Asphalt composition

Abstract

To provide an asphalt composition, an asphalt modifier, an asphalt mixture, and a paving method for yielding asphalt pavement having both superior resistance to deflection and cracking.SOLUTION: An asphalt composition comprises asphalt, a polyester resin, and a polyhydric phenol compound.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an asphalt composition, an asphalt modifier, an asphalt mixture, and a paving method.

Background Art

[0002] For paving roads such as motorways, parking lots, freight yards, and sidewalks, asphalt paving using an asphalt mixture is carried out because it is relatively easy to lay and the time from the start of paving work to the start of traffic is short. Since this asphalt paving forms a road surface with an asphalt mixture in which aggregates are bound with asphalt, the paved road has good hardness and durability. However, the asphalt pavement surface deteriorates due to long-term use, and ruts and cracks occur, so it is necessary to repair the pavement. Repairing the pavement has increased maintenance costs and has also had a significant impact on automobile traffic.

[0003] Patent Document 1 discloses an asphalt composition containing asphalt, a polyester resin, and a powder of a salt composed of an anion derived from a strong acid and an alkaline earth metal cation, as an asphalt composition capable of forming a pavement surface having excellent durability and flexibility.

Prior Art Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] ​The asphalt composition described in Patent Document 1 can obtain an asphalt pavement having excellent strength, durability, and flexibility by modifying asphalt with a polyester resin. On the other hand, there is a demand for an asphalt composition that suppresses cracking of asphalt pavement caused by long-term use. The present invention relates to an asphalt composition, an asphalt modifier, an asphalt mixture, and a paving method for obtaining an asphalt pavement capable of achieving both excellent flexibility and crack resistance.

Means for Solving the Problems

[0006] The present invention relates to the following [1] to [4]. 〔1〕 An asphalt composition containing asphalt, a polyester resin, and a polyhydric phenol compound. 〔2〕 An asphalt mixture containing the asphalt composition according to [1] above and aggregates. 〔3〕 A paving method having a step of constructing the asphalt mixture according to [2] above on a paving target to form an asphalt paving material layer. 〔4〕 An asphalt modifier containing a polyester resin and a polyhydric phenol compound.

Effects of the Invention

[0007] According to the present invention, it is possible to provide an asphalt composition, an asphalt modifier, an asphalt mixture, and a paving method for obtaining an asphalt pavement capable of achieving both excellent flexibility and crack resistance.

Modes for Carrying Out the Invention

[0008] [Asphalt Composition] The asphalt composition of the present invention contains asphalt, a polyester resin, and a polyhydric phenol compound.

[0009] The inventors have found that an asphalt pavement having excellent flexibility and crack resistance can be obtained by using an asphalt mixture containing the asphalt composition of the present invention and an aggregate. Although the detailed mechanism by which the effects of the present invention are obtained is unknown, it is thought as follows in part. The asphalt composition of the present invention contains asphalt, a polyester resin, and a polyhydric phenol compound. In the asphalt mixture containing this asphalt composition and an aggregate, when the polyester resin dispersed in the asphalt composition melts when used for road paving or the like, and the melted polyester resin covers the aggregate surface when it comes into contact with the aggregate, the adhesion between the aggregate and the asphalt becomes strong, and the adhesion strength between the aggregates can also be increased, and it is considered that the stability of the asphalt pavement can be maintained and the flexibility is improved. In addition to this, a polyhydric phenol compound such as a gallic acid compound having a polar part and a nonpolar part interacts more easily with the aggregate than the polyester resin in the asphalt pavement. When the melted polyester resin comes into contact with the aggregate and covers the aggregate surface, it is interposed between the aggregate and the polyester resin, and it is considered that the flexibility and tackiness of the asphalt pavement are improved. As a result, it is considered that the crack resistance of the asphalt pavement is improved. As described above, the asphalt pavement using the asphalt mixture containing the asphalt composition of the present invention and the aggregate is considered to have excellent crack resistance while maintaining excellent flexibility because it achieves a high balance between strength and flexibility.

[0010] The definitions of various terms in this specification are shown below. In the polyester resin, the "structural unit derived from the alcohol component" means a structure obtained by removing a hydrogen atom from the hydroxy group of the alcohol component, and the "structural unit derived from the carboxylic acid component" means a structure obtained by removing a hydroxy group from the carboxy 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 generate an acid and alkyl esters of carboxylic acids (for example, the alkyl group has 1 to 3 carbon atoms). When the carboxylic acid component is an alkyl ester of a carboxylic acid, the number of carbon atoms of the carboxylic acid does not include the number of carbon atoms of the alkyl group that is the alcohol residue of the ester. Whether the resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the temperature of the maximum endothermic peak (softening point (°C) / maximum endothermic peak temperature (°C)). A crystalline resin is one with a crystallinity index of 0.3 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index is less than 0.3 or more than 1.4. The crystallinity index can be appropriately adjusted according to the type and ratio of the raw material monomers, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate.

[0011] <Polyester resin> The polyester resin contained in the asphalt composition of the present invention is a polycondensate of an alcohol component and a carboxylic acid component, including a structural unit derived from the alcohol component and a structural unit derived from the carboxylic acid component. Examples of the polyester resin include an amorphous polyester resin and a crystalline polyester resin, and an amorphous polyester resin is preferred. Hereinafter, the physical properties of the alcohol component, carboxylic acid component, and polyester resin will be described.

[0012] (Alcohol component) Examples of the alcohol component include aliphatic diols, alicyclic diols, aromatic diols, polyhydric alcohols with a valence of 3 or more, etc. These alcohol components can be used alone or in combination of two or more.

[0013] The aliphatic diol is preferably a straight-chain or branched aliphatic diol with 2 to 12 carbon atoms in the main chain, more preferably a straight-chain or branched aliphatic diol with 2 to 8 carbon atoms in the main chain. Moreover, the aliphatic diol is preferably a saturated aliphatic diol. Specific examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,10-decanediol, and 1,12-dodecanediol.

