Asphalt mixture

Abstract

To provide an asphalt modifier that gives an asphalt pavement having excellent durability and capable of keeping its blackness even after the start of traffic.SOLUTION: The present invention relates to an asphalt mixture containing a polyester resin (A), a compound (B) illustrated below, asphalt, and aggregate, wherein the aggregate contains an asphalt recycled aggregate. The compound (B): an 8C or greater compound having a hydroxyl group or an amino group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to asphalt mixtures, asphalt modifiers, road paving methods, and additives for recycled asphalt mixtures. [Background technology]

[0002] Asphalt paving is used for roads, parking lots, freight yards, and sidewalks because it is relatively easy to lay and the time from the start of paving work to the start of traffic is short. This asphalt pavement has good hardness and durability because the road surface is formed from an asphalt mixture in which aggregates are bound together with asphalt. However, asphalt pavements develop ruts and cracks over time, necessitating repairs, which increases maintenance costs and significantly impacts automobile traffic. Furthermore, prolonged use caused the asphalt coating on the asphalt pavement to peel off, resulting in a whitening that reduced the visibility of the white lines, which also had a significant impact on automobile traffic.

[0003] Patent Document 1 discloses an asphalt composition for road paving that is excellent in dry strength, water immersion strength, and petroleum immersion strength, comprising asphalt, a specific amount of polyester resin, and aggregate, wherein the polyester resin is a polyester having structural units derived from an alcohol component containing a specific amount of an alkylene oxide adduct of bisphenol A, and structural units derived from a carboxylic acid component containing a specific amount of one or more selected from terephthalic acid and isophthalic acid, and having a specific softening point and hydroxyl value. Patent Document 2 discloses a method for producing a heat-type pavement material that has an excellent effect in preventing delamination between bituminous material and aggregate, characterized by adding a specific amount of a composition to bituminous material, which is a composition obtained by reacting a polyalkylene polyamine of a specific structure with a specific fatty acid and a modified polyolefin resin having carboxyl groups of a specific acid value, in a specific ratio. Patent Document 3 discloses an additive for hot asphalt containing a specific gallic acid amide, which can further improve the effect of preventing delamination between asphalt and aggregate, and in which this effect is not lost even after prolonged heating. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2017 / 125421 [Patent Document 2] Japanese Patent Publication No. 2001-2928 [Patent Document 3] Japanese Patent Publication No. 2004-323695 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The technology described in Patent Document 1 provides a durable asphalt pavement that is resistant to rutting. However, in the construction of asphalt pavement, after compaction with a rolling machine and opening to traffic, the asphalt coating tends to peel off due to external factors such as friction from repeated vehicle traffic, rainwater, and ultraviolet light exposure, causing the color to change from the original black to white, thus impairing the appearance. This problem is particularly pronounced when recycled asphalt aggregate is used. Furthermore, it is desirable to maintain the black color not only from the perspective of surface aesthetics but also from the perspective of visibility. While the technology described in Patent Document 2 can provide an anti-peeling effect, it is considered to have little effect on improving durability. Furthermore, it is presumed that sufficient effect cannot be obtained when using recycled aggregate in which asphalt and aggregate are fixed together. The technology described in Patent Document 3 is specifically focused on preventing peeling and does not have the effect of improving durability.

[0006] The present invention relates to an asphalt mixture, an asphalt modifier, a road paving method, and an additive for recycled asphalt mixtures for obtaining an asphalt pavement that is highly durable and maintains its black color even after being opened to traffic.

[0007] The present invention relates to the following [1] to [4]. [1] Contains polyester resin (A), the following compound (B), asphalt and aggregate, An asphalt mixture wherein the aggregate contains recycled asphalt aggregate. Compound (B): A compound having 8 or more carbon atoms and containing a hydroxyl group or an amino group. [2] An asphalt modifier containing a polyester resin (A) and the following compound (B). Compound (B): A compound having 8 or more carbon atoms and containing a hydroxyl group or an amino group. [3] A road paving method comprising the step of compacting and constructing the asphalt mixture described in [1] above, A road paving method in which the compaction temperature of the asphalt mixture is between 100°C and 200°C. [4] An additive for recycled asphalt mixtures containing one or more compounds having 8 or more carbon atoms selected from alkylamines, alkyl alcohols, sugar alcohols, and alkylamide compounds. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an asphalt mixture, an asphalt modifier, a road paving method, and an additive for recycled asphalt mixtures for obtaining asphalt pavement that is highly durable and maintains its black color even after traffic is opened to the public. [Modes for carrying out the invention]

[0009] The asphalt mixture of the present invention contains an aggregate including asphalt and recycled aggregate, and a polyester resin (A) and a compound (B) which is a compound having 8 or more carbon atoms and having a hydroxyl group or an amino group as an asphalt modifier. The asphalt modifier can be used alone or in combination of two or more kinds. Hereinafter, the asphalt modifier contained in the asphalt mixture, its production method, the asphalt composition and its production method, the asphalt mixture and its production method, the road paving method, and the additive for the recycled asphalt mixture will be described in this order.

[0010] [Asphalt modifier] The asphalt modifier of the present invention contains a polyester resin (A) and the following compound (B). Compound (B): A compound having 8 or more carbon atoms and having a hydroxyl group or an amino group The inventors have found that an asphalt pavement excellent in durability and maintaining blackness even after traffic opening can be obtained by incorporating an asphalt modifier using a polyester resin (A) and a predetermined compound (B) in combination into an asphalt composition or an asphalt mixture. The amino group mentioned here includes a primary amino group (-NH2), a secondary amino group (-NRH), and a tertiary amino group (-NRR'). The amino group also includes -NH- and -NR- of an amide bond (-NH-CO-, or -NR-CO-).

[0011] Although the detailed mechanism for obtaining the effects of the present invention is unclear, it is considered in part as follows. It is considered that the coating state of the aggregate by the binder composition is improved by the asphalt modifier using the polyester resin (A) having high affinity and the specific compound (B) in combination. When using asphalt recycled aggregate as an aggregate, since the asphalt in the asphalt recycled aggregate deteriorates over time due to thermal history, asphalt may not be efficiently extracted in some cases. The present invention uses a specific compound (B) having a high affinity with the asphalt recycled aggregate, so that even when using recycled aggregate as an aggregate, the asphalt in the asphalt recycled aggregate is efficiently extracted, and it is considered that a good coating state of the aggregate is achieved. Specifically, it is considered that the carbon atoms of the compound (B) have a high affinity with the asphalt in the asphalt recycled aggregate, and the hydroxyl group or amino group of the compound (B) has a high affinity with the surface of the aggregate not covered by the asphalt. Due to these affinities, the compound (B) acts on the interface between the asphalt in the asphalt recycled aggregate and the aggregate, promoting the peeling of the asphalt in the recycled aggregate from the aggregate and the elution into the newly blended asphalt, and functioning as a binder in combination with the polyester resin (A), so that a good coating state of the aggregate is considered to be achieved. And because the aggregate is firmly held during paving due to the good coating state of the aggregate, it is considered that the durability and blackness of the paving are maintained. As described above, by incorporating the asphalt modifier of the present invention into an asphalt composition or an asphalt mixture, an asphalt pavement excellent in durability and capable of maintaining blackness even after traffic opening can be obtained, particularly when including asphalt recycled aggregate.

