Asphaltic concrete

Abstract

Provided is an asphaltic concrete capable of exhibiting excellent physical properties even when a recycled asphalt aggregate having an advanced degree of deterioration is used therefor. Specifically provided is an asphaltic concrete including a recycled asphalt aggregate and an amine compound represented by formula (I). [In the formula, Ra represents an alkyl group having a carbon number of no more than 20. Rb and Rc independently represent an alkyl group having a carbon number of 6-22 or -(RdO)X-H. Rd is an alkylene group having a carbon number of 2-4, and x is the average number of added moles of the oxyalkylene group. When Rb and Rc are -(RdO)X-H, the total of the average numbers of added moles of the oxyalkylene groups is no more than 20.]

Description

Asphalt mixture

[0001] This invention relates to asphalt mixtures, methods for producing the same, and additives for recycling recycled asphalt aggregate.

[0002] Asphalt pavement 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 is formed by an asphalt mixture in which aggregate is bound together with asphalt, and it has good hardness and durability.

[0003] In recent years, from the perspective of reducing environmental impact and rising crude oil prices, the use of recycled asphalt aggregate (recycled asphalt aggregate) as a new paving material has been increasing in popularity.

[0004] Patent Document 1 discloses an asphalt mixture for obtaining an asphalt pavement that is highly durable and maintains its black color even after traffic is opened, which contains a polyester resin, a compound having 8 or more carbon atoms having a hydroxyl group or an amino group, asphalt, and aggregate, wherein the aggregate contains recycled asphalt aggregate. Patent Document 2 discloses an asphalt composition as a technology that enables a wider range of uses for recovered asphalt, which contains recovered asphalt and an ester-functionalized regenerating agent, wherein the recovered asphalt contains aggregate and an oxidized asphalt binder, and the regenerating agent is present in an amount effective in reducing the glass transition onset temperature of the oxidized asphalt binder by at least 5°C compared to the glass transition onset temperature of an oxidized asphalt binder without the regenerating agent.

[0005] Japanese Patent Publication No. 2023-36018, International Publication No. 2013 / 090283

[0006] The asphalt contained in asphalt recycled aggregates has undergone a thermal history and is modified to be harder and more brittle compared to fresh asphalt. When using asphalt recycled aggregates, a technique has become widespread where a recycling additive is blended to soften the deteriorated asphalt and enable the production of an asphalt mixture close to the conventional quality. However, as the repeated use of asphalt recycled aggregates progresses and the blending ratio of asphalt recycled aggregates also tends to increase, the conventional recycling additives may sometimes result in insufficient recycling effects. According to the technique described in Patent Document 1, by effectively acting on the fixed asphalt in the asphalt recycled aggregates, a pavement excellent in durability and blackness can be obtained, but the effects on various asphalt recycled aggregates are low, and in particular, softening is insufficient. According to the technique described in Patent Document 2, even for hard and deteriorated asphalt, a softening effect can be obtained without impairing the necessary physical properties. However, this is mainly a verification for extracted and plasticized deteriorated asphalt, and it is considered that the effect on the asphalt fixed in the asphalt recycled aggregates is insufficient.

[0007] The present invention relates to an asphalt mixture capable of exhibiting excellent physical properties even when using asphalt recycled aggregates with advanced deterioration degree, a method for producing the same, and a recycling additive for asphalt recycled aggregates capable of obtaining such an asphalt mixture.

[0008] The present invention relates to the following [1] to [3]. [1] An asphalt mixture containing an amine compound represented by the following formula (I) and asphalt recycled aggregates. [In the formula, R ａ represents an alkyl group having 20 or less carbon atoms. R ｂ and R ｃ independently represent an alkyl group having 6 or more and 22 or less carbon atoms, or -(R ｄ O) Ｘ -H. R ｄ is an alkylene group having 2 or more and 4 or less carbon atoms, and x is the average number of moles of oxyalkylene groups added. R ｂ and R ｃ being -(R ｄ O) Ｘ-If it is H, the total average number of moles of oxyalkylene groups added is 20 or less. [2] A method for producing an asphalt mixture, comprising the step of mixing an amine compound represented by the following formula (I) and recycled asphalt aggregate. [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ -If it is H, the total average number of moles of oxyalkylene groups added is 20 or less. ] [3] A recycling additive for recycled asphalt aggregate containing an amine compound represented by the following formula (I). [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ If it is -H, the total average number of moles of oxyalkylene groups added is 20 or less.

[0009] According to the present invention, there is an asphalt mixture that can exhibit excellent physical properties even when using recycled asphalt aggregate that has deteriorated to an advanced degree, a method for producing the same, and an additive for recycling recycled asphalt aggregate that can produce such an asphalt mixture.

[0010] [Asphalt mixture] The asphalt mixture of the present invention comprises an amine compound represented by the following formula (I) and recycled asphalt aggregate. [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ -When H is present, the total average number of added moles of oxyalkylene groups is 20 or less. The asphalt mixture is useful because, by containing the amine compound represented by the above formula (I), it can exhibit excellent physical properties even when using recycled asphalt aggregate that has deteriorated to a high degree, due to its interaction with deteriorated asphalt fixed to the recycled asphalt aggregate.

[0011] The asphalt mixture of the present invention can exhibit excellent physical properties even when using recycled asphalt aggregate that has deteriorated to an advanced degree. In this specification, an asphalt mixture that can exhibit excellent physical properties means that the asphalt pavement using the asphalt mixture achieves both excellent durability and excellent workability during paving. The durability of the asphalt pavement can be evaluated by Marshall stability, for example, as shown in the examples described later. Workability during paving can be evaluated by void ratio, for example, as shown in the examples described later.

[0012] In this invention, a large amount of recycled asphalt aggregate can be incorporated without impairing the pavement's properties. Therefore, it is expected that the generation of carbon dioxide derived from raw materials and costs can be significantly reduced, thereby contributing to reduced environmental impact and economic efficiency.

[0013] Although the detailed mechanism by which the effects of this invention are obtained is unknown, it is thought that a high softening effect was obtained by using a specific amine compound that has a high affinity for asphaltene, which is particularly deteriorated and modified in asphalt derived from recycled asphalt aggregate and takes on an aggregated structure.

[0014] <Recycled Asphalt Aggregate> The asphalt mixture of the present invention contains recycled asphalt aggregate as aggregate. Recycled asphalt aggregate is obtained by recovering, crushing, and classifying used asphalt pavement. Used asphalt pavement from which recycled asphalt aggregate is derived contains asphalt and aggregate, and may contain other additives as needed.