[0014] Examples of the alicyclic diol include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), an alkylene oxide adduct of hydrogenated bisphenol A, cyclohexanediol, and cyclohexanedimethanol.

[0015] Examples of the aromatic diol include bisphenol A (2,2-bis(4-hydroxyphenyl)propane) and an alkylene oxide adduct of bisphenol A. Examples of the alkylene oxide adduct of bisphenol A include an alkylene oxide adduct of bisphenol A represented by the following formula (I).

[0016]

Chemical formula

[0017] In formula (I), OR 1 and R 1 O is an alkyleneoxy group, R 1 is an alkylene group having 2 or 3 carbon atoms, x and y represent positive numbers indicating the average number of moles of alkylene oxide added, and the sum of x and y is preferably 1 or more, more preferably 1.5 or more, and preferably 16 or less, more preferably 8 or less, still more preferably 4 or less, from the viewpoints of the productivity and availability of the alkylene oxide adduct of bisphenol A.

[0018] Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A. These alkylene oxide adducts of bisphenol A can be used alone or in combination of two or more.

[0019] From the viewpoint of facilitating the control of the glass transition point and softening point of the polyester resin, the polyhydric alcohol having 3 or more valences is preferably a trihydric alcohol. The number of carbon atoms of the polyhydric alcohol having 3 or more valences is 3 or more and 6 or less from the viewpoints of availability and economy. Examples of the polyhydric alcohol having 3 or more valences include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0020] From the viewpoint of physical property adjustment, the alcohol component can further contain a monohydric aliphatic alcohol. Examples of the monohydric aliphatic alcohol include lauryl alcohol, myristyl alcohol, palmityl alcohol, and stearyl alcohol. These monohydric aliphatic alcohols can be used alone or in combination of two or more.

[0021] (Carboxylic acid component) Examples of the carboxylic acid component include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids having 3 or more valences and 6 or less valences. These carboxylic acid components can be used alone or in combination of two or more.

[0022] Examples of the aliphatic dicarboxylic acid include aliphatic dicarboxylic acids having preferably 4 or more carbon atoms in the main chain, and preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less carbon atoms, such as fumaric acid, maleic acid, oxalic acid, malonic acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, or anhydrides thereof, and alkyl esters thereof (for example, having 1 to 3 carbon atoms in the alkyl group). Examples of the substituted succinic acid include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid.

[0023] Examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or anhydrides thereof, and alkyl esters thereof (for example, having 1 to 3 carbon atoms in the alkyl group). Among the above aromatic dicarboxylic acids, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred, from the viewpoint of improving the flexibility and crack resistance.

[0024] The polyvalent carboxylic acid having 3 to 6 valences is preferably a trivalent carboxylic acid. Examples of the polyvalent carboxylic acid having 3 to 6 valences include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, or acid anhydrides thereof.

[0025] From the viewpoint of physical property adjustment, the carboxylic acid component may further contain a monovalent aliphatic carboxylic acid. Examples of the monovalent aliphatic carboxylic acid include monovalent aliphatic carboxylic acids having 12 to 20 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, and alkyl (having 1 to 3 carbon atoms) esters of these acids. These monovalent aliphatic carboxylic acids can be used alone or in combination of two or more.

[0026] (Constituent unit derived from polyethylene terephthalate) The polyester resin can contain structural units derived from ethylene glycol and terephthalic acid derived from polyethylene terephthalate. Polyethylene terephthalate may contain a small amount of components such as butanediol and isophthalic acid in addition to the structural units derived from ethylene glycol and terephthalic acid. Polyethylene terephthalate is preferably recycled polyethylene terephthalate. When the polyester resin contains structural units composed of ethylene glycol and terephthalic acid derived from polyethylene terephthalate, the "structural unit derived from the alcohol component" includes the structural unit derived from ethylene glycol derived from polyethylene terephthalate, and the "structural unit derived from the carboxylic acid component" includes the structural unit derived from terephthalic acid derived from polyethylene terephthalate.

[0027] (Preferred embodiments of the polyester resin) In a preferred embodiment of the polyester resin, from the viewpoint of ensuring compatibility with asphaltenes in asphalt, the content of terephthalic acid in 100 mol% of the carboxylic acid component is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, still more preferably 75 mol% or more, and preferably 100 mol% or less. Also, in a preferred embodiment of the polyester resin, from the viewpoint of interacting with asphaltenes in asphalt to further improve the resistance to deflection, the content of the alkylene oxide adduct of bisphenol A represented by formula (I) in 100 mol% of the alcohol component is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, and preferably 100 mol% or less.

[0028] (Physical properties of the polyester resin) From the viewpoint of improving the resistance to deflection and cracking of asphalt pavement, the softening point of the polyester resin is preferably 80 °C or higher, more preferably 90 °C or higher, and preferably 140 °C or lower, more preferably 130 °C or lower, still more preferably 120 °C or lower. From the same perspective, the glass transition temperature of the polyester resin is preferably 40°C or higher, more preferably 45°C or higher, still more preferably 48°C or higher, and preferably 80°C or lower, more preferably 75°C or lower, still more preferably 70°C or lower. From the same perspective, the maximum peak temperature of the endotherm of the polyester resin is preferably 40°C or higher, more preferably 45°C or higher, still more preferably 48°C or higher, and preferably 80°C or lower, more preferably 75°C or lower, still more preferably 70°C or lower. From the same perspective, the weight average molecular weight Mw of the polyester resin is preferably 5000 or higher, more preferably 7000 or higher, still more preferably 8000 or higher, and preferably 70000 or lower, more preferably 40000 or lower, still more preferably 25000 or lower. From the perspective of the productivity of the polyester resin, the acid value of the polyester resin is preferably 0 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, still more preferably 5 mgKOH / g or higher, and from the perspective of forming an asphalt pavement surface with excellent durability, it is preferably 30 mgKOH / g or lower, more preferably 25 mgKOH / g or lower, still more preferably 20 mgKOH / g or lower. From the perspective of the productivity of the polyester resin, the hydroxyl value of the polyester resin is preferably 0 mgKOH / g or higher, more preferably 5 mgKOH / g or higher, still more preferably 10 mgKOH / g or higher, even more preferably 15 mgKOH / g or higher, and from the perspective of forming an asphalt pavement surface with excellent durability, it is preferably 40 mgKOH / g or lower, more preferably 35 mgKOH / g or lower, still more preferably 30 mgKOH / g or lower.