[0012] The definitions of various terms in this specification are shown below. In the polyester resin, 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 term "carboxylic acid component" is a concept that includes not only the carboxylic acid itself, but also the anhydride that decomposes during the reaction to produce an acid, and alkyl esters of carboxylic acids (for example, alkyl groups with 1 to 3 carbon atoms). When the carboxylic acid component is an alkyl ester of a carboxylic acid, the number of carbon atoms in the alkyl group, which is the alcohol residue of the ester, is not included in the calculation of the carbon number of the carboxylic acid. Whether a resin is crystalline or amorphous is determined by its crystallinity index. The crystallinity index is defined as the ratio of the resin's softening point to the temperature of the maximum endothermic peak (softening point (°C) / maximum endothermic peak temperature (°C)). Crystalline resins are those with a crystallinity index of 0.3 or higher and 1.4 or lower. Amorphous resins are those in which no endothermic peak is observed, or, if observed, have a crystallinity index of less than 0.3 or greater than 1.4. The crystallinity index can be appropriately adjusted depending on the type and ratio of raw material monomers, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate.

[0013] [Polyester resin (A)] The asphalt modifier of the present invention contains a polyester resin (A). The polyester resin (A) contains structural units derived from an alcohol component and structural units derived from a carboxylic acid component. Examples of polyester resin (A) include amorphous polyester resin and crystalline polyester resin, with amorphous polyester resin being preferred. The following describes the properties of the alcohol component, carboxylic acid component, and polyester resin.

[0014] <Alcohol content> Examples of alcohol components include aliphatic diols, alicyclic diols, aromatic diols, and polyhydric alcohols with a hydride of three or more. These alcohol components can be used individually or in combination of two or more.

[0015] The aliphatic diol is preferably a straight-chain or branched aliphatic diol with 2 to 12 carbon atoms in the main chain, and more preferably a straight-chain or branched aliphatic diol with 2 to 8 carbon atoms in the main chain. Furthermore, the aliphatic diol is preferably a saturated aliphatic diol. Specific examples of aliphatic diols 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.

[0016] Examples of alicyclic diols include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), alkylene oxide adducts of hydrogenated bisphenol A, cyclohexanediol, and cyclohexanedimethanol.

[0017] Examples of aromatic diols include bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and alkylene oxide adducts of bisphenol A. Examples of alkylene oxide adducts of bisphenol A include those represented by the following formula (I).

[0018] [ka]

[0019] [In the formula, OR 1 and R 1 O is an alkylene oxide, and R 1 x is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers representing the average number of added moles of alkylene oxide, 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, and even more preferably 4 or less.

[0020] Examples of alkylene oxide adducts of bisphenol A represented by formula (I) include propylene oxide adducts of bisphenol A and ethylene oxide adducts of bisphenol A. These alkylene oxide adducts of bisphenol A can be used individually or in combination of two or more.

[0021] The polyhydric alcohol with a valency of three or higher is preferably a trihydric alcohol. Examples of polyhydric alcohols with a valency of three or higher include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0022] The alcohol component may further contain monohydric aliphatic alcohols from the viewpoint of adjusting physical properties. Examples of monohydric aliphatic alcohols include lauryl alcohol, myristyl alcohol, palmityl alcohol, and stearyl alcohol. These monohydric aliphatic alcohols can be used individually or in combination of two or more.

[0023] <Carboxylic acid components> Examples of carboxylic acid components include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids with a valency of 3 to 6. These carboxylic acid components can be used individually or in combination of two or more.

[0024] Examples of aliphatic dicarboxylic acids include those having a main chain with four or more carbon atoms, preferably 10 or fewer, more preferably 8 or fewer, and more preferably 6 or fewer carbon atoms, such as fumaric acid, maleic acid, oxalic acid, malonic acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanediic 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 their anhydrides, or their alkyl esters (for example, alkyl groups with 1 to 3 carbon atoms). Examples of substituted succinic acids include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.

[0025] Examples of aromatic dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or their anhydrides, or their alkyl esters (for example, alkyl groups with 1 to 3 carbon atoms). Among these aromatic dicarboxylic acids, isophthalic acid and terephthalic acid are preferred from the viewpoint of durability of asphalt pavement, and terephthalic acid is more preferred.

[0026] The polycarboxylic acid with a valency of 3 to 6 is preferably a tricarboxylic acid. Examples of polycarboxylic acids with a valency of 3 to 6 include trimellitic acid, 2,5,7-naphthalentricarboxylic acid, pyromellitic acid, or their acid anhydrides.

[0027] From the viewpoint of adjusting physical properties, the carboxylic acid component may further contain monovalent aliphatic carboxylic acids. Examples of monovalent aliphatic carboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, and monovalent aliphatic carboxylic acids with 12 to 20 carbon atoms, such as alkyl (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.

[0028] <Constituent units derived from polyethylene terephthalate> The polyester resin (A) may contain constituent units derived from polyethylene terephthalate, specifically ethylene glycol and terephthalic acid. In addition to the ethylene glycol and terephthalic acid-derived constituent units, the polyethylene terephthalate may also contain small amounts of other components such as butanediol and isophthalic acid. The polyethylene terephthalate is preferably recovered polyethylene terephthalate. When the polyester resin (A) contains constituent units consisting of ethylene glycol and terephthalic acid derived from polyethylene terephthalate, the "constituent units derived from the alcohol component" include constituent units derived from ethylene glycol derived from polyethylene terephthalate, and the "constituent units derived from the carboxylic acid component" include constituent units derived from terephthalic acid derived from polyethylene terephthalate.

[0029] <Molar ratio of constituent units derived from carboxylic acid component to constituent units derived from alcohol component> The molar ratio of constituent units derived from the carboxylic acid component to constituent units derived from the alcohol component [carboxylic acid component / alcohol component] is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and preferably 1.5 or less, more preferably 1.3 or less, and even more preferably 1.0 or less.

[0030] In one preferred embodiment of the present invention, the polyester resin (A) comprises structural units derived from an alcohol component and structural units derived from a carboxylic acid component, The alcohol component is one or more selected from aliphatic diols, alicyclic diols, aromatic diols, and polyhydric alcohols of trihydric or higher hydric value. The carboxylic acid component is one or more selected from aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids with a valency of 3 to 6.

[0031] <Physical properties of polyester resin (A)> The softening point or melting point of the polyester resin (A) is preferably 60°C or higher, more preferably 70°C or higher, even more preferably 90°C or higher, even more preferably 100°C or higher, and preferably 150°C or lower, more preferably 145°C or lower, and even more preferably 140°C or lower, from the viewpoint of durability of asphalt pavement. The melting point (the temperature of the maximum endothermic peak) is generally observed when the polyester resin (A) is a crystalline polyester resin. The softening point of polyester resin (A) can be measured by the method described in the examples. The softening point can be adjusted by the raw material monomer composition, molecular weight, catalyst amount, or reaction conditions.

