Asphalt modifier

Abstract

The present invention provides an asphalt modifier comprising a crystalline polyester that has a melting point of 65-160°C and that includes a structural unit derived from an alcohol component including a straight-chain aliphatic alcohol and a structural unit derived from a carboxylate component.

Description

Technical Field

[0001] The present invention relates to an asphalt modifier, an asphalt composition, an asphalt mixture, methods for producing them, and a road paving method.

Background Art

[0002] For paving roads such as motorways, parking lots, freight yards, and sidewalks, asphalt paving using an asphalt composition is carried out because it is relatively easy to lay and the time from the start of paving work to the start of traffic can be shortened. In this asphalt paving, the road surface is formed by an asphalt mixture in which aggregates are bound with asphalt, so the paved road has good hardness and durability. However, the asphalt paving surface deteriorates due to long-term use, and it becomes necessary to repair the paving. By repairing the paving, the maintenance cost increases and it has a great impact on automobile traffic.

[0003] Patent Document 1 (Japanese Patent Laid-Open No. 04-8766) discloses an asphalt composition containing asphalt and a polyester-based polymer. Patent Document 2 (Japanese Patent Laid-Open No. 08-311299) contains at least one polymer block (A) mainly composed of a vinyl aromatic hydrocarbon and at least one polymer block (B) mainly composed of a conjugated diene, and the content of the vinyl aromatic hydrocarbon is 5 to 95% by weight, and the content of the conjugated diene is 95 to 5% by weight. A bitumen modifier containing a block copolymer and an oil-soluble polyester obtained by polycondensing a polyvalent higher carboxylic acid and a polyhydric alcohol as active ingredients is disclosed.

Summary of the Invention

[0004] The present invention relates to an asphalt modifier comprising a crystalline polyester containing a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and having a melting point of 65°C or higher and 160°C or lower.

Brief Description of the Drawings

[0005]

Figure 1

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Mode for Carrying Out the Invention

[0006] If the asphalt pavement surface has insufficient fuel resistance, it will deteriorate due to leakage of gasoline or engine oil for automobiles from vehicles, and irregularities will occur on the surface. In addition, an asphalt composition containing polyester has a problem of storage stability in that the polyester separates when stored at high temperatures. If the storage stability at high temperatures is insufficient, the performance of the asphalt pavement will become non-uniform. For example, in the prior arts disclosed in Patent Documents 1 and 2, it has been difficult to simultaneously satisfy fuel resistance and the storage stability of the asphalt composition at high temperatures. The present invention relates to an asphalt modifier, an asphalt composition, an asphalt mixture, methods for producing them, and a road paving method, which can obtain an asphalt composition and an asphalt mixture that are excellent in storage stability and have excellent fuel resistance of the paved surface after construction by being blended into the asphalt composition and the asphalt mixture.

[0007] The present invention relates to the following [1] to [6]. [1] An asphalt modifier comprising a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and consisting of a crystalline polyester having a melting point of 65°C or higher and 160°C or lower. [2] An asphalt composition containing asphalt and the asphalt modifier described in [1] above. [3]An asphalt mixture comprising the asphalt composition according to [2] above and aggregates. [4]A method for producing the asphalt composition according to [2] above, the method comprising a step of mixing the asphalt and the crystalline polyester. [5]A method for producing an asphalt mixture, the method comprising a step of mixing asphalt, heated aggregates, and a crystalline polyester simultaneously or in any order. [6]A road paving method, the method comprising a step of constructing the asphalt mixture according to [4] above to form an asphalt pavement layer.

[0008] According to the present invention, there can be provided an asphalt modifier, an asphalt composition, an asphalt mixture, methods for producing them, and a road paving method, which can provide an asphalt composition and an asphalt mixture that are excellent in storage stability and have excellent oil resistance of the pavement surface after construction by being blended into the asphalt composition and the asphalt mixture.

[0009] [Asphalt modifier] The asphalt modifier of the present invention is composed of a crystalline polyester containing a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and having a melting point of 65°C or higher and 160°C or lower.

[0010] The inventors have found that by incorporating an asphalt modifier composed of a crystalline polyester containing a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and having a melting point of 65°C or higher and 160°C or lower, into an asphalt composition and an asphalt mixture, an asphalt composition and an asphalt mixture that are excellent in storage stability and have excellent oil resistance of the pavement surface after construction can be obtained. Although the detailed mechanism by which the effects of the present invention are obtained is unclear, it is partly considered as follows. The crystalline polyester having a structural unit derived from an aliphatic alcohol constituting the asphalt modifier of the present invention has a high affinity for the maltene component having a large content in asphalt, and it is considered that the dispersion in asphalt becomes good. As a result, it is presumed that the dispersed particle size of the crystalline polyester is refined, the precipitation of the crystalline polyester is suppressed, and the storage stability is improved. Further, in an asphalt mixture containing polyester, it is considered that the polyester adsorbs to the aggregate and exhibits a coating effect, thereby preventing the penetration of oil into the aggregate surface and improving the oil resistance of the asphalt mixture. When the dispersion diameter of the polyester is large and / or the addition amount is insufficient, the adsorption of the polyester to the aggregate becomes non-uniform, and it is considered that oil penetrates from the portion of the aggregate where the polyester is not adsorbed, resulting in the peeling of the aggregate. In the present invention, it is considered that by refining the dispersed particle size of the asphalt modifier composed of crystalline polyester, an excellent coating effect on the aggregate is exhibited in the asphalt mixture. On the other hand, when the affinity between the polyester and the asphalt is increased to obtain an excellent coating effect, there is a concern that the affinity with oil components such as automotive gasoline and engine oil also increases and the oil resistance decreases. However, the polyester constituting the asphalt modifier of the present invention is a crystalline polyester that is insoluble in oil components at low temperatures, and thus is considered to have excellent oil resistance. In particular, a crystalline polyester having a melting point of 65°C or higher has extremely low solubility in oil components, and it is considered that an excellent oil resistance improvement effect can be obtained. Further, a crystalline polyester having a melting point of 160°C or lower has good miscibility with asphalt, suppresses the coarsening of the dispersed particle size, and is considered to exhibit a good coating effect on the aggregate. Thus, in the present invention, it is presumed that both the storage stability and the oil resistance of the paved surface after construction are achieved.