[0029] The softening point, glass transition temperature, maximum peak temperature of the endotherm, weight average molecular weight Mw, acid value and hydroxyl value of the polyester resin can be measured by the methods described in the examples. Incidentally, the softening point, glass transition temperature, maximum peak temperature of the endotherm, weight average molecular weight Mw, acid value and hydroxyl value can be adjusted by the raw material monomer composition, molecular weight, catalyst amount or reaction conditions.

[0030] The polyester resin may be a polyester resin modified to such an extent that its properties are not substantially impaired. Specifically, examples of the modified polyester resin include polyester resins grafted or blocked with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Preferred modified polyester resins include urethane-modified polyester resins obtained by extending a polyester resin with a polyisocyanate compound.

[0031] (Content of polyester resin) From the viewpoint of improving flexibility, the content of the polyester resin is preferably 1 part by mass or more, more preferably 4 parts by mass or more, still more preferably 8 parts by mass or more, based on 100 parts by mass of asphalt. From the viewpoint of improving crack resistance, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, still more preferably 30 parts by mass or less.

[0032] (Production method of polyester resin) The production method of the polyester resin contained in the modified asphalt composition of the present invention 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 viewpoint of adjusting reactivity and productivity, it is preferably 160°C or higher and 260°C or lower.

[0033] When the polyester resin used in the present invention contains a structural unit derived from ethylene glycol derived from polyethylene terephthalate and a structural unit derived from terephthalic acid derived from polyethylene terephthalate, the abundance of polyethylene terephthalate in the raw materials is preferably 5% by mass or more, more preferably 15% by mass or more, still more preferably 25% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, still more preferably 50% by mass or less in the total amount of polyethylene terephthalate, alcohol component, and carboxylic acid component. By adding polyethylene terephthalate during the polycondensation reaction of the alcohol component and the carboxylic acid component, a transesterification reaction occurs, and a polyester resin in which the structural units of polyethylene terephthalate are incorporated into the structural units derived from the alcohol component and the structural units derived from the carboxylic acid component can be obtained. Polyethylene terephthalate may be present from the start of the polycondensation reaction or added to the reaction system during the polycondensation reaction. From the viewpoint of improving the flexibility and crack resistance of asphalt pavement, the addition timing of polyethylene terephthalate is preferably at the stage where the reaction rate of the alcohol component and the carboxylic acid component is 10% or less, and more preferably at the stage of 5% or less. The reaction rate refers to the value of the amount of water generated in the production reaction (mol) / theoretical amount of water generated (mol)×100.

[0034] From the viewpoint of the reaction rate, an esterification catalyst can be used in the polycondensation reaction. Examples of the esterification catalyst include tin(II) compounds having no Sn-C bond such as tin(II) bis(2-ethylhexanoate). The amount of the esterification catalyst used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, still more preferably 0.2 part by mass or more, and preferably 1.5 parts by mass or less, more preferably 1.0 part by mass or less, still more preferably 0.6 part by mass or less with respect to 100 parts by mass of the total amount of polyethylene terephthalate, alcohol component, and carboxylic acid component from the viewpoint of the reaction rate. In the polycondensation reaction, a cocatalyst can be used in addition to the esterification catalyst. Examples of the cocatalyst include pyrogallol compounds such as gallic acid. The amount of the cocatalyst used 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 0.08 part by mass or less, still more preferably 0.05 part by mass or less with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0035] <Polyhydric phenol compound> A polyhydric phenol compound is a compound having two or more phenolic hydroxy groups (hydroxyl groups). The phenolic hydroxy group is a hydroxy group present on an aromatic ring. Examples of the polyhydric phenol compound include a compound having two or more phenolic hydroxy groups on the same aromatic ring, a compound having a plurality of aromatic rings having one or more phenolic hydroxy groups in the molecule, and the like. Examples of the aromatic ring of the polyhydric phenol compound include a benzene ring, a naphthalene ring, and an anthracene ring. From the viewpoint of improving the flexibility and crack resistance of the asphalt pavement, a benzene ring is preferable. When two or more phenolic hydroxy groups are present on the same aromatic ring, the number of hydroxy groups (hydroxyl groups) is preferably 2 or 3 from the same viewpoint.

[0036] From the viewpoint of improving the flexibility and crack resistance of the asphalt pavement, the polyhydric phenol compound is preferably at least one selected from the group consisting of tannin compounds, gallic acid esters, gallic acid amides, and lignin compounds. In one aspect of the present invention, the asphalt composition can contain a gallic acid compound which is at least one selected from gallic acid esters, gallic acid amides, and tannic acid. The gallic acid compound is, for example, at least one selected from gallic acid esters and gallic acid amides.

[0037] 〔Tannin compound〕 Examples of tannin compounds include tannin, tannic acid, etc. · Tannin Tannin is a polyphenol compound derived from plants that exists in nature. Tannins derived from various plants can be used. Also, examples of tannins include condensed tannins and hydrolyzable tannins. Specific examples of tannins include, for example, as condensed tannins, those derived from mimosa (also called wattles), quebracho, gambier, kaki, etc. Examples of hydrolyzable tannins include those derived from chestnut oak, oak, myrobalan, tara, gallnuts, sumac, etc.

[0038] An example of tannin derived from mimosa, which is a condensed tannin, is shown in the following general formula (4).

[0039]

Chemical formula

[0040] [In the formula, R is the same or different and represents a hydrogen atom or a hydroxy group (hydroxyl group). n is the number of repetitions and represents an integer of 1 or more.]

[0041] An example of the structure of a hydrolyzable tannin is shown in the following formula (5).

