Asphalt mixture

Abstract

To provide an asphalt composition which is excellent in filling properties, has no problem in workability, and can form asphalt pavement excellent in durability.SOLUTION: The asphalt composition contains a semi-carbonized material derived from nonwoven fabric products, the semi-carbonized material containing 50 to 90 mass% of asphalt and volatile components and 7 to 40 mass% of a fixed carbon content.SELECTED DRAWING: None

Description

[[Technical Field]]

[0001] The present invention relates to an asphalt mixture, a method for producing the same, an asphalt composition, and a road paving method. [[Background Art]]

[0002] For paving roads, parking lots, cargo yards, sidewalks and the like, asphalt paving using an asphalt mixture is widely employed, since laying is relatively easy and the time from the start of paving work to the opening of traffic can be shortened. In this asphalt paving, the road surface is formed of an asphalt mixture in which aggregates are bound with asphalt, so the paved road has favorable hardness and durability.

[0003] However, asphalt paved surfaces deteriorate due to long-term use, making it necessary to repair the pavement. Repairing the pavement increases maintenance costs and has resulted in a significant impact on automobile traffic. For example, Patent Document 1 discloses an asphalt composition obtained by blending specific cellulose fibers with asphalt, as an asphalt composition that enables asphalt paving excellent in rutting resistance and fatigue crack resistance.

[0004] On the other hand, the amount of organic waste has been increasing year by year. Technologies for carbonizing organic waste have been developed, and various applications of the obtained carbide have been studied. For example, Patent Document 2 discloses a method for producing carbide, which comprises: bringing waste containing a superabsorbent resin that has absorbed chloride-containing moisture into contact with an aqueous solution containing at least one of a water-soluble phosphate or sulfate to remove chloride ions from the waste; and after removing the chloride ions, heating the waste for carbonization. It is also disclosed that the obtained carbide can be effectively utilized as a soil modifier, a water purification agent, building materials such as heat insulating materials, adsorbents, antidotes, deodorants, raw materials for disposable body warmers, fuel, activated carbon as described later, and the like.

[0005] Furthermore, there is a technology that utilizes carbonized materials obtained by carbonizing organic waste in a carbonization device, such as using them as road paving materials containing asphalt. For example, Patent Document 3 discloses an asphalt mixture obtained by mixing predetermined amounts of heated aggregates of various particle sizes, stone powder, and molten asphalt, and then mixing a predetermined amount of charred material obtained by carbonizing organic waste. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2019-210384 [Patent Document 2] Japanese Patent Publication No. 2022-21365 [Patent Document 3] Japanese Patent Publication No. 2003-184013 [Overview of the project] [Problems that the invention aims to solve]

[0007] The technology described in Patent Document 1 improves the dispersibility of cellulose fibers in the asphalt composition, resulting in an asphalt composition that enables asphalt pavement with excellent rutting resistance and fatigue crack resistance. However, since it requires the use of specific cellulose fibers, further investigation is desirable from the viewpoint of ease of availability and other factors. Even when using carbonization, the utilization of organic waste is limited to the uses described in Patent Document 2 and other documents mentioned above, so there is a need for new uses that can be expected to be consumed on a large scale. Patent Document 3 does not consider the durability of asphalt pavement, such as its resistance to rutting.

[0008] Furthermore, asphalt mixtures used to form asphalt pavements require specific workability properties, such as fillability. Fillability can be improved, for example, by increasing the heating temperature during the manufacturing and / or construction process, but this has the problem of increased fuel consumption. Therefore, other means of improving workability, such as fillability, are desirable.

[0009] The present invention relates to an asphalt mixture that utilizes semi-carbides derived from nonwoven fabric products to form an asphalt pavement with excellent filling properties, no problems with workability, and excellent durability, as well as a method for producing the same, an asphalt composition, and a road paving method. [Means for solving the problem]

[0010] The present invention relates to the following: <1> ~ <4> Regarding. <1> An asphalt mixture containing asphalt, aggregate, and semi-carbides derived from nonwoven fabric products having a volatile content of 50% to 90% by mass and a fixed carbon content of 7% to 40% by mass. <2> A method for producing an asphalt mixture, comprising the step of mixing asphalt, heated aggregate, and a semi-carbide derived from a nonwoven fabric product having a volatile matter content of 50% by mass or more and 90% by mass or less, and a fixed carbon content of 7% by mass or more and 40% by mass or less. <3> An asphalt composition comprising asphalt and a semi-carbide derived from a nonwoven fabric product having a volatile matter content of 50% by mass or more and 90% by mass or less, and a fixed carbon content of 7% by mass or more and 40% by mass or less. <4> the above <1> A road paving method comprising the step of applying the asphalt mixture described above to a road to form an asphalt pavement layer. [Effects of the Invention]

[0011] According to the present invention, an asphalt composition is provided that offers excellent filling properties, no problems with workability, and excellent durability for asphalt pavement. [Brief explanation of the drawing]