[0011] The definitions of various terms in this specification are shown below. In the polyester, the "structural unit derived from the alcohol component" means the structure obtained by removing a hydrogen atom from the hydroxyl group of the alcohol component, and the "structural unit derived from the carboxylic acid component" means the structure obtained by removing a hydroxyl group from the carboxyl group of the carboxylic acid component. The "carboxylic acid component" is a concept that includes not only the carboxylic acid itself but also anhydrides that decompose during the reaction to form an acid and alkyl esters of carboxylic acids (for example, those having 1 to 3 carbon atoms in the alkyl group). When the carboxylic acid component is an alkyl ester of a carboxylic acid, the number of carbon atoms of the carboxylic acid component does not include the number of carbon atoms of the alkyl group that is the alcohol residue of the ester. Whether the polyester is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the polyester to the maximum peak temperature of endotherm in the measurement method described in the examples below (softening point (°C) / maximum peak temperature of endotherm (°C)). A crystalline polyester is one having a crystallinity index of 0.6 or more and 1.4 or less. The crystallinity index can be appropriately adjusted by the types and ratios of the raw material monomers and production conditions such as reaction temperature, reaction time, and cooling rate.

[0012] [Crystalline Polyester] The asphalt modifier of the present invention is a crystalline polyester containing a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and is composed of a crystalline polyester having a melting point of 65°C or higher and 160°C or lower. (Alcohol Component) As the alcohol component in the crystalline polyester, from the viewpoints of storage stability and oil resistance, it is necessary to contain a linear aliphatic alcohol, preferably a linear aliphatic diol, more preferably an α,ω-linear aliphatic diol. The number of carbon atoms of the linear aliphatic alcohol is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, and is preferably 20 or less, more preferably 16 or less, still more preferably 12 or less. Examples of the linear aliphatic alcohol include linear aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, etc. Among these, ethylene glycol, 1,6-hexanediol, 1,12-dodecanediol, and 1,16-hexadecanediol are preferable. These linear aliphatic diols can be used alone or in combination of two or more. From the viewpoints of storage stability and oil resistance, the content of the linear aliphatic diol is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, and more preferably 100 mol% in the alcohol component.

[0013] The alcohol component may contain other alcohol components different from the linear aliphatic alcohol. Examples of the other alcohol components include aliphatic alcohols other than linear aliphatic alcohols such as 1,2-propylene glycol and neopentyl glycol; aromatic diols such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used singly or in combination of two or more.

[0014] (Carboxylic acid component) Examples of the carboxylic acid component in the crystalline polyester include aliphatic monocarboxylic acids, aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acid compounds having a valence of 3 or more and 6 or less. From the viewpoints of storage stability and oil resistance, the carboxylic acid component is preferably an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid, more preferably a linear aliphatic dicarboxylic acid or an aromatic dicarboxylic acid. These carboxylic acid components can be used alone or in combination of two or more. From the viewpoints of storage stability and oil resistance, the number of carbon atoms in the main chain of the aliphatic dicarboxylic acid is preferably 2 or more, more preferably 4 or more, still more preferably 5 or more, and even more preferably 6 or more, and is preferably 20 or less, more preferably 18 or less, and still more preferably 16 or less. Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, fumaric acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosanedioic acid. Among these, sebacic acid, dodecanedioic acid, tetradecanedioic acid, or hexadecanedioic acid is preferable. From the viewpoints of storage stability and oil resistance, the number of carbon atoms of the aromatic dicarboxylic acid is preferably 8 or more, and is preferably 20 or less, more preferably 16 or less, and still more preferably 12 or less. Examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid, and the like. Among these, terephthalic acid is preferable. The content of the aliphatic dicarboxylic acid or the aromatic dicarboxylic acid is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, and even more preferably 95 mol% or more in the carboxylic acid component, and is 100 mol% or less, and more preferably 100 mol%. The carboxylic acid component may contain other carboxylic acid components different from aliphatic dicarboxylic acids and aromatic dicarboxylic acids. Examples of other carboxylic acid components include aliphatic monocarboxylic acids such as stearic acid, capric acid, lauric acid, myristic acid, palmitic acid, arachidic acid, behenic acid, and lignoceric acid; polyvalent carboxylic acids having a valence of 3 or more such as trimellitic acid and pyromellitic acid. These carboxylic acid components may be used alone or in combination of two or more.

[0015] In the crystalline polyester of the present invention, from the viewpoints of storage stability and oil resistance, the total number of carbon atoms of the structural units derived from the alcohol component containing a linear aliphatic alcohol and the structural units derived from the carboxylic acid component is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more, and even more preferably 10 or more, and is preferably 40 or less, more preferably 32 or less, still more preferably 28 or less, and even more preferably 26 or less.

[0016] In one of the preferred embodiments from the viewpoints of storage stability and oil resistance of the present invention, the crystalline polyester is a crystalline polyester containing structural units derived from a linear aliphatic diol having 2 to 12 carbon atoms and structural units derived from a linear aliphatic dicarboxylic acid having 4 to 14 carbon atoms or an aromatic dicarboxylic acid having 8 to 12 carbon atoms, and the total number of carbon atoms of the structural units derived from the diol and the structural units derived from the dicarboxylic acid is 10 or more and 26 or less.

