WO2023032609A1 - Asphalt binder and asphalt mixture for paving - Google Patents

Asphalt binder and asphalt mixture for paving Download PDF

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Publication number
WO2023032609A1
WO2023032609A1 PCT/JP2022/030321 JP2022030321W WO2023032609A1 WO 2023032609 A1 WO2023032609 A1 WO 2023032609A1 JP 2022030321 W JP2022030321 W JP 2022030321W WO 2023032609 A1 WO2023032609 A1 WO 2023032609A1
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Prior art keywords
asphalt
mass
plastic
paving
asphalt binder
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PCT/JP2022/030321
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French (fr)
Japanese (ja)
Inventor
尚之 小早川
智至 ▲高▼田
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Ｅｎｅｏｓ株式会社
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Application filed by Ｅｎｅｏｓ株式会社 filed Critical Ｅｎｅｏｓ株式会社
Priority to CN202280057792.9A priority Critical patent/CN117836374A/en
Publication of WO2023032609A1 publication Critical patent/WO2023032609A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L95/00—Compositions of bituminous materials, e.g. asphalt, tar, pitch
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C7/00—Coherent pavings made in situ
    • E01C7/08—Coherent pavings made in situ made of road-metal and binders
    • E01C7/18—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders
    • E01C7/26—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders mixed with other materials, e.g. cement, rubber, leather, fibre

Definitions

  • the present disclosure relates to asphalt binders and asphalt mixtures for paving.
  • Asphalt mixtures used for pavement contain at least aggregate such as crushed stone and asphalt binder.
  • Polymer-modified asphalts to which elastomers such as styrene-butadiene-styrene block copolymers (SBS) are added are known as asphalt binders.
  • SBS styrene-butadiene-styrene block copolymers
  • waste plastics have been used as raw materials (aggregates, etc.) for asphalt mixtures for paving as material recycling of industrial waste plastics (waste plastics). (See Patent Documents 1 to 6 below.)
  • aggregates made of plastic such as waste plastic (plastic aggregates) are lighter than conventional aggregates.
  • the surface of the plastic aggregate is smoother than that of the conventional aggregate.
  • the surface of the plastic aggregate is curved like a cylindrical (pellet) or spherical particle, point contact or line contact between the plastic aggregates may occur, but meshing and friction between the plastic aggregates is difficult to occur. That is, even if the asphalt binder fixes the arrangement of the aggregates, physical interference between the aggregates cannot be expected, and the structural strength of the pavement is significantly reduced.
  • pavements formed from conventional asphalt mixtures containing plastic aggregates must exert their structural strength primarily due to the adhesive forces possessed by the asphalt binder and have a sufficiently high dynamic stability (unit: times/mm).
  • the dynamic stability is a value measured by a wheel tracking test (standard number: pavement survey/test method handbook B003).
  • An object of one aspect of the present invention is to provide an asphalt binder that enables pavement with excellent dynamic stability and is difficult to exude from the asphalt mixture for paving, and an asphalt mixture for paving containing the asphalt binder.
  • One aspect of the present invention relates to the following asphalt binder and paving asphalt mixture.
  • thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene.
  • an asphalt binder that enables pavement with excellent dynamic stability and is difficult to exude from the asphalt mixture for paving, and an asphalt mixture for paving containing the asphalt binder are provided.
  • the asphalt binder according to this embodiment contains straight asphalt and thermoplastic resin.
  • the content of the thermoplastic resin in the asphalt binder is 15% by mass or more.
  • the content of the thermoplastic resin in the asphalt binder may be 30% by mass or more.
  • the pavement formed from the asphalt mixture containing the asphalt binder and aggregate can have high dynamic stability. That is, since the content of the thermoplastic resin in the asphalt binder is 15% by mass or more, a sufficiently high dynamic stability is achieved. As the content of thermoplastic resin increases, the dynamic stability of the pavement tends to increase. Pavements formed using asphalt binders according to the present embodiments can have greater dynamic stability than pavements formed using conventional polymer-modified asphalts.
  • exudation of the asphalt binder from the asphalt mixture is suppressed. That is, since the content of the thermoplastic resin in the asphalt binder is 15% by mass or more, the exudation of the asphalt binder from the asphalt mixture is sufficiently suppressed. As the content of the thermoplastic resin increases, the viscosity of the asphalt binder increases, and the exudation of the asphalt binder from the asphalt mixture is easily suppressed. In other words, as the content of thermoplastic resin decreases, the natural properties of straight asphalt become more pronounced, the viscosity of the asphalt binder decreases, and the asphalt binder tends to exude from the asphalt mixture.
  • the asphalt binder may contain only one type of thermoplastic resin as the thermoplastic resin.
  • the asphalt binder may contain multiple types of thermoplastic resins. That is, multiple types of thermoplastic resins may be mixed in the asphalt binder.
  • the thermoplastic resin is used so that the viscosity of the asphalt mixture at the time of mixing is in an appropriate range. are selected, and their mixing ratio may be adjusted.
  • the thermoplastic resin content is the total content of the multiple types of thermoplastic resins.
  • the content of the thermoplastic resin in the asphalt binder is 15% by mass to 70% by mass, 15% by mass to 63% by mass, 15% by mass to 50% by mass, 30% by mass to 70% by mass, It may be 30% by mass or more and 63% by mass or less, or 30% by mass or more and 50% by mass or less.
  • the content of straight asphalt in the asphalt binder is 30% by mass to 85% by mass, 37% by mass to 85% by mass, 50% by mass to 85% by mass, 30% by mass to 70% by mass, 37 It may be 50% by mass or more and 70% by mass or less, or 50% by mass or more and 70% by mass or less.
  • Asphalt binders do not contain aggregates.
  • the asphalt binder may consist only of straight asphalt and thermoplastic resin.
  • the asphalt binder according to this embodiment may not contain the thermoplastic elastomer contained in conventional polymer-modified asphalt.
  • thermoplastic resin contained in the asphalt binder is not limited.
  • the thermoplastic resin may be at least one of polyethylene, polypropylene, polybutene, polybutadiene, polystyrene, polyvinyl chloride, polyvinylidene chloride, and ABS resin (a copolymer of acrylonitrile, butadiene and styrene).
  • the thermoplastic resin may preferably be at least one polyolefin selected from the group consisting of polyethylene, polypropylene, polybutene and polybutadiene.
  • the asphalt mixture for pavement contains the above-described asphalt binder and aggregate. At least some of the aggregate may be plastic.
  • the asphalt binder may be used in paving asphalt mixtures containing aggregates made of plastic (plastic aggregates).
  • Asphalt binders may be used in paving asphalt mixtures containing aggregates made of materials other than plastics (non-plastic aggregates).
  • the aggregates contained in the paving asphalt mixture may be plastic aggregates only.
  • the aggregate contained in the asphalt mixture may be exclusively non-plastic aggregate. Paving asphalt mixtures may contain both plastic and non-plastic aggregates.
  • the pavement can have a high degree of dynamic stability, and exudation of the asphalt binder from the asphalt mixture is suppressed.
  • the inventors speculate that the pavement has greater dynamic stability and inhibits asphalt binder exudation from the asphalt mixture due to the following mechanism.
  • Thermoplastic resin like the plastic aggregate, is an organic substance, so the thermoplastic resin has a chemical affinity for the plastic aggregate.
  • the thermoplastic resin contained in the asphalt binder tends to entangle a plurality of adjacent aggregates as fine fibers melted or dissolved in the straight asphalt. As a result, a plurality of aggregates are fixed to each other via the thermoplastic resin.
  • straight asphalt clings to thermoplastic resin that is entwined with multiple aggregates. As a result, multiple aggregates are firmly fixed to each other through the thermoplastic resin and the straight asphalt, increasing the dynamic stability of the pavement containing plastic aggregates.
  • thermoplastic resin increases the viscosity of the asphalt binder, thereby suppressing exudation of the asphalt binder from the asphalt mixture.
  • conventional asphalt mixtures containing non-plastic aggregates such as crushed stone contain stone dust (filler) to increase the mechanical strength of pavements formed from conventional asphalt mixtures.
  • stone powder which is an inorganic substance, does not have a chemical affinity for plastic aggregates.
  • stone dust since stone dust is particles, stone dust cannot be entangled with a plurality of adjacent aggregates. Therefore, it is difficult to increase the dynamic stability of pavement containing plastic aggregate only with conventional stone powder, and it is difficult to suppress exudation of asphalt binder from the asphalt mixture.
  • At least part of the thermoplastic resin contained in the asphalt binder may be at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene. All thermoplastic resins contained in the asphalt binder may be at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene.
  • the thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene, the dynamic stability of the pavement (especially the dynamic stability of the pavement containing plastic aggregate) is It is easy to increase, and the exudation of the asphalt binder from the asphalt mixture is easy to be suppressed.
  • thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene
  • the low-density polyethylene, linear polyethylene and high-density polyethylene easily melt in straight asphalt. mechanism may occur easily.
  • the dynamic stability of pavement especially the dynamic stability of pavement containing plastic aggregate
  • the thermoplastic resin is low-density polyethylene
  • linear polyethylene and high density polyethylene it is preferable to include at least one of low density polyethylene and linear polyethylene.
  • Low Density Polyethylene (LDPE) is a randomly branched, crystalline polyethylene.
  • the density (specific gravity) of low-density polyethylene may be 0.910 or more and less than 0.930.
  • Linear polyethylene Linear Low Density Polyethylene; L-LDPE
  • L-LDPE Linear Low Density Polyethylene
  • Linear polyethylene may be polyethylene defined by Japanese Industrial Standards (JIS K6899-1:2000). That is, the linear polyethylene may be a linear polyethylene copolymer having a density (specific gravity) of 0.910 or more and 0.925 or less.
  • Linear polyethylene may be rephrased as linear low-density polyethylene.
  • High Density Polyethylene HDPE is a crystalline linear polyethylene. The density (specific gravity) of high-density polyethylene may be 0.942 or more. High density polyethylene may be referred to as rigid polyethylene.
  • thermoplastic resin may be melted or dissolved in the straight asphalt. All thermoplastic resins may be melted or dissolved in the straight asphalt.