[0015] Furthermore, the asphalt contained in recycled asphalt aggregate is physically and chemically degraded compared to new asphalt 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 degree, softening point, flexural strength, fracture strain, and asphalt composition. Generally, asphalt in which the marten fraction in the asphalt has migrated to asphaltene and the penetration degree has decreased is often called degraded asphalt. However, even if the penetration degree of recycled asphalt is the same as that of new asphalt, it may not exhibit the same performance as new asphalt due to changes in other properties. In the present invention, the recycled asphalt aggregate is preferably degraded recycled asphalt aggregate in which the extracted asphalt has a penetration degree of 25 or less. The penetration of asphalt contained in recycled asphalt aggregate can be measured according to the procedure of JIS K 2207:1996 for asphalt extracted according to "G028 Asphalt Extraction Test Method" in the "Pavement Survey and Testing Methods Handbook (FY2019 Edition)" (edited by the Japan Road Association).

[0016] Asphalt mixtures derived from used asphalt pavement contain aggregates. Examples of such aggregates include those commonly used in road paving asphalt mixtures, such as crushed stone, pebbles, gravel, sand, and ceramics. Furthermore, the asphalt mixture derived from the used asphalt pavement itself may use recycled asphalt aggregate as its aggregate.

[0017] <Novel Aggregates> The asphalt mixture of the present invention may include novel aggregates in addition to recycled asphalt aggregates. Specific examples of novel aggregates include crushed stone, boulders, gravel, sand, ceramics, etc., which can be arbitrarily selected and used. Furthermore, as aggregates, coarse aggregates with a particle size of 2.36 mm or more, fine aggregates with a particle size of 0.075 mm or more and less than 2.36 mm, and fillers with a particle size of less than 0.075 mm can be used. Examples of coarse aggregates 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. Examples of fine aggregates include river sand, hill sand, mountain sand, sea sand, crushed sand, fine sand, screenings, crushed stone dust, silica sand, artificial sand, glass cullet, and foundry sand. The particle sizes of coarse and fine aggregates are based on the sieving test method specified in JIS A5001:2008.

[0018] Examples of fillers include sand, fly ash, calcium carbonate-containing powders such as limestone powder, and slaked lime. Among these, calcium carbonate-containing powder is preferred from the viewpoint of improving the strength of asphalt pavement. The average particle size of the filler is preferably 0.001 mm or more, preferably 0.05 mm or less, more preferably 0.03 mm or less, and even more preferably 0.02 mm or less, from the viewpoint of improving the strength of asphalt pavement. Here, the average particle size is the average particle size (D) at 50% volume accumulation. ５０ This means that it can be measured with a laser diffraction particle size distribution analyzer.

[0019] It is preferable to use both coarse aggregate and fine aggregate as aggregate. In this case, 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, from the viewpoint of durability of the asphalt pavement.

[0020] <Amine Compounds> The asphalt mixture of the present invention contains an amine compound represented by the following formula (I), and recycled asphalt aggregate. [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ -In the case of H, the total average number of added moles of oxyalkylene groups is 20 or less. The asphalt mixture is useful because, by containing the amine compound represented by the above formula (I), it can exhibit excellent physical properties even when using recycled asphalt aggregate that has deteriorated to a high degree, due to interaction with deteriorated asphalt fixed to the recycled asphalt aggregate.

[0021] The aforementioned R ａ The alkyl group has 20 or fewer carbon atoms, and from the viewpoint of miscibility with asphalt components, the number of carbon atoms is preferably 19 or less, more preferably 18 or less, even more preferably 16 or less, and preferably 6 or more, more preferably 8 or more, and even more preferably 10 or more.

[0022] The aforementioned R ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ -H.

[0023] The aforementioned R ｄ This is an alkylene group having 2 to 4 carbon atoms, and from the viewpoint of the mixability of the asphalt material, it is preferably 2 or more, and preferably 3 or less.

[0024] The aforementioned R ｂ and R ｃ ga- (R ｄ O) ＸWhen it is -H, the above x is the average number of moles of oxyalkylene groups added, and its total is 20 or less, preferably 16 or less, more preferably 12 or less, preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more.

[0025] The aforementioned R ｂ and R ｃ When R is independently an alkyl group having 6 to 22 carbon atoms, ａ Preferably, it is an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0026] The asphalt mixture of the present invention preferably contains one or more amine compounds represented by the above formula (I) selected from dialkylmethylamines represented by the following formula (II) and polyoxyethylene alkylamines represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ represents an alkyl group with 20 or fewer carbon atoms. a and b represent the average number of moles of oxyethylene groups added, and a + b is 20 or less. The amine compound represented by the above formula (I) contains one or more selected from the dialkylmethylamine represented by the above formula (II) and the polyoxyethylene alkylamine represented by the following general formula (III), which exhibits high affinity for asphaltene, which is particularly deteriorated and modified in asphalt derived from recycled asphalt aggregate, and takes on an aggregated structure, thereby obtaining a high softening effect and being useful.

[0027] <Dialkylmethylamine> The asphalt mixture of the present invention preferably contains a dialkylmethylamine represented by the following formula (II) as the amine compound represented by the above formula (I). The dialkylmethylamine is a component that functions as a regeneration additive that restores the properties of deteriorated asphalt derived from recycled asphalt aggregate. [In the formula, R １ and R ２This independently represents an alkyl group having 6 to 22 carbon atoms.

[0028] Although the detailed mechanism by which the effects of this invention are obtained is unknown, it is thought that a high softening effect was obtained by using a specific dialkylmethylamine that has a high affinity for asphaltene, which is particularly deteriorated and modified in asphalt derived from recycled asphalt aggregate and takes on an aggregated structure.

[0029] In the formula, R １ and R ２ R independently represents an alkyl group having 6 to 22 carbon atoms. １ and R ２ The alkyl group represented by R may be either a linear alkyl group or a branched alkyl group. １ and R ２ The number of carbon atoms in the alkyl group represented is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and preferably 20 or less, more preferably 16 or less, and even more preferably 14 or less.

[0030] In the dialkylmethylamine, R １ and R ２ From the viewpoint of the effects of the present invention, the average number of carbon atoms in the alkyl group represented is preferably 8 to 22, more preferably 10 or more, even more preferably 12 or more, and more preferably 20 or less, more preferably 18 or less, more preferably 16 or less, and more preferably 14 or less.

[0031] The aforementioned R １ and R ２ From the viewpoint of affinity with asphalt components, the total number of carbon atoms is preferably 16 or more, more preferably 20 or more, even more preferably 24 or more, and preferably 40 or less, more preferably 32 or less, and even more preferably 28 or less.

[0032] From the viewpoint of the effects of the present invention, the amine value of the dialkylmethylamine is preferably 70 to 220, more preferably 100 or more, and more preferably 180 or less.

[0033] As the dialkylmethylamine, a mixture of multiple compounds that satisfy the above requirements can be used. The average number of carbon atoms is calculated using only the dialkylmethylamine. In the manufacturing process of the dialkylmethylamine, compounds other than the dialkylmethylamine may be introduced as impurities, for example, due to unavoidable circumstances. The asphalt mixture of the present invention may contain such impurities.