[0012] [Figure 1]FIG. 1 shows the configuration of a furnace having stirring blades for stirring, a heater and an air blowing mechanism used in the production of semicarbide. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Asphalt Mixture] The asphalt mixture of the present invention comprises asphalt, aggregate, and semicarbide derived from nonwoven fabric products having a volatile content of 50 mass% or more and 90 mass% or less and a fixed carbon content of 7 mass% or more and 40 mass% or less. The inventors of the present invention found that an asphalt mixture containing semicarbide derived from nonwoven fabric products having a volatile content of 50 mass% or more and 90 mass% or less and a fixed carbon content of 7 mass% or more and 40 mass% or less can provide an asphalt pavement that is excellent in filling property, has no problem in workability, and is excellent in durability.

[0014] Asphalt pavement with excellent durability is, for example, excellent in rutting resistance. The rutting resistance of asphalt pavement can be evaluated, for example, by a wheel tracking test shown in the examples described later.

[0015] In addition, the filling property of the asphalt mixture can be evaluated, for example, by measuring the void content shown in the examples described later. Filling property is also referred to as degree of compaction. An asphalt mixture excellent in filling property (degree of compaction) forms an asphalt pavement with less occurrence of hair cracks (microcracks) and excellent surface appearance.

[0016] <Asphalt> Various asphalts can be used as the asphalt contained in the asphalt mixture of the present invention. The asphalt is preferably asphalt that has no history of being used in asphalt pavement (also referred to as virgin asphalt or unused asphalt). On the other hand, used asphalt derived from recycled asphalt aggregate can also be used in combination. Specific examples of asphalt include, for example, straight asphalt which is petroleum asphalt for paving, as well as modified asphalt. Examples of modified asphalt include blown asphalt; and polymer-modified asphalt modified with polymer materials such as thermoplastic elastomers and thermoplastic resins. Straight asphalt refers to residual bituminous substances obtained by subjecting crude oil to atmospheric distillation units, vacuum distillation units, and the like. Blown asphalt refers to asphalt obtained by heating a mixture of straight asphalt and heavy oil, then blowing air into the mixture to oxidize it. Asphalt is preferably selected from straight asphalt and polymer-modified asphalt; polymer-modified asphalt is more preferable from the viewpoint of durability of asphalt pavement, and straight asphalt is more preferable from the viewpoint of general versatility. As the polymer-modified asphalt, asphalt modified with a thermoplastic elastomer is more preferable. The modified asphalt is preferably polymer-modified asphalt, more preferably polymer-modified asphalt modified with a thermoplastic elastomer.

[0017] (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 the 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, as thermoplastic elastomers, from the viewpoint of durability of asphalt pavement, 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 styrene / butadiene block copolymer, styrene / butadiene / styrene block copolymer, styrene / butadiene random copolymer, styrene / isoprene block copolymer and styrene / isoprene random copolymer At least one selected from the following, more preferably at least one selected from styrene / butadiene random copolymers and styrene / butadiene / styrene block copolymers. 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 the asphalt pavement.

[0018] <Aggregates> As aggregate, crushed stone, pebbles, gravel, sand, ceramics, etc., can be arbitrarily selected and used. In addition, as aggregate, coarse aggregate with a particle size of 2.36 mm or more, fine aggregate with a particle size of 0.075 mm or more and less than 2.36 mm, and filler with a particle size of less than 0.075 mm can be used. 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. 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.

[0019] 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 the durability of asphalt pavement. The average particle size of the filler is preferably 0.001 mm or larger, more preferably 0.05 mm or smaller, more preferably 0.03 mm or smaller, and even more preferably 0.02 mm or smaller, from the viewpoint of the durability of the asphalt pavement. 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.

[0020] It is preferable to use both coarse and fine aggregates 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 the durability of the asphalt pavement.

[0021] The aggregate may include 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.

[0022] 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, 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 degraded 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.

[0023] Asphalt mixtures derived from used asphalt pavement contain aggregate. This aggregate is derived from the asphalt mixture itself, which uses recycled asphalt aggregate. Examples of such aggregates include crushed stone, pebbles, gravel, sand, and ceramics, which are commonly used aggregates in asphalt mixtures for road paving.

[0024] <Semi-carbide derived from nonwoven fabric products> The asphalt composition of the present invention contains a semi-carbide derived from a nonwoven fabric product, having a volatile content of 50% by mass or more and 90% by mass or less, and a fixed carbon content of 7% by mass or more and 40% by mass or less. Semi-carbides derived from nonwoven fabric products refer to components in which the raw nonwoven fabric product has been subjected to relatively low-temperature heat treatment, resulting in virtually zero moisture content while retaining virtually no combustible material (energy).

[0025] The semi-carbide has a volatile content of 50% to 90% by mass, preferably 55% or more, more preferably 60% or more, and preferably 85% or less, and more preferably 80% or less, based on 100% by mass of the total mass of the semi-carbide, from the viewpoint of durability and workability. Volatile components are the flammable elements in semi-carbides that, when heated, generate flammable gases, mainly hydrocarbon gases. The volatile content can be measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods".