  • the dynamic stability of the pavement especially the dynamic stability of the pavement containing plastic aggregate
  • the exudation of the asphalt binder from the asphalt mixture is easily suppressed. If the thermoplastic resin is melted or dissolved in the straight asphalt, the above mechanism may easily occur.
  • Plastic aggregates include, for example, polystyrene, polyolefins (polyethylene, polypropylene, polybutene, polybutadiene, etc.), polyethylene terephthalate, polyamides, polycarbonates, polyurethanes, ABS resins, foamed polyurethanes, unsaturated polyester resins and epoxy resins. At least one kind of plastic made of resin may be used.
  • a paving asphalt mixture may contain aggregates of different compositions.
  • the shape of the plastic aggregate is not limited.
  • the plastic aggregate may be cylindrical pellets or spherical particles.
  • the plastic aggregate may be distorted particles.
  • the dimensions of the plastic aggregate are not particularly limited.
  • the plastic aggregate may have a single particle size (eg, particle size within the range of 3-5 mm).
  • the plastic aggregate may have a particle size distribution suitable for paving like conventional aggregate (eg, dense grain 13 described below). According to this embodiment, the dynamic stability of the pavement can be increased even if the plastic aggregate does not have a particle size distribution suitable for pavement.
  • At least part of the plastic contained in the aggregate may be waste plastic. That is, some or all of the plastic aggregate may be waste plastic. All aggregates contained in paving asphalt mixtures may be waste plastics. As a material recycling of waste plastic, the cost of pavement is reduced by using waste plastic as an aggregate of asphalt mixture for pavement.
  • the proportion of plastic in the aggregate may be 0% by mass to 100% by mass, 50% by mass to 100% by mass, 85% by mass to 100% by mass, or 90% by mass to 100% by mass.
  • the proportion of the plastic aggregate in the asphalt mixture for paving is 0% by mass or more and 100% by mass or less, 50% by mass or more and 100% by mass or less with respect to the total mass of all aggregates contained in the asphalt mixture for paving. , 85% by mass or more and 100% by mass or less, or 90% by mass or more and 100% by mass or less.
  • the paving asphalt mixture according to this embodiment can contain a higher amount of plastic aggregate than conventional paving asphalt mixtures without compromising the dynamic stability of the pavement. As a result, a larger amount of waste plastic than before can be used as the aggregate of the asphalt mixture for pavement.
  • Straight asphalt is a bituminous substance obtained by vacuum distillation of crude oil. That is, the straight asphalt may be the remainder (vacuum residue) of crude oil excluding the light fraction.
  • the quality of straight asphalt is defined by Japanese Industrial Standards (JIS K2207).
  • straight asphalt may be at least one kind of asphalt selected from the group consisting of straight asphalt 40-60, straight asphalt 60-80, straight asphalt 80-100 and straight asphalt 150-200.
  • the aggregate made of substances other than plastic may be, for example, at least one aggregate selected from the group consisting of crushed stone, stone dust, lime, sand, gravel, and steel slag.
  • the proportion of the non-plastic aggregate in the aggregate may be 0% to 100% by mass, 0% to 50% by mass, or 0% to 15% by mass.
  • the proportion of non-plastic aggregate in the asphalt mixture for paving is 0% by mass or more and 100% by mass or less, 0% by mass or more and 50% by mass with respect to the total mass of all aggregates contained in the asphalt mixture for paving or less, or 0% by mass or more and 15% by mass or less.
  • the content of aggregate (plastic aggregate and non-plastic aggregate) in the asphalt mixture for paving is 64.0% by mass or more and 95.0% by mass or less, or 66.7% by mass or more and 87.0% by mass or less. It can be.
  • the content of the asphalt binder in the paving asphalt mixture may be from 5.0% to 36.0% by weight, or from 13.0% to 33.3% by weight.
  • the content of the thermoplastic resin in the asphalt mixture for paving is 0.7% by mass or more and 25.2% by mass or less, 1.9% by mass or more and 16.7% by mass or less, or 0.9% by mass or more and 14.5% by mass. % by mass or less.
  • the content of straight asphalt in the asphalt mixture for paving is 1.5% by mass or more and 30.6% by mass or less, 6.5% by mass or more and 28.3% by mass or less, or 4.8% by mass or more and 28.3% by mass. % or less.
  • the pavement tends to have high dynamic stability, and the exudation of the asphalt binder from the asphalt mixture tends to be suppressed.
  • At least one of the asphalt binder and the paving asphalt mixture comprises a styrene-butadiene-styrene block copolymer (SBS), a styrene-isoprene-styrene block copolymer (SIS), and a styrene-ethylene-butylene-styrene block copolymer. It may further contain at least one thermoplastic elastomer selected from the group consisting of polymers (SEBS).
  • SEBS thermoplastic elastomer selected from the group consisting of polymers
  • the content of the thermoplastic resin in the asphalt binder according to the present embodiment means the content of the thermoplastic resin excluding the thermoplastic elastomer.
  • the asphalt binder may be produced by mixing the above components such as straight asphalt and thermoplastic resin while heating at 160-240°C. By mixing at the above temperature, the thermoplastic resin is easily melted in the straight asphalt, and combustion of light oil remaining in the asphalt binder can be suppressed.
  • a paving asphalt mixture may be produced by mixing the above components, such as the asphalt binder and aggregate, with heating at 160-200°C.
  • the paving asphalt mixture heats the above components, such as the asphalt binder and plastic aggregate, at a temperature that is below the melting point of the plastic aggregate (for example, 130 to 160 ° C).
  • a temperature that is below the melting point of the plastic aggregate for example, 130 to 160 ° C.
  • Plastic aggregate (PS) mentioned below means an aggregate consisting of polystyrene.
  • Plastic aggregates (PS) are cylindrical pellets produced by material recycling of industrial waste (waste plastic).
  • Dense-grained 13 (crushed stone), described below, refers to coarse and fine aggregates for the dense-grained asphalt mixture 13 .
  • Dense grains 13 are non-plastic aggregates.
  • Modified asphalt described below means polymer modified asphalt type II as defined by pavement design and construction guidelines. Pavement Design and Construction Guidelines are issued by the Japan Road Association.
  • the asphalt binders used in Examples 1-8 were prepared by mixing straight asphalt and low density polyethylene (LDPE), including linear polyethylene (L-LDPE).
  • LDPE low density polyethylene
  • L-LDPE linear polyethylene
  • the content of straight asphalt in the asphalt binder was 85% by mass.
  • the content of low density polyethylene (LDPE including L-LDPE) in the asphalt binder was 15% by weight.
  • the content of low density polyethylene in the asphalt binder is expressed as LDPE/(Asp+LDPE) in Table 1 below.
  • the asphalt binder used in Example 9 was prepared by mixing straight asphalt and low density polyethylene (LDPE).
  • the content of straight asphalt in the asphalt binder was 70% by mass.
  • the content of low density polyethylene in the asphalt binder was 30% by weight.
  • the low density polyethylene (LDPE) used in Example 9 did not contain linear polyethylene (L-LDPE).
  • the asphalt binder used in Example 10 was prepared by mixing straight asphalt and low density polyethylene (LDPE).
  • the content of straight asphalt in the asphalt binder was 37.3% by mass.
  • the content of low density polyethylene in the asphalt binder was 62.7% by weight.
  • the low density polyethylene (LDPE) used in Example 10 also did not contain linear polyethylene (L-LDPE).
  • the asphalt binder used in Comparative Example 6 was prepared by mixing straight asphalt and low density polyethylene (LDPE) containing linear polyethylene (L-LDPE).
  • LDPE low density polyethylene
  • L-LDPE linear polyethylene
  • the content of straight asphalt in the asphalt binder was 95% by mass.
  • the content of low-density polyethylene (LDPE including L-LDPE) in the asphalt binder was 5% by mass.
  • the asphalt binder used in Comparative Example 7 was prepared by mixing straight asphalt and low density polyethylene (LDPE) containing linear polyethylene (L-LDPE).
  • LDPE low density polyethylene
  • L-LDPE linear polyethylene
  • the content of straight asphalt in the asphalt binder was 90% by mass.
  • the content of low density polyethylene (LDPE including L-LDPE) in the asphalt binder was 10% by weight.
  • the paving asphalt mixtures of Examples 6 and 7, respectively, were prepared by mixing the asphalt binder and dense granules 13.
  • the paving asphalt mixture of Example 8 was prepared by mixing asphalt binder, dense granules 13 and stone flour.
  • a paving asphalt mixture of Comparative Example 1 was prepared by mixing straight asphalt, dense grain 13 and stone dust.
  • ⁇ Cantabro test (standard number: pavement survey and test method manual B010)> Cylindrical specimens were formed from paving asphalt mixtures. The mass Mi of the sample was measured. After measuring the mass Mi, the sample was placed in a Los Angeles tester (rotatable drum). The Los Angeles testing machine containing the sample was rotated 300 times in a room temperature environment. The rotation speed of the Los Angeles tester was adjusted to 30-33 rpm. After 300 rotations of the Los Angeles tester, the mass Mf of the sample removed from the Los Angeles tester was measured.
  • the strength of the asphalt binder to bind the aggregates together is greater, the detachment of the aggregates from the sample due to the rotation of the Los Angeles tester is suppressed, and the mass of the sample is less likely to decrease. That is, the greater the strength of the asphalt binder to bind the aggregates together, the smaller the Cantabro loss rate.
  • the smaller the Cantabro loss rate the more difficult it is for aggregates to detach from pavement due to vehicle traffic. Therefore, it is preferable that the Cantabro loss factor is small.
  • Pavements flat samples were formed from paving asphalt mixtures.
  • a load (0.63 MPa) was applied to the surface of the sample by pressing a solid rubber tire against the flat surface of the sample. While applying a load to the surface of the sample, the tire was reciprocated in the longitudinal direction at a speed of 42 times ⁇ 1 time/min. The tire cycle was repeated for 60 minutes while maintaining the temperature of the sample at 60°C.
  • the depth Di (unit: mm) of the rut formed on the surface of the sample was measured at time Ti, 45 minutes after the start of reciprocation of the tire.