[0042]

Chemical formula

[0043] · Tannic acid Tannic acid is a plant polyphenol that exists in nature and is a gallic acid ester of glucose. Gallic acid may be further ester-bonded to the phenolic hydroxyl group of gallic acid ester-bonded to glucose. Although not particularly limited, from the viewpoint of improving the flexibility and crack resistance of asphalt pavement, it is preferably tannic acid in which at least one of the phenolic hydroxyl groups derived from gallic acid is not modified. Examples of tannic acid include compounds represented by the following formula (3) (also called albumin tannate).

[0044] [Chemical formula]

[0045] [Gallic acid ester, gallic acid amide] As the gallic acid ester and gallic acid amide, preferably, they are gallic acid esters and gallic acid amides in which at least one of the phenolic hydroxyl groups derived from gallic acid is not modified.

[0046] ·Compound represented by general formula (1) From the viewpoint of improving the flexibility and crack resistance of asphalt pavement, the gallic acid ester is preferably a compound represented by the following general formula (1).

[0047] [Chemical formula]

[0048] In general formula (1), R 1 represents a hydrocarbon group having 6 to 22 carbon atoms.

[0049] R 1 Examples of the hydrocarbon group having 6 to 22 carbon atoms as R include saturated or unsaturated hydrocarbon groups, and branched or straight-chain hydrocarbon groups. Examples of the hydrocarbon group having 6 to 22 carbon atoms include alkyl groups such as hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group (lauryl group), tridecyl group, tetradecyl group (myristyl group), pentadecyl group, hexadecyl group (palmitoyl group), heptadecyl group, octadecyl group (stearyl group), nonadecyl group, eicosyl group, isostearyl group, 2-ethylhexyl group, etc.; alkylphenyl groups such as octylphenyl group, nonylphenyl group, decylphenyl group, dodecylphenyl group, tridecylphenyl group, tetradecylphenyl, etc. R1 As the hydrocarbon group having 6 to 22 carbon atoms, from the viewpoint of improving the flexibility and crack resistance of asphalt pavement, it is preferably a linear alkyl group having 10 to 20 carbon atoms, more preferably a linear alkyl group having 10 to 18 carbon atoms.

[0050] (Process for producing the compound represented by general formula (1)) The process for producing the compound represented by general formula (1) is not particularly limited, but examples thereof include a method of reacting an alcohol and / or an alkylphenol having the hydrocarbon group having 6 to 22 carbon atoms with gallic acid contained in a hydrolyzable tannin substance at a high temperature of 100 °C or higher. Examples of the hydrolyzable tannin substance include condensed tannins such as gallnut, galla, sumac, tara, valonia, chestnut, myrobalan, oak, divi-divi, and algarobia. In the process for producing the compound of general formula (1), it is preferable to use a strong acid catalyst for accelerating the reaction. Examples of the strong acid used as the catalyst include sulfuric acid, hydrogen chloride, p-toluenesulfonic acid, and phosphoric acid.

[0051] ·Compound represented by general formula (2) The gallic acid amide is preferably a compound represented by the following general formula (2) from the viewpoint of improving the flexibility and crack resistance of asphalt pavement.

[0052]

Chemical formula

[0053] In general formula (2), R 2 represents a hydrocarbon group having 6 to 22 carbon atoms, n represents the repeating number of ethyleneimine, and represents an integer of 0 or more and 5 or less.

[0054] R 2 As the hydrocarbon group having 6 to 22 carbon atoms, the same hydrocarbon groups as those of R 1 are exemplified, and the preferable ranges are also the same. The repeating number n of ethyleneimine is preferably an integer of 1 or more and 4 or less from the viewpoint of improving the flexibility and crack resistance of the asphalt pavement.

[0055] (Method for producing the compound represented by general formula (2)) The method for producing the compound represented by general formula (2) is not particularly limited, but an ammonolysis reaction is carried out by dropping an amine having a hydrocarbon group with 6 or more and 22 or less carbon atoms and / or its ethyleneimine adduct onto an ester of gallic acid contained in a hydrolyzable tannin substance at a high temperature of 150°C or higher. This method is preferable because the compound represented by general formula (2) can be easily obtained. Examples of the hydrolyzable tannin substance include the same ones as those mentioned in the method for producing the compound represented by general formula (1). The ester of gallic acid can be obtained in the same manner as the method for producing the compound represented by general formula (1) using a saturated or unsaturated, branched or straight-chain alcohol having 1 or more and 22 or less carbon atoms as the alcohol. When a lower alcohol is used as the alcohol, the alcohol generated as the ammonolysis reaction proceeds volatilizes, so a higher purity alkylamide gallate can be obtained by removing this from the system, which is preferable. The ammonolysis reaction may be carried out using an isolated ester of gallic acid and an amine having a hydrocarbon group with 6 or more and 22 or less carbon atoms and / or its ethyleneimine adduct, or after performing the above esterification reaction, without isolating the obtained ester of gallic acid, an amine having a hydrocarbon group with 6 or more and 22 or less carbon atoms and / or its ethyleneimine adduct may be dropped into the reaction system. When the ester is not isolated, it is preferable to neutralize the strong acid catalyst by adding an alkali in advance.

[0056] [Lignin] Lignin is a naturally occurring plant polyphenol. Examples of lignin include natural lignin and modified lignin. Natural lignin is a compound having a polyphenol structure in which structural units derived from one or more of three types of monolignols, p - coumaril alcohol, coniferyl alcohol, and sinapyl alcohol, are bonded by an enzymatic reaction, and is contained in various biomasses. Modified lignin has a structure in which a part of the intermolecular bonds of the natural lignin is decomposed and condensed. Industrially, lignin sulfonate is often used.

[0057] An example of the structure of lignin is shown in the following formula (6). The structure shown in the following formula (6) is a part of the higher - order structure.

[0058] [Chemical formula]

[0059] [In the formula, Me represents a methyl group. The wavy line indicates a bond to another wavy - line part.]

[0060] (Content of polyhydric phenol compound) From the viewpoint of improving crack resistance, the content of the polyhydric phenol compound is preferably 0.05 part by mass or more, more preferably 0.06 part by mass or more, still more preferably 0.08 part by mass or more, per 100 parts by mass of asphalt. And from the viewpoint of improving flexibility, it is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, still more preferably 3 parts by mass or less.