[0017] Examples of the preferred crystalline polyester from the viewpoints of storage stability and oil resistance in the asphalt composition of the present invention include the following crystalline polyesters. · A crystalline polyester containing structural units derived from 1,6 - hexanediol and structural units derived from sebacic acid, and having a melting point of 65°C or higher and 160°C or lower · A crystalline polyester containing structural units derived from ethylene glycol and structural units derived from dodecanedioic acid, and having a melting point of 65°C or higher and 160°C or lower ·A crystalline polyester containing structural units derived from 1,12-dodecanediol and structural units derived from sebacic acid, and having a melting point of 65°C or higher and 160°C or lower

[0018] (Molar ratio of the structural unit derived from the carboxylic acid component to the structural unit derived from the alcohol component) The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component (COOH group / OH group) is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0019] (Physical properties of the crystalline polyester) From the viewpoints of storage stability and oil resistance, the softening point of the crystalline polyester is preferably 45°C or higher, more preferably 60°C or higher, still more preferably 70°C or higher, and preferably 180°C or lower, more preferably 170°C or lower, still more preferably 160°C or lower. From the viewpoints of storage stability and oil resistance, the melting point of the crystalline polyester is 65°C or higher, preferably 66°C or higher, and 160°C or lower, preferably 155°C or lower, more preferably 150°C or lower.

[0020] From the viewpoints of promoting adsorption to the aggregate and improving oil resistance, the acid value of the crystalline polyester is preferably 2 mgKOH / g or more, more preferably 3 mgKOH / g or more, still more preferably 4 mgKOH / g or more, and from the viewpoint of storage stability, preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, still more preferably 20 mgKOH / g or less. From the viewpoints of storage stability and oil resistance, the weight average molecular weight Mw of the crystalline polyester is preferably 1000 or more, more preferably 2000 or more, still more preferably 3000 or more, and preferably 80000 or less, more preferably 40000 or less, still more preferably 20000 or less.

[0021] The softening point, melting point, acid value, hydroxyl value, and glass transition point of the crystalline polyester can be measured by the methods described in the Examples. Note that the softening point, melting point, acid value, hydroxyl value, and glass transition point can be adjusted by the raw material monomer composition, molecular weight, catalyst amount, or reaction conditions.

[0022] (Method for producing crystalline polyester) The method for producing the crystalline polyester is not particularly limited. For example, it can be produced by polycondensing the above-described alcohol component and carboxylic acid component. The temperature of the polycondensation reaction is not particularly limited, but from the viewpoints of adjusting reactivity, storage stability, and oil resistance, it is preferably 160°C or higher and 260°C or lower. For the polycondensation reaction, a tin(II) compound having no Sn-C bond, such as tin(II) bis(2-ethylhexanoate), can be used as a catalyst. From the viewpoints of storage stability and oil resistance, it is preferably 0.01 part by mass or more, more preferably 0.2 part by mass or more, and preferably 1.5 parts by mass or less, more preferably 0.6 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. For the polycondensation reaction, in addition to the catalyst, from the viewpoints of storage stability and oil resistance, a pyrogallol compound such as gallic acid can be used as an esterification co-catalyst. It is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, still more preferably 0.01 part by mass or more, and preferably 0.15 part by mass or less, more preferably 0.10 part by mass or less, still more preferably 0.05 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0023] The asphalt modifier of the present invention can be used, for example, to be mixed with asphalt to obtain an asphalt composition. After adding an aggregate to the obtained asphalt composition to form an asphalt mixture, it can be used for paving. The asphalt modifier of the present invention can be suitably used as a modifier for blending into an asphalt mixture containing an aggregate.

[0024] [Asphalt composition] The asphalt composition of the present invention is an asphalt composition containing asphalt and the above asphalt modifier. The asphalt composition of the present invention is an asphalt composition obtained by blending asphalt and the above asphalt modifier.

[0025] 〔Asphalt〕 The asphalt composition of the present invention contains asphalt. As the asphalt, various asphalts can be used. For example, in addition to straight asphalt which is paving petroleum asphalt, modified asphalt can be mentioned. Examples of the modified asphalt include blown asphalt; polymer-modified asphalt modified with a polymer material such as a thermoplastic elastomer or a thermoplastic resin. Straight asphalt is a residual asphalt substance obtained by subjecting crude oil to an atmospheric distillation unit, a vacuum distillation unit, etc. Further, blown asphalt means asphalt obtained by heating a mixture of straight asphalt and heavy oil and then blowing air thereinto for oxidation. The asphalt is preferably selected from the group consisting of straight asphalt and polymer-modified asphalt, more preferably modified asphalt from the viewpoint of further improving oil resistance, and more preferably straight asphalt from the viewpoint of versatility.

[0026] (Thermoplastic elastomer) Examples of the thermoplastic elastomer in the polymer-modified asphalt include at least one selected from styrene / butadiene block copolymer (hereinafter also simply referred to as "SB"), styrene / butadiene / styrene block copolymer (hereinafter also simply referred to as "SBS"), styrene / butadiene random copolymer (hereinafter also simply referred to as "SBR"), styrene / isoprene block copolymer (hereinafter also simply referred to as "SI"), styrene / isoprene / styrene block copolymer (hereinafter also simply referred to as "SIS"), styrene / isoprene random copolymer (hereinafter also simply referred to as "SIR"), ethylene / vinyl acetate copolymer, ethylene / acrylic ester copolymer, styrene / ethylene / butylene / styrene copolymer, styrene / ethylene / propylene / styrene copolymer, polyurethane-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, isobutylene / isoprene copolymer, polyisoprene, polychloroprene, synthetic rubbers other than the above, and natural rubber. Examples of commercially available products of the ethylene / acrylic ester copolymer include, for example, "Elvaroy" (manufactured by DuPont) and "Lexparl EEA" (manufactured by Mitsubishi Chemical Corporation). Among these, as the thermoplastic elastomer, from the viewpoint of the durability of asphalt pavement, it is preferably at least one selected from SB, SBS, SBR, SI, SIS, SIR, and ethylene / acrylic ester copolymer, more preferably at least one selected from SB, SBS, SBR, SI, SIS, and SIR, and still more preferably at least one selected from SBR and SBS. From the viewpoint of oil resistance, the content of the elastomer in the polymer-modified asphalt is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, still more preferably 2% by mass or more in 100% by mass of the polymer-modified asphalt, and is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, still more preferably 5% by mass or less.