[0032] The polyester resin (A) may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Specifically, modified polyester resins include polyester resins that have been grafted or blocked with phenol, urethane, epoxy, etc., by methods described in Japanese Patent Publication No. 11-133668, Japanese Patent Publication No. 10-239903, Japanese Patent Publication No. 8-20636, etc. A preferred modified polyester resin is a urethane-modified polyester resin obtained by urethane elongation of a polyester resin with a polyisocyanate compound.

[0033] <Method for manufacturing polyester resin (A)> The method for producing the polyester resin (A) constituting the asphalt modifier of the present invention is not particularly limited, but for example, it can be produced by polycondensation of the alcohol component and carboxylic acid component described above. The respective amounts of alcohol and carboxylic acid are such that the molar ratio of constituent units derived from the carboxylic acid component to constituent units derived from the alcohol component [carboxylic acid component / alcohol component] falls within the numerical range mentioned above. From the viewpoint of reactivity, the temperature of the polycondensation reaction is preferably 160°C or higher, more preferably 180°C or higher, even more preferably 190°C or higher, and preferably 260°C or lower, more preferably 250°C or lower, and even more preferably 240°C or lower.

[0034] When the polyester resin used in the present invention contains constituent units derived from polyethylene terephthalate and constituent units derived from polyethylene terephthalate and polyethylene terephthalic acid, the amount of polyethylene terephthalate present in the raw material is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 25% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on the total amount of polyethylene terephthalate, alcohol component and carboxylic acid component. By adding polyethylene terephthalate during the polycondensation reaction between the alcohol component and the carboxylic acid component, a transesterification reaction occurs, resulting in a polyester resin in which the constituent units of polyethylene terephthalate are incorporated into the constituent units derived from the alcohol component and the constituent units derived from the carboxylic acid component. Polyethylene terephthalate may be present from the start of the polycondensation reaction or added to the reaction system during the reaction. From the viewpoint of the durability of the asphalt pavement, the timing of adding polyethylene terephthalate is preferably when the reaction rate between the alcohol component and the carboxylic acid component is 10% or less, and more preferably when it is 5% or less. The reaction rate is defined as the value of (moles) of the amount of reaction water produced / (moles) of theoretical amount of reaction water produced × 100.

[0035] From the viewpoint of reaction rate, an esterification catalyst can be used in the polycondensation reaction. Examples of esterification catalysts include tin(II) compounds that do not have a Sn-C bond, such as di(2-ethylhexanoic acid)tin(II). From the viewpoint of reaction rate, the amount of esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1.0 part by mass or less, and even more preferably 0.6 parts by mass or less, per 100 parts by mass of the total amount of alcohol and carboxylic acid components. In addition to the esterification catalyst, a co-catalyst can be used in the polycondensation reaction. Examples of co-catalysts include pyrogallol compounds such as gallic acid. The amount of co-catalyst used is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.01 parts by mass or more, and preferably 0.15 parts by mass or less, more preferably 0.10 parts by mass or less, and even more preferably 0.05 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. In addition to the catalyst mentioned above, a polymerization inhibitor such as tert-butylcatechol may be used in the polycondensation reaction, preferably in an amount of 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, preferably 0.5 parts by mass or less, more preferably 0.2 parts by mass or less, and even more preferably 0.1 parts by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0036] <Compound (B)> The asphalt composition of the present invention contains one or more compounds (B) having 8 or more carbon atoms and having a hydroxyl group or an amino group, preferably selected from alkylamines, alkyl alcohols, sugar alcohols, and alkylamides, from the viewpoint of maintaining the black color of asphalt pavement. Compound (B) can be used alone or in combination of two or more. Compound (B) has 8 or more carbon atoms, preferably 10 or more, more preferably 12 or more, and preferably 30 or fewer, more preferably 25 or fewer, and even more preferably 20 or fewer. Compound (B) preferably has an alkyl or alkenyl group having 8 or more carbon atoms, more preferably has an alkyl group having 8 or more carbon atoms, and even more preferably has a linear alkyl group having 8 or more carbon atoms. Furthermore, the number of carbon atoms in the alkyl or alkenyl group is more preferably 10 or more, even more preferably 12 or more, and preferably 30 or less, more preferably 25 or less, and even more preferably 20 or less.

[0037] [Alkylamines with 8 or more carbon atoms] Alkylamines with 8 or more carbon atoms have one or more amino groups and an alkyl group, and there are no structural restrictions as long as the total number of carbon atoms is 8 or more. The number of amino groups in the alkylamine is not particularly limited, but from the viewpoint of maintaining the blackness of the asphalt pavement, it is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Furthermore, the amino group of the alkylamine may be a primary amino group, a secondary amino group, or a tertiary amino group. From the viewpoint of maintaining the black color of the asphalt pavement, a primary amino group or a secondary amino group is preferred, and a primary amino group is more preferred. When an alkylamine has two amino groups, for example, it may have one primary amino group and one secondary amino group within the molecule. Specific examples of alkylamines include primary amines such as octylamine, decylamine, laurylamine, myristylamine, palmitylamine, stearylamine, oleylamine, coconutamine, soyamine, beef tallowamine, and hydrogenated beef tallowamine; Secondary amines such as dibutylamine, dioctylamine, didecylamine, dilaurylamine, dimyristylamine, dipalmytilamine, distearylamine, dioleylamine, dicoconatamine, disoyaamine, ditafamine, and dihydrogenated tafamine; Tertiary amines such as dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dimethyloleylamine, dimethylcoconutamine, dimethylsoyamine, dimethyltallowamine, and dimethylhydrogenated tallowamine; Diamines such as octylpropylenediamine, decylpropylenediamine, laurylpropylenediamine, myristylpropylenediamine, palmitylpropylenediamine, stearylpropylenediamine, oleylpropylenediamine, coconut propylenediamine, soybean propylenediamine, beef tallow propylenediamine, and hardened beef tallow propylenediamine; Examples include triamines such as beef tallow dipropylene triamine. These alkylamines can be used individually or in combination of two or more. Preferably, the alkylamine is tallowamine, tallowtriamine, and dimethyldecylamine, more preferably tallowamine.

[0038] Furthermore, coconutamine, soyamine, beef tallowamine, hardened beef tallowamine, dicoconutamine, disoyaamine, dibeef tallowamine, dihydrogenated beef tallowamine, dimethylcoconutamine, dimethylsoyaamine, dimethylbeef tallowamine, dimethylhydrogenated beef tallowamine, coconut propylenediamine, soy propylenediamine, beef tallow propylenediamine, hardened beef tallow propylenediamine, and beef tallow dipropylenetriamine are mixed amines containing two or more alkylamines.

[0039] Examples of commercially available alkylamines include "DANOX AP," "ASFIER N480L," "Farmin 86T," "Farmin D86," "Farmin DM20," "Triamine T," and "Triamine R-86" (all brand names, manufactured by Kao Corporation), as well as "Armin 16D," "Armin 2C," and "Armin DMSD" (all brand names, manufactured by Lion Corporation).

