularly limited as long as it is used for road paving. For example, various crude oils are subjected to atmospheric distillation equipment and vacuum distillation equipment to remove light components and straight asphalt, which is a semi-solid and solid sticky substance mainly composed of bituminous material, or straight asphalt under normal pressure. Asphalts such as semi-blown asphalt, blown asphalt blown with air at a temperature of 230 to 300 ° C., modified asphalt in which a thermoplastic elastomer or the like is added to straight asphalt, and high viscosity modified asphalt can be used. In particular, asphalt for paved roads is preferred.

  The asphalt modifier of the present invention can be sufficiently compatible even by the plant mix method in an asphalt mixture plant which often has insufficient mixing time as described above. In this respect, it is not inferior to an asphalt modifier obtained by blending a conventional petroleum resin and heavy oil in a polymer.

(Other)
Furthermore, as a matter of course, the asphalt modifier of the present invention can be used for the above-mentioned plant mix method and can be used without any problem as a conventional asphalt modifier for premix.
That is, modified asphalt for premix by adding 5 to 10 parts by mass of the asphalt modifier of the present invention to 100 parts by weight of the asphalt and the asphalt and stirring and mixing for 0.5 to 3 hours. Can be manufactured. Moreover, a highly viscous modified asphalt can also be manufactured by selecting arbitrarily the addition amount of an asphalt modifier. The modified asphalt thus obtained is used, for example, as part or all of the asphalt to be charged in the asphalt mixture plant, and is mixed with aggregate to obtain an asphalt mixture.

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples.
[Examples 1-8 and Comparative Examples 1-10]
The polymer and petroleum resin are heated and melted at 150 to 180 ° C. at the base material mixing ratio shown in Table 1, extruded into a string using an extruder, and then pelletized with a pelletizer with a diameter of about 3 mm and a length of about 4 mm. Asphalt modifiers A to F were manufactured by cutting. The physical property values of the obtained asphalt modifiers A to F are also shown in Table 1.

As the polymer, Tafprene T315 (styrene content 20 mass%, weight average molecular weight 150,000) manufactured by Asahi Kasei Co., Ltd. was used.
Also, as Nippon Petrochemical Co., Ltd. Neopolymer NP90 (C9 petroleum resin, softening point 90 ° C., weight average molecular weight 1150) as Petroleum Resin A, Neopolymer made by Nippon Petrochemical Co., Ltd. as Petroleum Resin B NP130 (C9 petroleum resin, softening point 130 ° C., weight average molecular weight 1850) was used.

The physical property values of the asphalt modifier were evaluated by the following method.
The viscosity at 150 ° C. was measured in accordance with JIS K7117 “Method of measuring viscosity with a rotational viscometer”.
The weight average molecular weight (MW) was measured by gel permeation chromatography (GPC).
The melt flow rate (190 ° C., 21.2 N) was measured at a test temperature of 190 ° C. and a load of 21.2 N in ASTM D1238 “Test Method for Flow Rates of Thermoplastics by Extension Plasometer”.

(Preparation of mixture test specimen and mixture test)
The above asphalt modifier, the aggregate shown in Table 2, and the following asphalts were mixed to produce an asphalt mixture. Details of mixing will be described separately below.
Asphalt A Nippon Oil Corporation Negishi Refinery Straight Asphalt 60-80
Asphalt B Modified Nippon Asphalt Ecophalt K2 made by Nippon Oil Corporation
Asphalt C Nippon Oil Corporation high viscosity modified asphalt Ecophalt TA

(Production of dense particle size asphalt mixture (13))
Aggregate the aggregates shown in Table 2 and asphalt A or asphalt B using a pug mill mixer, and add asphalt modifiers A to F (shown in Table 3) and stir and mix for 1 minute. Produced an asphalt mixture (dense particle size asphalt mixture (13)). This production simulates a so-called plant mix system in an actual asphalt mixture plant.
The obtained asphalt mixture was divided into six equal parts to prepare six test specimens for Marshall test, and the Marshall stability was evaluated.
The amount of asphalt was blended so that the total amount of asphalt and asphalt modifier was 5.7% by mass with respect to the aggregate. (The amount of asphalt modifier added to asphalt is shown in Table 3.) Aggregate heating temperature is 180 ° C, asphalt heating temperature is 170 ° C, stirring and mixing temperature during preparation of asphalt mixture is 175 ° C, specimen compaction The temperature was 160 ° C. and the number of compactions was 50 times on one side.