[0027] The content of straight asphalt or modified asphalt in the asphalt composition is preferably 60% by mass or more, more preferably 65% by mass or more, still more preferably 70% by mass or more from the viewpoint of exerting asphalt performance, contains crystalline polyester, and is preferably 98% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass or less from the viewpoints of storage stability and oil resistance.

[0028] (Content of crystalline polyester) The content of the crystalline polyester contained in the asphalt composition of the present invention is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more with respect to 100 parts by mass of asphalt from the viewpoints of storage stability and oil resistance, and is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, still more preferably 20 parts by mass or less from the viewpoint of workability. However, the content of the crystalline polyester is determined according to the content of asphalt in the asphalt mixture.

[0029] [Method for producing asphalt composition] The method for producing the asphalt composition of the present invention preferably includes a step of mixing asphalt and the above asphalt modifier (crystalline polyester). The asphalt composition can be obtained by heating and melting asphalt, adding crystalline polyester, and stirring and mixing with a commonly used mixer until each component is uniformly dispersed. Examples of commonly used mixers include homomixers, dissolvers, paddle mixers, ribbon mixers, screw mixers, planetary mixers, vacuum countercurrent mixers, roll mills, twin-screw extruders, and the like.

[0030] The mixing temperature of asphalt and the asphalt modifier is preferably 100°C or higher, more preferably 120°C or higher, still more preferably 140°C or higher, and even more preferably 150°C or higher, from the viewpoint of uniformly dispersing the crystalline polyester constituting the asphalt modifier in the asphalt, and is preferably 230°C or lower, more preferably 210°C or lower, still more preferably 200°C or lower, and even more preferably 190°C or lower. Also, the mixing time of asphalt and the asphalt modifier is preferably 0.1 hour or longer, more preferably 0.5 hour or longer, still more preferably 1.0 hour or longer, and even more preferably 1.5 hours or longer, from the viewpoint of efficiently and uniformly dispersing the crystalline polyester constituting the asphalt modifier in the asphalt, and is preferably 10 hours or shorter, more preferably 7 hours or shorter, still more preferably 5 hours or shorter, and even more preferably 3 hours or shorter.

[0031] [Asphalt mixture] The asphalt composition of the present invention is a binder composition. For example, after adding aggregates to the asphalt composition to form an asphalt mixture, it can be used for paving. That is, the asphalt composition of the present invention is suitable for paving, and particularly suitable for road paving. The asphalt mixture of the present invention contains the aforementioned asphalt composition and aggregates. That is, the asphalt mixture contains at least asphalt, an asphalt modifier (crystalline polyester), and aggregates.

[0032] [Aggregates] As the aggregates, for example, crushed stones, cobblestones, gravels, sands, recycled aggregates, ceramics, etc. can be arbitrarily selected and used. Also, as the aggregates, either coarse aggregates with a particle size of 2.36 mm or more or fine aggregates with a particle size of less than 2.36 mm can be used. Examples of the coarse aggregates include crushed stones with a particle size range of 2.36 mm or more and less than 4.75 mm, crushed stones with a particle size range of 4.75 mm or more and less than 12.5 mm, crushed stones with a particle size range of 12.5 mm or more and less than 19 mm, and crushed stones with a particle size range of 19 mm or more and less than 31.5 mm. The fine aggregate is preferably a fine aggregate having a particle size of 0.075 mm or more and less than 2.36 mm. Examples of the fine aggregate include river sand, hill sand, mountain sand, sea sand, crushed sand, fine sand, screenings, crushed stone dust, silica sand, artificial sand, glass cullet, foundry sand, and recycled aggregate crushed sand. The above particle size is the value defined in JIS A5001:2008. Among these, a combination of coarse aggregate and fine aggregate is preferable.

[0033] Note that the fine aggregate may contain a filler having a particle size of less than 0.075 mm. Examples of the filler include sand, fly ash, calcium carbonate such as limestone powder, and slaked lime. Among these, calcium carbonate is preferable from the viewpoint of improving the dry strength. From the viewpoint of improving the dry strength, the average particle size of the filler is preferably 0.001 mm or more, and preferably 0.05 mm or less, more preferably 0.03 mm or less, and still more preferably 0.02 mm or less. The average particle size of the filler can be measured with a laser diffraction particle size distribution measuring device. Here, the average particle size means the average particle size (D 50 ) at 50% volume cumulative.

[0034] (Method for measuring the average particle size of the filler) The average particle size of the filler is a value measured under the following conditions using a laser diffraction particle size distribution measuring device "LA-950" (manufactured by Horiba, Ltd.). · Measurement method: Flow method · Dispersion medium: Ethanol · Sample preparation: 2 mg / 100 mL · Dispersion method: Stirring, built-in ultrasonic wave for 1 minute

[0035] From the viewpoint of the durability of the asphalt pavement, the mass ratio of the coarse aggregate to the fine aggregate (coarse aggregate / fine aggregate) is preferably 10 / 90 or more, more preferably 20 / 80 or more, still more preferably 30 / 70 or more, and preferably 90 / 10 or less, more preferably 80 / 20 or less, and still more preferably 70 / 30 or less.