[0026] The fixed carbon content of the semicarbide is preferably 7% to 40% by mass, more preferably 8% or more, more preferably 10% or more, and more preferably 35% or less by mass, and more preferably 30% or less by mass, based on 100% by mass of the total mass of the semicarbide, from the viewpoint of durability and workability. The fixed carbon content can be measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods".

[0027] Semi-carbides contain almost no moisture due to the semi-carbide treatment. For example, the moisture content is 0.01% or less of the total mass of the semi-carbide (100% by mass). Semi-carbides have a fuel ratio [fixed carbon (mass%) / volatile matter (mass%)] of preferably 0.08 or higher, more preferably 0.1 or higher, and preferably 0.8 or lower, more preferably 0.6 or lower, from the viewpoint of durability and workability. Semi-carbides are distinguished from carbides with a high fuel ratio in which complete carbonization has progressed.

[0028] In this invention, the semi-carbide is a semi-carbide derived from a nonwoven fabric product. Nonwoven fabrics that make up nonwoven products are planar fiber aggregates that have obtained a predetermined level of structural strength by physical and / or chemical methods, as defined in JIS L 0222:2022. The fibrous components constituting the nonwoven fabric are preferably fibrous components made of thermoplastic resin, more preferably polyester such as polyethylene terephthalate (PET); and fibrous components made of thermoplastic resin such as polyolefins such as polyethylene (PE) and polypropylene (PP). The fibrous components of thermoplastic resin are preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and 100% by mass or less of the fibrous components constituting the nonwoven fabric. Other fiber components besides thermoplastic resins include natural fibers such as pulp fibers and cotton fibers, and regenerated fibers such as rayon. Preferred examples of such nonwoven fabrics include air-through nonwoven fabrics, point-bonded nonwoven fabrics, spunbond nonwoven fabrics, spunlace nonwoven fabrics, three-dimensionally shaped nonwoven fabrics, and composite materials of two or more of these types.

[0029] Preferred examples of nonwoven fabric products include absorbent articles such as diapers for infants or adults, sanitary napkins, panty liners, and incontinence pads. Absorbent articles that are nonwoven fabric products typically have a surface material and an absorbent core made of nonwoven fabric. The absorbent core typically has an aggregate of pulp fibers or an aggregate of pulp fibers and a superabsorbent polymer material.

[0030] When fibrous components such as pulp and rayon are added to asphalt pavement to improve its durability, the high polarity of these fibrous components can lead to insufficient dispersion in the asphalt, causing the fibers to aggregate. As a result, the filling properties may be insufficient, resulting in poor workability. As described in the present invention, by using semi-carbides derived from nonwoven fabric products, particularly semi-carbides derived from absorbent articles, it is believed that an asphalt mixture can be obtained that provides an asphalt pavement with excellent filling properties, no problems with workability, and superior durability, as the fibrous components such as pulp and rayon contained in the nonwoven fabric product are uniformly dispersed in the asphalt. More specifically, it is presumed that the fibrous components of thermoplastic resins such as polyethylene and polypropylene that constitute the nonwoven fabric melt during the production of the semi-carbides and coat the fibrous components such as pulp and rayon. It is believed that the presence of these thermoplastic resin fibrous components, which have a high affinity for asphalt, improves the miscibility between the asphalt and the fibrous components such as pulp and rayon, enabling fine dispersion, thereby providing an asphalt pavement with excellent filling properties, no problems with workability, and superior durability.

[0031] The production of semicarbides is not limited to any method that can produce semicarbides having a volatile content of 50% by mass or more and 90% by mass or less, and a fixed carbon content of 7% by mass or more and 40% by mass or less, and can be produced by a process of heating raw materials at a predetermined low temperature.

[0032] The production of semi-carbides (semi-carbonization treatment) can be carried out by, for example, placing a nonwoven fabric product, which is the raw material, into a furnace and proceeding with carbonization of the raw material by heating. Heating can be carried out by raising the temperature from room temperature to the heating temperature and then maintaining the temperature after it has been reached. The heating temperature is preferably 150°C or higher, more preferably 200°C or higher, and 400°C or lower, more preferably 300°C or lower. The rate of heating from room temperature to the heating temperature is preferably 0.1°C / min or more, more preferably 0.3°C / min or more, preferably 5°C / min or less, and more preferably 3°C / min or less. The heating time can be set appropriately to obtain a semi-carbide, preferably 1 hour or more, more preferably 2 hours or more, and preferably 6 hours or less, more preferably 5 hours or less. Note that the heating time is the time maintained after reaching the above heating temperature. Heating is preferably carried out while preventing contact with air. After heating is complete, air or nitrogen can be circulated through the furnace to accelerate the cooling of the resulting semi-carbide. The cooling rate is preferably 0.05°C / min or more, more preferably 0.1°C / min or more, preferably 3°C / min or less, and more preferably 1°C / min or less.

