Paving composition and method for producing the same

Abstract

Paving compositions and methods for making the same are provided. In an exemplary embodiment, the paving composition includes a binder, the binder including bitumen, recycled plastic, and a performance-enhancing additive. The performance-enhancing additive is selected from the group consisting of low molecular weight polyolefins, glycidyl compounds, and combinations thereof. The low molecular weight polyolefins have a weight average molecular weight of about 500 to about 30,000 daltons. The glycidyl compounds include ethylene glycidyl (meth)acrylate polymers having a weight average molecular weight of about 500 to about 30,000 daltons.

Description

[Technical Field]

[0001] The present disclosure relates generally to paving compositions and methods for making the same. More particularly, the paving compositions include bitumen and reclaimed plastic, and performance-enhancing additives facilitate the incorporation of the reclaimed plastic into the paving composition. [Background technology]

[0002] In 2015, the United States generated 34.5 million tons of plastic waste, of which 9.1 percent was recycled. In 2018, the United States generated 38.5 million tons of plastic waste, of which 4.4 percent was recycled. Projections for 2019 are for 40 million tons of plastic waste, with a recycling rate of 2.9 percent. The Plastics Industry Association is leading an effort to identify end markets for recycled plastics. Their market research report indicates that the U.S. asphalt market is large enough to use up all recyclable polyethylene film in the United States. One of the major challenges with recycling polyethylene film in bitumen binders used in asphalt is the poor storage stability of bitumen binders containing recycled polyethylene. This poor storage stability dramatically limits the application of recycled plastics in asphalt.

[0003] Therefore, it would be desirable to find materials and processes that improve the storage stability of bitumen binders containing recycled waste polyethylene. It would also be desirable to find materials and methods for incorporating plastic waste into asphalt compositions. Furthermore, other desirable features and characteristics of the present embodiments will become apparent from the following detailed description and the appended claims, taken in conjunction with this background. Summary of the Invention

[0004] Paving compositions and methods for making the same are provided. In an exemplary embodiment, the paving composition includes a binder, the binder including bitumen, recycled plastic, and a performance-enhancing additive. The performance-enhancing additive is selected from the group consisting of low molecular weight polyolefins, glycidyl compounds, and combinations thereof. The low molecular weight polyolefins have a weight average molecular weight of about 500 to about 30,000 daltons. The glycidyl compounds include ethylene glycidyl (meth)acrylate polymers having a weight average molecular weight of about 500 to about 30,000 daltons.

[0005] In another embodiment, a method for preparing a paving composition is provided. The method includes preparing a binder comprising bitumen, a performance-enhancing additive, and recycled plastic. The performance-enhancing additive is dissolved in the binder and is selected from the group consisting of low molecular weight polyolefins, glycidyl compounds, and combinations thereof. The low molecular weight polyolefins have a weight average molecular weight of about 500 to about 30,000 daltons. The glycidyl compounds include ethylene glycidyl (meth)acrylate polymers having a weight average molecular weight of about 500 to about 30,000 daltons. The recycled plastic is also dissolved in the binder. The binder is mixed with aggregate to form the paving composition, the aggregate being a solid material that can be distinguished from the binder by inspection.

[0006] In yet another embodiment, another paving composition is provided. The paving composition includes a binder, aggregate, and a performance-enhancing additive. The binder is present in an amount of about 1 to about 15 weight percent, based on the total weight of the paving composition, and includes bitumen. The aggregate is present in an amount of about 85 to 99 weight percent, and the aggregate is a solid material that can be distinguished from the binder by inspection. The aggregate includes about 1 to 100 weight percent plastic waste, based on the total weight of the aggregate. The performance-enhancing additive is selected from the group consisting of low molecular weight polyolefins, glycidyl compounds, and combinations thereof. The low molecular weight polyolefin has a weight average molecular weight of about 500 to about 30,000 daltons, and the glycidyl compound includes an ethylene glycidyl (meth)acrylate polymer, which has a weight average molecular weight of about 500 to about 30,000 daltons. [Brief explanation of the drawings]

[0007] The present embodiments are described below in conjunction with the following drawings: [Figure 1] Photographs of aggregates with bitumen coatings, Figures 1 and 2 containing 100% bitumen, and Figures 3 and 4 containing 97% bitumen and 3% low molecular weight polyethylene oxide. [Figure 2] Photographs of aggregates with bitumen coatings, Figures 1 and 2 containing 100% bitumen, and Figures 3 and 4 containing 97% bitumen and 3% low molecular weight polyethylene oxide. [Figure 3] Photographs of aggregates with bitumen coatings, Figures 1 and 2 containing 100% bitumen, and Figures 3 and 4 containing 97% bitumen and 3% low molecular weight polyethylene oxide. [Figure 4] Photographs of aggregates with bitumen coatings, Figures 1 and 2 containing 100% bitumen, and Figures 3 and 4 containing 97% bitumen and 3% low molecular weight polyethylene oxide. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following Detailed Description is merely exemplary in nature and is not intended to limit the various embodiments described herein or the application and uses of the embodiments. Moreover, there is no intention to be bound by any expressed or implied theory presented in the preceding Technical Field, Background, or Summary or the following Detailed Description.