[0040] [Alkyl alcohols with 8 or more carbon atoms] Alkyl alcohols with 8 or more carbon atoms have one or more hydroxyl groups and an alkyl group, and there are no structural restrictions as long as the total number of carbon atoms is 8 or more. The number of hydroxyl groups in the alkyl alcohol is not particularly limited, but from the viewpoint of maintaining the blackness of the asphalt pavement, it is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Furthermore, the hydroxyl groups of the alkyl alcohol may be primary, secondary, or tertiary hydroxyl groups. From the viewpoint of maintaining the black color of the asphalt pavement, primary or secondary hydroxyl groups are preferred, and primary hydroxyl groups are more preferred.

[0041] Specific examples of alkyl alcohols include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol. These alkylamines can be used individually or in combination of two or more. The alkyl alcohol is preferably lauryl alcohol. Commercially available alkyl alcohol products include "Calcol 8098" and "Calcol 2098" (both product names, manufactured by Kao Corporation), which contain one type of alkyl alcohol, and "Calcol 8650," "Calcol 4250," "Leodor SP-S30V," and "Leodor SP-O30V" (all product names, manufactured by Kao Corporation), which contain two or more types of alkyl alcohol.

[0042] [Sugar alcohols with 8 or more carbon atoms] Sugar alcohols with 8 or more carbon atoms have one or more hydroxyl groups and a sugar alcohol skeleton, and their structure is not limited as long as the total number of carbon atoms is 8 or more. Preferably, they are esters of sugar alcohols and fatty acids. Examples of sugar alcohol skeletons include glycerol, sorbitol, and sorbitan. Examples of fatty acids that make up the esters include oleic acid, palmitic acid, and stearic acid. The number of hydroxyl groups in the sugar alcohol is not particularly limited, but from the viewpoint of maintaining the blackness of the asphalt pavement, it is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Furthermore, the hydroxyl groups of the sugar alcohol may be primary, secondary, or tertiary hydroxyl groups. From the viewpoint of maintaining the black color of the asphalt pavement, primary or secondary hydroxyl groups are preferred, and primary hydroxyl groups are more preferred.

[0043] Specific examples of sugar alcohols include sugar alcohols having two hydroxyl groups, such as glycerol monostearate, glycerol monooleate, sorbitan distearate, and sorbitan diolate; and sugar alcohols having three hydroxyl groups, such as sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate. These sugar alcohols can be used individually or in combination of two or more. Preferably, the sugar alcohol is sorbitan monostearate. Commercially available sugar alcohols include "Leodol MS-50," "Leodol MO-60," "Leodol SP-S20," "Leodol SP-L10," and "Leodol SP-S10V" (all are product names, manufactured by Kao Corporation).

[0044] [Alkylamides with 8 or more carbon atoms] Alkylamides with 8 or more carbon atoms have an amide group and an alkyl group, and their structure is not restricted as long as the total number of carbon atoms is 8 or more. Alkylamides also include alkylalkanolamides.

[0045] Specific examples of alkylamides include ethylene-bis-stearate amide, stearate amide, and oleate amide. Specific examples of alkylalkanolamides include stearylethanolamide and laurylethanolamide. These alkylamides can be used individually or in combination of two or more. The alkylamide is preferably ethylene bis-stearic acid amide. Examples of commercially available alkylamides include "Kao Wax EB-G," "Fatty Acid Amid T," "Fatty Acid Amid S," "Aminone L-02," and "Aminone PK-02S" (all are brand names, manufactured by Kao Corporation).

[0046] Compound (B) is preferably alkylamines, alkyl alcohols, and sugar alcohols, and more preferably alkylamines.

[0047] <Content of polyester resin (A) and compound (B)> In the asphalt modifier, the mass ratio of polyester resin (A) to compound (B) [polyester resin (A) / compound (B)] is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, and preferably 39 or less, more preferably 30 or less, and even more preferably 25 or less, from the viewpoint of durability of the asphalt pavement and the ability to maintain the blackness of the asphalt pavement.

[0048] The asphalt modifier of the present invention may contain components other than the polyester resin (A) and the compound (B) to the extent that they do not impair the effect, or it may consist only of the polyester resin (A) and the compound (B). The total content of polyester resin (A) and compound (B) in the asphalt modifier is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 85% by mass or more, based on the total mass of the asphalt modifier.

[0049] The asphalt modifier of the present invention can be used, for example, by mixing it with asphalt to obtain an asphalt composition. After adding heated 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 an asphalt modifier for blending into an asphalt mixture containing aggregate.

[0050] [Asphalt composition] The asphalt composition of the present invention contains the above-mentioned polyester resin (A), the above-mentioned compound (B), and asphalt.

[0051] <Asphalt> Various types of asphalt can be used. For example, in addition to straight asphalt, which is petroleum asphalt for paving, modified asphalt can be used. Modified asphalts include blown asphalt and polymer-modified asphalt, which is modified with polymer materials such as thermoplastic elastomers and thermoplastic resins. Straight asphalt refers to the residual bituminous substance obtained by subjecting crude oil to atmospheric distillation, vacuum distillation, etc. Blown asphalt refers to asphalt obtained by heating a mixture of straight asphalt and heavy oil, and then blowing air into it to oxidize it. It is preferable to select from straight asphalt and polymer-modified asphalt, with polymer-modified asphalt being more preferable from the viewpoint of durability of asphalt pavement, and straight asphalt being more preferable from the viewpoint of versatility. Among polymer-modified asphalts, asphalt modified with thermoplastic elastomers is more preferable.

[0052] (Thermoplastic elastomer) Examples of thermoplastic elastomers used in asphalt modified with thermoplastic elastomers include at least one selected from styrene / butadiene block copolymer, styrene / butadiene / styrene block copolymer, styrene / butadiene random copolymer, styrene / isoprene block copolymer, styrene / isoprene / styrene block copolymer, styrene / isoprene random copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid ester copolymer, styrene / ethylene / butylene / styrene copolymer, styrene / ethylene / propylene / styrene copolymer, polyurethane thermoplastic elastomer, polyolefin thermoplastic elastomer, isobutylene / isoprene copolymer, polyisoprene, polychloroprene, synthetic rubber other than those listed above, and natural rubber.

[0053] Among these, the thermoplastic elastomer is preferably at least one selected from styrene / butadiene block copolymer, styrene / butadiene / styrene block copolymer, styrene / butadiene random copolymer, styrene / isoprene block copolymer, styrene / isoprene / styrene block copolymer, styrene / isoprene random copolymer, and ethylene / acrylic acid ester copolymer, more preferably at least one selected from styrene / butadiene block copolymer, styrene / butadiene / styrene block copolymer, styrene / butadiene random copolymer, styrene / isoprene block copolymer, and styrene / isoprene random copolymer, and even more preferably at least one selected from styrene / butadiene random copolymer and styrene / butadiene / styrene block copolymer. From the viewpoint of durability of asphalt pavement, the content of thermoplastic elastomer in polymer-modified asphalt is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 5% by mass or less.