[0033] In the production of semi-carbides, it is preferable to carry out the production while stirring the raw materials. Generally, semi-carbides that have lost moisture are brittle, and the semi-carbides obtained by stirring are crushed and obtained as granular material.

[0034] Semi-carbides can be produced using a carbonization furnace. More specifically, shaft furnaces, kilns, etc., can be used.

[0035] <Additives> In addition to the above-mentioned asphalt, aggregate, and semi-carbide, the asphalt mixture of the present invention may optionally contain various additives conventionally used in asphalt mixtures, such as film-forming agents, thickening and stabilizing agents, emulsifiers, and the like.

[0036] <Polyester resin> As an example of an additive that can be included, we will describe polyester resin. Polyester resin is a polycondensate of an alcohol component and a carboxylic acid component, containing constituent units derived from an alcohol component and constituent units derived from a carboxylic acid component. Examples of polyester resins include amorphous polyester resins and crystalline polyester resins, with amorphous polyester resins being preferred. The alcohol and carboxylic acid components are described below.

[0037] (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.

[0038] 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.

[0039] Examples of alicyclic diols include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), alkylene oxide adducts of hydrogenated bisphenol A, cyclohexanediol, and cyclohexanedimethanol.

[0040] 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).

[0041] [ka]

[0042] [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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] (Carboxylic acid component) 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.

[0047] 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.

[0048] 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 suppressing aggregate scattering and water resistance, and terephthalic acid is more preferred.

[0049] 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.

[0050] 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.

[0051] (Constituent units derived from polyethylene terephthalate) The polyester resin may contain constituent units derived from polyethylene terephthalate, 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 a polyester resin contains constituent units consisting of ethylene glycol and terephthalic acid derived from polyethylene terephthalate, the "constituent units derived from alcohol components" include constituent units derived from ethylene glycol derived from polyethylene terephthalate, and the "constituent units derived from carboxylic acid components" include constituent units derived from terephthalic acid derived from polyethylene terephthalate.

[0052] The polyester resin may be a modified polyester resin to the 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.

[0053] <Content of each ingredient> From the viewpoint of durability, the asphalt content in the asphalt mixture is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0054] When an asphalt mixture contains recycled asphalt aggregate, the asphalt content refers to the total amount of asphalt contained in both the new asphalt and the recycled asphalt aggregate. To distinguish the asphalt contained in recycled asphalt aggregate from the new asphalt, it is sometimes referred to as recycled aggregate-derived asphalt or degraded asphalt. From the viewpoint of durability, the content of new asphalt is preferably 50% by mass or more, more preferably 60% by mass or more, and preferably 80% by mass or less, and more preferably 70% by mass or less. From the viewpoint of durability, the content of asphalt derived from recycled aggregate is preferably 20% by mass or more, more preferably 30% by mass or more, and preferably 50% by mass or less, and more preferably 40% by mass or less. The asphalt content derived from recycled aggregate 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 aggregate is determined according to the method specified in AASHTO (American Association of State Highway and Transportation Officials) T 308-10 (2015), which is a loss on ignition measurement. Since recycled asphalt aggregate is included as aggregate, the amount of asphalt is determined from the loss on ignition of the recycled asphalt aggregate and used in the mix design calculation.

[0055] The content of the above-mentioned semi-carbide in the asphalt mixture of the present invention is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of asphalt, from the viewpoint of durability of asphalt pavement, and preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of maintaining workability.

[0056] From the viewpoint of durability, the aggregate content in the asphalt mixture is preferably 50% by mass or more, more preferably 75% by mass or more, even more preferably 80% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 96% by mass or less. When an asphalt mixture contains recycled asphalt aggregate, the aggregate content refers to the total content of recycled asphalt aggregate and any newly included aggregate. From the viewpoint of reusing waste materials from asphalt pavement, the recycled asphalt aggregate content is preferably 15 parts by mass or more, more preferably 25 parts by mass or more, per 100 parts by mass of the total content of recycled asphalt aggregate and newly included aggregate. From the viewpoint of achieving both the use of recycled asphalt aggregate and excellent pavement properties, the recycled asphalt aggregate content is preferably 60 parts by mass or less, more preferably 50 parts by mass or less. Furthermore, the aggregate content will include the asphalt derived from recycled aggregate.

[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 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 the above-mentioned semi-carbide. 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.