  • the depth Df of the rut formed on the surface of the sample was measured at time Tf, 60 minutes after the start of reciprocation of the tire.
  • the dynamic stability S was calculated by Equation 2 below.
  • N in Equation 2 is the number of reciprocations (unit: times) of the tire from time Ti to time Tf.
  • S N/(Df ⁇ Di) (2)
  • the dynamic stability (unit: times/mm) of Examples 1 to 10 and Comparative Examples 1 to 5 are shown in Table 1 below.
  • "NG" shown in Table 1 below means that deep ruts were formed on the surface of the sample in just a few minutes. In other words, the paving asphalt mixtures of Comparative Examples 2-5, respectively, were significantly inferior to the paving asphalt mixtures of Examples 1-10, respectively, in dynamic stability.
  • the asphalt binder according to the invention is used as a component of paving asphalt mixtures.

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Abstract

Provided is an asphalt binder that enables paving with excellent dynamic stability and makes less likely bleed-out from an asphalt mixture for paving. The asphalt binder includes straight asphalt and a thermoplastic resin. The content of thermoplastic resin in the asphalt binder is 15 mass% or more.

Description

アスファルトバインダー、及び舗装用アスファルト混合物Asphalt binder and asphalt mixture for paving
　本開示は、アスファルトバインダー、及び舗装用アスファルト混合物に関する。 The present disclosure relates to asphalt binders and asphalt mixtures for paving.
　舗装に用いられる従来のアスファルト混合物は、少なくとも、砕石等の骨材とアスファルトバインダーを含む。アスファルトバインダーとしては、スチレン－ブタジエン－スチレンブロック共重合体（ＳＢＳ）等のエラストマーが添加されたポリマー改質アスファルトが知られている。近年、産業廃棄物であるプラスチック（廃プラスチック）のマテリアルリサイクルとして、廃プラスチックが舗装用アスファルト混合物の原料（骨材等）として利用されている。（下記特許文献１～６参照。） Conventional asphalt mixtures used for pavement contain at least aggregate such as crushed stone and asphalt binder. Polymer-modified asphalts to which elastomers such as styrene-butadiene-styrene block copolymers (SBS) are added are known as asphalt binders. In recent years, waste plastics have been used as raw materials (aggregates, etc.) for asphalt mixtures for paving as material recycling of industrial waste plastics (waste plastics). (See Patent Documents 1 to 6 below.)
特開昭５２－８６２７号公報JP-A-52-8627 特開平６－１９３００７号公報JP-A-6-193007 特開平８－１００４０４号公報JP-A-8-100404 特開２００６－２１２４号公報JP 2006-2124 A 特開２００７－１６５３５号公報JP 2007-16535 A 特開２００８－１６９２６１号公報JP 2008-169261 A
　砕石、砂及び砂利等の従来の骨材の場合、骨材の形状は歪であり、骨材の寸法（粒径）は均一ではなく、骨材の表面は粗い。その結果、従来のアスファルト混合物から形成される舗装内では、骨材が隙間なく充填され易く、骨材同士の物理的干渉（噛み合わせ及び摩擦）によって骨材の動きが抑制され易い。しかし骨材のみでは接着力が働かないため、舗装内の骨材の配置が外力等で容易に崩され、骨材同士の物理的干渉に由来する舗装の構造力を維持することが出来ない。そこで、アスファルトバインダーの持つ接着力が舗装内の骨材の配置を固定する役割を担うことで、骨材同士の物理的干渉に因る舗装の構造力がサポートされ、舗装の構造力が発揮されている、と言える。 In the case of conventional aggregates such as crushed stone, sand and gravel, the shape of the aggregates is distorted, the dimensions (grain size) of the aggregates are not uniform, and the surface of the aggregates is rough. As a result, in the pavement formed from the conventional asphalt mixture, the aggregates tend to be filled without any gaps, and the movement of the aggregates tends to be suppressed by physical interference (meshing and friction) between the aggregates. However, since aggregates alone do not exert adhesive force, the arrangement of aggregates in the pavement is easily disrupted by external forces, etc., and the structural strength of pavement derived from physical interference between aggregates cannot be maintained. Therefore, the adhesive strength of the asphalt binder plays a role in fixing the arrangement of the aggregates in the pavement, supporting the structural strength of the pavement due to the physical interference between the aggregates, and demonstrating the structural strength of the pavement. It can be said that there is
　対照的に、廃プラスチック等のプラスチックからなる骨材（プラスチック骨材）は、従来の骨材よりも軽い。またプラスチック骨材の表面は従来の骨材よりも平滑である。円柱（ペレット）又は球状粒子のように、プラスチック骨材の表面が曲面である場合、プラスチック骨材同士の点接触又は線接触は起き得るが、プラスチック骨材同士の噛み合わせ及び摩擦は起き難い。すなわち、アスファルトバインダーが骨材の配置を固定しても骨材同士の物理的干渉を期待できず、舗装体としての構造力は大幅に下がることになる。その結果、プラスチック骨材を含む従来のアスファルト混合物から形成される舗装は、主にアスファルトバインダーが持つ接着力に因って構造力を発揮せねばならず、十分に大きい動的安定度（単位：回／ｍｍ）を有し難い。動的安定度とは、ホイールトラッキング試験（規格番号：　舗装調査・試験法便覧Ｂ００３）によって測定される値である。動的安定度が大きいほど、車輪（ソリッドゴム製のタイヤ）からの荷重に因る骨材の配置の崩れが抑制され、骨材の配置の崩れに起因する轍が舗装に形成され難い。つまり、舗装の動的安定度は大きいことが好ましい。 In contrast, aggregates made of plastic such as waste plastic (plastic aggregates) are lighter than conventional aggregates. Also, the surface of the plastic aggregate is smoother than that of the conventional aggregate. When the surface of the plastic aggregate is curved like a cylindrical (pellet) or spherical particle, point contact or line contact between the plastic aggregates may occur, but meshing and friction between the plastic aggregates is difficult to occur. That is, even if the asphalt binder fixes the arrangement of the aggregates, physical interference between the aggregates cannot be expected, and the structural strength of the pavement is significantly reduced. As a result, pavements formed from conventional asphalt mixtures containing plastic aggregates must exert their structural strength primarily due to the adhesive forces possessed by the asphalt binder and have a sufficiently high dynamic stability (unit: times/mm). The dynamic stability is a value measured by a wheel tracking test (standard number: pavement survey/test method handbook B003). The higher the dynamic stability is, the more the collapse of the aggregate arrangement due to the load from the wheels (solid rubber tires) is suppressed, and the less likely ruts are formed in the pavement due to the collapse of the aggregate arrangement. That is, it is preferable that the dynamic stability of the pavement is large.
　その一方で、アスファルト混合物中のアスファルトバインダーの含有量には最適量があり、ある程度のアスファルトバインダーの添加量では、アスファルト混合物中の骨材同士の接着力が担保される。しかし、最適量を超えるアスファルトをアスファルト混合物へ配合することで、骨材同士の接着に寄与していない余剰のアスファルトバインダーが、アスファルト混合物から構成される構造体から滲み出ることになる。そのような状態では、むしろ舗装体が流動し易くなり、アスファルトバインダーの滲み出しは動的安定度が下がる要因となる。したがって、アスファルトバインダーの滲み出しは必要最小限にすることが望ましい。日本では、舗装用アスファルト混合物からのアスファルトバインダーの滲み出しは「ダレ」と呼ばれる。 On the other hand, there is an optimum amount of asphalt binder content in the asphalt mixture, and a certain amount of asphalt binder addition ensures the adhesive strength between aggregates in the asphalt mixture. However, by blending more than the optimum amount of asphalt into the asphalt mixture, excess asphalt binder that does not contribute to adhesion between aggregates will ooze out of the structure composed of the asphalt mixture. In such a state, the pavement becomes more likely to flow, and the exudation of the asphalt binder is a factor in lowering the dynamic stability. Therefore, it is desirable to minimize the exudation of the asphalt binder. In Japan, the exudation of asphalt binder from paving asphalt mixtures is called "dare".
　本発明の一側面の目的は、動的安定度に優れた舗装を可能にし、且つ舗装用アスファルト混合物から滲み出し難いアスファルトバインダー、及び当該アスファルトバインダーを含む舗装用アスファルト混合物を提供することである。 An object of one aspect of the present invention is to provide an asphalt binder that enables pavement with excellent dynamic stability and is difficult to exude from the asphalt mixture for paving, and an asphalt mixture for paving containing the asphalt binder.
　本発明の一側面は、下記のアスファルトバインダー及び舗装用アスファルト混合物に関する。 One aspect of the present invention relates to the following asphalt binder and paving asphalt mixture.
　［１］　ストレートアスファルト及び熱可塑性樹脂を含み、熱可塑性樹脂の含有量が１５質量％以上である、アスファルトバインダー。 [1] An asphalt binder containing straight asphalt and a thermoplastic resin with a thermoplastic resin content of 15% by mass or more.
　［２］　少なくとも一部の熱可塑性樹脂が、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンからなる群より選ばれる少なくとも一種のポリオレフィンである、［１］に記載のアスファルトバインダー。 [2] The asphalt binder according to [1], wherein at least a portion of the thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene.
　［３］　熱可塑性樹脂がストレートアスファルト中に融解している、［１］又は「２」に記載のアスファルトバインダー。 [3] The asphalt binder according to [1] or "2", wherein the thermoplastic resin is melted in the straight asphalt.
　［４］　プラスチックを含む骨材を有する舗装用アスファルト混合物に用いられる、［１］～［３］のいずれか一項に記載のアスファルトバインダー。 [4] The asphalt binder according to any one of [1] to [3], which is used for paving asphalt mixtures having plastic-containing aggregates.
　［５］　［１］～［４］のいずれか一項に記載のアスファルトバインダーと、骨材と、を含む舗装用アスファルト混合物。 [5] An asphalt mixture for paving containing the asphalt binder according to any one of [1] to [4] and an aggregate.