[0061] From the viewpoint of improving crack resistance, the mass ratio of the polyhydric phenol compound to the polyester resin in the asphalt composition (polyhydric phenol compound / polyester resin) is preferably 0.003 or more, more preferably 0.004 or more, still more preferably 0.005 or more. And from the viewpoint of improving flexibility, it is preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.6 or less, still more preferably 0.4 or less, still more preferably 0.2 or less.

[0062] <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 polymer materials such as thermoplastic elastomers and thermoplastic resins. Straight asphalt is a residual asphalt substance obtained by subjecting crude oil to an atmospheric distillation unit, a vacuum distillation unit, etc. Also, blown asphalt means asphalt obtained by heating a mixture of straight asphalt and heavy oil and then blowing air into it for oxidation. The asphalt is preferably selected from straight asphalt and polymer modified asphalt, more preferably polymer modified asphalt from the viewpoint of the durability of asphalt paving, and more preferably straight asphalt from the viewpoint of versatility. As the polymer modified asphalt, asphalt modified with a thermoplastic elastomer is more preferable. From the viewpoint of the durability of asphalt paving, the modified asphalt is preferably polymer modified asphalt, and more preferably polymer modified asphalt modified with a thermoplastic elastomer.

[0063] (Thermoplastic elastomer) Examples of the thermoplastic elastomer in the polymer-modified asphalt modified with a thermoplastic elastomer include at least one selected from a styrene / butadiene block copolymer, a styrene / butadiene / styrene block copolymer, a styrene / butadiene random copolymer, a styrene / isoprene block copolymer, a styrene / isoprene / styrene block copolymer, a styrene / isoprene random copolymer, an ethylene / vinyl acetate copolymer, an ethylene / acrylic acid ester copolymer, a styrene / ethylene / butylene / styrene copolymer, a styrene / ethylene / propylene / styrene copolymer, a polyurethane-based thermoplastic elastomer, a polyolefin-based thermoplastic elastomer, an isobutylene / isoprene copolymer, polyisoprene, polychloroprene, synthetic rubbers other than the above, and natural rubber. The thermoplastic elastomer in the modified asphalt is preferably at least one selected from a styrene / butadiene block copolymer, a styrene / butadiene / styrene block copolymer, a styrene / butadiene random copolymer, a styrene / isoprene block copolymer, a styrene / isoprene / styrene block copolymer, a styrene / isoprene random copolymer, an ethylene / vinyl acetate copolymer, and an ethylene / acrylic acid ester copolymer from the viewpoint of the durability of asphalt pavement. Among these, as the thermoplastic elastomer, from the viewpoint of the durability of asphalt pavement, more preferably at least one selected from styrene / butadiene block copolymers, styrene / butadiene / styrene block copolymers, styrene / butadiene random copolymers, styrene / isoprene block copolymers, styrene / isoprene / styrene block copolymers, styrene / isoprene random copolymers, and ethylene / acrylic ester copolymers; still more preferably at least one selected from styrene / butadiene block copolymers, styrene / butadiene / styrene block copolymers, styrene / butadiene random copolymers, styrene / isoprene block copolymers, and styrene / isoprene random copolymers; still more preferably at least one selected from styrene / butadiene random copolymers and styrene / butadiene / styrene block copolymers. The content of the thermoplastic 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, and preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, from the viewpoints of the durability and surface appearance of asphalt pavement.

[0064] [Method for producing asphalt composition] The method for producing the asphalt composition of the present invention preferably includes a step of mixing asphalt, the above polyester resin, and the above gallic acid compound.

[0065] The asphalt composition is obtained by heating and melting asphalt, adding a polyester resin and a gallic acid compound, 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.

[0066] The mixing temperature of asphalt, the polyester resin, and the gallic acid compound is preferably 100°C or higher, more preferably 130°C or higher, still more preferably 160°C or higher, even more preferably 170°C or higher, from the viewpoint of uniformly dispersing the polyester resin and the gallic acid compound in the asphalt, and is preferably 230°C or lower, more preferably 210°C or lower, still more preferably 200°C or lower, even more preferably 190°C or lower.

[0067] Also, the mixing time of asphalt, the polyester resin, and the gallic acid compound is preferably 0.1 hour or longer, more preferably 0.5 hour or longer, still more preferably 1.0 hour or longer, even more preferably 1.5 hours or longer, from the viewpoint of efficiently and uniformly dispersing the polyester resin and the gallic acid compound in the asphalt, and is preferably 10 hours or shorter, more preferably 7 hours or shorter, still more preferably 5 hours or shorter, even more preferably 3 hours or shorter.

[0068] [Asphalt modifier] By mixing the above polyester resin and the above polyhydric phenol compound with asphalt, the asphalt can be modified. In other words, the asphalt modifier of the present invention contains the above polyester resin and the above polyhydric phenol compound. The asphalt modifier can be used for paving after being made into an asphalt mixture by mixing with asphalt and the aggregate described below.

[0069] Also, a method for modifying asphalt can be provided by mixing the above polyester resin and the above polyhydric phenol compound with asphalt. The method for modifying asphalt is not limited to the method of mixing asphalt with the above polyester resin and the above polyhydric phenol compound, and also includes the method of adding and mixing the above polyester resin and the above polyhydric phenol compound to a mixture of asphalt and aggregate. The addition and mixing of the polyester resin and the polyhydric phenol compound may be carried out by adding the polyester resin and the polyhydric phenol compound simultaneously, or either one of them may be added first. When adding the polyester resin and the polyhydric phenol compound simultaneously, the polyester resin and the polyhydric phenol compound may be added as a mixture thereof.

[0070] [Asphalt mixture] The asphalt mixture of the present invention contains the above asphalt composition and aggregate. The asphalt mixture of the present invention is suitable for paving, and particularly suitable for road paving.