[0036] Suitable compounding examples in the asphalt mixture are as follows. (1) One example of the asphalt mixture includes, for example, coarse aggregate of 30% by volume or more and less than 45% by volume, fine aggregate of 30% by volume or more and 50% by volume or less, and an asphalt composition of 5% by volume or more and 10% by volume or less (fine-grained asphalt). (2) One example of the asphalt mixture includes, for example, coarse aggregate of 45% by volume or more and less than 70% by volume, fine aggregate of 20% by volume or more and 45% by volume or less, and an asphalt composition of 3% by volume or more and 10% by volume or less (dense-grained asphalt). (3) One example of the asphalt mixture includes, for example, coarse aggregate of 70% by volume or more and 80% by volume or less, fine aggregate of 10% by volume or more and 20% by volume or less, and an asphalt composition of 3% by volume or more and 10% by volume or less (porous asphalt).

[0037] Other components may be further compounded in the asphalt mixture as needed. Regarding the blending ratio of asphalt in a conventional asphalt mixture containing aggregate and asphalt, it is usually used according to the optimum asphalt amount determined from the "Blending Design of Asphalt Composition" described in the "Pavement Design and Construction Guidelines" issued by the Japan Road Association, a public interest incorporated association. In the present invention, the above optimum asphalt amount corresponds to the total amount of asphalt and an asphalt modifier (crystalline polyester). However, it is not necessary to be limited to the method described in the "Pavement Design and Construction Guidelines", and it may be determined by other methods.

[0038] [Method for manufacturing asphalt mixture] The method for manufacturing the asphalt mixture of the present invention includes a step of mixing asphalt, heated aggregate, and an asphalt modifier (crystalline polyester) simultaneously or in any order. Specific production methods of asphalt mixtures include conventional production methods of asphalt mixtures such as the plant mix method and the premix method. All of them are methods of adding asphalt and crystalline polyester to heated aggregates. Examples of the addition method include the premix method in which asphalt and crystalline polyester are dissolved in advance, or the plant mix method in which crystalline polyester is introduced into asphalt. Among these, from the perspective of the durability of asphalt pavement, the premix method is preferred. More specifically, the production method of the asphalt mixture preferably includes, in the mixing step, (i) adding and mixing asphalt to the heated aggregate and then adding and mixing crystalline polyester, (ii) adding and mixing asphalt and crystalline polyester to the heated aggregate simultaneously, or (iii) adding and mixing a mixture of pre-heated and mixed asphalt and crystalline polyester to the heated aggregate. Among these, from the perspective of the durability of asphalt pavement, the method (iii) is preferred.

[0039] From the perspective of the durability of asphalt pavement, the temperature of the heated aggregate in the methods (i) to (iii) is preferably 130 °C or higher, more preferably 150 °C or higher, still more preferably 170 °C or higher, and even more preferably 180 °C or higher. From the perspective of preventing thermal degradation of asphalt, it is preferably 230 °C or lower, more preferably 210 °C or lower, and still more preferably 200 °C or lower.

[0040] In the mixing step, from the viewpoint of the durability of the asphalt pavement, the mixing temperature is preferably 130°C or higher, more preferably 150°C or higher, still more preferably 170°C or higher, and even more preferably 180°C or higher. From the viewpoint of preventing thermal degradation of the asphalt, it is preferably 230°C or lower, more preferably 210°C or lower, and still more preferably 200°C or lower. The mixing time in the mixing step is not particularly limited, and is preferably 30 seconds or longer, more preferably 1 minute or longer, still more preferably 2 minutes or longer, and even more preferably 5 minutes or longer. The upper limit of the time is not particularly limited, and is preferably about 30 minutes.

[0041] From the viewpoint of the durability of the asphalt pavement, the method for producing the asphalt mixture preferably has a step of holding the obtained mixture at the above mixing temperature after the mixing step. In the holding step, the mixture may be further mixed, but it is sufficient to hold it at a temperature not lower than the aforementioned temperature. In the holding step, the mixing temperature is preferably 130°C or higher, more preferably 150°C or higher, still more preferably 170°C or higher, and even more preferably 180°C or higher. From the viewpoint of preventing thermal degradation of the asphalt composition, it is preferably 230°C or lower, more preferably 210°C or lower, and still more preferably 200°C or lower. The holding time in the holding step is preferably 0.5 hour or longer, more preferably 1 hour or longer, and still more preferably 1.5 hours or longer. The upper limit of the time is not particularly limited, but is, for example, about 5 hours.

[0042] [Road Paving Method] The asphalt mixture of the present invention is suitable for road paving. As described above, an asphalt mixture obtained by adding an aggregate to an asphalt composition is used for road paving. The road paving method includes a step of constructing the aforementioned asphalt mixture on a road to form an asphalt paving material layer. Specifically, the road paving method includes a step of obtaining an asphalt mixture by mixing asphalt, the aforementioned crystalline polyester, and aggregates (step 1), and a step of constructing the asphalt mixture obtained in step 1 on a road to form an asphalt paving material layer (step 2). The asphalt paving material layer is usually a base layer or a surface layer, and preferably a surface layer from the viewpoint of exhibiting the effect of oil resistance.

[0043] The asphalt mixture may be compacted and constructed by a known construction machine composition in a similar manner. When used as a heated asphalt mixture, the compaction temperature is preferably 100°C or higher, more preferably 120°C or higher, still more preferably 130°C or higher, and preferably 200°C or lower, more preferably 180°C or lower, from the viewpoint of the durability of asphalt paving.