[0054] <Content of polyester resin (A) and compound (B)> In the asphalt composition of the present invention, the total content of the polyester resin (A) and the compound (B) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of durability of the asphalt pavement and the ability to maintain the blackness of the asphalt pavement, per 100 parts by mass of asphalt.

[0055] The asphalt composition of the present invention is a binder composition, and for example, by adding aggregate to the asphalt composition to make an asphalt mixture, it can be used for paving. In other words, the asphalt composition of the present invention is suitable for paving, and is particularly suitable for road paving.

[0056] [Method for producing asphalt composition] A method for producing the asphalt composition of the present invention preferably includes a step of mixing asphalt with the polyester resin (A) and the compound (B).

[0057] The asphalt composition is obtained by heating and melting asphalt, adding polyester resin (A) and compound (B), and stirring and mixing in a commonly used mixer until each component is uniformly dispersed. Commonly used mixers include homomixers, dissolvers, paddle mixers, ribbon mixers, screw mixers, planetary mixers, vacuum backflow mixers, roll mills, and twin-screw extruders.

[0058] The mixing temperature of the asphalt with the polyester resin (A) and compound (B) is preferably 100°C or higher, more preferably 130°C or higher, even more preferably 160°C or higher, and even more preferably 170°C or higher, and preferably 230°C or lower, more preferably 210°C or lower, even more preferably 200°C or lower, and even more preferably 190°C or lower, from the viewpoint of uniformly dispersing the polyester resin (A) and compound (B) in the asphalt.

[0059] Furthermore, from the viewpoint of efficiently and uniformly dispersing the polyester resin (A) and compound (B) in the asphalt, the mixing time is preferably 0.1 hours or more, more preferably 0.5 hours or more, even more preferably 1.0 hour or more, and even more preferably 1.5 hours or more, and preferably 10 hours or less, more preferably 7 hours or less, even more preferably 5 hours or less, and even more preferably 3 hours or less.

[0060] [Asphalt mixture] The asphalt mixture of the present invention contains the above-mentioned polyester resin (A), the above-mentioned compound (B), asphalt, and aggregate, wherein the aggregate contains recycled asphalt aggregate.

[0061] The total content of the polyester resin (A) and compound (B) in the asphalt mixture is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.10% by mass or more, even more preferably 0.15% by mass or more, and preferably 4% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less. The asphalt content in the asphalt mixture is preferably 2.5% by mass or more, more preferably 3% by mass or more, even more preferably 3.5% by mass or more, even more preferably 4% by mass or more, and preferably 10% by mass or less, more preferably 9% by mass or less, even more preferably 8% by mass or less, and even more preferably 7% by mass or less.

[0062] In the asphalt mixture of the present invention, the total content of the polyester resin (A) and the compound (B) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of durability of the asphalt pavement and the ability to maintain the blackness of the asphalt pavement, per 100 parts by mass of asphalt. The asphalt content in the asphalt mixture is the total content of new asphalt and asphalt derived from recycled asphalt aggregate. The asphalt content in an asphalt mixture can be determined from the blending ratio. Alternatively, it can be determined by measuring the loss on ignition using the asphalt mixture or asphalt pavement. The loss on ignition measurement is performed according to the method specified in AASHTO (American Association of State Highway and Transportation Officials) T 308-10 (2015). Since the mixture includes recycled aggregate (described later), the asphalt content is determined from the loss on ignition of the recycled asphalt aggregate and used in the mix design calculation.

[0063] <Aggregates> The aggregate must include recycled asphalt aggregate, and other materials such as crushed stone, pebbles, gravel, sand, and ceramics may be optionally selected and used. Furthermore, both coarse aggregate with a particle size of 2.36 mm or larger and fine aggregate with a particle size of less than 2.36 mm can be used as aggregate. Examples of 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 fine aggregate with a particle size of 0.075 mm or more and less than 2.36 mm. Examples of 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 particle size values ​​mentioned above are those specified in JIS A5001:2008. Among these, a combination of coarse aggregate and fine aggregate is preferred.

[0064] Furthermore, the fine aggregate may contain fillers with a particle size of less than 0.075 mm. Examples of fillers include sand, fly ash, calcium carbonate powder such as limestone powder, and slaked lime. Among these, calcium carbonate powder is preferred from the viewpoint of improving the strength of the asphalt pavement. From the viewpoint of improving the strength of the asphalt pavement, the average particle size of the filler is preferably 0.001 mm or more, more preferably 0.05 mm or less, more preferably 0.03 mm or less, and even more preferably 0.02 mm or less. Here, the average particle size is the average particle size at 50% volume accumulation (D 50 This means that it can be measured with a laser diffraction particle size distribution analyzer.

[0065] From the viewpoint of durability of asphalt pavement, the mass ratio of coarse aggregate to fine aggregate is preferably 10 / 90 or more, more preferably 15 / 85 or more, even more preferably 20 / 80 or more, and preferably 90 / 10 or less, more preferably 80 / 20 or less, and even more preferably 70 / 30 or less.

[0066] The aggregate includes recycled asphalt aggregate. Recycled asphalt aggregate is made by collecting used asphalt pavement, crushing it, and classifying it. Used asphalt pavements derived from recycled asphalt aggregate may contain asphalt and aggregate, and may contain other additives as needed. Furthermore, the asphalt contained in recycled asphalt aggregate deteriorates in physical and chemical properties due to the influence of environmental factors such as heat and light. The physical and chemical properties of asphalt can be evaluated by measuring the penetration, softening point, flexural strength, fracture strain, and asphalt composition. Generally, asphalt in which the marten fraction has migrated to asphaltene and the penetration has decreased is often called deteriorated asphalt. However, even if the penetration of recycled asphalt is equivalent to that of new asphalt, changes in other properties may prevent it from exhibiting the same performance as new asphalt.

[0067] The aggregate content in the asphalt mixture is preferably 90% by mass or more, more preferably 92% by mass or more, even more preferably 93% by mass or more, and preferably 98% by mass or less, more preferably 97% by mass or less, and even more preferably 96% by mass or less. From the viewpoint of reducing environmental impact and manufacturing costs, the content of recycled asphalt aggregate in the asphalt mixture is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. From the viewpoint of ensuring quality stability and workability, it is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0068] The following (1) to (3) are examples of suitable formulations for asphalt mixtures. (1) Fine-grained asphalt comprising coarse aggregate of 30% to less than 45% by volume, fine aggregate of 30% to 50% by volume, and an asphalt composition of 5% to 10% by volume. (2) An example of an asphalt mixture is a dense-graded asphalt comprising, for example, 45% by volume or more and less than 70% by volume of coarse aggregate, 20% by volume or more and 45% by volume of fine aggregate, and 3% by volume or more and 10% by volume of asphalt composition. (3) Porous asphalt comprising 70% to 80% by volume of coarse aggregate, 10% to 20% by volume of fine aggregate, and 3% to 10% by volume of asphalt composition. In addition, the mixing ratio of asphalt in conventional asphalt mixtures containing aggregate and asphalt is usually determined according to the optimal amount of asphalt found in the "Asphalt Composition Mix Design" described in the "Pavement Design and Construction Guidelines" published by the Japan Road Association. In this invention, the above-mentioned optimal amount of asphalt corresponds to the total amount of asphalt and asphalt modifier. However, it is not necessary to limit the method to the method described in the "Guidelines for Pavement Design and Construction," and it may be determined by other methods.