(Marshall test)
Japan Road Association "Pavement Test Method Handbook" 3-7-1 "Marshall Stability Test Method"
The side surface of the above-mentioned Marshall test specimen (cylindrical specimen (diameter: about 100 mm, thickness: about 63 mm)) is sandwiched between two arc-shaped loading heads and loaded at a specified temperature (60 ° C) and a specified loading speed. And the maximum load (stability kN) shown until the specimen breaks is measured.
The larger the maximum load (kN) value, the better the stability of the asphalt mixture.

(Wheel tracking test)
3-7-3 “Wheel Tracking Test Method” of the Japan Road Association “Pavement Test Method Handbook”
A specimen formed by placing an asphalt mixture in a predetermined mold (300 × 300 × 50 mm) was reciprocated with a small wheel with a specified load (686 ± 10 N) in a constant temperature room at 60 ° C., and the deformation amount at 45 minutes and 60 minutes ( The amount of rutting is measured, the dynamic stability (times / mm) is determined, and the resistance of the asphalt mixture to rutting is evaluated.
The larger the value of the dynamic stability (DS), the better the rutting resistance of the asphalt mixture at high temperature.

(Evaluation result of dense particle size asphalt mixture (13))
Table 3 shows the evaluation results of the Marshall test and the wheel tracking test of the dense particle size asphalt mixture (13).
Examples 1 to 4 are examples in which an asphalt mixture produced by modifying asphalt A and asphalt B with the asphalt modifiers A to C of the present invention was tested and evaluated. Since the asphalt modifiers A to C are excellent in melt dispersibility, the modifier can be uniformly dispersed during the production of the asphalt mixture. A uniform specimen has been produced.
Furthermore, in the comparison between Examples 1, 2, 4 and Comparative Example 1, the addition of asphalt modifiers A to C shows an improvement in Marshall strength, that is, an improvement in the physical strength of the mixture. In addition, it is confirmed that the dynamic stability is improved by the wheel tracking test, that is, the rutting resistance is improved.

Also in the comparison between Example 3 and Comparative Example 2, the addition of asphalt modifier B also shows improvement in Marshall strength, that is, improvement in physical strength of the mixture. In addition, it is confirmed that the dynamic stability is improved by the wheel tracking test, that is, the rutting resistance is improved.
In Comparative Example 3, the softening point of the used petroleum resin exceeds 120 ° C., and the molecular weight of the petroleum resin exceeds 1800. Asphalt modifiers cannot be evenly dispersed during the production of asphalt mixtures, the Marshall stability of the prepared Marshall specimens is very large, and the modification effect is not very good. It is unsuitable.
In Comparative Example 4, the amount of petroleum resin in the asphalt modifier E is insufficient, so that the compatibility of the high molecular polymer cannot be sufficiently increased, and can be quickly and uniformly mixed in the asphalt. In addition, the Marshall specimen prepared in the same manner has a very large variation in the Marshall stability, and the modification effect is not obtained so much that it is not suitable as a paving material.
Furthermore, since the comparative example 5 has an excessive amount of petroleum resin in the asphalt modifier F, the blending ratio of the polymer polymer in the asphalt modifier is small, so that the asphalt modification effect cannot be obtained. The value of the Marshall stability cannot be improved, the variation is large, and it is not suitable as a pavement material.

(Evaluation using asphalt mixture for drainage pavement)
Aggregate the aggregates shown in Table 4 and asphalt B or asphalt C using a pug mill mixer, and add a predetermined amount (as shown in Table 5) of asphalt modifiers A to F and stir and mix for 1 minute. Asphalt mixture (drainage pavement asphalt mixture) was manufactured. This production simulates a so-called plant mix system in an actual asphalt mixture plant.
The obtained asphalt mixture was divided into six equal parts, six test specimens for cantable tests were prepared, and the cantable loss rate at 20 ° C. was evaluated.
The amount of asphalt was blended so that the total amount of asphalt and asphalt modifier was 5.8% by mass with respect to the aggregate. The aggregate heating temperature was 180 ° C., the asphalt heating temperature was 170 ° C., the stirring and mixing temperature during preparation of the asphalt mixture was 175 ° C., the specimen compaction temperature was 160 ° C., and the number of compactions was 50 times on both sides.