[0034] Specific examples of the dialkylmethylamine include didecylmonomethylamine, didodecylmethylamine, and dioctadecylmethylamine. The dialkylmethylamine according to the present invention can be manufactured in accordance with the manufacturing method described in Japanese Patent Publication No. 61-15865. In addition, commercially available products can be used as the dialkylmethylamine. Specifically, the "Farmin" series (product name) manufactured by Kao Corporation can be mentioned.

[0035] <Polyoxyethylene alkylamine> The asphalt mixture of the present invention preferably contains a polyoxyethylene alkylamine represented by the following formula (III) as the amine compound represented by the above formula (I). The polyoxyethylene alkylamine is a component that functions as a regeneration additive that restores the properties of deteriorated asphalt derived from recycled asphalt aggregate.

[0036] [In the formula, R ３ [where 'a' represents an alkyl group with 20 or fewer carbon atoms. 'a' and 'b' represent the average number of moles of oxyethylene groups added, where a + b is 20 or less.]

[0037] Although the detailed mechanism by which the effects of this invention are obtained is unknown, it is thought that a high softening effect was obtained by using a specific polyoxyethylene alkylamine that has a high affinity for asphaltene, which is particularly deteriorated and modified in asphalt derived from recycled asphalt aggregate and takes on an aggregated structure.

[0038] In the formula, R ３ R represents an alkyl group with 20 or fewer carbon atoms. ３ R may be either a linear alkyl group or a branched alkyl group. ３The number of carbon atoms in the alkyl group represented is preferably 12 or more, and 18 or less.

[0039] In formula (III), a and b represent the average number of moles of oxyethylene groups added, and their sum, a + b, is 20 or less. From the viewpoint of the present invention, a + b is preferably 2 or more and 15 or less, more preferably 2 or more, and more preferably 10 or less. Note that a and b are each 1 or more.

[0040] As the polyoxyethylene alkylamine, the above R ３ Multiple mixtures satisfying the required number of carbon atoms and average number of added oxyethylene groups can be used. In the production process of the polyoxyethylene alkylamine, compounds other than the polyoxyethylene alkylamine may be introduced as impurities, for example, due to unavoidable circumstances. The asphalt mixture of the present invention may contain such impurities.

[0041] Specific examples of the polyoxyethylene alkylamine include polyoxyethylene laurylamine and polyoxyethylene stearylamine. The polyoxyethylene alkylamine according to the present invention can be produced by adding an alkylene oxide to an aliphatic primary amine having an alkyl group with 20 or fewer carbon atoms. For example, a polyoxyethylene alkylamine can be produced in accordance with the production method described in Japanese Patent Application Publication No. 11-158125. In addition, commercially available products can be used as the polyoxyethylene alkylamine. Specifically, the "Amito" series (product name) manufactured by Kao Corporation can be mentioned.

[0042] <New Asphalt> The asphalt mixture of the present invention may contain new asphalt in addition to the asphalt contained in the recycled asphalt aggregate. New asphalt is also called virgin asphalt or unused asphalt, and means asphalt that has not been used in asphalt pavement. Various types of asphalt can be used as new asphalt, as long as they have not been used in asphalt pavement. Examples include straight asphalt, which is petroleum asphalt for paving, and modified asphalt. Examples of modified asphalt include blown asphalt; polymer-modified asphalt, which is modified with polymer materials such as thermoplastic elastomers and thermoplastic resins. Straight asphalt refers to residual bituminous material 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. The asphalt is preferably selected from straight asphalt and polymer-modified asphalt, with polymer-modified asphalt being more preferred from the viewpoint of durability of the asphalt pavement, and straight asphalt being more preferred from the viewpoint of versatility. As the polymer-modified asphalt, asphalt modified with a thermoplastic elastomer is more preferred. The modified asphalt is preferably polymer-modified asphalt, and more preferably polymer-modified asphalt modified with a thermoplastic elastomer.

[0043] (Thermoplastic Elastomer) Examples of thermoplastic elastomers used in polymer-modified 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-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, isobutylene / isoprene copolymer, polyisoprene, polychloroprene, synthetic rubber other than those listed above, and natural rubber. The thermoplastic elastomer in modified asphalt 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, ethylene / vinyl acetate copolymer, and ethylene / acrylic acid ester copolymer. 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.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 20% by mass or less, and even more preferably 10% by mass or less, from the viewpoint of durability and surface aesthetics of asphalt pavement.

[0044] <Content of each component> From the viewpoint of the effects of the present invention, the aggregate content in the asphalt mixture is preferably 60% by mass or more and 99.9% by mass or less, more preferably 75% by mass or more, and even more preferably 80% by mass or more. In the present invention, the aggregate content refers to the total content of recycled asphalt aggregate and optionally included new aggregate. The asphalt content derived from recycled asphalt aggregate is included in the aggregate content.

[0045] From the viewpoint of reusing waste materials from asphalt pavement, the content of recycled asphalt aggregate in the asphalt mixture is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, and 100 parts by mass or less, per 100 parts by mass of the asphalt mixture.

[0046] When the aggregate includes new aggregate, the content of recycled asphalt aggregate in the asphalt mixture is preferably 50 parts by mass or more, more preferably 75 parts by mass or more, even more preferably 90 parts by mass or more, and 100 parts by mass or less, out of 100 parts by mass of the total content of recycled asphalt aggregate and new aggregate.

[0047] The asphalt mixture of the present invention contains the recycled asphalt aggregate in an amount of preferably 60 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, and preferably 100 parts by mass or less, and more preferably 95 parts by mass or less, based on 100 parts by mass of the total mass of the asphalt mixture.

[0048] The asphalt mixture of the present invention has an asphalt content of the amine compound represented by formula (I) of the above formula (I) of the total of 100 parts by mass of asphalt in the recycled asphalt aggregate and the amine compound represented by formula (I) of the above formula, preferably 3 parts by mass or more and 50 parts by mass or less, more preferably 4 parts by mass or more, even more preferably 5 parts by mass or more, preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less.

[0049] The content of the amine compound represented by formula (I) in the asphalt mixture is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less.

[0050] In this specification, "asphalt derived from recycled asphalt aggregate" means asphalt contained in recycled asphalt aggregate. Asphalt derived from recycled asphalt aggregate is distinguished from new asphalt. Asphalt derived from recycled asphalt aggregate is sometimes also called deteriorated asphalt. The asphalt content in recycled asphalt aggregate can be measured by solvent extraction or ignition loss method. Typically, the asphalt content in recycled asphalt aggregate derived from used asphalt pavement is approximately 5.5% by mass. In this invention, the asphalt content derived from recycled asphalt aggregate is measured according to the method specified in AASHTO (American Association of State Highway and Transportation Officials) T 308-10 (2015), which is an ignition loss measurement. Since the mixture contains recycled asphalt aggregate, the amount of asphalt is determined from the loss on ignition of the recycled asphalt aggregate and used in the mix design calculations.