[0009] Generally, recycled plastics can be incorporated into asphalt compositions in two different ways. In one method, recycled plastics are melted into a molten binder and become part of the binder. This is referred to herein as the "wet" process, and recycled plastics used in the wet process are referred to as "recycled plastics." Alternatively, plastic waste is added to the asphalt composition as a solid, and the binder flows around the plastic waste but does not significantly melt it, so that the particulate plastic waste remains separately identifiable from the binder in the asphalt composition. This is referred to herein as the "dry" process, and recycled plastics used in the dry process are referred to herein as "plastic waste" to distinguish the use of recycled plastics. Both wet and dry processes can also be used simultaneously. Both recycled plastics and waste plastics are recovered plastics previously used, such as by consumers or industrially, or are plant scrap. After use, recovered plastics are collected for reuse and recycling. In some embodiments, recovered plastics can be washed and / or sorted before reuse. As used herein, "asphalt composition" is a general term that includes compositions that include bitumen.

[0010] A technique is provided for improving the storage stability of asphalt compositions containing reclaimed plastics. The reclaimed plastics can be included in wet processes, dry processes, or both. In wet processes, bitumen and recycled plastics are melted together to form a binder, and performance-enhancing additives are used to enhance the storage stability of the binder. The performance-enhancing additives also provide other benefits, such as improved PG grades of the paving compositions, easier compaction, reduced bitumen content for cost savings, and higher mechanical strength, when compared to equivalent compositions without the performance-enhancing additives.

[0011] The performance-enhancing additive is selected from one or both of two components: (1) a low molecular weight polyolefin having a weight-average molecular weight of about 500 to about 30,000 daltons, and (2) a glycidyl compound, including an ethylene glycidyl (meth)acrylate polymer having a weight-average molecular weight of about 500 to about 30,000 daltons. The performance-enhancing additive allows for higher concentrations of recycled plastic to be incorporated into the binder and also improves the stability of binders containing recycled plastic. Plastic waste is used as a component of, or entirely as, the aggregate in a dry process where a binder is added to solid aggregate to form an asphalt composition. The performance-enhancing additive increases the density of the asphalt composition because it compacts more strongly and results in fewer and / or smaller air bubbles. The performance-enhancing additive also increases the coverage of the aggregate by the binder, thereby reducing the moisture sensitivity of the asphalt composition, resulting in a better paving or waterproofing composition.

[0012] The asphalt compositions described herein can be used for a variety of purposes. In some embodiments, the asphalt compositions are intended for use in road construction or other paving purposes, and much of the following description is directed to such paving asphalt compositions. Asphalt compositions intended for road construction or paving purposes are referred to herein as "paving compositions." However, the asphalt compositions described herein can also be used for roofing applications, including asphalt shingles and asphalt roofing membranes. The asphalt compositions may also be used in certain waterproofing products, such as waterproofing membranes suitable for applications to bridges, parking structures, promenade decks, walkways, bicycle paths, vertical narrow space barriers, underground structures, and the like. Asphalt compositions intended for use as waterproofing materials are referred to herein as "waterproofing compositions." The concentrations of bitumen, performance-enhancing additives, recycled plastics, aggregates, and other components may vary for different applications, but the inclusion of recycled plastics with improved storage stability is beneficial for all such asphalt compositions.

[0013] Paving compositions for paving purposes generally include two main components: a binder, which generally incorporates bitumen, and an aggregate, which historically has primarily incorporated minerals such as crushed stone, sand, gravel, dust, slag, and various recycled materials, which historically have not included plastic waste.

[0014] aggregate The term "aggregate," as used herein, includes components that can be distinguished from binders by inspection, which serve to bind and connect aggregates. Thus, crushed stone, gravel, slag, rock, dust, sand, various recycled materials, and other components that do not melt into binders are grouped together within the meaning of the term "aggregate." Distinction by inspection includes close inspection, and dust and fine particles are included within the definition of aggregate. However, inspection refers to visual inspection, not inspection without the use of a lens such as a microscope. The term "filler" is used to describe rock dust, lime, and other fine particulate materials that may optionally be included in paving compositions; these filler materials are included within the definition of "aggregate" herein, just as filler materials are a subset of aggregate. The composition, shape, size, and amount of aggregate are typically selected to fit various hot-mix designs, such as Superpave, Marshalls, Hveem, and others known in the art.