[0058] [Method for producing asphalt mixture] The present invention provides a method for producing an asphalt mixture, comprising the step of mixing asphalt, aggregate, and the above-mentioned semi-carbide. The mixing is preferably done under heated conditions, and the aggregate is more preferably heated. The mixing process can involve mixing asphalt, aggregate, and the above-mentioned semi-carbide simultaneously or in any order. From the viewpoint of durability of the asphalt pavement, it is preferable to mix the above-mentioned semi-carbide with the aggregate after the asphalt. Specific methods for manufacturing asphalt mixtures include conventional methods such as the premix method and the plant mix method. Both methods involve adding asphalt and semi-carbides to heated aggregate. Addition methods include, for example, the premix method in which asphalt and semi-carbides are dissolved in advance, or the plant mix method in which asphalt is added to heated aggregate, and then the semi-carbide salts are added simultaneously or in any order. Among these, the plant mix 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) After adding and mixing asphalt to heated aggregate to obtain a mixture, the above-mentioned semi-carbide is added and mixed. (ii) Add and mix asphalt and the above-mentioned semi-carbonized material to the heated aggregate simultaneously, or (iii) Add and mix the mixture of preheated asphalt and the above-mentioned semi-carbonized material to the heated aggregate. Among these, the mixing step is preferably method (i).

[0059] In method (iii), the mixing temperature for preheating and mixing the asphalt and the semi-carbide 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 semi-carbide in the asphalt. Furthermore, the mixing time between the asphalt and the semi-carbide is preferably 30 seconds or more, more preferably 1 minute or more, even more preferably 2 minutes or more, and preferably 2 hours or less, more preferably 1 hour or less, and even more preferably 30 minutes or less, from the viewpoint of uniformly dispersing the semi-carbide in the asphalt. The mixing of asphalt and the above-mentioned semi-carbide can be carried out using, for example, a homomixer, dissolver, paddle mixer, ribbon mixer, screw mixer, planetary mixer, vacuum backflow mixer, roll mill, twin-screw extruder, etc.

[0060] In methods (i) to (iii), the temperature of the heated aggregate is preferably 140°C or higher, more preferably 145°C or higher, and even more preferably 150°C or higher, and from the viewpoint of the stability of the asphalt performance, it is preferably 350°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. From the viewpoint of improving durability through sufficient mixing, the heating temperature is preferably 140°C or higher, more preferably 145°C or higher, and even more preferably 150°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. The mixing temperature is preferably 140°C or higher, more preferably 145°C or higher, and even more preferably 150°C or higher, from the viewpoint of durability of the asphalt pavement, and preferably 350°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower, from the viewpoint of performance stability of the asphalt. The mixing time is not particularly limited. Preferably it is 30 seconds or more, more preferably 1 minute or more, even more preferably 2 minutes or more, and preferably 2 hours or less, more preferably 1 hour or less, and even more preferably 30 minutes or less.

[0061] The method for preparing the mixture is not particularly limited, but it is preferable to include the steps of heating and melting asphalt, adding the above-mentioned semi-carbide and other additives as needed, and stirring and mixing in a commonly used mixer until each component is uniformly dispersed. Commonly used mixers include twin-screw pug mill type, forced twin-screw type, horizontal single-screw type, and pan-type mixer.

[0062] The asphalt mixture of the present invention 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 and the like may be added to this emulsion to be used as a room-temperature asphalt mixture. From the viewpoint of exhibiting asphalt performance, the mixture of asphalt and the above semi-carbide preferably contains substantially no water.

[0063] 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.

[0064] The present invention's method for producing an asphalt mixture may include a step of producing a semi-carbide from raw materials. One such embodiment is a method for producing an asphalt mixture, which includes the following steps 1a and 2a. Step 1a: A process to produce a semi-carbide by heating the raw material at a temperature of 150°C to 400°C, wherein the volatile matter content is 50% to 90% by mass and the fixed carbon content is 7% to 40% by mass. Step 2a: A step of mixing asphalt, heated aggregate, and the semi-carbide obtained in step 1a.

[0065] The heating temperature in step 1a above is preferably 150°C or higher, more preferably 200°C or higher, and 400°C or lower, more preferably 300°C or lower. The heating time can be set appropriately to achieve partial carbonization, preferably 1 hour or more, more preferably 2 hours or more, and preferably 6 hours or less, more preferably 5 hours or less. Heating is preferably carried out while preventing contact with air. It is preferable to manufacture the semi-carbide while stirring the raw materials. Semi-carbides can be produced using a carbonization furnace. More specifically, shaft furnaces, kilns, etc., can be used.

[0066] [Road paving construction methods] The asphalt mixture of the present invention is suitable for road paving. The road paving 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 paving material layer is usually the base layer or surface layer of the road, and from the viewpoint of exhibiting durability, it is preferably the surface layer of the road.

[0067] 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.

[0068] Asphalt pavement materials formed by applying asphalt mixtures to roads and the like have a void ratio of preferably 2.5% or more, more preferably 3% or more, preferably 20% or less, more preferably 10% or less, and even more preferably 6% or less, from the viewpoint of durability and workability. The void ratio can be determined in accordance with the measurement method specified in "B008-1 Density Test Method for Dense-Graded Asphalt Mixtures, etc." of the "Pavement Survey and Testing Methods Handbook (FY2019 Edition)" (edited by the Japan Road Association). Furthermore, the void ratio can be adjusted by the ratio of coarse aggregate, fine aggregate, and filler in the aggregate.