[0069] [Method for producing asphalt mixture] The asphalt mixture of the present invention can be obtained, for example, by a manufacturing method that includes the step of adding and mixing a mixture of preheated asphalt, polyester resin (A), and the above compound (B) to heated aggregate. Specific methods for manufacturing asphalt mixtures include conventional methods such as the plant mix method and the premix method. Both methods involve adding polyester resin (A) and compound (B) to heated aggregate along with asphalt (and, if necessary, a thermoplastic elastomer). Addition methods include, for example, the premix method, in which asphalt (and, if necessary, a thermoplastic elastomer), polyester resin (A), and compound (B) are dissolved in advance, or the plant mix method, in which modified asphalt (in which a thermoplastic elastomer is dissolved in asphalt) is added to the aggregate, and then the polyester resin (A) and compound (B) are added. Among these, the premix method is preferred from the viewpoint of exhibiting asphalt performance. More specifically, the method for producing an asphalt mixture preferably involves the following steps in the mixing process: (i) Add and mix asphalt (and thermoplastic elastomer as needed) to heated aggregate to obtain a mixture, then add polyester resin (A) and compound (B) and mix the mixture with the polyester resin. (ii) Add and mix asphalt (and thermoplastic elastomer as needed), polyester resin (A) and compound (B) simultaneously to heated aggregate, or (iii) Add and mix the mixture of preheated and mixed asphalt (and thermoplastic elastomer if necessary), polyester resin (A), and compound (B) to the heated aggregate. Among these, method (iii) is preferred from the viewpoint of achieving asphalt performance.

[0070] The temperature at which the heated aggregate is mixed with asphalt, polyester resin (A), and compound (B) is preferably 130°C or higher, more preferably 140°C or higher, and more preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower, from the viewpoint of softening the asphalt and exhibiting asphalt performance. Furthermore, the time for mixing the heated aggregate with the asphalt, polyester resin (A), and compound (B) is preferably 30 seconds or more, more preferably 1 minute or more, even more preferably 2 minutes or more, and even more preferably 5 minutes or more, from the viewpoint of exhibiting asphalt performance. The upper limit of the time is not particularly limited, but is for example about 30 minutes.

[0071] In the method described in (iii) above, the method for preparing the mixture of preheated and mixed asphalt (and optionally a thermoplastic elastomer), polyester resin (A), and compound (B) is not particularly limited, but it is preferable to include the step of heating and melting the asphalt, adding the polyester resin (A), compound (B), and optionally other additives, and stirring and mixing in a commonly used mixer until each component is uniformly dispersed. Commonly used mixers include homomixers, dissolvers, paddle mixers, ribbon mixers, screw mixers, planetary mixers, vacuum backflow mixers, roll mills, twin-screw extruders, etc.

[0072] The mixing temperature of the above-mentioned asphalt, polyester resin (A), and compound (B) is preferably 100°C or higher, more preferably 130°C or higher, even more preferably 160°C or higher, even more preferably 170°C or higher, and preferably 230°C or lower, more preferably 210°C or lower, even more preferably 200°C or lower, and even more preferably 190°C or lower, from the viewpoint of uniformly dispersing the polyester resin in the asphalt and exhibiting asphalt performance.

[0073] Furthermore, the mixing time for the asphalt, polyester resin (A), and compound (B) is preferably 0.1 hours or more, more preferably 0.5 hours or more, even more preferably 1.0 hour or more, even more preferably 1.5 hours or more, and preferably 10 hours or less, more preferably 7 hours or less, even more preferably 5 hours or less, and even more preferably 3 hours or less, from the viewpoint of efficiently and uniformly dispersing the polyester resin (A) and compound (B) in the asphalt and exhibiting asphalt performance. The preferred content of polyester resin (A) and compound (B) in relation to asphalt is as described above.

[0074] In the method described in (iii) above, the mixture of asphalt, polyester resin (A), and compound (B) may be used as a hot asphalt mixture that is substantially free of water, or an emulsifier and water may be added to the above asphalt mixture to form an asphalt emulsion, and aggregates, etc., may be added to this emulsion to be used as a cold asphalt mixture. From the viewpoint of exhibiting asphalt performance, the mixture of asphalt and polyester resin is preferably substantially free of water.

[0075] When an asphalt mixture is used as a heated asphalt mixture, there are no particular restrictions on the method of manufacturing the asphalt mixture, and it may be manufactured by any method, but it is generally acceptable to manufacture it in accordance with the method for manufacturing an asphalt mixture containing aggregate and asphalt composition.

[0076] [Road paving construction methods] The asphalt mixture of the present invention is suitable for road paving. The road paving construction method of the present invention preferably includes the step of applying the asphalt mixture of the present invention to a road or the like to form an asphalt paving material layer. The asphalt mixture of the present invention produces an asphalt paving material that is excellent in suppressing aggregate scattering and water resistance, and can be suitably used in permeable pavements.

[0077] Furthermore, the road pavement construction method of the present invention preferably includes a step of applying the asphalt mixture of the present invention to the surface layer of the road. In particular, it is preferable to apply the asphalt mixture of the present invention to the surface layer of a highway.

[0078] In road paving methods, the asphalt mixture can be compacted using the same construction machinery configuration and method as for ordinary asphalt mixtures. When used as a heated asphalt mixture, the compaction temperature of the asphalt mixture is preferably 100°C or higher, more preferably 120°C or higher, even more preferably 130°C or higher, and preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 170°C or lower, from the viewpoint of exhibiting asphalt performance. In other words, one preferred embodiment of the road paving method of the present invention is a road paving method that includes a step of compacting the above-mentioned asphalt mixture, wherein the compaction temperature of the asphalt mixture is 100°C or more and 200°C or less.

[0079] [Additive for recycled asphalt mixtures] As shown in the examples described later, compound (B) alone exhibits the effect of maintaining the black color of asphalt pavement even after traffic is opened. Accordingly, the present invention also provides an additive for recycled asphalt mixtures containing one or more compounds having 8 or more carbon atoms and having a hydroxyl group or an amino group, preferably selected from alkylamines, alkyl alcohols, sugar alcohols, and alkylamide compounds. From the viewpoint of maintaining the blackness of the asphalt pavement, the amount of compound (B) used is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1.0 part by mass or more, and preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.0 parts by mass or less, per 100 parts by mass of asphalt. The additive of the present invention is used as an additive when manufacturing a recycled asphalt mixture that includes recycled asphalt aggregate as aggregate. [Examples]

[0080] The physical properties of resins and other materials were measured and evaluated using the following methods. [Measurement method] (1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample was heated at a heating rate of 6°C / min while 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 amount of plunger descent of the flow tester was plotted against temperature, and the temperature at which half of the sample flowed out was defined as the softening point.