[0051] From the viewpoint of the effects of the present invention, the content of the amine compound represented by formula (I) in the asphalt mixture of the present invention is preferably 3 parts by mass or more and 30 parts by mass or less, more preferably 5 parts by mass or more, even more preferably 6 parts by mass or more, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, based on the total content of the three components: asphalt derived from recycled asphalt aggregate, the amine compound represented by formula (I), and optionally included new asphalt, per 100 parts by mass.

[0052] From the viewpoint of the effects of the present invention, the content of dialkylmethylamine in the asphalt mixture of the present invention is preferably 3 to 30 parts by mass, more preferably 5 parts by mass or more, even more preferably 6 parts by mass or more, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, based on the total content of the three components: asphalt derived from recycled asphalt aggregate, dialkylmethylamine, and optionally included new asphalt, per 100 parts by mass.

[0053] From the viewpoint of the effects of the present invention, the polyoxyethylene alkylamine content in the asphalt mixture of the present invention is preferably 3 to 30 parts by mass, more preferably 5 parts by mass or more, even more preferably 6 parts by mass or more, and more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, based on 100 parts by mass of the total content of the three components: asphalt derived from recycled asphalt aggregate, polyoxyethylene alkylamine, and optionally included new asphalt.

[0054] From the viewpoint of the effects of the present invention, the content of the three components in the asphalt mixture—asphalt derived from recycled asphalt aggregate, the amine compound represented by the above formula (I), and optionally included new asphalt—is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more, even more preferably 4% by mass or more, and even more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0055] From the viewpoint of the effects of the present invention, the content of the three components in the asphalt mixture—asphalt derived from recycled asphalt aggregate, dialkylmethylamine, and optionally novel asphalt—is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more, even more preferably 4% by mass or more, and even more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0056] From the viewpoint of the effects of the present invention, the content of the three components in the asphalt mixture—asphalt derived from recycled asphalt aggregate, polyoxyethylene alkylamine, and optionally novel asphalt—is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more, even more preferably 4% by mass or more, and even more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0057] Examples of suitable aggregate compositions in asphalt mixtures include the following (1) to (3): (1) Fine-graded asphalt comprising 30% to less than 45% by volume of coarse aggregate, 30% to 50% by volume of fine aggregate, and 5% to 10% by volume of asphalt composition. (2) An example of an asphalt mixture is dense-graded asphalt comprising, for example, 45% to less than 70% by volume of coarse aggregate, 20% to 45% by volume of fine aggregate, and 3% to 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 conventional asphalt mixtures containing aggregate and asphalt, the proportion of asphalt is usually determined according to the optimal amount of asphalt found in the "Asphalt Composition Mix Design" section of 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. However, it is not necessary to limit the method to the method described in the "Pavement Design and Construction Guidelines," and it may be determined by other methods.

[0058] [Method for Producing Asphalt Mixture]The method for producing an asphalt mixture according to the present invention includes a step of mixing an amine compound represented by the following formula (I) and asphalt recycled aggregate. [In the formula, R ａ represents an alkyl group having 20 or less carbon atoms. R ｂ and R ｃ independently represent an alkyl group having 6 or more and 22 or less carbon atoms, or -(R ｄ O) ｘ -H. R ｄ is an alkylene group having 2 or more and 4 or less carbon atoms, and x is the average number of added moles of oxyalkylene groups. When R ｂ and R ｃ are -(R ｄ O) ｘ -H, the total average number of added moles of oxyalkylene groups is 20 or less. ] In the method for producing the asphalt mixture, by including the amine compound represented by the above formula (I), excellent physical properties can be exhibited even when using asphalt recycled aggregate with advanced deterioration due to the interaction with asphalt that has deteriorated and adhered to the asphalt recycled aggregate, which is useful. [[ID=2E]]

[0059] The method for producing an asphalt mixture according to the present invention preferably includes one or more selected from dialkylmethylamine represented by the following formula (II) and polyoxyethylene alkylamine represented by the following general formula (III) as the amine compound represented by the above formula (I). [In the formula, R １ and R ２ independently represent an alkyl group having 6 or more and 22 or less carbon atoms. ] [In the formula, R ３represents an alkyl group having 20 or fewer carbon atoms. a and b represent the average number of moles of oxyethylene groups added, and a + b is 20 or less. The amine compound represented by formula (I) used in the method for producing the asphalt mixture contains one or more selected from the dialkylmethylamine represented by formula (II) and the polyoxyethylene alkylamine represented by the following general formula (III), which exhibits high affinity for asphaltene, which is particularly deteriorated and modified in asphalt derived from recycled asphalt aggregate, and takes on an aggregated structure, thereby providing a high softening effect and being useful.

[0060] In the method for producing the asphalt mixture of the present invention, it is preferable that the recycled asphalt aggregate is deteriorated recycled asphalt aggregate with a penetration degree of 25 or less of the extracted asphalt.

[0061] The present invention provides a method for producing an asphalt mixture, which includes a step of mixing recycled asphalt aggregate and an amine compound represented by formula (I) under heating conditions. The mixing step may involve simultaneously or in any order mixing the recycled asphalt aggregate and the amine compound represented by formula (I), as well as optionally added new asphalt and new aggregate. The mixing under heating conditions is preferably carried out using heated recycled asphalt aggregate. When new asphalt is added, from the viewpoint of durability and flexibility of the asphalt pavement, the amine compound is preferably mixed with the recycled asphalt aggregate at the same time as the new asphalt or after the new asphalt. When the asphalt mixture includes new aggregate in addition to recycled asphalt aggregate, the recycled asphalt aggregate and the new aggregate can be mixed and used in such a way that they have the above-mentioned content. Specific methods for producing the asphalt mixture include methods for producing asphalt mixtures such as the simultaneous addition method and the pre-addition method. Both methods involve adding the amine compound to heated recycled asphalt aggregate. Methods of addition include, for example, a pre-addition method in which recycled asphalt aggregate and the amine compound are mixed in advance, or a simultaneous addition method in which the amine compound is added to heated recycled asphalt aggregate simultaneously or in any order. Among these, the plant mix method is preferred from the viewpoint of exhibiting asphalt performance.

[0062] The present invention provides a method for producing an asphalt mixture, which includes a step of mixing recycled asphalt aggregate and a dialkylmethylamine represented by formula (II) under heating conditions. The mixing step may involve simultaneously or in any order mixing the recycled asphalt aggregate and the dialkylmethylamine represented by formula (II), as well as optionally added new asphalt and new aggregate. The mixing under heating conditions is preferably carried out using heated recycled asphalt aggregate. When new asphalt is added, from the viewpoint of durability and flexibility of the asphalt pavement, the dialkylmethylamine is preferably mixed with the recycled asphalt aggregate at the same time as the new asphalt or after the new asphalt. When the asphalt mixture includes new aggregate in addition to recycled asphalt aggregate, the recycled asphalt aggregate and the new aggregate can be mixed and used in such a way that they have the above-mentioned content. Specific methods for producing the asphalt mixture include methods for producing asphalt mixtures such as the simultaneous addition method and the pre-addition method. Both methods involve adding the dialkylmethylamine to heated recycled asphalt aggregate. Methods of addition include, for example, a pre-addition method in which recycled asphalt aggregate and the above-mentioned dialkylmethylamine are mixed in advance, or a simultaneous addition method in which the above-mentioned dialkylmethylamine is added to heated recycled asphalt aggregate simultaneously or in any order. Among these, the plant mix method is preferred from the viewpoint of exhibiting asphalt performance.