　［６］　少なくとも一部の骨材がプラスチックである、［５］に記載の舗装用アスファルト混合物。 [6] The paving asphalt mixture according to [5], wherein at least part of the aggregate is plastic.
　［７］　少なくとも一部のプラスチックが廃プラスチックである、［６］に記載の舗装用アスファルト混合物。 [7] The paving asphalt mixture according to [6], wherein at least part of the plastic is waste plastic.
　［８］　骨材におけるプラスチックの割合が５０質量％以上である、［６］又は［７］に記載の舗装用アスファルト混合物。 [8] The asphalt mixture for paving according to [6] or [7], wherein the proportion of plastic in the aggregate is 50% by mass or more.
　本発明の一側面によれば、動的安定度に優れた舗装を可能にし、且つ舗装用アスファルト混合物から滲み出し難いアスファルトバインダー、及び当該アスファルトバインダーを含む舗装用アスファルト混合物が提供される。 According to one aspect of the present invention, an asphalt binder that enables pavement with excellent dynamic stability and is difficult to exude from the asphalt mixture for paving, and an asphalt mixture for paving containing the asphalt binder are provided.
　以下では本発明の好適な実施形態が説明される。本発明は下記実施形態に限定されるものではない。 Preferred embodiments of the present invention are described below. The present invention is not limited to the following embodiments.
　本実施形態に係るアスファルトバインダーは、ストレートアスファルト及び熱可塑性樹脂を含む。アスファルトバインダー中の熱可塑性樹脂の含有量は、１５質量％以上である。アスファルトバインダー中の熱可塑性樹脂の含有量は、３０質量％以上であってもよい。本実施形態に係るアスファルトバインダーによれば、アスファルトバインダー及び骨材を含むアスファルト混合物から形成される舗装が大きい動的安定度を有することができる。つまり、アスファルトバインダー中の熱可塑性樹脂の含有量が１５質量％以上であるので、十分に大きい動的安定度が達成される。熱可塑性樹脂の含有量の増加に伴って、舗装の動的安定度が増加し易い。本実施形態に係るアスファルトバインダーを用いて形成される舗装は、従来のポリマー改質アスファルトを用いて形成される舗装に比べて、大きい動的安定度を有することができる。さらに本実施形態に係るアスファルトバインダーによれば、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制される。つまり、アスファルトバインダー中の熱可塑性樹脂の含有量が１５質量％以上であるので、アスファルト混合物からのアスファルトバインダーの滲み出しが十分に抑制される。熱可塑性樹脂の含有量の増加に伴って、アスファルトバインダーの粘度が増加し、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制され易い。換言すれば、熱可塑性樹脂の含有量の減少に伴って、ストレートアスファルトの元来の性質が顕著になり、アスファルトバインダーの粘度が減少し、アスファルトバインダーがアスファルト混合物から滲み出し易い。 The asphalt binder according to this embodiment contains straight asphalt and thermoplastic resin. The content of the thermoplastic resin in the asphalt binder is 15% by mass or more. The content of the thermoplastic resin in the asphalt binder may be 30% by mass or more. According to the asphalt binder according to the present embodiment, the pavement formed from the asphalt mixture containing the asphalt binder and aggregate can have high dynamic stability. That is, since the content of the thermoplastic resin in the asphalt binder is 15% by mass or more, a sufficiently high dynamic stability is achieved. As the content of thermoplastic resin increases, the dynamic stability of the pavement tends to increase. Pavements formed using asphalt binders according to the present embodiments can have greater dynamic stability than pavements formed using conventional polymer-modified asphalts. Furthermore, according to the asphalt binder according to the present embodiment, exudation of the asphalt binder from the asphalt mixture is suppressed. That is, since the content of the thermoplastic resin in the asphalt binder is 15% by mass or more, the exudation of the asphalt binder from the asphalt mixture is sufficiently suppressed. As the content of the thermoplastic resin increases, the viscosity of the asphalt binder increases, and the exudation of the asphalt binder from the asphalt mixture is easily suppressed. In other words, as the content of thermoplastic resin decreases, the natural properties of straight asphalt become more pronounced, the viscosity of the asphalt binder decreases, and the asphalt binder tends to exude from the asphalt mixture.
　アスファルトバインダーは、熱可塑性樹脂として、一種類の熱可塑性樹脂のみを含んでよい。アスファルトバインダーは、複数の種類の熱可塑性樹脂を含んでもよい。つまり、複数種の熱可塑性樹脂が、アスファルトバインダー中で混合されていてよい。複数種の熱可塑性樹脂が混合される場合、アスファルト混合物を製造する過程（アスファルトバインダー及び骨材を混合する過程）において、混合時のアスファルト混合物の粘度が適度な範囲となるように、熱可塑性樹脂の種類が選定され、これらの混合割合が調整されてよい。アスファルトバインダーが複数種の熱可塑性樹脂を含む場合、熱可塑性樹脂の含有量は、複数種の熱可塑性樹脂の含有量の合計である。 The asphalt binder may contain only one type of thermoplastic resin as the thermoplastic resin. The asphalt binder may contain multiple types of thermoplastic resins. That is, multiple types of thermoplastic resins may be mixed in the asphalt binder. When multiple types of thermoplastic resins are mixed, in the process of producing the asphalt mixture (the process of mixing the asphalt binder and aggregate), the thermoplastic resin is used so that the viscosity of the asphalt mixture at the time of mixing is in an appropriate range. are selected, and their mixing ratio may be adjusted. When the asphalt binder contains multiple types of thermoplastic resins, the thermoplastic resin content is the total content of the multiple types of thermoplastic resins.
　例えば、アスファルトバインダー中の熱可塑性樹脂の含有量は、１５質量％以上７０質量％以下、１５質量％以上６３質量％以下、１５質量％以上５０質量％以下、３０質量％以上７０質量％以下、３０質量％以上６３質量％以下、又は３０質量％以上５０質量％以下であってよい。
　例えば、アスファルトバインダー中のストレートアスファルトの含有量は、３０質量％以上８５質量％以下、３７質量％以上８５質量％以下、５０質量％以上８５質量％以下、３０質量％以上７０質量％以下、３７質量％以上７０質量％以下、又は５０質量％以上７０質量％以下であってよい。
　アスファルトバインダーは、骨材を含まない。アスファルトバインダーは、ストレートアスファルト及び熱可塑性樹脂のみからなっていてもよい。本実施形態に係るアスファルトバインダーは、従来のポリマー改質アスファルトに含まれる熱可塑性エラストマーを含まなくてもよい。 For example, the content of the thermoplastic resin in the asphalt binder is 15% by mass to 70% by mass, 15% by mass to 63% by mass, 15% by mass to 50% by mass, 30% by mass to 70% by mass, It may be 30% by mass or more and 63% by mass or less, or 30% by mass or more and 50% by mass or less.
For example, the content of straight asphalt in the asphalt binder is 30% by mass to 85% by mass, 37% by mass to 85% by mass, 50% by mass to 85% by mass, 30% by mass to 70% by mass, 37 It may be 50% by mass or more and 70% by mass or less, or 50% by mass or more and 70% by mass or less.
Asphalt binders do not contain aggregates. The asphalt binder may consist only of straight asphalt and thermoplastic resin. The asphalt binder according to this embodiment may not contain the thermoplastic elastomer contained in conventional polymer-modified asphalt.
　アスファルトバインダーに含まれる熱可塑性樹脂は限定されない。例えば、熱可塑性樹脂は、ポリエチレン、ポリプロピレン、ポリブテン、ポリブタジエン、ポリスチレン、ポリ塩化ビニル、ポリ塩化ビニリデン、及びＡＢＳ樹脂（アクリロニトリル、ブタジエン及びスチレンの共重合体）からなる少なくとも一種の樹脂であってよい。熱可塑性樹脂は、好ましくは、ポリエチレン、ポリプロピレン、ポリブテン、ポリブタジエンからなる群より選ばれる少なくとも一種のポリオレフィンであってよい。 The thermoplastic resin contained in the asphalt binder is not limited. For example, the thermoplastic resin may be at least one of polyethylene, polypropylene, polybutene, polybutadiene, polystyrene, polyvinyl chloride, polyvinylidene chloride, and ABS resin (a copolymer of acrylonitrile, butadiene and styrene). The thermoplastic resin may preferably be at least one polyolefin selected from the group consisting of polyethylene, polypropylene, polybutene and polybutadiene.
　本実施形態に係る舗装用アスファルト混合物は、上記のアスファルトバインダーと、骨材と、を含む。少なくとも一部の骨材は、プラスチックであってよい。つまりアスファルトバインダーは、プラスチックからなる骨材（プラスチック骨材）を含む舗装用アスファルト混合物に用いられてよい。アスファルトバインダーは、プラスチック以外の物質からなる骨材（非プラスチック骨材）を含む舗装用アスファルト混合物に用いられてもよい。舗装用アスファルト混合物に含まれる骨材は、プラスチック骨材のみであってよい。アスファルト混合物に含まれる骨材は非プラスチック骨材のみであってもよい。舗装用アスファルト混合物は、プラスチック骨材及び非プラスチック骨材の両方を含んでもよい。 The asphalt mixture for pavement according to this embodiment contains the above-described asphalt binder and aggregate. At least some of the aggregate may be plastic. Thus, the asphalt binder may be used in paving asphalt mixtures containing aggregates made of plastic (plastic aggregates). Asphalt binders may be used in paving asphalt mixtures containing aggregates made of materials other than plastics (non-plastic aggregates). The aggregates contained in the paving asphalt mixture may be plastic aggregates only. The aggregate contained in the asphalt mixture may be exclusively non-plastic aggregate. Paving asphalt mixtures may contain both plastic and non-plastic aggregates.
　本実施形態によれば、舗装用の骨材としてプラスチックを用いた場合であっても、舗装が大きい動的安定度を有することができ、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制される。発明者達は、以下のメカニズムにより、舗装が大きい動的安定度を有し、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制される、と推察する。 According to this embodiment, even when plastic is used as the aggregate for paving, the pavement can have a high degree of dynamic stability, and exudation of the asphalt binder from the asphalt mixture is suppressed. The inventors speculate that the pavement has greater dynamic stability and inhibits asphalt binder exudation from the asphalt mixture due to the following mechanism.