[0044] The present invention further discloses the following aspects. <1> An asphalt modifier comprising a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and consisting of a crystalline polyester having a melting point of 65°C or higher and 160°C or lower. <2> The asphalt modifier according to <1> above, wherein the linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 20 carbon atoms, and the carboxylic acid component contains one or more selected from linear aliphatic dicarboxylic acids having 2 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. <3> The asphalt modifier according to <1> or <2> above, wherein the linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 12 carbon atoms, and the carboxylic acid component contains one or more selected from linear aliphatic dicarboxylic acids having 2 to 16 carbon atoms and aromatic dicarboxylic acids having 8 to 12 carbon atoms. <4> The linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 12 carbon atoms, and the carboxylic acid component contains one or more selected from linear aliphatic dicarboxylic acids having 4 to 14 carbon atoms and aromatic dicarboxylic acids having 8 to 12 carbon atoms. The asphalt modifier according to any one of <1> to <3> above. <5> The linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 20 carbon atoms, the carboxylic acid component contains a linear aliphatic dicarboxylic acid having 2 to 20 carbon atoms, and the sum of the carbon atoms of the structural units derived from the alcohol component containing the linear aliphatic alcohol and the carbon atoms of the structural units derived from the carboxylic acid component is 4 or more and 40 or less. The asphalt modifier according to <1> or <2> above. <6> The linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 12 carbon atoms, the carboxylic acid component contains a linear aliphatic dicarboxylic acid having 2 to 16 carbon atoms, and the sum of the carbon atoms of the structural units derived from the alcohol component containing the linear aliphatic alcohol and the carbon atoms of the structural units derived from the carboxylic acid component is 4 or more and 28 or less. The asphalt modifier according to any one of <1> to <3> above. <7> The linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 12 carbon atoms, the carboxylic acid component contains a linear aliphatic dicarboxylic acid having 4 to 14 carbon atoms, and the sum of the carbon atoms of the structural units derived from the alcohol component containing the linear aliphatic alcohol and the carbon atoms of the structural units derived from the carboxylic acid component is 6 or more and 26 or less. The asphalt modifier according to any one of <1> to <4> above. <8> The linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 20 carbon atoms, the carboxylic acid component contains an aromatic dicarboxylic acid having 8 to 20 carbon atoms, and the sum of the carbon atoms of the structural units derived from the alcohol component containing the linear aliphatic alcohol and the carbon atoms of the structural units derived from the carboxylic acid component is 10 or more and 40 or less. The asphalt modifier according to <1> or <2> above. <9> The linear aliphatic alcohol contains an α,ω-linear aliphatic diol having 2 to 16 carbon atoms, the carboxylic acid component contains an aromatic dicarboxylic acid having 8 to 12 carbon atoms, and the total number of carbon atoms of the structural unit derived from the linear aliphatic alcohol and the number of carbon atoms of the structural unit derived from the carboxylic acid component is 10 or more and 26 or less. The asphalt modifier according to <1> or <2> above.

Examples

[0045] For various physical properties, measurement and evaluation were performed by the following methods. In the following examples and comparative examples, parts and % are based on mass unless otherwise specified.

[0046] 〔Softening point of resin (T s )〕 Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating 1 g of the sample at a heating rate of 6 °C / min, a load of 1.96 MPa was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger descent amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[0047] 〔Crystallinity index〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan and cooled from room temperature (20 °C) to 0 °C at a cooling rate of 10 °C / min. Then the sample was maintained at the same temperature for 1 minute, and thereafter, the heat quantity was measured while heating from 0 °C to 180 °C at a heating rate of 10 °C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (T max ). T s / T max The crystallinity index was determined by. A crystalline polyester is one having a crystallinity index of 0.6 or more and 1.4 or less.

[0048] 〔Melting point of resin (T m ) and glass transition point (T g)〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, heated to 200 °C, and then cooled from that temperature to 0 °C at a cooling rate of 10 °C / min. Subsequently, measurement was carried out while heating to 150 °C at a heating rate of 10 °C / min. The temperature of the peak with the maximum peak area was taken as the melting point if the difference from the softening point was within 20 °C. The temperature at the intersection of the extension line of the baseline below the maximum peak temperature of endotherm and the tangent line showing the maximum slope from the rising part of the peak to the apex of the peak was defined as the glass transition point.

[0049] Production Examples 1 to 4 and 10 (Crystalline polyesters C1 to C4 and C10) The raw material monomers shown in Table 1-1 and Table 1-3 were placed in a 10 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a dehydrating tube, a nitrogen inlet tube, and a thermocouple, held at 140 °C for 6 hours under a nitrogen atmosphere, further heated to 200 °C over 6 hours, then tin(II) bis(2-ethylhexanoate) and gallic acid were added, reacted at 200 °C for 1 hour, and then reacted at 8.3 kPa for 1 hour to obtain crystalline polyesters C1 to C4 and C10.

[0050] Production Examples 5, 6, 9 (Crystalline polyesters C5, C6, C9) The raw material monomers shown in Table 1-2 and 2 g of tertiary butyl catechol were placed in a 10 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a dehydrating tube, a nitrogen inlet tube, and a thermocouple, held at 140 °C for 6 hours under a nitrogen atmosphere, further heated to 200 °C over 6 hours, then tin(II) bis(2-ethylhexanoate) and gallic acid were added, reacted at 200 °C for 1 hour, and then reacted at 8.3 kPa for 1 hour to obtain crystalline polyesters C5, C6, and C9.

[0051] Production Examples 7, 8 (Crystalline polyesters C7, C8) The raw material monomers shown in Table 1-2 were placed in a 10 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a dehydrating tube, a nitrogen inlet tube, and a thermocouple. Under a nitrogen atmosphere, tin(II) bis(2-ethylhexanoate) and gallic acid were added, and the temperature was raised to 180 °C. After holding at 180 °C for 1 hour, the temperature was raised from 180 °C to 210 °C at a rate of 10 °C / hour, and then a polycondensation reaction was carried out at 210 °C for 6 hours. Thereafter, the reaction was carried out at 210 °C and 8.3 kPa for 1 hour to obtain crystalline polyesters C7 and C8.