[0063] The present invention provides a method for producing an asphalt mixture, which includes a step of mixing recycled asphalt aggregate and a polyoxyethylene alkylamine represented by the above formula (III) under heating conditions. The mixing step may involve simultaneously or in any order mixing the recycled asphalt aggregate and the polyoxyethylene alkylamine represented by the above formula (III), as well as optionally added new asphalt and new aggregate. When mixing under heating conditions, it is preferable to use heated recycled asphalt aggregate. When new asphalt is added, from the viewpoint of durability and flexibility of the asphalt pavement, it is preferable to mix the polyoxyethylene alkylamine with the recycled asphalt aggregate simultaneously with the new asphalt or after the new asphalt. When the asphalt mixture includes new aggregate in addition to recycled asphalt aggregate, the recycled asphalt aggregate and the new aggregate can be mixed and used in such a way that they have the above-mentioned content. Specific methods for producing an asphalt mixture include methods for producing an asphalt mixture such as the simultaneous addition method and the pre-addition method. Both methods involve adding the above-mentioned polyoxyethylene alkylamine to heated recycled asphalt aggregate. Examples of addition methods include a pre-addition method in which the recycled asphalt aggregate and the above-mentioned polyoxyethylene alkylamine are mixed in advance, or a simultaneous addition method in which the above-mentioned polyoxyethylene alkylamine is added to the heated recycled asphalt aggregate simultaneously or in any order.

[0064] From the viewpoint of improving durability through sufficient mixing, the heating temperature is preferably 160°C or higher, more preferably 165°C or higher, and even more preferably 170°C or higher. Furthermore, from the viewpoint of performance stability, it is preferably 350°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower.

[0065] [Asphalt Recycled Aggregate Regeneration Additive] The asphalt recycled aggregate regeneration additive of the present invention contains an amine compound represented by the following formula (I). [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃThese are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) ｘ When it is -H, the total average number of added moles of oxyalkylene groups is 20 or less. The recycling additive for the recycled asphalt aggregate contains the amine compound represented by the above formula (I), and through interaction with the deteriorated asphalt fixed to the recycled asphalt aggregate, it is possible to exhibit excellent physical properties even when using recycled asphalt aggregate that has deteriorated to a high degree, making it useful.

[0066] The additive for recycling asphalt aggregate of the present invention preferably contains one or more amine compounds represented by the above formula (I) selected from dialkylmethylamines represented by the following formula (II) and polyoxyethylene alkylamines represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ represents an alkyl group with 20 or fewer carbon atoms. a and b represent the average number of moles of oxyethylene groups added, and a + b is 20 or less. The amine compound represented by the above formula (I) contained in the recycling additive for the recycled asphalt aggregate includes one or more selected from the dialkylmethylamine represented by the above formula (II) and the polyoxyethylene alkylamine represented by the following general formula (III), which shows high affinity for asphaltene, which is particularly deteriorated and modified in asphalt derived from recycled asphalt aggregate and takes on an aggregated structure, thereby obtaining a high softening effect and being useful.

[0067] [Paving Method] The asphalt mixture of the present invention is suitable for paving, and suitable surfaces for paving include roads, parking lots, etc. The paving method comprises the step of applying the aforementioned asphalt mixture to the surface to be paved to form an asphalt paving material layer. The asphalt paving material layer is usually a base layer or a surface layer, and is preferably a surface layer from the viewpoint of improving deflection resistance and crack resistance.

[0068] The thickness of the asphalt pavement layer is preferably 3 cm or more, more preferably 4 cm or more, even more preferably 4.5 cm or more, and preferably 7 cm or less, more preferably 6 cm or less, and even more preferably 5.5 cm or less, from the viewpoint of improving deflection resistance and crack resistance. In another embodiment 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, even more preferably 2 cm or more, and preferably 4 cm or less, more preferably 3.5 cm or less, and even more preferably 3 cm or less. The asphalt mixture can be compacted and constructed using a known construction machinery setup in a similar manner. When used as a heated asphalt mixture, the compaction temperature is preferably 100°C or more, more preferably 120°C or more, even more preferably 130°C or more, and preferably 200°C or less, and even more preferably 180°C or less, from the viewpoint of improving deflection resistance and crack resistance of the asphalt pavement.