(Cantablo test)
1-1-2T “Cantablo Test Method” of the Japan Road Association “Pavement Test Method Handbook”
Using the Lost test machine (machine specified in the coarse aggregate grinding test method) for the above test specimen for cantabulo test, rotate the drum 300 times at a rotation speed of 30 to 33 revolutions per minute, and calculate the loss after the test. taking measurement.
Loss rate (%) = (Sample weight before test (g) −Sample weight after test (g)) / Sample weight before test (g) × 100
The smaller the value of the loss rate (%), the better the stability of the drainage pavement asphalt mixture.

(Wheel tracking test)
The evaluation test of the asphalt mixture for drainage pavement was conducted in the same manner as the evaluation test of the dense particle size asphalt mixture (13).

(Evaluation results of asphalt mixture for drainage pavement)
Table 5 shows the evaluation results of the cantabulo test and the wheel tracking test of the asphalt mixture for drainage pavement.

Examples 5 to 8 are examples in which asphalt B and asphalt C were modified with the asphalt modifiers A to C of the present invention and were tested and evaluated. Since the asphalt modifiers A to C are excellent in melt dispersibility, they can be uniformly dispersed during the production of the asphalt mixture. Therefore, the specimens with a small variation in the cantabulo loss rate of the prepared cantabulo specimens and a uniform physical strength Is made.
Furthermore, in the comparison between Examples 5, 6, and 8 and Comparative Example 6, the addition of asphalt modifiers A to C confirms a decrease in cantabulo loss rate, that is, an improvement in aggregate scattering resistance. In addition, it is confirmed that the dynamic stability is improved by the wheel tracking test, that is, the rutting resistance is improved.
Also in the comparison between Example 7 and Comparative Example 7, it is confirmed that the addition of the asphalt modifier B reduces the cantabulo loss rate, that is, improves the aggregate scattering resistance. In addition, it is confirmed that the dynamic stability is improved by the wheel tracking test, that is, the rutting resistance is improved.

In Comparative Example 8, since the softening point of the petroleum resin used for the asphalt modifier is high and the molecular weight is large, the melt dispersibility in the asphalt and the compatibility with the high molecular weight polymer are lowered. Sometimes the asphalt modifier cannot be evenly dispersed, the variation in the cantabulous loss rate of the prepared Marshall specimen is very large, and the reforming effect is not seen so much. is there.
In Comparative Example 9, since the amount of petroleum resin in the asphalt modifier D is insufficient, the compatibility of the high molecular polymer cannot be sufficiently improved, and the asphalt can be quickly and uniformly mixed in the asphalt. In addition, the variation of the cantabulo loss rate of the cantabulo test specimens prepared in the same manner is very large, and the modification effect is not so much seen, so that it is not suitable as a paving material.
Further, in Comparative Example 10, since the amount of petroleum resin in the asphalt modifier E is excessive, the melt viscosity of the asphalt modifier becomes high and becomes viscous even under melting. The mixture cannot be uniformly mixed, the variation in the cantabulo loss rate of the prepared cantabro test specimen is very large, and the modification effect is not so much, so that it is not suitable as a paving material.

Claims (3)

The viscosity at 150 ° C. obtained by heating and mixing 50 to 200 parts by weight of a petroleum resin having a softening point of 120 ° C. or less and a weight average molecular weight (Mw) of 1800 or less with respect to 100 parts by weight of the high molecular weight polymer is 200 × 10 ³ to 400 × 10 ³ mPa · s, weight average molecular weight (Mw) is 10 × 10 ^{3 to} 150 × 10 ³ , and melt flow rate (190 ° C., 21.2 N) is 10 to 100 g / 10 min. Plant mix type asphalt modifier. In the asphalt mixture plant, 3 to 3 parts of the plant mix type asphalt modifier according to claim 1, based on 100 parts by weight of asphalt and asphalt in an amount of 4 to 10% by mass with respect to aggregate, aggregate. Asphalt mixture obtained by heating and mixing 40 parts by weight. The plant mix type asphalt modifier 3 to 40 according to claim 1, wherein the aggregate is 100 to 100 parts by weight of the asphalt and the asphalt in an amount of 4 to 10% by mass with respect to the aggregate and the aggregate in the asphalt mixture plant. A method for producing an asphalt mixture comprising heating and mixing parts by weight.