　熱可塑性樹脂は、プラスチック骨材と同様に有機物であるため、熱可塑性樹脂はプラスチック骨材に対する化学的な親和力を有している。そして、アスファルトバインダーに含まれる上記の熱可塑性樹脂は、ストレートアスファルト中に融解又は溶解した微細な繊維として、隣り合う複数の骨材に絡み付き易い。その結果、熱可塑性樹脂を介して、複数の骨材が互いに固定される。さらにストレートアスファルトが、複数の骨材に絡み付いた熱可塑性樹脂にまとわりつく。その結果、熱可塑性樹脂及びストレートアスファルトを介して、複数の骨材が互いに強固に固定され、プラスチック骨材を含む舗装の動的安定度が増加する。更に、熱可塑性樹脂の含有によってアスファルトバインダーの粘度が増加するので、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制される。対照的に、砕石等の非プラスチック骨材を含む従来のアスファルト混合物は石粉（フィラー）を含むことにより、従来のアスファルト混合物から形成される舗装の機械的強度が高まる。しかし、無機物である石粉は、プラスチック骨材に対する化学的な親和力を有していない。また石粉は粒子であるため、石粉は隣り合う複数の骨材に絡み付くことができない。したがって、従来の石粉のみによってプラスチック骨材を含む舗装の動的安定度を増加させることは困難であり、アスファルト混合物からのアスファルトバインダーの滲み出しを抑制し難い。 　Thermoplastic resin, like the plastic aggregate, is an organic substance, so the thermoplastic resin has a chemical affinity for the plastic aggregate. The thermoplastic resin contained in the asphalt binder tends to entangle a plurality of adjacent aggregates as fine fibers melted or dissolved in the straight asphalt. As a result, a plurality of aggregates are fixed to each other via the thermoplastic resin. In addition, straight asphalt clings to thermoplastic resin that is entwined with multiple aggregates. As a result, multiple aggregates are firmly fixed to each other through the thermoplastic resin and the straight asphalt, increasing the dynamic stability of the pavement containing plastic aggregates. Furthermore, the inclusion of the thermoplastic resin increases the viscosity of the asphalt binder, thereby suppressing exudation of the asphalt binder from the asphalt mixture. In contrast, conventional asphalt mixtures containing non-plastic aggregates such as crushed stone contain stone dust (filler) to increase the mechanical strength of pavements formed from conventional asphalt mixtures. However, stone powder, which is an inorganic substance, does not have a chemical affinity for plastic aggregates. Moreover, since stone dust is particles, stone dust cannot be entangled with a plurality of adjacent aggregates. Therefore, it is difficult to increase the dynamic stability of pavement containing plastic aggregate only with conventional stone powder, and it is difficult to suppress exudation of asphalt binder from the asphalt mixture.
　上記のメカニズムは仮説であり、本発明の技術的範囲は上記のメカニズムによって限定されない。 The above mechanism is a hypothesis, and the technical scope of the present invention is not limited by the above mechanism.
　アスファルトバインダーに含まれる少なくとも一部の熱可塑性樹脂は、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンからなる群より選ばれる少なくとも一種のポリオレフィンであってよい。アスファルトバインダーに含まれる全部の熱可塑性樹脂が、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンからなる群より選ばれる少なくとも一種のポリオレフィンであってもよい。熱可塑性樹脂が、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンからなる群より選ばれる少なくとも一種のポリオレフィンである場合、舗装の動的安定度（特にプラスチック骨材を含む舗装の動的安定度）が増加し易く、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制され易い。熱可塑性樹脂が、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンからなる群より選ばれる少なくとも一種のポリオレフィンである場合、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンはストレートアスファルト中に融解し易いので、上記のメカニズムが起き易い可能性がある。舗装の動的安定度（特にプラスチック骨材を含む舗装の動的安定度）が増加し易く、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制され易いことから、熱可塑性樹脂は、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンのうち、低密度ポリエチレン及びリニアポリエチレンのうち少なくとも一つを含むことが好ましい。
　低密度ポリエチレン（Ｌｏｗ　Ｄｅｎｓｉｔｙ　Ｐｏｌｙｅｔｈｙｌｅｎｅ；　ＬＤＰＥ）は、ランダムに分岐を有する結晶性のポリエチレンである。低密度ポリエチレンの密度（比重）は、０．９１０以上０．９３０未満であってよい。
　リニアポリエチレン（Ｌｉｎｅａｒ　Ｌｏｗ　Ｄｅｎｓｉｔｙ　Ｐｏｌｙｅｔｈｙｌｅｎｅ；　Ｌ－ＬＤＰＥ）は、繰り返し単位であるエチレンとα－オレフィンとの共重合体である直鎖状ポリエチレンコポリマーである。リニアポリエチレンは、日本産業規格（ＪＩＳ　Ｋ６８９９－１：２０００）によって規定されたポリエチレンであってよい。つまり、リニアポリエチレンは、密度（比重）が０．９１０以上０．９２５以下である直鎖状ポリエチレンコポリマーであってよい。リニアポリエチレンは、直鎖状低密度ポリエチレンと言い換えられてよい。
　高密度ポリエチレン（Ｈｉｇｈ　Ｄｅｎｓｉｔｙ　Ｐｏｌｙｅｔｈｙｌｅｎｅ；　ＨＤＰＥ）は、結晶性の直鎖状ポリエチレンである。高密度ポリエチレンの密度（比重）は０．９４２以上であってよい。高密度ポリエチレンは、硬質ポリエチレンと言い換えられてよい。 At least part of the thermoplastic resin contained in the asphalt binder may be at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene. All thermoplastic resins contained in the asphalt binder may be at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene. When the thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene, the dynamic stability of the pavement (especially the dynamic stability of the pavement containing plastic aggregate) is It is easy to increase, and the exudation of the asphalt binder from the asphalt mixture is easy to be suppressed. When the thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene, the low-density polyethylene, linear polyethylene and high-density polyethylene easily melt in straight asphalt. mechanism may occur easily. The dynamic stability of pavement (especially the dynamic stability of pavement containing plastic aggregate) tends to increase, and the exudation of the asphalt binder from the asphalt mixture is easily suppressed, so the thermoplastic resin is low-density polyethylene, Among linear polyethylene and high density polyethylene, it is preferable to include at least one of low density polyethylene and linear polyethylene.
Low Density Polyethylene (LDPE) is a randomly branched, crystalline polyethylene. The density (specific gravity) of low-density polyethylene may be 0.910 or more and less than 0.930.
Linear polyethylene (Linear Low Density Polyethylene; L-LDPE) is a linear polyethylene copolymer that is a copolymer of repeating units ethylene and α-olefin. Linear polyethylene may be polyethylene defined by Japanese Industrial Standards (JIS K6899-1:2000). That is, the linear polyethylene may be a linear polyethylene copolymer having a density (specific gravity) of 0.910 or more and 0.925 or less. Linear polyethylene may be rephrased as linear low-density polyethylene.
High Density Polyethylene (HDPE) is a crystalline linear polyethylene. The density (specific gravity) of high-density polyethylene may be 0.942 or more. High density polyethylene may be referred to as rigid polyethylene.
　少なくとも一部の熱可塑性樹脂が、ストレートアスファルト中に融解又は溶解していてよい。全部の熱可塑性樹脂が、ストレートアスファルト中に融解又は溶解していてもよい。熱可塑性樹脂がストレートアスファルト中に融解又は溶解している場合、舗装の動的安定度（特にプラスチック骨材を含む舗装の動的安定度）が増加し易く、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制され易い。熱可塑性樹脂がストレートアスファルト中に融解又は溶解している場合、上記のメカニズムが起き易い可能性がある。 At least part of the thermoplastic resin may be melted or dissolved in the straight asphalt. All thermoplastic resins may be melted or dissolved in the straight asphalt. When the thermoplastic resin is melted or dissolved in the straight asphalt, the dynamic stability of the pavement (especially the dynamic stability of the pavement containing plastic aggregate) tends to increase, and the exudation of the asphalt binder from the asphalt mixture is easily suppressed. If the thermoplastic resin is melted or dissolved in the straight asphalt, the above mechanism may easily occur.
　プラスチックからなる骨材（プラスチック骨材）は、例えば、ポリスチレン、ポリオレフィン（ポリエチレン、ポリプロピレン、ポリブテン及びポリブタジエン等）、ポリエチレンテレフタラート、ポリアミド、ポリカーボネート、ポリウレタン、ＡＢＳ樹脂、発泡ポリウレタン、不飽和ポリエステル樹脂及びエポキシ樹脂からなる少なくとも一種のプラスチックであってよい。舗装用アスファルト混合物は、組成の異なる複数種の骨材を含んでよい。プラスチック骨材の形状は限定されない。例えば、プラスチック骨材は、円柱状のペレット、又は球状粒子であってよい。プラスチック骨材は、歪な粒子であってもよい。プラスチック骨材の寸法は特に限定されない。プラスチック骨材は、単一の粒径（例えば、３～５ｍｍの範囲内にある粒径）を有してよい。プラスチック骨材は、従来の骨材（例えば、後述される密粒１３）のように舗装に適した粒度分布を有してもよい。本実施形態によれば、プラスチック骨材が舗装に適した粒度分布を有していない場合であっても、舗装の動的安定度を増加させることができる。 Plastic aggregates (plastic aggregates) include, for example, polystyrene, polyolefins (polyethylene, polypropylene, polybutene, polybutadiene, etc.), polyethylene terephthalate, polyamides, polycarbonates, polyurethanes, ABS resins, foamed polyurethanes, unsaturated polyester resins and epoxy resins. At least one kind of plastic made of resin may be used. A paving asphalt mixture may contain aggregates of different compositions. The shape of the plastic aggregate is not limited. For example, the plastic aggregate may be cylindrical pellets or spherical particles. The plastic aggregate may be distorted particles. The dimensions of the plastic aggregate are not particularly limited. The plastic aggregate may have a single particle size (eg, particle size within the range of 3-5 mm). The plastic aggregate may have a particle size distribution suitable for paving like conventional aggregate (eg, dense grain 13 described below). According to this embodiment, the dynamic stability of the pavement can be increased even if the plastic aggregate does not have a particle size distribution suitable for pavement.