[0069] In addition to the embodiments described above, the present invention discloses the following: <1> An asphalt mixture comprising an amine compound represented by the following formula (I) and recycled asphalt aggregate. [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ-If it is H, the total average number of moles of oxyalkylene groups added is 20 or less. ] <2> The above R ａ The asphalt mixture according to <1>, wherein R has 20 or fewer carbon atoms, or 19 or fewer carbon atoms, or 18 or fewer carbon atoms, or 16 or fewer carbon atoms, and 6 or more, or 8 or more, or 10 or more alkyl groups. <3> The R ｂ and R ｃ ga- (R ｄ O) Ｘ - When H, the sum of x is 20 or less, or 16 or less, or 12 or less, and 1 or more, or 2 or more, or 3 or more, asphalt mixture according to <1> or <2>. <4> The R ｂ and R ｃ When R is independently an alkyl group having 6 to 22 carbon atoms, ａ The asphalt mixture according to any one of <1> to <3>, wherein the alkyl group has 1 to 5 carbon atoms, or a methyl group, or an ethyl group. <5> The asphalt mixture according to any one of <1> to <4>, wherein the amine compound represented by the above formula (I) contains one or more selected from the dialkylmethylamine represented by the following formula (II) and the polyoxyethylene alkylamine represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ represents an alkyl group with 20 or fewer carbon atoms. a and b represent the average number of moles of oxyethylene groups added, and a + b is 20 or less. ] <6> The above R １ and R ２ The asphalt mixture according to <5>, wherein the average number of carbon atoms of the alkyl group represented by is 8 or more, or 10 or more, or 12 or more, and 22 or less, or 20 or less, or 16 or less. <7> The R １ and R ２The asphalt mixture according to <5> or <6>, wherein the total number of carbon atoms is 16 or more, or 20 or more, or 24 or more, and 40 or less, or 32 or less, or 28 or less. <8> The asphalt mixture according to any one of <5> to <7>, wherein the amine value of general formula (II) is 70 or more, or 100 or more, and 220 or less, or 180 or less. <9> The R ３ An asphalt mixture according to any one of <5> to <8>, wherein the number of carbon atoms of the alkyl group represented by is 20 or less, and 12 or more, or 18 or more. <10> An asphalt mixture according to any one of <5> to <9>, wherein a + b is 2 or more, and 15 or less, or 10 or less. <11> An asphalt mixture according to any one of <1> to <10>, wherein the recycled asphalt aggregate is deteriorated recycled asphalt aggregate with a penetration degree of 25 or less of the extracted asphalt. <12> An asphalt mixture according to any one of <1> to <11>, wherein the recycled asphalt aggregate is contained in an amount of 60 parts by mass or more, or 70 parts by mass or more, or 80 parts by mass or more, per 100 parts by mass of the total mass of the asphalt mixture. <13> An asphalt mixture according to any one of <1> to <12>, further containing new asphalt. <14> An asphalt mixture according to any one of <1> to <13>, further comprising new aggregate. <15> An asphalt mixture according to any one of <1> to <14>, wherein the content of the amine compound represented by formula (I) in the recycled asphalt aggregate is 3 parts by mass or more, or 4 parts by mass or more, or 5 parts by mass or more, and 50 parts by mass or less, or 20 parts by mass or less, or 15 parts by mass or less, per 100 parts by mass of the total of asphalt and the amine compound represented by formula (I) in the recycled asphalt aggregate. <16> An asphalt mixture according to any one of <1> to <15>, wherein the content of the amine compound represented by formula (I) in the asphalt mixture is 0.05% by mass or more, or 0.1% by mass or more, or 0.3% by mass or more, and 5% by mass or less, or 3% by mass or less, or 2% by mass or less. <17> A method for producing an asphalt mixture, comprising the step of mixing an amine compound represented by the following formula (I) and recycled asphalt aggregate. [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ And Rc is -(R ｄ O) Ｘ -When it is H, the total average number of moles of oxyalkylene groups added is 20 or less. ] <18> A method for producing an asphalt mixture according to <17>, wherein the amine compound represented by formula (I) above comprises one or more selected from dialkylmethylamine represented by the following formula (II) and polyoxyethylene alkylamine represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ represents an alkyl group having 20 or fewer carbon atoms. a and b represent the average number of moles of oxyethylene groups added, and a + b is 20 or less. ] <19> A method for producing an asphalt mixture according to <17> or <18>, wherein the recycled asphalt aggregate is a deteriorated recycled asphalt aggregate in which the penetration of the extracted asphalt is 25 or less. <20> A recycling additive for recycled asphalt aggregate comprising an amine compound represented by the following formula (I). [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (RdO) Ｘ-When it is H, the total average number of moles of oxyalkylene groups added is 20 or less. ] <21> The additive for recycling asphalt aggregate according to <20>, wherein the amine compound represented by formula (I) above comprises one or more selected from dialkylmethylamine represented by the following formula (II) and polyoxyethylene alkylamine represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ [where 'a' represents an alkyl group with 20 or fewer carbon atoms. 'a' and 'b' represent the average number of moles of oxyethylene groups added, where a + b is 20 or less.]

[0070] In the following examples and comparative examples, unless otherwise specified, parts and percentages are based on mass.

[0071] (Embodiment 1) The following describes in detail the case in which the dialkylmethylamine represented by formula (II) is used as the amine compound represented by formula (I).

[0072] The dialkylmethylamines (1) to (7) used are shown in Table 1 below. The dialkylmethylamines (1) to (7) were prepared with reference to Examples 5 and 6 of Japanese Patent Publication No. 61-15865.

[0073]

[0074] Example 1-1 (1) Preparation of asphalt mixture 1.3 kg of recycled asphalt aggregate with the composition shown below, heated to 165°C, was placed in a frying pan, 8 g of dialkylmethylamine (1) was added, and the mixture was mixed for 2 minutes to obtain an asphalt mixture.

[0075] <Aggregate Composition> Percentage of Asphalt Recycled Aggregate Passing Through: 15 mm Sieve Mesh: 99.7% by mass 10 mm Sieve Mesh: 84.3% by mass 5 mm Sieve Mesh: 70.1% by mass 2.5 mm Sieve Mesh: 52.3% by mass 1.2 mm Sieve Mesh: 30.7% by mass 0.6 mm Sieve Mesh: 21.4% by mass 0.3 mm Sieve Mesh: 9.8% by mass 0.15 mm Sieve Mesh: 4.1% by mass

[0076] The asphalt content (asphalt derived from recycled asphalt aggregate) in 1.3 kg of recycled asphalt aggregate was 72 g. The asphalt content derived from recycled asphalt aggregate was determined according to the method specified in AASHTO T 308-10 (2015). The dialkylmethylamine (1) content in the asphalt mixture was 10 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and dialkylmethylamine. The penetration degree of the asphalt derived from recycled asphalt aggregate was 21. The penetration degree was measured according to the procedure of JIS K 2207:1996 for asphalt extracted according to "G028 Asphalt Extraction Test Method" in the "Pavement Survey and Test Method Handbook (FY2019 Edition)" (edited by the Japan Road Association).

[0077] (2) Measurement of Marshall Stability 1.2 kg of the obtained asphalt mixture was weighed out, and cylindrical specimens were prepared using a Marshall test compaction machine (manufactured by Nakajima Gihan Co., Ltd., "Automatic Asphalt Compaction Machine"). The specimens were slowly cooled to room temperature and demolded using a demolding machine. Four asphalt specimens were prepared. After demolding, the cylindrical specimens were immersed in a 60°C constant temperature water bath for 30 minutes, and then subjected to a Marshall stability test according to "B001 Marshall Stability Test Method" in the "Pavement Survey and Test Method Handbook (FY2019 Edition)" (edited by the Japan Road Association), and the Marshall stability (kN) of asphalt specimen M-1 was measured. Marshall stability is the maximum load required to break the asphalt specimen, and the larger the value, the more durable the asphalt pavement. The results are shown in Table 2.

[0078] (3) Measurement of void ratio The void ratio of the asphalt specimen M-1 was determined from the air mass and water mass of the asphalt specimen in accordance with the measurement method specified in "B008-1 Density Test Method for Dense-Graded Asphalt Mixtures, etc." described in Volume 3 of the "Pavement Survey and Test Methods Handbook (FY2019 Edition)" (edited by the Japan Road Association).

[0079] Specifically, the porosity was calculated according to the following formula: Porosity = 100 × {1 - (bulk density of the specimen) / (theoretical maximum density)} The physical properties used in calculating the porosity were calculated according to the following formula: Bulk density of the specimen = (mass in air) / (surface-dry mass - mass in water) Theoretical maximum density = 2.505 Note that surface-dry mass is the mass of the specimen after immersing it in water for 3 minutes and then wiping the surface.

[0080] By measuring the void ratio under identical conditions, the workability of the asphalt mixture can be evaluated. The results are shown in Table 2.