[0052] Production Example 11 (Amorphous Polyester A2) The raw material monomers other than adipic acid shown in Table 1-3 were placed in a 10 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a dehydrating tube, a nitrogen inlet tube, and a thermocouple. Under a nitrogen atmosphere, tin(II) bis(2-ethylhexanoate) and gallic acid were added, and the temperature was raised to 180 °C. After holding at 180 °C for 1 hour, the temperature was raised from 180 °C to 210 °C at a rate of 10 °C / hour, and then a polycondensation reaction was carried out at 210 °C for 7 hours. Further, the reaction was carried out at 210 °C and 8.3 kPa for 1 hour. Next, adipic acid was added, and the reaction was carried out at 210 °C and 10 kPa until the described softening point was reached to obtain amorphous polyester A2.

[0053] Production Example 12 (Crystalline Polyester A3) The raw material monomers shown in Table 1-3 were placed in a 10 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a dehydrating tube, a nitrogen inlet tube, and a thermocouple. Under a nitrogen atmosphere, tin(II) bis(2-ethylhexanoate) and gallic acid were added, and the temperature was raised to 180 °C. After holding at 180 °C for 1 hour, the temperature was raised from 180 °C to 210 °C at a rate of 10 °C / hour, and then a polycondensation reaction was carried out at 210 °C for 6 hours. Thereafter, the reaction was carried out at 210 °C and 8.3 kPa for 1 hour to obtain crystalline polyester A3.

[0054]

Table 1-1

[0055]

Table 1-2

[0056]

Table 1-3

[0057] The abbreviations of the alcohol components and carboxylic acid components used are as follows. BPA-PO: Polyoxypropylene (2.2) adduct of bisphenol A BPA-EO: Polyoxyethylene (2.2) adduct of bisphenol A EG: Ethylene glycol BD: Butanediol HD: Hexanediol DD: Dodecanediol HDD: Hexadecanediol FA: Fumaric acid SA:: Sebacic acid DDA: Dodecanedioic acid TDA: Tetradecanedioic acid HDA: Hexadecanedioic acid TPA: Terephthalic acid ADA: Adipic acid

[0058] As polyester A1, poly-ε-caprolactone (molecular weight of about 10,000, manufactured by Fujifilm Wako Pure Chemical Corporation) was used (*1 in the table).

[0059] In the following examples, asphalts with a PG grade of 64-22 (straight asphalt) and a PG grade of 76-22 (modified asphalt) manufactured by Associated Asphalt were used as the asphalt. Also, aggregates manufactured by Blythe Construction were used as the aggregates. Among 3000 g of the aggregates, it contains 750 g of gravel (coarse aggregate), 1950 g of screenings (fine aggregate), and 300 g of mountain sand (fine aggregate). The passing mass percentages of each component are as follows. Passing mass percentage: 〔Gravel〕 Sieve size 9.50 mm: 90.4 mass% Sieve size 8.00 mm: 73.3 mass% Sieve size 4.75 mm: 24.8 mass% Sieve size 2.80 mm: 3.9 mass% Sieve size 1.00 mm: 1.2 mass% Sieve size 0.50 mm: 0.8 mass% 〔Screenings〕 Sieve size 9.50 mm: 100.0 mass% Sieve size 8.00 mm: 99.9 mass% Sieve size 4.75 mm: 98.2 mass% Sieve size 2.80 mm: 77.4 mass% Sieve size 1.00 mm: 36.8 mass% Sieve size 0.50 mm: 22.1 mass% 〔Mountain sand〕 Sieve size 9.50 mm: 100.0 mass% Sieve size 8.00 mm: 100.0 mass% Sieve size 4.75 mm: 98.0 mass% Sieve size 2.80 mm: 94.2 mass% Sieve size 1.00 mm: 70.6 mass% Sieve size 0.50 mm: 33.6 mass%

[0060] Example 1-1 〔Asphalt composition〕 Weighed 100 g of asphalt pre-heated to 180 °C into a 200 mL stainless steel beaker, added 5 g of crystalline polyester C1 thereto, and stirred at 180 °C and a stirring speed of 400 rpm for 2 hours. The asphalt composition AS-1 prepared by the above process was subjected to a storage stability test. The results are shown in Table 2. Examples 1-2 to 1-11, Comparative Examples 1-1 to 1-3 An asphalt composition was prepared in the same manner as in Example 1-1, except that the formulation shown in Table 2 was changed. A storage stability test was conducted, and the results are shown in Table 2.

[0061] Example 2-1 [Asphalt Mixture] Among 233 g of asphalt, 2.33 g of crystalline polyester C1, and 3000 g of aggregate, the aggregate was put into a mortar mixer and mixed at 180 °C for 30 seconds. Then, asphalt was added and mixed for 1 minute. Further, crystalline polyester C1 was added and mixed for 1 minute. The obtained asphalt mixture was stored at 180 °C for 15 minutes, then 1200 g of the mixture was filled into a mold, and after molding by tamping on one side 75 times and both sides using an asphalt automatic tamping device (NA-507) manufactured by Nakajima Giken Co., Ltd., it was allowed to cool slowly to room temperature over 15 hours to obtain an asphalt specimen M-1. This specimen was subjected to an oil resistance evaluation test. The results are shown in Table 3.

[0062] Examples 2-2 to 2-11, Comparative Examples 2-1 to 2-4 An asphalt specimen was prepared in the same manner as in Example 2-1, except that the formulation shown in Table 3 was changed. An oil resistance evaluation test was conducted, and the results are shown in Table 3.