[0015] The aggregate may include plastic waste. In an exemplary embodiment, the aggregate includes plastic waste in an amount of about 0 to 100 weight percent based on the total weight of the aggregate. In alternative embodiments, the aggregate may include plastic waste in an amount of about 1 to about 100 weight percent, or about 5 to about 70 weight percent, or about 5 to about 40 weight percent based on the total weight of the aggregate. Generally, paving materials include aggregates having various size categories. The aggregate size distribution, or size sequence, is one of the most important characteristics in determining how a paving material will perform. Aggregates can be used in various size sequences, such as dense, gap, open, uniform, fine, coarse, or combinations of these. In an exemplary embodiment, large mineral aggregate particles (i.e., larger than about 5 millimeters (mm)) can be replaced with plastic waste to produce an aggregate having about 60 weight percent plastic waste particles having a particle size of about 5 to about 6 mm, based on the total weight of the aggregate, and can also include about 40 weight percent fine aggregate having a particle size of about 0.15 to about 5 mm, and up to about 3 weight percent filler (such as lime) having an average particle size of about 0.01 to about 1 mm. Embodiments including both mineral aggregate and plastic waste aggregate can have the mineral aggregate having a first particle size, and the plastic waste can have a different particle size or the same particle size.

[0016] In another exemplary embodiment, large mineral aggregate particles (i.e., greater than about 10 mm) can be replaced with plastic waste to produce an aggregate having about 9 weight percent plastic waste particles having a particle size of about 5 to about 6 mm, and can also include about 10 weight percent aggregate having a particle size of about 11 mm. This aggregate may also include about 32 weight percent aggregate having a particle size of about 6.3 mm, about 46 weight percent fine aggregate having a particle size of about 0.15 to about 5 mm, and up to about 3 weight percent filler (such as lime) having an average particle size of about 0.01 to about 1 mm, based on the total weight of the aggregate.

[0017] In an alternative embodiment, the plastic waste and mineral aggregate are mixed at a temperature above the melting point of the plastic waste. In this embodiment, the molten plastic waste coats the mineral aggregate to form a coated aggregate with the plastic waste substantially surrounding and encapsulating the mineral aggregate. The plastic waste may not completely encapsulate the mineral aggregate, and in some embodiments, a portion of the mineral aggregate may be exposed.

[0018] bitumen Bitumen is a component of the binder. As used herein, the term "bitumen" is as defined by ASTM and is a dark brown to black cement-like material whose major constituent is naturally occurring or petroleum-processed bitumen. Bitumen characteristically contains saturates, aromatics, resins, and asphaltenes. The terms "asphalt" and "bitumen" are often used interchangeably to refer to both natural and manufactured forms of the material, all of which are within the scope of the compositions and methods contemplated and described herein.

[0019] The types of bitumen suitable for use in the compositions and methods contemplated and described herein are not particularly limited and include any naturally occurring bitumen, synthetically produced bitumen, and modified bitumen known now or in the future. Naturally occurring bitumen includes bitumen such as natural rock asphalt, buton asphalt, uniter stone material, lake asphalt, etc. Synthetically produced bitumen is often a by-product of petroleum refining operations and includes airblown bitumen, blended bitumen, crack or residue bitumen, petroleum bitumen, propane bitumen, straight-run bitumen, thermal bitumen, etc. Bituminous binders include several types of bitumen (e.g., neat or unmodified bitumen, which may be naturally occurring or synthetically produced), and may be modified with elastomers, processing oils, tackifiers, phosphoric acid, polyphosphoric acid, plastomers, ground tire rubber (GTR), reclaimed asphalt pavement (RAP), reclaimed asphalt shingle (RAS), and other materials, or various combinations of these modifiers.

[0020] Additionally, industrial grade bitumens, including but not limited to paving grade bitumens, are advantageous for use in the compositions and methods contemplated and described herein. Non-exclusive examples of paving grade bitumens include, but are not limited to, bitumens (or asphalts) having any one of the following performance grade ratings: PG 46-40, PG 46-34, PG 52-40, PG 52-34, PG 52-28, PG-58-40, PG 58-34, PG 58-28, PG 64-40, PG 64-34, PG 64-28. , PG64-22, PG64-16, PG64-10, PG67-22, PG70-40, PG70-34, PG70-28, PG70-22, PG70-16, PG70-10, PG76-34, PG76-28, PG76-22, PG76-16, PG76-10, PG82-22, PG82-16, PG82-10, PG88-22, PG88-16, and PG88-10. Additionally, non-exclusive examples of paving-grade bitumen within the scope of the present disclosure include, but are not limited to, paving-grade bitumen (or asphalt) having any one of the following penetration grades: 50 / 70, 60 / 70, 60 / 90, 70 / 100, 80 / 110, 120 / 150, 150 / 180, 150 / 200, 160 / 220, 200 / 300, and 300+ dmm penetration.