[0081] Example 1-2 An asphalt mixture was obtained in the same manner as in Example 1-1, except that the content of dialkylmethylamine (1) was 3.8 g (5 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and dialkylmethylamine). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0082] Example 1-3 An asphalt mixture was obtained in the same manner as in Example 1-1, except that the content of dialkylmethylamine (1) was 12.7 g (15 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and dialkylmethylamine). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0083] Examples 1-4 to 1-9: Asphalt mixtures were obtained in the same manner as in Example 1-1, except that 8 g of dialkylmethylamine (2) to (7) shown in Table 1 was used instead of 8 g of dialkylmethylamine (1). Asphalt specimens were prepared using the obtained asphalt mixtures, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0084] Comparative Example 1-1 An asphalt mixture was obtained in the same manner as in Example 1-1, except that 8 g of dialkylmethylamine (1) was not used. Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0085] Comparative Example 1-2 An asphalt mixture was obtained in the same manner as in Example 1-1, except that 8 g of laurylamine was used instead of 8 g of dialkylmethylamine (1). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0086] Comparative Example 1-3: An asphalt mixture was obtained in the same manner as in Example 1-1, except that 8 g of dimethyl laurylamine was used instead of 8 g of dialkylmethylamine (1). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0087] Comparative Example 1-4 An asphalt mixture was obtained in the same manner as in Example 1-1, except that 12.7 g of dimethyl laurylamine (15 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and dimethyl laurylamine) was used instead of 8 g of dialkylmethylamine (1). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0088]

[0089] As shown in Examples 1-1 to 1-9, the asphalt mixture of the present invention exhibits high Marshall stability and low porosity, and is therefore capable of exhibiting excellent physical properties even when using recycled asphalt aggregate that has deteriorated to a high degree. The particularly low porosity observed in Examples 1-1, 1-4, and 1-5 indicates that the effect of dialkylmethylamine, which has a relatively large number of carbon atoms (12 or more), is particularly significant. Furthermore, it can be seen that the higher the effect, the more effective it is in improving both durability and workability. This is thought to be because fluidizing the solidified binder in the recycled asphalt aggregate made it possible to improve durability and workability.

[0090] (Embodiment 2) The following describes in detail the case in which the polyoxyethylene alkylamine represented by formula (III) is used as the amine compound represented by formula (I).

[0091] The polyoxyethylene alkylamines (1) to (7) used are shown in Table 3 below. Polyoxyethylene alkylamines (1) to (7) were produced by changing the type of aliphatic primary amine used as a raw material and the amount of ethylene oxide, based on Example 1 of Japanese Patent Publication No. 11-158125.

[0092]

[0093] Example 2-1 (1) Preparation of asphalt mixture 1.3 kg of recycled asphalt aggregate with the composition shown below, heated to 165°C, was placed in a frying pan, 8.7 g of polyoxyethylene alkylamine (1) was added, and the mixture was mixed for 2 minutes to obtain an asphalt mixture.

[0094] <Aggregate Composition> Percentage of Asphalt Recycled Aggregate Passing Through: 15 mm Sieve Mesh: 100% by mass 10 mm Sieve Mesh: 74.5% by mass 5 mm Sieve Mesh: 64.3% by mass 2.5 mm Sieve Mesh: 46.8% by mass 1.2 mm Sieve Mesh: 33.6% by mass 0.6 mm Sieve Mesh: 18.3% by mass 0.3 mm Sieve Mesh: 9.8% by mass 0.15 mm Sieve Mesh: 2.4% by mass

[0095] The asphalt content (asphalt derived from recycled asphalt aggregate) in 1.3 kg of recycled asphalt aggregate was 78 g. The asphalt content derived from recycled asphalt aggregate was determined according to the method specified in AASHTO T 308-10 (2015). The polyoxyethylene alkylamine (1) content in the asphalt mixture was 10 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and polyoxyethylene alkylamine (1). The penetration degree of the asphalt derived from recycled asphalt aggregate was 7. The penetration degree was measured according to the procedure of JIS K 2207:1996 for asphalt extracted according to "G028 Asphalt Extraction Test Method" in the "Pavement Survey and Test Method Handbook (FY2019 Edition)" (edited by the Japan Road Association).

[0096] (2) Measurement of Marshall Stability 1.2 kg of the obtained asphalt mixture was weighed out, and cylindrical specimens were prepared using a Marshall test compaction machine (manufactured by Nakajima Gihan Co., Ltd., "Automatic Asphalt Compaction Machine"). The specimens were slowly cooled to room temperature and demolded using a demolding machine. Four asphalt specimens were prepared. After demolding, the cylindrical specimens were immersed in a 60°C constant temperature water bath for 30 minutes, and then subjected to a Marshall stability test according to "B001 Marshall Stability Test Method" in the "Pavement Survey and Test Method Handbook (FY2019 Edition)" (edited by the Japan Road Association), and the Marshall stability (kN) of asphalt specimen M-1 was measured. Marshall stability is the maximum load required to break the asphalt specimen, and the larger the value, the more durable the asphalt pavement. The results are shown in Table 4.

[0097] (3) Measurement of void ratio The void ratio of the asphalt specimen M-1 was determined from the air mass and water mass of the asphalt specimen in accordance with the measurement method specified in "B008-1 Density Test Method for Dense-Graded Asphalt Mixtures, etc." described in Volume 3 of the "Pavement Survey and Test Methods Handbook (FY2019 Edition)" (edited by the Japan Road Association).

[0098] Specifically, the porosity was calculated according to the following formula: Porosity = 100 × {1 - (bulk density of the specimen) / (theoretical maximum density)} The physical properties used in calculating the porosity were calculated according to the following formula: Bulk density of the specimen = (mass in air) / (surface-dry mass - mass in water) Theoretical maximum density = 2.512 Note that surface-dry mass is the mass of the specimen after immersing it in water for 3 minutes and then wiping the surface.

[0099] By measuring the void ratio under identical conditions, the workability of the asphalt mixture can be evaluated. The results are shown in Table 4.