[0069] [Asphalt composition] The present invention also provides an asphalt composition. The asphalt composition of the present invention comprises asphalt and a semi-carbide having a volatile matter content of 50% by mass or more and 90% by mass or less, and a fixed carbon content of 7% by mass or more and 40% by mass or less. The description and preferred embodiments of asphalt and semi-carbides are as stated above.

[0070] In the asphalt composition of the present invention, the content of the above-mentioned semi-carbide is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of asphalt, from the viewpoint of durability.

[0071] 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.

[0072] [Method for producing asphalt composition] The method for producing the asphalt composition of the present invention preferably includes a step of mixing asphalt with the above-mentioned semi-carbide.

[0073] Asphalt compositions are obtained by heating and melting asphalt, adding semi-carbides, 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.

[0074] The mixing temperature of the asphalt and the semi-carbide 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 semi-carbide in the asphalt.

[0075] Furthermore, the mixing time between the asphalt and the semi-carbide 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, from the viewpoint of uniformly dispersing the semi-carbide in the asphalt.

[0076] The method for producing the asphalt composition of the present invention may include a step of producing a semi-carbide from raw materials. One such embodiment is a method for producing an asphalt composition, which includes the following steps 1b and 2b. Step 1b: A process to produce a semi-carbide by heating the raw material at a temperature of 150°C to 400°C, wherein the volatile matter content is 50% to 90% by mass and the fixed carbon content is 7% to 40% by mass. Step 2b: A step of mixing asphalt, heated aggregate, and the semi-carbide obtained in step 1b.

[0077] The heating temperature in step 1b above is preferably 150°C or higher, more preferably 200°C or higher, and preferably 400°C or lower, more preferably 300°C or lower. The heating time can be set appropriately to achieve partial carbonization, preferably 1 hour or more, more preferably 2 hours or more, and preferably 6 hours or less, more preferably 5 hours or less. Heating is preferably carried out while preventing contact with air. It is preferable to manufacture the semi-carbide while stirring the raw materials. Semi-carbides can be produced using a carbonization furnace. More specifically, shaft furnaces, kilns, etc., can be used.

[0078] [Asphalt modifier] The present invention also provides an asphalt modifier. The asphalt modifier of the present invention contains a semi-carbide having a volatile content of 50% by mass or more and 90% by mass or less, and a fixed carbon content of 7% by mass or more and 40% by mass or less. The description of the semicarbide and preferred embodiments are as described above.

[0079] 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 also be used as a modifier for incorporation into asphalt mixtures containing aggregate. [Examples]

[0080] Various physical properties were measured and evaluated using the following methods. In the following examples and comparative examples, unless otherwise specified, parts and percentages are based on mass.

[0081] [Measurement method] (1) Measurement of volatile content The volatile content was measured in accordance with the measurement method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". (2) Measurement of fixed carbon content The fixed carbon content was measured in accordance with the measurement method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods".

[0082] Sample 1 As sample 1 for partial carbonization and carbonization treatment, 15 kg of unused infant diapers (product name "Merries Pants Sarasa Airy Through L size", manufactured by Kao Corporation) were soaked in 7.5 kg of tap water, and then 0.6 kg of ammonium dihydrogen phosphate was added.

[0083] The materials used in "Merries Pants Sarasa Airy Through L size" are as follows. Please note that the material information is based on the guidelines of the Japan Hygiene Materials Industry Association. Surface material: Polyester / Polyolefin nonwoven fabric Absorbent material: Absorbent paper / Cotton pulp / Acrylic polymer absorbent material Waterproofing material: Polyolefin film Fastening material: Polyolefin film Elastic material: Polyurethane Binder: Styrene-based elastomer synthetic resin, etc.

[0084] Polyester / polyolefin nonwoven fabrics consist of materials such as polyethylene terephthalate (PET) and polyolefins such as polyethylene (PE) and polypropylene (PP).

[0085] The above conditions simulate those of used absorbent material, and ammonium dihydrogen phosphate simulates a component found in urine.

[0086] Sample 2 As sample 2 for the partial carbonization treatment, 15 kg of used infant diapers, the same type used in sample 1, was used.

[0087] Manufacturing Example 1 (Manufacturing of Semicarbide 1) Sample 1 was heated using a furnace equipped with stirring blades, a heater, and a blower mechanism for stirring the raw materials. The temperature was raised from 20°C to 250°C at a rate of 0.5°C / min, and maintained at 250°C for 180 minutes. After that, the sample was cooled from 250°C to 30°C at a rate of 0.2°C / min while blowing air. The sample was continuously stirred during heating and cooling. Semi-carbide 1, which is a semi-carbide of the granular material of disposable diapers, was obtained. Figure 1 shows the configuration of the furnace used, which includes stirring blades, a heater, and a blower mechanism for agitation. The volatile content in semi-carbide 1 was 70.4% by mass. The fixed carbon content in semi-carbide 1 was 17.2% by mass.