　骨材に含まれる少なくとも一部のプラスチックは、廃プラスチックであってよい。つまり、一部又は全部のプラスチック骨材が、廃プラスチックであってよい。舗装用アスファルト混合物に含まれる全ての骨材が、廃プラスチックであってもよい。廃プラスチックのマテリアルリサイクルとして、廃プラスチックを舗装用アスファルト混合物の骨材に用いることにより、舗装のコストが低減される。 At least part of the plastic contained in the aggregate may be waste plastic. That is, some or all of the plastic aggregate may be waste plastic. All aggregates contained in paving asphalt mixtures may be waste plastics. As a material recycling of waste plastic, the cost of pavement is reduced by using waste plastic as an aggregate of asphalt mixture for pavement.
　骨材におけるプラスチックの割合は、０質量％以上１００質量％以下、５０質量％以上１００質量％以下、８５質量％以上１００質量％以下、又は９０質量％以上１００質量％以下であってよい。つまり、舗装用アスファルト混合物におけるプラスチック骨材の割合は、舗装用アスファルト混合物に含まれる全ての骨材の質量の合計に対して、０質量％以上１００質量％以下、５０質量％以上１００質量％以下、８５質量％以上１００質量％以下、又は９０質量％以上１００質量％以下であってよい。１５質量％以上の上記熱可塑性樹脂を含まない従来のアスファルトバインダーを用いた場合、骨材におけるプラスチックの割合が高いほど、舗装が大きい動的安定度を有することは困難である。例えば、１５質量％以上の上記熱可塑性樹脂を含まない従来のアスファルトバインダーを用いた場合、骨材におけるプラスチックの割合が８５質量％以上である舗装が大きい動的安定度を有することは困難である。一方、本実施形態によれば、骨材におけるプラスチックの割合が８５質量％以上である舗装が大きい動的安定度を有することができる。したがって、本実施形態に係る舗装用アスファルト混合物は、舗装の動的安定度を損なうことなく、従来の舗装用アスファルト混合物よりも多量のプラスチック骨材を含むことができる。その結果、従来よりも多量の廃プラスチックを舗装用アスファルト混合物の骨材に用いることができる。 The proportion of plastic in the aggregate may be 0% by mass to 100% by mass, 50% by mass to 100% by mass, 85% by mass to 100% by mass, or 90% by mass to 100% by mass. In other words, the proportion of the plastic aggregate in the asphalt mixture for paving is 0% by mass or more and 100% by mass or less, 50% by mass or more and 100% by mass or less with respect to the total mass of all aggregates contained in the asphalt mixture for paving. , 85% by mass or more and 100% by mass or less, or 90% by mass or more and 100% by mass or less. When using conventional asphalt binders that do not contain more than 15% by weight of said thermoplastic resin, the higher the proportion of plastic in the aggregate, the more difficult it is for the pavement to have greater dynamic stability. For example, when using a conventional asphalt binder that does not contain 15% by weight or more of the above thermoplastic resin, it is difficult to have a high dynamic stability for pavement with a plastic proportion of 85% by weight or more in the aggregate. . On the other hand, according to this embodiment, a pavement having a proportion of plastic in the aggregate of 85 mass % or more can have a high dynamic stability. Thus, the paving asphalt mixture according to this embodiment can contain a higher amount of plastic aggregate than conventional paving asphalt mixtures without compromising the dynamic stability of the pavement. As a result, a larger amount of waste plastic than before can be used as the aggregate of the asphalt mixture for pavement.
　ストレートアスファルトは、原油の減圧蒸留によって得られる瀝青物質である。つまりストレートアスファルトは、原油のうち軽質分を除く残部（減圧残油）であってよい。ストレートアスファルトの品質は、日本産業規格（ＪＩＳ　Ｋ２２０７）によって規定される。例えば、ストレートアスファルトは、ストレートアスファルト４０－６０、ストレートアスファルト６０－８０、ストレートアスファルト８０－１００及びストレートアスファルト１５０－２００からなる群より選ばれる少なくとも一種のアスファルトであってよい。 Straight asphalt is a bituminous substance obtained by vacuum distillation of crude oil. That is, the straight asphalt may be the remainder (vacuum residue) of crude oil excluding the light fraction. The quality of straight asphalt is defined by Japanese Industrial Standards (JIS K2207). For example, straight asphalt may be at least one kind of asphalt selected from the group consisting of straight asphalt 40-60, straight asphalt 60-80, straight asphalt 80-100 and straight asphalt 150-200.
　プラスチック以外の物質からなる骨材（非プラスチック骨材）は、例えば、砕石、石粉、石灰、砂、砂利及び鉄鋼スラグからなる群より選ばれる少なくとも一種の骨材であってよい。骨材における非プラスチック骨材の割合は、０質量％以上１００質量％以下、０質量％以上５０質量％以下、又は０質量％以上１５質量％以下であってよい。つまり、舗装用アスファルト混合物における非プラスチック骨材の割合は、舗装用アスファルト混合物に含まれる全ての骨材の質量の合計に対して、０質量％以上１００質量％以下、０質量％以上５０質量％以下、又は０質量％以上１５質量％以下であってよい。 The aggregate made of substances other than plastic (non-plastic aggregate) may be, for example, at least one aggregate selected from the group consisting of crushed stone, stone dust, lime, sand, gravel, and steel slag. The proportion of the non-plastic aggregate in the aggregate may be 0% to 100% by mass, 0% to 50% by mass, or 0% to 15% by mass. In other words, the proportion of non-plastic aggregate in the asphalt mixture for paving is 0% by mass or more and 100% by mass or less, 0% by mass or more and 50% by mass with respect to the total mass of all aggregates contained in the asphalt mixture for paving or less, or 0% by mass or more and 15% by mass or less.
　舗装用アスファルト混合物中の骨材（プラスチック骨材及び非プラスチック骨材）の含有量は、６４．０質量％以上９５．０質量％以下、又は６６．７質量％以上８７．０質量％以下であってよい。
　舗装用アスファルト混合物中のアスファルトバインダーの含有量は、５．０質量％以上３６．０質量％以下、又は１３．０質量％以上３３．３質量％以下であってよい。
　舗装用アスファルト混合物中の熱可塑性樹脂の含有量は、０．７質量％以上２５．２質量％以下、１．９質量％以上１６．７質量％以下、又は０．９質量％以上１４．５質量％以下であってよい。
　舗装用アスファルト混合物中のストレートアスファルトの含有量は、１．５質量％以上３０．６質量％以下、６．５質量％以上２８．３質量％以下、又は４．８質量％以上２８．３質量％以下であってよい。
　舗装用アスファルト混合物中の各成分の含有量が上記の範囲内である場合、舗装が大きい動的安定度を有し易く、アスファルト混合物からのアスファルトバインダーの滲み出しが抑制され易い。 The content of aggregate (plastic aggregate and non-plastic aggregate) in the asphalt mixture for paving is 64.0% by mass or more and 95.0% by mass or less, or 66.7% by mass or more and 87.0% by mass or less. It can be.
The content of the asphalt binder in the paving asphalt mixture may be from 5.0% to 36.0% by weight, or from 13.0% to 33.3% by weight.
The content of the thermoplastic resin in the asphalt mixture for paving is 0.7% by mass or more and 25.2% by mass or less, 1.9% by mass or more and 16.7% by mass or less, or 0.9% by mass or more and 14.5% by mass. % by mass or less.
The content of straight asphalt in the asphalt mixture for paving is 1.5% by mass or more and 30.6% by mass or less, 6.5% by mass or more and 28.3% by mass or less, or 4.8% by mass or more and 28.3% by mass. % or less.
When the content of each component in the asphalt mixture for pavement is within the above range, the pavement tends to have high dynamic stability, and the exudation of the asphalt binder from the asphalt mixture tends to be suppressed.
　アスファルトバインダー及び舗装用アスファルト混合物のうち少なくとも一方は、スチレン－ブタジエン－スチレンブロック共重合体（ＳＢＳ）、スチレン－イソプレン－スチレンブロック共重合体（ＳＩＳ）、及びスチレン－エチレン－ブチレン－スチレンブロックブロック共重合体（ＳＥＢＳ）からなる群より選ばれる少なくとも一種の熱可塑性エラストマーを更に含んでよい。ただし、本実施形態に係るアスファルトバインダー中の熱可塑性樹脂の含有量は、上記の熱可塑性エラストマーを除く熱可塑性樹脂の含有量を意味する。 At least one of the asphalt binder and the paving asphalt mixture comprises a styrene-butadiene-styrene block copolymer (SBS), a styrene-isoprene-styrene block copolymer (SIS), and a styrene-ethylene-butylene-styrene block copolymer. It may further contain at least one thermoplastic elastomer selected from the group consisting of polymers (SEBS). However, the content of the thermoplastic resin in the asphalt binder according to the present embodiment means the content of the thermoplastic resin excluding the thermoplastic elastomer.
　アスファルトバインダーは、ストレートアスファルト及び熱可塑性樹脂等の上記成分を１６０～２４０℃で加熱しながら混合することによって製造されてよい。上記の温度での混合により、熱可塑性樹脂がストレートアスファルト中に融解し易く、アスファルトバインダー中に残存する軽質油の燃焼を抑制することができる。 The asphalt binder may be produced by mixing the above components such as straight asphalt and thermoplastic resin while heating at 160-240°C. By mixing at the above temperature, the thermoplastic resin is easily melted in the straight asphalt, and combustion of light oil remaining in the asphalt binder can be suppressed.
　舗装用アスファルト混合物は、アスファルトバインダー及び骨材等の上記成分を１６０～２００℃で加熱しながら混合することによって製造されてよい。
　舗装用アスファルト混合物がプラスチック骨材を含む場合、舗装用アスファルト混合物は、アスファルトバインダー及びプラスチック骨材等の上記成分を、プラスチック骨材の融点未満である温度（例えば、１３０～１６０℃）で加熱しながら混合することによって製造されてよい。融点未満である温度での混合により、プラスチック骨材の溶融を抑制することができる。 A paving asphalt mixture may be produced by mixing the above components, such as the asphalt binder and aggregate, with heating at 160-200°C.