[0100] Example 2-2 An asphalt mixture was obtained in the same manner as in Example 2-1, except that the content of polyoxyethylene alkylamine (1) was 4.1 g (5 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and polyoxyethylene alkylamine (1)). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0101] Example 2-3 An asphalt mixture was obtained in the same manner as in Example 2-1, except that the content of polyoxyethylene alkylamine (1) was 13.8 g (15 parts by mass per 100 parts by mass of the total content of asphalt derived from recycled asphalt aggregate and polyoxyethylene alkylamine (1)). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0102] Examples 2-4 to 2-8: Asphalt mixtures were obtained in the same manner as in Example 2-1, except that 8.7 g of polyoxyethylene alkylamines (2) to (6) shown in Table 3 were used instead of 8.7 g of polyoxyethylene alkylamine (1). Asphalt specimens were prepared using the obtained asphalt mixtures, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0103] Comparative Example 2-1 An asphalt mixture was obtained in the same manner as in Example 2-1, except that 8.7 g of polyoxyethylene alkylamine (1) was not used. Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0104] Comparative Example 2-2 An asphalt mixture was obtained in the same manner as in Example 2-1, except that 8.7 g of the recycling additive "ReproVital 500" (trade name, manufactured by Idemitsu Kosan Co., Ltd.) was used instead of 8.7 g of polyoxyethylene alkylamine (1) (10 parts by mass per 100 parts by mass of the total asphalt content derived from recycled asphalt aggregate and recycling additive). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0105] Comparative Example 2-3 An asphalt mixture was obtained in the same manner as in Example 2-1, except that 13.8 g of the recycling additive "ReproVital 500" (trade name, manufactured by Idemitsu Kosan Co., Ltd.) was used instead of 8.7 g of polyoxyethylene alkylamine (1) (15 parts by mass per 100 parts by mass of the total amount of asphalt derived from recycled asphalt aggregate and recycling additive). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0106] Comparative Example 2-4 An asphalt mixture was obtained in the same manner as in Example 2-1, except that 8.7 g of polyoxyethylene alkylamine (7) shown in Table 3 was used instead of 8.7 g of polyoxyethylene alkylamine (1). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0107] Comparative Example 2-5 An asphalt mixture was obtained in the same manner as in Example 2-1, except that 8.7 g of "Farmin 20D" (trade name, manufactured by Kao Corporation; laurylamine) was used instead of 8.7 g of polyoxyethylene alkylamine (1). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0108] Comparative Example 2-6 An asphalt mixture was obtained in the same manner as in Example 2-1, except that "Farmin DM4098" (trade name, manufactured by Kao Corporation; dimethyl myristylamine) was used instead of polyoxyethylene alkylamine (1). Asphalt specimens were prepared using the obtained asphalt mixture, and the Marshall stability and porosity were measured in the same manner as in Example 2-1. The results are shown in Table 4.

[0109]

[0110] As shown in Examples 2-1 to 2-8, the asphalt mixture of the present invention exhibits high Marshall stability and low porosity, demonstrating excellent physical properties even when using deteriorated recycled asphalt aggregate. Examples 2-1, 2-4, and 2-5 showed particularly excellent reduction in porosity, while Example 2-8 showed relatively low performance improvement, indicating that compounds with approximately 10 oxyethylene addition moles have a particularly significant effect. This is because the interaction between the deteriorated asphalt and the aggregate in the recycled asphalt aggregate was most effectively controlled. Conversely, a higher addition mole number resulted in excessive polarity, significantly disrupting this balance. Furthermore, compounds with a higher effect were found to be more effective in improving both porosity and stability. This is thought to be because fluidizing the solidified binder in the recycled asphalt aggregate improved workability and hardness.

Claims

1. An asphalt mixture comprising an amine compound represented by the following formula (I) and asphalt recycled aggregate. [In the formula, R ａ represents an alkyl group having 20 or less carbon atoms. R ｂ and R ｃ independently represent an alkyl group having 6 or more and 22 or less carbon atoms, or -(R ｄ O) Ｘ -H. R ｄ is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. When R ｂ and R ｃ are -(R ｄ O) Ｘ -H, the total average number of moles of oxyalkylene groups added is 20 or less. ] 2. The asphalt mixture according to claim 1, wherein the amine compound represented by formula (I) above comprises one or more selected from dialkylmethylamine represented by the following formula (II) and polyoxyethylene alkylamine represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ [where 'a' represents an alkyl group with 20 or fewer carbon atoms. 'a' and 'b' represent the average number of moles of oxyethylene groups added, where a + b is 20 or less.] 3. The aforementioned R １ and R ２ The asphalt mixture according to claim 2, wherein the average number of carbon atoms of the alkyl group represented is 8 or more and 22 or less.

4. The aforementioned R ３ The asphalt mixture according to claim 2 or 3, wherein the number of carbon atoms in the alkyl group represented by is 12 or more.

5. The asphalt mixture according to any one of claims 2 to 4, wherein a + b is 2 or more and 15 or less.

6. The asphalt mixture according to any one of claims 1 to 5, wherein the recycled asphalt aggregate is deteriorated recycled asphalt aggregate with a penetration degree of 25 or less of the extracted asphalt.

7. The asphalt mixture according to any one of claims 1 to 6, wherein the recycled asphalt aggregate is contained in an amount of 60 parts by mass or more per 100 parts by mass of the total mass of the asphalt mixture.

8. The asphalt mixture according to any one of claims 1 to 7, further comprising new asphalt.

9. The asphalt mixture according to any one of claims 1 to 8, further comprising a novel aggregate.

10. The asphalt mixture according to any one of claims 1 to 9, wherein the content of the amine compound represented by formula (I) is 3 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the total of the asphalt and the amine compound represented by formula (I) in the recycled asphalt aggregate.

11. A method for producing an asphalt mixture, comprising the step of mixing an amine compound represented by the following formula (I) and recycled asphalt aggregate. [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ If it is -H, the total average number of moles of oxyalkylene groups added is 20 or less.

12. A method for producing an asphalt mixture according to claim 11, wherein the amine compound represented by formula (I) above comprises one or more selected from dialkylmethylamines represented by the following formula (II) and polyoxyethylene alkylamines represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ [where 'a' represents an alkyl group with 20 or fewer carbon atoms. 'a' and 'b' represent the average number of moles of oxyethylene groups added, where a + b is 20 or less.] 13. The method for producing an asphalt mixture according to claim 11 or 12, wherein the recycled asphalt aggregate is deteriorated recycled asphalt aggregate with a penetration degree of 25 or less of the extracted asphalt.

14. A recycling additive for recycled asphalt aggregate, comprising an amine compound represented by the following formula (I). [In the formula, R ａ R represents an alkyl group with 20 or fewer carbon atoms. ｂ and R ｃ These are independently alkyl groups having 6 to 22 carbon atoms, or -(R ｄ O) Ｘ - Represents H. R ｄ R is an alkylene group having 2 to 4 carbon atoms, and x is the average number of moles of oxyalkylene groups added. ｂ and R ｃ ga- (R ｄ O) Ｘ If it is -H, the total average number of moles of oxyalkylene groups added is 20 or less.

15. The additive for recycling recycled asphalt aggregate according to claim 14, wherein the amine compound represented by formula (I) above comprises one or more selected from dialkylmethylamine represented by the following formula (II) and polyoxyethylene alkylamine represented by the following general formula (III). [In the formula, R １ and R ２ This independently represents an alkyl group having 6 to 22 carbon atoms. [In the formula, R ３ [where 'a' represents an alkyl group with 20 or fewer carbon atoms. 'a' and 'b' represent the average number of moles of oxyethylene groups added, where a + b is 20 or less.]

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