[0088] Manufacturing Example 2 (Manufacturing of Semicarbide 2) Except for changing the heating temperature to 200°C, semi-carbide 2, which is a semi-carbide of disposable diapers, was obtained in the same manner as in Production Example 1. The volatile content in semi-carbide 2 was 81.6% by mass. The fixed carbon content in semi-carbide 2 was 9.9% by mass.

[0089] Manufacturing Example 3 (Manufacturing of Semicarbide 3) Except for using sample 2 (used disposable diaper) instead of sample 1, semi-carbide 3, which is a semi-carbide of disposable diapers, was obtained in the same manner as in manufacturing example 1. The volatile content in semi-carbide 3 was 55.6% by mass. The fixed carbon content in semi-carbide 3 was 27.8% by mass.

[0090] Manufacturing Example 4 (Manufacturing of Semicarbide 4) Except for changing the heating temperature to 300°C, the same procedure as in Production Example 1 was used to obtain semi-carbide 4, which is a semi-carbide of disposable diapers. The volatile content in semi-carbide 4 was 59.0% by mass. The fixed carbon content in semi-carbide 3 was 11.7% by mass.

[0091] Manufacturing Example 5 (Manufacturing of Carbide 1) Sample 1 was placed in a crucible and heated in an electric furnace from 20°C to 800°C at a rate of 10°C / min, maintaining the temperature at 800°C for 30 minutes to heat Sample 1. Subsequently, the temperature was lowered from 800°C to 30°C at a rate of 10°C / min to cool the sample and obtain carbide 1. The volatile content in carbide 1 was 0% by mass. The fixed carbon content in carbide 1 was 54.1% by mass.

[0092] Manufacturing example 6 (unprocessed material 1) Unused infant diapers (product name "Merries Pants Sarasa Airy Through L size") were cut into approximately 1 cm squares using scissors to obtain unprocessed material 1. It was not possible to obtain a uniformly mixed asphalt mixture using untreated material 1.

[0093] Example 1 15 kg of aggregate heated to 180°C (see below for aggregate composition) was placed in an asphalt mixer and mixed at 180°C for 60 seconds. Then, 820 g of straight asphalt (manufactured by Mitsubishi Corporation Energy Co., Ltd.) was added and mixed in the asphalt mixer for 1 minute. Next, 41g of the semi-carbide 1 obtained in Production Example 1 was added and mixed for 2 minutes in an asphalt mixer to obtain an asphalt mixture. The content of semi-carbide 1 was 10 parts by mass per 100 parts by mass of straight asphalt. (Composition of aggregate:) Crushed stone No. 6, 40.0 parts by mass Crushed stone No. 7, 13.0 parts by mass Crushed sand 10.0 parts by mass River sand 22.0 parts by mass Mountain sand 10.0 parts by mass Stone powder (calcium carbonate) 5.0 parts by mass Passed mass%: Sieve mesh size 15 mm: 100% by mass Sieve mesh size 10 mm: 88.7% by mass Sieve mesh size 5 mm: 60.5% by mass Sieve mesh size 2.5 mm: 42.6% by mass Sieve mesh size 1.2 mm: 29.9% by mass Sieve mesh size 0.6 mm: 19.8% by mass Sieve mesh size 0.3 mm: 11.5% by mass Sieve mesh size 0.15 mm: 6.2% by mass

[0094] The obtained asphalt mixture was quickly filled into a 300mm x 300mm x 50mm mold, and asphalt specimens were prepared by applying pressure for 25 rotations at a temperature of 150°C and a load of 0.44kPa using a roller compactor (manufactured by Iwata Kogyosho Co., Ltd.), followed by heat curing at 180°C for 2 hours. In addition, 1.2 kg of asphalt mixture was weighed and cylindrical specimens were prepared using a Marshall test compactor (manufactured by Nakajima Gihan Co., Ltd., "Automatic Asphalt Compactor"). The specimens were slowly cooled to room temperature and demolded using a demolding machine.

[0095] [evaluation] <Wheel tracking test: Evaluation of rutting depth> Asphalt specimens were immersed in hot water set to 60°C in a 60°C constant temperature chamber. A wheel tracking test machine (manufactured by Iwata Industries Co., Ltd., load 1716N, wheel width 47mm, line pressure 291.5N / cm) was used to move a wheel back and forth over the specimen at a speed of 15 reciprocations / minute, and the displacement was measured after 1,250 reciprocations. Other measurement conditions followed the measurement method specified in "B003 Wheel Tracking Test Method" described in the "Pavement Survey and Testing Methods Handbook (FY2019 Edition)" (edited by the Japan Road Association). The results are shown in Table 1.