[0071] <Aggregate> As the aggregate, crushed stone, cobblestone, gravel, sand, recycled aggregate, ceramics, etc. can be arbitrarily selected and used. Also, as the aggregate, either coarse aggregate with a particle size of 2.36 mm or more or fine aggregate with a particle size of less than 2.36 mm can be used. Recycled aggregate is obtained by collecting, crushing and classifying used asphalt pavement. Examples of the coarse aggregate include crushed stone with a particle size range of 2.36 mm or more and less than 4.75 mm, crushed stone with a particle size range of 4.75 mm or more and less than 12.5 mm, crushed stone with a particle size range of 12.5 mm or more and less than 19 mm, and crushed stone with a particle size range of 19 mm or more and less than 31.5 mm. The fine aggregate is preferably a fine aggregate with 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, recycled aggregate crushed sand, etc. The above particle sizes are the values specified in JIS A5001:2008. Among these, a combination of coarse aggregate and fine aggregate is preferable.

[0072] In addition, the fine aggregate may contain a filler with 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 strength of the asphalt pavement. From the viewpoint of improving the dry strength, the average particle size of the filler is preferably 0.001 mm or more, and preferably 0.06 mm or less, more preferably 0.04 mm or less, and still more preferably 0.03 mm or less. The average particle size of the filler can be measured by a laser diffraction particle size distribution measuring device. Here, the average particle size means the average particle size at 50% volume accumulation.

[0073] From the viewpoints of improving the flexibility and crack resistance 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.

[0074] Preferable blending examples of the asphalt mixture include the following (1) to (3). (1) For example, fine-grained asphalt containing 30% by volume or more and less than 45% by volume of coarse aggregate, 30% by volume or more and 50% by volume or less of fine aggregate, and 5% by volume or more and 10% by volume or less of an asphalt composition. (2) For example, dense-grained asphalt containing 45% by volume or more and less than 70% by volume of coarse aggregate, 20% by volume or more and 45% by volume or less of fine aggregate, and 3% by volume or more and 10% by volume or less of an asphalt composition. (3) For example, porous asphalt containing 70% by volume or more and 80% by volume or less of coarse aggregate, 10% by volume or more and 20% by volume or less of fine aggregate, and 3% by volume or more and 10% by volume or less of an asphalt composition.

[0075] The above porous asphalt can be suitably used for drainage pavement.

[0076] The content of the aggregate in the asphalt mixture is preferably 50% by mass or more, more preferably 75% by mass or more, still more preferably 80% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less, still more preferably 96% by mass or less, from the viewpoint of improving flexibility and crack resistance.

[0077] 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 obtained from the "Mix 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-mentioned optimum asphalt amount corresponds to the total amount of asphalt, polyester resin, and gallic acid compound, that is, the amount of the asphalt composition of the present invention. 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.

[0078] (Content of asphalt composition) The content of the asphalt composition in the asphalt mixture is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 4% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, from the viewpoints of the filling efficiency of the asphalt binder and the improvement of the flexibility and crack resistance of the asphalt pavement.

[0079] The asphalt mixture may further contain other components as needed.

[0080] [Method for producing asphalt mixture] The asphalt mixture of the present invention can be obtained by blending aggregate, asphalt, polyester resin, and a polyhydric phenol compound. The method for producing the asphalt mixture of the present invention includes a step of mixing the aggregate, asphalt, polyester resin, and gallic acid compound simultaneously or in any order. Specific production methods of asphalt mixtures include production methods of asphalt mixtures such as the conventional plant mix method and the premix method. All of them are methods of adding asphalt, polyester resin, and polyhydric phenol compounds to heated aggregates.

[0081] The mixing step is preferably any one of the following (i) to (iii). (i) After adding and mixing asphalt to the heated aggregates, adding and mixing polyester resin and polyhydric phenol compounds. (ii) Adding and mixing asphalt, polyester resin, and polyhydric phenol compounds to the heated aggregates simultaneously, or (iii) Adding and mixing a mixture of asphalt, polyester resin, and polyhydric phenol compounds that has been pre-heated and mixed, that is, the asphalt composition of the present invention, to the heated aggregates. In the above (i), the addition of the polyester resin and the polyhydric phenol compound may be carried out by adding them simultaneously or sequentially. When adding the polyester resin and the polyhydric phenol compound simultaneously, they may be added as a mixture. When adding the polyester resin and the polyhydric phenol compound sequentially, either the polyester resin or the polyhydric phenol compound may be added first.

[0082] (i)~(iii) In the method, the temperature of the heated aggregates is preferably 130°C or higher, more preferably 150°C or higher, still more preferably 170°C or higher, from the viewpoint of improving the rutting resistance and crack resistance of the asphalt pavement, and preferably 230°C or lower, more preferably 210°C or lower, still more preferably 200°C or lower, from the viewpoint of preventing thermal degradation of asphalt.

[0083] From the perspective of improving the flexibility and crack resistance of asphalt pavement, the mixing temperature of the aggregate, asphalt, polyester resin, and polyhydric phenol compound is preferably 130°C or higher, more preferably 150°C or higher, still more preferably 170°C or higher, and from the perspective of preventing thermal degradation of asphalt, it is preferably 230°C or lower, more preferably 210°C or lower, still more preferably 200°C or lower. The mixing time of the aggregate, asphalt, polyester resin, and polyhydric phenol compound is not particularly limited, preferably 30 seconds or longer, more preferably 1 minute or longer, still more preferably 2 minutes or longer, and the upper limit of the time is not particularly limited, preferably about 30 minutes. The mixing time is the time from when any one of the aggregate, asphalt, polyester resin, and polyhydric phenol compound is added and mixed until the mixing is completed.

[0084] From the perspective of improving the flexibility and crack resistance of asphalt pavement, the method for producing the asphalt mixture preferably includes a step of holding the obtained mixture at the above mixing temperature after the mixing step. In the step of holding the asphalt mixture, the mixture may be further mixed. The holding time is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, and the upper limit of the time is not particularly limited, for example, about 5 hours.