When the paving asphalt mixture contains plastic aggregate, the paving asphalt mixture heats the above components, such as the asphalt binder and plastic aggregate, at a temperature that is below the melting point of the plastic aggregate (for example, 130 to 160 ° C). may be produced by mixing while Mixing at a temperature below the melting point can inhibit melting of the plastic aggregate.
　本発明は必ずしも上述された実施形態に限定されるものではない。本発明の趣旨を逸脱しない範囲において、本発明の種々の変更が可能であり、これ等の変更例も本発明に含まれる。 The present invention is not necessarily limited to the embodiments described above. Various modifications of the present invention are possible without departing from the gist of the present invention, and these modifications are also included in the present invention.
　以下の実施例及び比較例により、本発明が詳細に説明される。本発明は以下の実施例によって限定されるものではない。 The present invention will be described in detail with the following examples and comparative examples. The invention is not limited by the following examples.
　以下に記載のストレートアスファルト（Ａｓｐ）は、ストレートアスファルト６０－８０を意味する。
　以下に記載のプラスチック骨材（ＰＳ）は、ポリスチレンからなる骨材を意味する。プラスチック骨材（ＰＳ）は、産業廃棄物（廃プラスチック）のマテリアルリサイクルによって製造された円柱状のペレットである。
　以下に記載の密粒１３（砕石）は、密粒度アスファルト混合物１３用の粗骨材及び細骨材を意味する。密粒１３は、非プラスチック骨材である。
　以下に記載の改質アスファルトは、舗装設計施工指針によって規定されたポリマー改質アスファルトＩＩ型を意味する。舗装設計施工指針は、社団法人日本道路協会によって発行される。 Straight asphalt (Asp) mentioned below means straight asphalt 60-80.
The plastic aggregate (PS) mentioned below means an aggregate consisting of polystyrene. Plastic aggregates (PS) are cylindrical pellets produced by material recycling of industrial waste (waste plastic).
Dense-grained 13 (crushed stone), described below, refers to coarse and fine aggregates for the dense-grained asphalt mixture 13 . Dense grains 13 are non-plastic aggregates.
Modified asphalt described below means polymer modified asphalt type II as defined by pavement design and construction guidelines. Pavement Design and Construction Guidelines are issued by the Japan Road Association.
　ストレートアスファルト、及びリニアポリエチレン（Ｌ－ＬＤＰＥ）を含む低密度ポリエチレン（ＬＤＰＥ）の混合により、実施例１～８に用いるアスファルトバインダーが調製された。アスファルトバインダー中のストレートアスファルトの含有量は、８５質量％であった。アスファルトバインダー中の低密度ポリエチレン（Ｌ－ＬＤＰＥを含むＬＤＰＥ）の含有量は、１５質量％であった。アスファルトバインダー中の低密度ポリエチレンの含有量は、下記表１においてＬＤＰＥ／(Ａｓｐ＋ＬＤＰＥ)と表記される。 The asphalt binders used in Examples 1-8 were prepared by mixing straight asphalt and low density polyethylene (LDPE), including linear polyethylene (L-LDPE). The content of straight asphalt in the asphalt binder was 85% by mass. The content of low density polyethylene (LDPE including L-LDPE) in the asphalt binder was 15% by weight. The content of low density polyethylene in the asphalt binder is expressed as LDPE/(Asp+LDPE) in Table 1 below.
　ストレートアスファルト及び低密度ポリエチレン（ＬＤＰＥ）の混合により、実施例９に用いるアスファルトバインダーが調製された。アスファルトバインダー中のストレートアスファルトの含有量は、７０質量％であった。アスファルトバインダー中の低密度ポリエチレンの含有量は、３０質量％であった。実施例９に用いられた低密度ポリエチレン（ＬＤＰＥ）は、リニアポリエチレン（Ｌ－ＬＤＰＥ）を含んでいなかった。 The asphalt binder used in Example 9 was prepared by mixing straight asphalt and low density polyethylene (LDPE). The content of straight asphalt in the asphalt binder was 70% by mass. The content of low density polyethylene in the asphalt binder was 30% by weight. The low density polyethylene (LDPE) used in Example 9 did not contain linear polyethylene (L-LDPE).
　ストレートアスファルト及び低密度ポリエチレン（ＬＤＰＥ）の混合により、実施例１０に用いるアスファルトバインダーが調製された。アスファルトバインダー中のストレートアスファルトの含有量は、３７．３質量％であった。アスファルトバインダー中の低密度ポリエチレンの含有量は、６２．７質量％であった。実施例１０に用いられた低密度ポリエチレン（ＬＤＰＥ）も、リニアポリエチレン（Ｌ－ＬＤＰＥ）を含んでいなかった。 The asphalt binder used in Example 10 was prepared by mixing straight asphalt and low density polyethylene (LDPE). The content of straight asphalt in the asphalt binder was 37.3% by mass. The content of low density polyethylene in the asphalt binder was 62.7% by weight. The low density polyethylene (LDPE) used in Example 10 also did not contain linear polyethylene (L-LDPE).
　ストレートアスファルト、及びリニアポリエチレン（Ｌ－ＬＤＰＥ）を含む低密度ポリエチレン（ＬＤＰＥ）の混合により、比較例６に用いるアスファルトバインダーが調製された。アスファルトバインダー中のストレートアスファルトの含有量は、９５質量％であった。アスファルトバインダー中の低密度ポリエチレン（Ｌ－ＬＤＰＥを含むＬＤＰＥ）の含有量は、５質量％であった。 The asphalt binder used in Comparative Example 6 was prepared by mixing straight asphalt and low density polyethylene (LDPE) containing linear polyethylene (L-LDPE). The content of straight asphalt in the asphalt binder was 95% by mass. The content of low-density polyethylene (LDPE including L-LDPE) in the asphalt binder was 5% by mass.
　ストレートアスファルト、及びリニアポリエチレン（Ｌ－ＬＤＰＥ）を含む低密度ポリエチレン（ＬＤＰＥ）の混合により、比較例７に用いるアスファルトバインダーが調製された。アスファルトバインダー中のストレートアスファルトの含有量は、９０質量％であった。アスファルトバインダー中の低密度ポリエチレン（Ｌ－ＬＤＰＥを含むＬＤＰＥ）の含有量は、１０質量％であった。 The asphalt binder used in Comparative Example 7 was prepared by mixing straight asphalt and low density polyethylene (LDPE) containing linear polyethylene (L-LDPE). The content of straight asphalt in the asphalt binder was 90% by mass. The content of low density polyethylene (LDPE including L-LDPE) in the asphalt binder was 10% by weight.
　アスファルトバインダー及びプラスチック骨材の混合により、実施例１～５、９、１０、比較例６及び７其々の舗装用アスファルト混合物が調製された。 By mixing the asphalt binder and plastic aggregate, paving asphalt mixtures of Examples 1 to 5, 9, 10 and Comparative Examples 6 and 7 were prepared.
　アスファルトバインダー及び密粒１３の混合により、実施例６及び７其々の舗装用アスファルト混合物が調製された。アスファルトバインダー、密粒１３及び石粉の混合により、実施例８の舗装用アスファルト混合物が調製された。 The paving asphalt mixtures of Examples 6 and 7, respectively, were prepared by mixing the asphalt binder and dense granules 13. The paving asphalt mixture of Example 8 was prepared by mixing asphalt binder, dense granules 13 and stone flour.
　以下の比較例１～５其々の舗装用アスファルト混合物は、上記のアスファルトバインダーを用いることなく作製された。 The pavement asphalt mixtures of Comparative Examples 1 to 5 below were prepared without using the above asphalt binder.
　ストレートアスファルト、密粒１３及び石粉の混合により、比較例１の舗装用アスファルト混合物が調製された。 A paving asphalt mixture of Comparative Example 1 was prepared by mixing straight asphalt, dense grain 13 and stone dust.
　改質アスファルト及びプラスチック骨材の混合により、比較例２及び３其々の舗装用アスファルト混合物が調製された。 By mixing modified asphalt and plastic aggregate, paving asphalt mixtures of Comparative Examples 2 and 3 were prepared.
　改質アスファルト、プラスチック骨材及び石粉の混合により、比較例４及び５其々の舗装用アスファルト混合物が調製された。 By mixing modified asphalt, plastic aggregate and stone dust, paving asphalt mixtures of Comparative Examples 4 and 5 were prepared.
　実施例１～１０及び比較例１～７其々の舗装用アスファルト混合物の組成は、下記表１に示される組成に調整された。下記表１に記載の「混合物」は、舗装用アスファルト混合物を意味する。 The compositions of the pavement asphalt mixtures of Examples 1-10 and Comparative Examples 1-7 were adjusted to the compositions shown in Table 1 below. "Mixture" in Table 1 below means a paving asphalt mixture.
　下記の３つの試験により、実施例１～１０及び比較例１～７其々の舗装用アスファルト混合物が評価された。 The paving asphalt mixtures of Examples 1-10 and Comparative Examples 1-7 were evaluated by the following three tests.
＜ダレ試験（規格番号：舗装調査・試験法便覧Ｂ００９）＞
　ダレ試験では、ある一定量のアスファルトバインダーをアスファルト混合物へ添加した際に、アスファルト混合物から滲み出す余剰のアスファルトバインダーが観測された。
　ダレ試験は、実施例１～１０其々のアスファルト混合物からのアスファルトバインダーの滲み出しが十分に抑制されていることを実証した。
　一方、比較例６の場合、多量のアスファルトバインダーがアスファルト混合物から滲み出した。比較例７の場合、若干量のアスファルトバインダーがアスファルト混合物から滲み出した。特に比較例６の場合、アスファルト混合物は不安定であったので、後述されるカンタブロ試験及びホイールトラッキング試験は実施されなかった。比較例７の場合も、アスファルト混合物からのアスファルトバインダーの滲み出しが十分に抑制されなかったので、後述されるカンタブロ試験及びホイールトラッキング試験は実施されなかった。 <Sagging test (standard number: pavement survey and test method manual B009)>
In the sag test, excess asphalt binder was observed to exude from the asphalt mixture when a certain amount of asphalt binder was added to the asphalt mixture.