[0081] Manufacturing Example 1 (Polyester Resin A1) The alcohol component and terephthalic acid from the raw material monomers shown in Table 1 were placed in a 10 L four-necked flask equipped with a thermometer, stainless steel stirring rod, dehydration tube, drop-through condenser, and nitrogen inlet tube. Under a nitrogen atmosphere, the amounts of tin(II) di(2-ethylhexanoate) and gallic acid shown in Table 1 were added, and the mixture was heated to 235°C over 3 hours in a mantle heater and held at 235°C for 5 hours. After that, a reduced-pressure reaction was carried out at 8.0 kPa for 1 hour. After cooling to 180°C, alkenyl succinic anhydride was added. The mixture was heated to 210°C over 2 hours, held at 210°C for 1 hour, and a reduced-pressure reaction was carried out at 8.3 kPa. The reaction was then continued until the softening point shown in Table 1 was reached to obtain polyester resin A1.

[0082] Manufacturing Example 2 (Polyester Resin A2) The alcohol component, terephthalic acid, and PET (polyethylene terephthalate) from the raw material monomers shown in Table 1 were placed in a 10 L four-necked flask equipped with a thermometer, stainless steel stirring rod, dehydration tube, fall-flow condenser, and nitrogen inlet tube. Under a nitrogen atmosphere, the amount of di(2-ethylhexanoate)tin(II) shown in Table 1 was added, and the temperature was raised to 235°C over 3 hours in a mantle heater and held at 235°C for 5 hours, after which a reduced pressure reaction was carried out at 8.0 kPa for 1 hour. After visual confirmation that the PET particles had disappeared from the reaction mixture, it was cooled to 180°C and alkenyl succinic anhydride was added. The temperature was raised to 210°C over 2 hours, held at 210°C for 1 hour, and a reduced pressure reaction was carried out at 8.3 kPa, and the reaction was continued until the softening point shown in Table 1 was reached to obtain polyester resin A2.

[0083] Manufacturing Example 3 (Polyester Resin A3) The raw material monomers shown in Table 1 were placed in a 10L four-necked flask equipped with a thermometer, stainless steel stirring rod, dehydration tube, nitrogen inlet tube, and thermocouple. Di(2-ethylhexanoic acid)tin(II) and gallic acid were added, and the mixture was maintained at 180°C for 2 hours under a nitrogen atmosphere. After further heating to 210°C over 3 hours, the mixture was reacted at 210°C for 4 hours, followed by a reduced pressure reaction at 8.3 kPa for 1 hour to obtain polyester resin A3.

[0084] Manufacturing Example 4 (Polyester Resin A4) The raw material monomers shown in Table 1 were placed in a 10L four-necked flask equipped with a thermometer, stainless steel stirring rod, dehydration tube, nitrogen inlet tube, and thermocouple. The flask was maintained at 140°C for 6 hours under a nitrogen atmosphere, and then the temperature was raised to 200°C over 6 hours. Di(2-ethylhexanoate)tin(II) and gallic acid were added, and the mixture was reacted at 200°C for 1 hour. Finally, the mixture was subjected to a reduced pressure reaction at 8.3 kPa for 1 hour to obtain polyester resin A4.

[0085] [Table 1]

[0086] Example 1 12 kg of aggregate (mixture A; see below for aggregate composition) heated to 180°C was placed in an asphalt mixer and mixed at 180°C for 60 seconds. Next, 540 g of straight asphalt (manufactured by Idemitsu Kosan Co., Ltd.) was added and mixed in the asphalt mixer for 1 minute. Then, 146 g of polyester resin A1 and 7.7 g of compound B1 ("DANOX AP"; beef tallow amine mixture, manufactured by Kao Corporation) were added and mixed in the asphalt mixer for 2 minutes to obtain asphalt mixture M-1. "DANOX AP" is a mixture of various amines and amidates (main component: beef tallow amine) obtained as a residue in the beef tallow amine purification process. (1) Preparation of asphalt specimen T1 for wheel tracking test The obtained asphalt mixture M-1 was promptly filled into a 300 x 300 x 50 mm mold, and after heat curing at 180°C for 2 hours, it was subjected to 25 rotations of pressure treatment using a roller compactor (manufactured by Iwata Industries Co., Ltd.) at a temperature of 150°C and a load of 0.44 kPa to produce asphalt specimen T1-1.

[0087] (2) Preparation of asphalt specimen T2 for Marshall stability test 1.2 kg of the obtained asphalt mixture M-1 was weighed out and subjected to heat curing by storing it at 180°C for 2 hours. Then, using a Marshall test compaction machine, "Automatic Asphalt Compaction Device" (manufactured by Nakajima Gihan Co., Ltd.), it was compacted 50 times on each side for a total of 100 times to prepare a cylindrical asphalt specimen T2-1 for the Marshall stability test.

[0088] Furthermore, the asphalt mixture includes newly blended straight asphalt and asphalt derived from recycled asphalt aggregate. The polyester resin A1 content in the asphalt mixture is 19 parts by mass per 100 parts by mass of the total asphalt content, and the compound B1 content is 1 part by mass.

[0089] <Composition of aggregates> [Formulation A] Crushed stone No. 6, 31.0 parts by mass Crushed sand 6.0 parts by mass River sand 13.0 parts by mass Mountain sand 6.0 parts by mass Stone powder (calcium carbonate powder) 4.0 parts by mass Recycled asphalt aggregate: 40.0 parts by mass (Asphalt content: 4.7% by mass (estimated value)) Passed mass%: Sieve mesh size 15 mm: 100% by mass Sieve mesh size 10 mm: 87.9% by mass Sieve mesh size 5 mm: 57.5% by mass Sieve mesh size 2.5 mm: 53.1% by mass Sieve mesh size 1.2 mm: 36.7% by mass Sieve mesh size 0.6 mm: 23.1% by mass Sieve mesh size 0.3 mm: 12.7% by mass Sieve mesh size 0.15 mm: 6.5% by mass

[0090] The asphalt content in recycled asphalt aggregate was estimated according to the method specified in AASHTO T 308-10 (2015).

[0091] Examples 2-3 Asphalt specimens T1-2 to T1-3 for wheel tracking testing were prepared in the same manner as in Example 1, except that the amount of compound B1 added was changed as shown in Table 2. Examples 4-8 Asphalt specimens T1-4 to T1-8 for wheel tracking testing were prepared in the same manner as in Example 1, except that compound B1 was replaced with compounds B2 to B6 shown in Table 2. Examples 9-11 Asphalt specimens T1-9 to T1-11 for wheel tracking testing were prepared in the same manner as in Example 1, except that polyester resin A1 was replaced with polyester resins A2 to A4 obtained in Production Examples 2 to 4 shown in Table 2. Example 12 Asphalt specimen T1-12 for wheel tracking testing was prepared in the same manner as in Example 1, except that polyester resin A1 was not added. Comparative Example 1 Asphalt specimens T1-C1 for wheel tracking testing were prepared in the same manner as in Example 1, except that polyester resin A1 and compound B1 were not added. Comparative Example 2 Asphalt specimens T1-C2 for wheel tracking testing and T2-C2 for Marshall stability testing were prepared in the same manner as in Example 1, except that compound B1 was not added. Comparative Examples 3-5 Asphalt specimens T1-C3 to T1-C5 for wheel tracking testing were prepared in the same manner as in Example 1, except that compound B1 was replaced with compounds C1 to C3 shown in Table 2.