[0096] <Measurement of porosity> The void ratio of asphalt specimens was determined in accordance with the measurement method specified in "B008-1 Density Test Method for Dense-Graded Asphalt Mixtures, etc." of the "Pavement Survey and Testing Methods Handbook (FY2019 Edition)" (compiled by the Japan Road Association). By measuring the void ratio under identical conditions, the workability of the asphalt mixture can be evaluated.

[0097] Examples 2-3 Except for changing the amount of semi-carbide 1 in the formulation to the amount shown in Table 1, asphalt specimens were prepared in the same manner as in Example 1, and wheel tracking tests were conducted. The porosity of the asphalt specimens was also measured. The results are shown in Table 1.

[0098] Examples 4-6 Except for replacing semi-carbide 1 with semi-carbides 2-4 shown in Table 1, asphalt specimens were prepared in the same manner as in Example 1, and wheel tracking tests were performed. The porosity of the asphalt specimens was also measured. The results are shown in Table 1.

[0099] Comparative Example 1 Asphalt specimens were prepared in the same manner as in Example 1, except that semi-carbide 1 was not included, and a wheel tracking test was performed. The porosity of the asphalt specimens was also measured.

[0100] Comparative Example 2 Asphalt specimens were prepared in the same manner as in Example 1, except that semi-carbide 1 was replaced with carbide 1, and a wheel tracking test was performed. The porosity of the asphalt specimens was also measured.

[0101] [Table 1]

[0102] The results shown in Table 1 indicate that the present invention provides an asphalt mixture capable of producing asphalt pavement with superior durability. Examples 1-6 achieved a filling rate of 3-6%, indicating that incorporating semi-carbides 1-4 does not pose a problem to the workability of the pavement. Furthermore, a comparison of Examples 1, 4, and 6 reveals that as the amount of volatile matter increases, the amount of rutting decreases, while the void ratio tends to increase. This is thought to be because the thermoplastic resin fiber components contained in the nonwoven fabric product, which are thought to contribute to the amount of volatile matter, melt due to the semi-carbonization treatment, contributing to improved durability, but also increasing the viscosity of the asphalt binder and reducing its fluidity. Furthermore, a comparison of Examples 5 and 6 reveals that, when the volatile content is approximately the same, a lower fixed carbon content tends to result in a smaller porosity. Although the exact reason is unclear, it is presumed that a higher fixed carbon content leads to the aggregation of semi-carbides, reducing packing efficiency. [Explanation of Symbols]

[0103] 100 Stirring device 101 Processing tank 101b Containment Section 102 Stirring shaft 102a Shaft 102b Wing section 103 Heater 104 Blower mechanism C Rotation axis

Claims

1. An asphalt mixture containing asphalt, aggregate, and semi-carbides derived from nonwoven fabric products, In the nonwoven fabric product, the fibrous component of the nonwoven fabric is 50% by mass or more, The volatile content of the combustible component in the semi-carbide is 50% by mass or more and 90% by mass or less, relative to 100% by mass of the total mass of the semi-carbide. The volatile content is measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". The fixed carbon content is 7% by mass or more and 40% by mass or less, relative to 100% by mass of the total mass of the semicarbide. The fixed carbon content is measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". An asphalt mixture wherein the moisture content of the semi-carbide is 0.01% by mass or less relative to 100% by mass of the total mass of the semi-carbide.

2. The asphalt mixture according to claim 1, wherein the content of semi-carbides is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of asphalt.

3. A method for producing an asphalt mixture, comprising the step of mixing asphalt, heated aggregate, and semi-carbonized material derived from nonwoven fabric products, In the nonwoven fabric product, the fibrous component of the nonwoven fabric is 50% by mass or more, The volatile content of the combustible component in the semi-carbide is 50% by mass or more and 90% by mass or less, relative to 100% by mass of the total mass of the semi-carbide. The volatile content is measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". The fixed carbon content is 7% by mass or more and 40% by mass or less, relative to 100% by mass of the total mass of the semicarbide. The fixed carbon content is measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". A method for producing an asphalt mixture, wherein the moisture content of the semi-carbide is 0.01% by mass or less relative to 100% by mass of the total mass of the semi-carbide.

4. An asphalt composition comprising asphalt and semi-carbides derived from nonwoven fabric products, In the nonwoven fabric product, the fibrous component of the nonwoven fabric is 50% by mass or more, The volatile content of the combustible component in the semi-carbide is 50% by mass or more and 90% by mass or less, relative to 100% by mass of the total mass of the semi-carbide. The volatile content is measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". The fixed carbon content is 7% by mass or more and 40% by mass or less, relative to 100% by mass of the total mass of the semicarbide. The fixed carbon content is measured in accordance with the method described in JIS M8812:2006 "Coal and coke - Industrial analytical methods". An asphalt composition wherein the moisture content of the semi-carbide is 0.01% by mass or less relative to 100% by mass of the total mass of the semi-carbide.

5. A road paving method comprising the step of applying the asphalt mixture described in claim 1 or 2 to a road to form an asphalt pavement layer.

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