The sagging test demonstrated that the exudation of the asphalt binder from each of the asphalt mixtures of Examples 1-10 was sufficiently suppressed.
On the other hand, in the case of Comparative Example 6, a large amount of asphalt binder exuded from the asphalt mixture. In the case of Comparative Example 7, some amount of asphalt binder was exuded from the asphalt mixture. Especially in the case of Comparative Example 6, the asphalt mixture was unstable, so the Cantabro test and wheel tracking test described below were not performed. In the case of Comparative Example 7 as well, the seepage of the asphalt binder from the asphalt mixture was not sufficiently suppressed, so the Cantabro test and wheel tracking test, which will be described later, were not carried out.
＜カンタブロ試験（規格番号：舗装調査・試験法便覧Ｂ０１０）＞
　円柱状の試料が、舗装用アスファルト混合物から形成された。試料の質量Ｍｉが測定された。質量Ｍｉの測定後、試料がロサンゼルス試験機（回転可能なドラム）に容れられた。常温の環境下で、試料が収容されたロサンゼルス試験機を３００回回転させた。ロサンゼルス試験機の回転速度は、３０～３３回／分に調整された。ロサンゼルス試験機が３００回回転した後、ロサンゼルス試験機から取り出された試料の質量Ｍｆが測定された。下記の数式１により、カンタブロ損失率Ｒが算出された。
Ｒ＝１００×（Ｍｉ－Ｍｆ）／Ｍｉ　　　（１）
　実施例１～１０及び比較例１～５其々のカンタブロ損失率（単位：％）は、下記表１に示される。アスファルトバインダーが骨材同士を結着する力が大きいほど、ロサンゼルス試験機の回転に伴う試料からの骨材の脱離が抑制され、試料の質量は減少し難い。つまり、アスファルトバインダーが骨材同士を結着する力が大きいほど、カンタブロ損失率は小さい。カンタブロ損失率が小さいほど、車両の通行に伴う舗装からの骨材の脱離が起き難い。したがって、カンタブロ損失率は小さいことが好ましい。 <Cantabro test (standard number: pavement survey and test method manual B010)>
Cylindrical specimens were formed from paving asphalt mixtures. The mass Mi of the sample was measured. After measuring the mass Mi, the sample was placed in a Los Angeles tester (rotatable drum). The Los Angeles testing machine containing the sample was rotated 300 times in a room temperature environment. The rotation speed of the Los Angeles tester was adjusted to 30-33 rpm. After 300 rotations of the Los Angeles tester, the mass Mf of the sample removed from the Los Angeles tester was measured. The Cantabro loss rate R was calculated by the following formula 1.
R=100×(Mi−Mf)/Mi (1)
The Cantablo loss rate (unit: %) of each of Examples 1-10 and Comparative Examples 1-5 is shown in Table 1 below. As the strength of the asphalt binder to bind the aggregates together is greater, the detachment of the aggregates from the sample due to the rotation of the Los Angeles tester is suppressed, and the mass of the sample is less likely to decrease. That is, the greater the strength of the asphalt binder to bind the aggregates together, the smaller the Cantabro loss rate. The smaller the Cantabro loss rate, the more difficult it is for aggregates to detach from pavement due to vehicle traffic. Therefore, it is preferable that the Cantabro loss factor is small.
＜ホイールトラッキング試験（規格番号：舗装調査・試験法便覧Ｂ００３）＞
　舗装（平坦な試料）が、舗装用アスファルト混合物から形成された。ソリッドゴム製のタイヤを試料の平坦な表面に押し当てることにより、荷重（０．６３ＭＰａ）が試料の表面に加えられた。荷重を試料の表面に加えながら、４２回±１回／分の速さで、タイヤを前後方向において往復させた。試料の温度を６０℃に維持しながらタイヤの往復が６０分間繰り返された。タイヤの往復を開始してから４５分経過した時点Ｔｉにおいて、試料の表面に形成された轍の深さＤｉ（単位：ｍｍ）が測定された。タイヤの往復を開始してから６０分経過した時点Ｔｆにおいて、試料の表面に形成された轍の深さＤｆが測定された。下記の数式２により、動的安定度Ｓが算出された。数式２中のＮは、時点Ｔｉから時点Ｔｆまでのタイヤの往復回数（単位：回）である。
Ｓ＝Ｎ／（Ｄｆ－Ｄｉ）　　　（２）
　実施例１～１０及び比較例１～５其々の動的安定度（単位：回／ｍｍ）は、下記表１に示される。動的安定度が大きいほど、車両の通行に伴う舗装の流動が抑制され、轍が形成され難い。したがって、動的安定度は大きいことが好ましい。下記表１に示される「ＮＧ」は、わずか数分の間に深い轍が試料の表面に形成されたことを意味する。つまり、比較例２～５其々の舗装用アスファルト混合物は、動的安定度において、実施例１～１０其々の舗装用アスファルト混合物に著しく劣っていた。 <Wheel tracking test (standard number: pavement survey and test method manual B003)>
Pavements (flat samples) were formed from paving asphalt mixtures. A load (0.63 MPa) was applied to the surface of the sample by pressing a solid rubber tire against the flat surface of the sample. While applying a load to the surface of the sample, the tire was reciprocated in the longitudinal direction at a speed of 42 times ±1 time/min. The tire cycle was repeated for 60 minutes while maintaining the temperature of the sample at 60°C. The depth Di (unit: mm) of the rut formed on the surface of the sample was measured at time Ti, 45 minutes after the start of reciprocation of the tire. The depth Df of the rut formed on the surface of the sample was measured at time Tf, 60 minutes after the start of reciprocation of the tire. The dynamic stability S was calculated by Equation 2 below. N in Equation 2 is the number of reciprocations (unit: times) of the tire from time Ti to time Tf.
S=N/(Df−Di) (2)
The dynamic stability (unit: times/mm) of Examples 1 to 10 and Comparative Examples 1 to 5 are shown in Table 1 below. The greater the dynamic stability, the more the flow of the pavement due to the passage of vehicles is suppressed, and the less likely ruts are formed. Therefore, high dynamic stability is preferred. "NG" shown in Table 1 below means that deep ruts were formed on the surface of the sample in just a few minutes. In other words, the paving asphalt mixtures of Comparative Examples 2-5, respectively, were significantly inferior to the paving asphalt mixtures of Examples 1-10, respectively, in dynamic stability.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　例えば、本発明に係るアスファルトバインダーは、舗装用アスファルト混合物の成分として用いられる。

  For example, the asphalt binder according to the invention is used as a component of paving asphalt mixtures.

Claims (8)

  1. 　ストレートアスファルト及び熱可塑性樹脂を備え、
    　前記熱可塑性樹脂の含有量が、１５質量％以上である、
    アスファルトバインダー。     Equipped with straight asphalt and thermoplastic resin,
    The content of the thermoplastic resin is 15% by mass or more,
    asphalt binder.
  2. 　少なくとも一部の前記熱可塑性樹脂が、低密度ポリエチレン、リニアポリエチレン及び高密度ポリエチレンからなる群より選ばれる少なくとも一種のポリオレフィンである、
    請求項１に記載のアスファルトバインダー。     At least part of the thermoplastic resin is at least one polyolefin selected from the group consisting of low-density polyethylene, linear polyethylene and high-density polyethylene,
    The asphalt binder according to claim 1.
  3. 　前記熱可塑性樹脂が前記ストレートアスファルト中に融解している、
    請求項１に記載のアスファルトバインダー。     the thermoplastic resin is melted in the straight asphalt;
    The asphalt binder according to claim 1.
  4. 　プラスチックを含む骨材を備える舗装用アスファルト混合物に用いられる、
    請求項１に記載のアスファルトバインダー。     used in paving asphalt mixtures with plastic-containing aggregates,
    The asphalt binder according to claim 1.
  5. 　請求項１～４のいずれか一項に記載のアスファルトバインダーと、骨材と、を備える、舗装用アスファルト混合物。 An asphalt mixture for paving, comprising the asphalt binder according to any one of claims 1 to 4 and an aggregate.
  6. 　少なくとも一部の前記骨材が、プラスチックである、
    請求項５に記載の舗装用アスファルト混合物。     at least some of the aggregates are plastic;
    A paving asphalt mixture according to claim 5 .
  7. 　少なくとも一部の前記プラスチックが、廃プラスチックである、
    請求項６に記載の舗装用アスファルト混合物。     at least a portion of the plastic is waste plastic
    A paving asphalt mixture according to claim 6 .
  8. 　前記骨材における前記プラスチックの割合が、５０質量％以上である、
    請求項６に記載の舗装用アスファルト混合物。     The proportion of the plastic in the aggregate is 50% by mass or more,
    A paving asphalt mixture according to claim 6 .
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JP2002322604A (en) * 2001-04-25 2002-11-08 San & Shii Consultant Kk Manufacturing method for binder for pavement, pavement method and binder material
JP2004218283A (en) * 2003-01-15 2004-08-05 Koichiro Kimura Binder for pavement, water permeable resin mortar for pavement, and function-retaining and reinforcing method of drainable pavement
JP2006143954A (en) * 2004-11-24 2006-06-08 Hiroshima Industrial Promotion Organization Modified asphalt, manufacturing method of modified asphalt and asphalt mixture
JP2011148928A (en) * 2010-01-22 2011-08-04 Fukuda Road Construction Asphalt mixture
CN103804927A (en) * 2012-11-07 2014-05-21 中国石油化工股份有限公司 Asphalt mixture modifier and preparation method thereof
CN103923473A (en) * 2013-01-15 2014-07-16 上海市政工程设计研究总院（集团）有限公司 Environment-friendly asphalt mixture warm mix modifier and preparation method thereof
CN103709770A (en) * 2013-12-26 2014-04-09 中华人民共和国泰州出入境检验检疫局 Polyethylene/rubber powder blend modified asphalt and preparation method thereof

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