[0063] [Evaluation Method] [Storage Stability Test of Asphalt-Polyester Mixture] 50 mL of the asphalt composition was poured into a sample bottle (inner diameter 3.5 cm × height 7.8 cm), stored in an oven at 180 °C for 18 hours, and then the height of the precipitation of the polyester in the asphalt composition was measured as an index of storage stability. The smaller the height of the precipitation, the better the storage stability.

[0064] 〔Oil resistance of asphalt specimens〕 The asphalt specimen was immersed in kerosene (manufactured by FUJIFILM Wako Pure Chemical Corporation) for 2 minutes. A 4L round can for oil was used as the immersion container, and a wire mesh platform with a height of 1 cm and a length and width of about 7 cm was installed at the bottom of the can so that the kerosene could come into good contact with all surfaces of the specimen. After 2 minutes of immersion, the specimen was taken out, the kerosene on the surface was wiped off with a paper towel, and the weight was measured. The weight at this time was designated as W a . After the weight measurement, the specimen was immersed in kerosene again for 24 hours. After 24 hours, the specimen was taken out, the kerosene on the surface was wiped off with a paper towel, and after drying at room temperature (20°C) in an air atmosphere for another 24 hours, the weight was measured again. The weight at this time was designated as W b . The weight loss rate, which is an index of oil resistance, was determined by the following calculation formula. Weight loss rate (%) = [(W a - W b ) / W a × 100 The smaller the weight loss rate, the better the oil resistance of the asphalt specimen can be said to be. In addition, the appearance of the specimen immersed in kerosene for 24 hours was evaluated according to the following criteria. A: Maintains the same appearance as before oil immersion B: Slight peeling of asphalt is observed C: Partial peeling of asphalt and loss of aggregates are observed D: Peeling of asphalt and loss of aggregates are significant

[0065]

Table 2

[0066]

Table 3

[0067] In the asphalt compositions of Comparative Examples 1-2 containing an amorphous polyester and Comparative Example 1-3 containing a crystalline polyester with a high melting point, precipitation of the polyester was remarkable after storage at 180°C for 18 hours, and the storage stability was insufficient. Further, Comparative Example 2-1 not containing a crystalline polyester, Comparative Examples 2-2, 2-3, and 2-4 containing a polyester other than a specific crystalline polyester had insufficient oil resistance to kerosene. In contrast, according to the present invention, an asphalt composition containing a predetermined amount of a specific crystalline polyester does not cause precipitation even after storage at 180°C for 18 hours and has excellent storage stability, and it can be seen that an asphalt specimen containing a predetermined amount of a specific crystalline polyester has excellent oil resistance to kerosene. Figures 1 to 4 are external appearance photographs of asphalt specimens immersed in kerosene for 24 hours. Figure 1 is an external appearance photograph of a specimen using the asphalt mixture of Example 2-1. The asphalt is uniformly distributed, no exposure of the aggregate is seen, and the asphalt specimen maintains the same appearance as before oil immersion. Figure 2 is an external appearance photograph of a specimen using the asphalt mixture of Example 2-9. Although slight peeling of the asphalt is seen, the asphalt is almost uniformly distributed, and the asphalt specimen as a whole maintains its shape and is considered not to have a problem for actual use. Figure 3 is an external appearance photograph of a specimen using the asphalt mixture of Comparative Example 2-2. There are parts where peeling of the asphalt is progressing and loss of the aggregate is seen, and it is not suitable for use. Figure 4 is an external appearance photograph of a specimen using the asphalt mixture of Comparative Example 2-1. The peeling of the asphalt and the loss of the aggregate are remarkable, and the asphalt specimen does not maintain its original shape and is not suitable for use.

Claims

1. It consists of a crystalline polyester containing a structural unit derived from an alcohol component containing a linear aliphatic alcohol and a structural unit derived from a carboxylic acid component, and has a melting point of 65°C or higher and 160°C or lower. An asphalt modifier in which the content of the linear aliphatic alcohol is 80 mol% or more in the alcohol component.

2. The asphalt modifier according to claim 1, wherein the linear aliphatic alcohol contains a linear aliphatic diol.

3. The asphalt modifier according to claim 2, wherein the linear aliphatic diol is a linear aliphatic diol having 2 to 20 carbon atoms.

4. The asphalt modifier according to claim 2 or 3, wherein the linear aliphatic diol is an α,ω-linear aliphatic diol.

5. The asphalt modifier according to any one of claims 1 to 4, wherein the carboxylic acid component contains one or more selected from a linear aliphatic dicarboxylic acid and an aromatic dicarboxylic acid.

6. The asphalt modifier according to claim 5, wherein the linear aliphatic dicarboxylic acid is a linear aliphatic dicarboxylic acid having 2 to 20 carbon atoms, and the aromatic dicarboxylic acid is an aromatic dicarboxylic acid having 8 to 20 carbon atoms.

7. The asphalt modifier according to claim 5 or 6, wherein the total content of the linear aliphatic dicarboxylic acid and the aromatic dicarboxylic acid is 80 mol% or more in the carboxylic acid component.

8. The asphalt modifier according to any one of claims 1 to 7, wherein the total number of carbon atoms of the structural unit derived from the alcohol component containing the linear aliphatic alcohol and the structural unit derived from the carboxylic acid component is 4 or more and 40 or less.

9. An asphalt composition containing asphalt and the asphalt modifier according to any one of claims 1 to 8.

10. The asphalt composition according to claim 9, wherein the content of the asphalt modifier is 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the asphalt.

11. An asphalt mixture containing the asphalt composition according to claim 9 or 10 and an aggregate.

12. A method for producing the asphalt composition according to claim 9 or 10, the method having a step of mixing the asphalt and the crystalline polyester.

13. A road paving method having a step of constructing the asphalt mixture according to claim 11 on a road to form an asphalt pavement layer.

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