[0085] [Pavement Method] The asphalt mixture of the present invention is suitable for paving, and examples of the paving target include roads, parking lots, etc. The paving method includes a step of constructing the aforementioned asphalt mixture on the paving target to form an asphalt pavement layer. The asphalt pavement layer is usually a base layer or a surface layer, and from the perspective of improving flexibility and crack resistance, it is preferably a surface layer.

[0086] From the viewpoint of improving flexibility resistance and crack resistance, the thickness of the asphalt pavement layer is preferably 3 cm or more, more preferably 4 cm or more, still more preferably 4.5 cm or more, and preferably 7 cm or less, more preferably 6 cm or less, still more preferably 5.5 cm or less. In another aspect of the present invention, the asphalt pavement layer can be a thin layer pavement, and the thickness of the surface layer is preferably 1 cm or more, more preferably 1.5 cm or more, still more preferably 2 cm or more, and preferably 4 cm or less, more preferably 3.5 cm or less, still more preferably 3 cm or less. The asphalt mixture may be compacted by a known construction machine formation in the same manner. When used as a heated asphalt mixture, the compaction temperature is preferably 100°C or more, more preferably 120°C or more, still more preferably 130°C or more, and preferably 200°C or less, more preferably 180°C or less, from the viewpoint of improving flexibility resistance and crack resistance of the asphalt pavement.

Examples

[0087] For various physical properties, measurement and evaluation were performed by the following methods. In the following examples and comparative examples, unless otherwise specified, parts and % are based on mass.

[0088] 〔Softening point (Ts) of polyester resin〕 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 drop 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.

[0089] 〔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. Subsequently, the sample was maintained at the same temperature for 1 minute, and then the heat quantity was measured while heating from that temperature 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 (Tmax). The crystallinity index was determined by Ts / Tmax.

[0090] [Melting point (Tm) and glass transition temperature (Tg) of the polyester resin] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 - 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, it was measured while heating from that temperature to 150 °C at a heating rate of 10 °C / min. The temperature of the peak with the largest 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 endothermic peak temperature and the tangent line showing the maximum slope from the rising part of the peak to the peak apex was taken as the glass transition temperature.

[0091] [Acid value and hydroxyl value of the polyester resin] The acid value and hydroxyl value of the polyester resin were measured based on the method of JIS K0070:1992. However, the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K0070:1992 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0092] [Method for measuring the weight-average molecular weight of the polyester resin] The molecular weight distribution was measured by the following gel permeation chromatography (GPC) method, and the weight-average molecular weight was determined. (i) Preparation of the sample solution The sample was dissolved in a solvent at 25°C so that the concentration became 0.5 g / 100 mL. Then, this solution was filtered using a fluororesin filter with a pore size of 0.2 μm (manufactured by Toyo Roshi Kaisha, Ltd., "DISMIC-25JP") to remove insoluble matter, and a sample solution was obtained. Tetrahydrofuran was used as the solvent. (ii) Molecular weight measurement Using the following measuring device and analytical column, the same solvent used for preparing the sample solution was flowed at a flow rate of 1 mL per minute, and the column was stabilized in a constant temperature bath at 40°C. Then, 100 μL of the sample solution was injected for measurement. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. The calibration curve at this time included several types of monodisperse polystyrenes "A-500" (5.0×10 2 ), "A-1000" (1.01×10 3 ), "A-2500" (2.63×10 3 ), "A-5000" (5.97×10 3 ), "F-1" (1.02×10 3 ), "F-2" (1.81×10 4 ), "F-4" (3.97×10 4 ), "F-10" (9.64×10 4 ), "F-20" (1.90×10 5 ), "F-40" (4.27×10 5 ), "F-80" (7.06×10 5 ), "F-128" (1.09×10 6 ) (all manufactured by Tosoh Corporation) were used as standard samples. Measuring device: "HLC-8220CPC" (manufactured by Tosoh Corporation) Analytical column: "GMHXL" + "G3000HXL" (manufactured by Tosoh Corporation)

[0093] Production Example 1 (Production of Polyester Resin 1) 1759 g of BPA-PO (propylene oxide (2.2) adduct of bisphenol A) was placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a reflux condenser, and a nitrogen inlet tube and heated to 100°C. After adding 492 g of terephthalic acid at 100°C, 20 g of tin(II) bis(2-ethylhexanoate) and 2 g of gallic acid were added under a nitrogen atmosphere at 100°C, and the temperature was raised to 235°C at 2.0°C / min. After reaching 235°C, a polycondensation reaction was carried out for 3 hours. After cooling to 180°C, 1447 g of polyethylene terephthalate (manufactured by Indorama Ventures, RAMAPET L1) was added. The temperature was raised to 235°C at 2.0°C / min, and after a polycondensation reaction was carried out for 8 hours after reaching 235°C, it was cooled to 180°C and 302 g of dodecenyl succinic anhydride was added. The temperature was raised from 180°C to 220°C at 0.3°C / min, and the reaction was carried out at 220°C and 20 kPa until the following softening point was reached to obtain Polyester Resin 1. The softening point of Polyester Resin 1 was 105.3°C, the weight average molecular weight was 9390, the maximum peak temperature of endotherm was 58.4°C, the glass transition temperature was 58.4°C, the acid value was 8.1 mgKOH / g, the hydroxyl value was 25.9 mgKOH / g, and the crystallinity index was 1.8. Polyester Resin 1 was an amorphous polyester resin. When the total number of moles of ethylene glycol units in BPA-PO and polyethylene terephthalate used in the above production method was 100, the molar ratio of BPA-PO was 40, the molar ratio of ethylene glycol units in polyethylene terephthalate was 60, the molar ratio of terephthalic acid was 83.6, and the molar ratio of dodecenyl succinic anhydride was 9.4.