[0092] The compounds B2-B6 and C1-C3 used in the examples are as follows: Compound B2: "ASFIER N480L"; Beef tallow triamine (manufactured by Kao Corporation) Compound B3: "Kao Wax EB-G"; Ethylene bis-stearic acid amide (manufactured by Kao Corporation) Compound B4: "Leodol SP-S10V"; Sorbitan monostearate (manufactured by Kao Corporation) Compound B5: "Calcol 2098"; Lauryl alcohol (manufactured by Kao Corporation) Compound B6: "Farmin DM1098"; Dimethyldecylamine (manufactured by Kao Corporation) Compound C1: γ-aminobutyric acid Compound C2: n-heptanol Compound C3: "Gripper 4131"; a mixture of stearyl phosphate and phosphoric acid (manufactured by Kao Corporation)

[0093] [Rating (1)] The asphalt specimens T1-1 to T1-12 and T1-C1 to T1-C5 obtained in Examples 1 to 12 and Comparative Examples 1 to 5 were subjected to the following evaluation tests. <Durability evaluation: Rutting depth (wheel tracking test)> Asphalt specimens were immersed in warm water set to 65°C in a 60°C constant temperature chamber. A wheel tracking test machine (manufactured by Iwata Industries Co., Ltd., load 686N, wheel width 47mm, line pressure 291.5N / cm) was used to move a wheel back and forth over the specimen at a speed of 21 times / minute, and the displacement was measured after 2,000 passes. Other measurement conditions followed the "B003 Wheel Tracking Test" described in the "Pavement Survey and Testing Methods Handbook" published by the Japan Road Association. The results are shown in Table 2.

[0094] <Evaluation of the blackness of the pavement> In the asphalt specimens before the wheel tracking test, a portable colorimeter (TES-3250, manufactured by Sato Shoji Co., Ltd.) was used to measure L at four randomly selected locations.* a * b * The L value in the color system was measured. The average value was used as the measured value before the test. * In the asphalt specimen after the wheel tracking test, the L value was similarly measured at four randomly selected locations from the wheel running area. The average value was used as the measured value after the test. In the asphalt specimen after the wheel tracking test, the L value was similarly measured at four randomly selected locations from the wheel running area. * The average value was used as the measured value after the test. As an index of the change in the L value before and after the wheel tracking test, [measured value before the test / measured value after the test] was calculated. * The results are shown in Table 2. The results are shown in Table 2.

[0095] Note that the L * a * b * The L value in the color system * is a value between 0 and 100 representing brightness. A smaller numerical value means a stronger blackness, and a larger numerical value means a stronger whiteness. From the viewpoints of surface appearance and visibility, a stronger blackness, that is, a smaller numerical value, is preferable. [Measured value before the test / measured value after the test] being closer to 1.0 means that the blackness can be maintained. The asphalt specimen before being subjected to the wheel tracking test corresponds to the asphalt pavement immediately after compaction, and the asphalt specimen after the wheel tracking test corresponds to the asphalt pavement that has deteriorated over time after the opening to traffic.

[0096]

Table 2

[0097] From the results shown in Table 2, it can be seen that an asphalt pavement with excellent durability and capable of maintaining blackness even after the opening to traffic can be obtained by using an asphalt modifier containing polyester resin (A) and a predetermined compound (B), even when the aggregate contains asphalt recycled aggregate (for example, Examples 1 to 11). It can also be seen that an asphalt modifier containing no polyester resin (A) but containing a predetermined compound (B) exhibits such an effect (for example, Example 12).

[0098] [Rating (2)] The Marshall stability test asphalt specimens T2-1 and T2-C2 obtained in Example 1 and Comparative Example 2 were subjected to the following evaluation tests. <Marshall Stability Test> After demolding, the asphalt specimen T2 was immersed in a 60°C constant temperature water bath for 30 minutes. Then, using a Marshall loading device (manufactured by Nakajima Gihan Co., Ltd.), the overturned asphalt specimen T2 was crushed with a flat plate at a speed of 50 mm / min. The maximum load shown before failure was defined as the Marshall stability. In addition, the amount of displacement from the starting point of the displacement slope to the maximum load was measured and defined as the flow value. Other measurement conditions followed the "B001 Marshall Stability Test" described in the "Pavement Survey and Testing Methods Handbook" published by the Japan Road Association. The flow value of asphalt specimen T2-1 (Example 1) was 30 [1 / 100 cm], and the flow value of asphalt specimen T2-C2 (Comparative Example 2) was 18 [1 / 100 cm]. The flow value in the Marshall stability test is an indicator of the flexibility and crack resistance of asphalt pavement at its service temperature; the higher the flow value, the better the flexibility and crack resistance of the asphalt pavement.

[0099] These results show that asphalt specimens obtained using an asphalt modifier containing polyester resin (A) and a specified compound (B) exhibit superior flexibility and crack resistance compared to asphalt specimens without compound (B) (for example, comparing Example 1 with Comparative Example 2).

Claims

1. An asphalt mixture containing a polyester resin (A), the following compound (B), asphalt, and aggregate, wherein the aggregate contains asphalt recycled aggregate. Compound (B): A compound having 8 or more carbon atoms and having a hydroxyl group or an amino group

2. The asphalt mixture according to Claim 1, wherein the compound (B) has 30 or less carbon atoms.

3. The asphalt mixture according to Claim 1, wherein the compound (B) is one or more compounds selected from alkylamines, alkyl alcohols, sugar alcohols, and alkylamide compounds.

4. The asphalt mixture according to Claim 1, wherein the mass ratio of the polyester resin (A) to the compound (B) [polyester resin (A) / compound (B)] is 4 or more and 39 or less.

5. The asphalt mixture according to Claim 1, wherein the content of the asphalt recycled aggregate in the asphalt mixture is 10% by mass or more and 80% by mass or less.

6. The asphalt mixture according to Claim 1, wherein the softening point or melting point of the polyester resin (A) is 90°C or higher.

7. An asphalt modifier containing a polyester resin (A) and the following compound (B). Compound (B): A compound having 8 or more carbon atoms and having a hydroxyl group or an amino group

8. A road paving method including a step of compacting the asphalt mixture according to any one of Claims 1 to 6, wherein the compacting temperature of the asphalt mixture is 100°C or higher and 200°C or lower.

9. An additive for a recycled asphalt mixture containing one or more compounds having 8 or more carbon atoms selected from alkylamines, alkyl alcohols, sugar alcohols, and alkylamide compounds.