[0094] Example 1 (Production of Asphalt Specimen 1) 15 kg of aggregate 1 heated to 180°C was put into an asphalt mixer and mixed at 180°C for 60 seconds. Next, 0.81 kg of modified type II asphalt (manufactured by Nisshin Kasei Co., Ltd., Epok Falt D) heated to 180°C was added and mixed in the asphalt mixer for 1 minute. Thereafter, 143.6 g of the polyester resin obtained in Production Example 1 and 4.1 g of stearyl alcohol gallate were simultaneously added and further mixed for 1 minute to obtain an asphalt mixture, and 1180 g of the asphalt mixture was collected. 1180 g of the obtained asphalt mixture was filled into a mold, and when the temperature of the asphalt mixture reached about 165°C, it was compacted on both sides 75 times each using an automatic asphalt compactor (manufactured by Nakajima Gikenhan Co., Ltd., NA-507) and molded. Then, it was allowed to cool naturally to room temperature over 15 hours to produce a cylindrical asphalt specimen 1. Asphalt specimen 1 was subjected to a Marshall stability test according to the "B001 Marshall Stability Test Method" in the "Convenience Manual for Pavement Investigation and Test Methods (2019 Edition)" (edited by the Japan Road Association, a public interest incorporated foundation), and the Marshall stability (kN) and flow value (1 / 100 cm) of asphalt specimen 1 were measured. The results are shown in Table 1. Note that the larger the value of the Marshall stability, the more excellent the durability of the asphalt pavement. And the larger the value of the flow value, the more excellent the flexibility and crack resistance at the service temperature of the asphalt pavement.

[0095] <Composition of Aggregate 1> The composition of aggregate 1 used in Example 1 is as follows. No. 6 crushed stone: 40.0 parts by mass No. 7 crushed stone: 13.0 parts by mass Crushed sand: 10.0 parts by mass River sand: 22.0 parts by mass Mountain sand: 10.0 parts by mass Stone powder (calcium carbonate): 5.0 parts by mass Passing mass %: Sieve size 19.0 mm: 100 mass % Sieve size 9.50 mm: 80.1 mass % Sieve size 4.75 mm: 59.4 mass % Sieve size 2.36 mm: 43.4 mass % Sieve size 1.18 mm: 29.1 mass % Sieve size 600 μm: 18.9 mass % Sieve size 300 μm: 11.7 mass % Sieve size 150 μm: 7.6 mass %

[0096] Examples 2 to 20 and Comparative Example 1 Except that the gallic acid compound and its addition amount were changed as shown in Table 1, asphalt specimens 2 to 20 and asphalt specimen C1 were produced in the same manner as in Example 1. The obtained asphalt specimens 2 to 20 and asphalt specimen C1 were subjected to the Marshall stability test in the same manner as asphalt specimen 1, and the Marshall stability (kN) and flow value (1 / 100 cm) were measured.

[0097] Examples 21 to 24 and Comparative Example 2 Except that the gallic acid compound was changed and aggregate 1 was changed to aggregate 2, asphalt specimens 21 to 24 and asphalt specimen C2 were produced in the same manner as in Example 1. The obtained asphalt specimens 21 to 24 and asphalt specimen C2 were subjected to the Marshall stability test in the same manner as asphalt specimen 1, and the Marshall stability (kN) and flow value (1 / 100 cm) were measured.

[0098] <Composition of Aggregate 2> The composition of aggregate 2 used in Examples 21 to 24 and Comparative Example 2 is as follows. No. 6 crushed stone: 40.0 parts by mass No. 7 crushed stone: 13.0 parts by mass Sea sand: 41.0 parts by mass Stone powder (calcium carbonate): 6.0 parts by mass Passing mass %: Sieve size 19.0 mm: 100 mass % Sieve size 9.50 mm: 80.1 mass % Sieve size 4.75 mm: 59.4 mass % Sieve size 2.36 mm: 40.2 mass % Sieve size 1.18 mm: 32.1 mass% Sieve size 600 μm: 23.4 mass% Sieve size 300 μm: 15.3 mass% Sieve size 150 μm: 7.6 mass%

[0099]

Table 1

[0100] From Table 1, it can be seen that Asphalt Specimens 1 to 20 of Examples 1 to 20 produced from asphalt mixtures using an asphalt composition containing a polyester resin and a polyhydric phenol compound, compared with Asphalt Specimen C1 of Comparative Example 1 produced from an asphalt mixture not containing a gallic acid compound, maintain stability equivalent to that of the prior art asphalt mixture while having a large flow value, indicating that excellent flexibility and crack resistance can be achieved simultaneously. It can also be seen that there is a similar tendency in Asphalt Specimens 21 to 24 of Examples 21 to 24 and Asphalt Specimen C2 of Comparative Example 2 where the types of aggregates are different.

Claims

1. An asphalt composition comprising asphalt, a polyester resin, and a polyhydric phenol compound.

2. The asphalt composition according to claim 1, wherein the polyhydric phenol compound is at least one selected from the group consisting of tannin compounds, gallic acid esters, gallic acid amides, and lignin compounds.

3. The asphalt composition according to claim 2, wherein the tannin compound is at least one selected from the group consisting of tannin and tannic acid.

4. The asphalt composition according to claim 2, wherein the gallic acid ester is a compound represented by the following general formula (1): 【Chemistry 1】 (In general formula (1), R １ represents a hydrocarbon group having 6 to 22 carbon atoms.

5. The asphalt composition according to claim 2, wherein the gallic acid amide is a compound represented by the following general formula (2): 【Chemistry 2】 (In general formula (2), R ２ represents a hydrocarbon group having 6 to 22 carbon atoms, and n represents an integer of 0 to 5.

6. The asphalt composition according to claim 1, wherein the content of the polyhydric phenol compound is 0.05 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the asphalt.

7. The asphalt composition according to claim 1, wherein the content of the polyester resin is 1 part by mass or more and 40 parts by mass or less per 100 parts by mass of the asphalt.

8. The asphalt composition according to claim 1, wherein a mass ratio of the polyhydric phenol compound to the polyester resin (polyhydric phenol compound / polyester resin) is 0.003 or more and 1.0 or less.

9. An asphalt mixture comprising the asphalt composition according to any one of claims 1 to 8 and aggregate.

10. A paving method comprising the steps of applying the asphalt mixture according to claim 9 to a paving object and forming an asphalt pavement layer.

11. An asphalt modifier comprising a polyester resin and a polyhydric phenol compound.

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