[0021] It is contemplated that industrial-grade bitumen, such as roofing-grade asphalt or bitumen, can be advantageously used in the waterproofing compositions contemplated and described herein. In such embodiments, the binder composition is useful for roofing or other waterproofing applications. Suitable roofing-grade bitumen includes, but is not limited to, bitumen having any one of the following hardness grades: 50 / 70 decimeter penetration (dmm pen), 60 / 90 dmm pen, 70 / 100 dmm pen, 80 / 110 dmm pen, 120 / 150 dmm pen, 100 / 150 dmm pen, 150 / 200 dmm pen, 200 / 300 dmm pen, and 300+ dmm pen. Hardness grades are determined according to the test method set forth in ASTM D5. In some embodiments of the waterproofing composition, the bitumen is present in a concentration of about 40 to about 98 weight percent (wt. %), based on the total weight of the waterproofing composition. Bitumen may be present in different concentrations in the different waterproofing binder compositions described herein (i.e., binder compositions useful for (i) self-adhesive membranes, (ii) shingles, or (iii) other waterproofing compositions). For example, in binders useful for self-adhesive membranes, bitumen may be present in a concentration of about 50 to about 60 weight percent, or about 51 to about 57 weight percent, or about 53 to about 55 weight percent. In asphalt binders useful for shingles, bitumen may be present in a concentration of about 20 to about 50 weight percent, or about 25 to about 40 weight percent, or about 30 to about 35 weight percent. Other concentrations may be useful for different waterproofing products.

[0022] recycled plastic Recycled plastics can include many types of plastics. For example, recycled plastics may include, but are not limited to, one or more of polystyrene, polyolefins, polyvinyl chloride, polymers made from ethylene propylene diene monomer, ethylene vinyl acetate, polyester, polytetrafluoroethylene, polyurethane, polycarbonate, polyamide, polyimide, polyacrylamide, polymethacrylamide, and the like. Recycled plastics may be cleaned and subjected to sorting or other processes before use, such as to remove residues from previous uses of the plastic. Recycled plastics may be chopped, shredded, crushed, pelletized, or otherwise processed to produce desired sizes and shapes for further processing.

[0023] Recycled plastics may include plastics that have been numbered for recycling. These plastic categories are listed below and may form part or all of the recycled plastics in exemplary embodiments. However, other sources or recycled plastics may also be used.

[0024] Plastic classification. There are many different types and varieties of plastics, and many are recyclable. The Society of Plastics Industry (SPI) has established the following classification system:

[0025] Category 1: Polyethylene terephthalate (PET) and polyethylene terephthalate ester (PETE), more commonly known as "polyester." PETE fibers are manufactured under the trade names DACRON® (EI DuPont de Nemours & Co., Wilmington, Delaware, USA) and FORTREL® (Wellman, Inc., Fort Mill, SC, USA). PETE film is commonly known as MYLAR® (EI DuPont de Nemours & Co., Wilmington, Del., USA). Many foods are packaged with PETE, and most clear and colored 2-liter beverage bottles sold in grocery stores are made from PETE, except for the opaque base, which is typically made from high-density polyethylene (HDPE).

[0026] Category 2: High-density polyethylene (HDPE). HDPE is used in plastic milk bottles, water bottles, cosmetic containers, most plastic shopping bags, and trash bags.

[0027] Category 3: Polyvinyl chloride (PVC). The majority of PVC produced is used to make plastic pipes and conduits. PVC is also used to make vinyl siding and vinyl window and door frames. PVC is also used to wrap many items such as tools and toys, and is still used to make plastic bottles. PVC can be made flexible with the addition of phthalates, so that it can be used to make raincoats, shower curtains, and rubber boots.

[0028] Category 4: Low density polyethylene (LDPE). LDPE is used in the production of lightweight plastic films and for food and sandwich bags.

[0029] Category 5: Polypropylene (PP). Most PP is used in the manufacture of car and truck interiors such as doors and instrument panels, but some is also used in food packaging. Another important use is in fibers for clothing and carpets.

[0030] Category 6: Polystyrene (PS). Polystyrene is used to make polystyrene foam, which is used in packaging, insulation, and food wrap. PS is also used in clear, thin, rigid food containers, such as containers for salads and bakery products. Many household items, including broom handles, television cases, computer cases, and dry cosmetic containers, are made from PS.

[0031] Category 7 includes any plastic that does not fall into any of categories 1 to 6. These include polytetrafluoroethylene (PTFE), polyurethane (PU), polycarbonate (PC), polyamides (PA) such as nylon, and polyacrylamide and polymethacrylamide (PMA), which are used as absorbents in diapers and potting soil.

[0032] plastic waste The plastic waste used as aggregate in the paving composition can include unsorted plastics or sorted plastics. A paving composition can provide suitable performance and durability using a wide variety of different types of plastics, and the different types of plastics can be mixed or combined in almost any way. For example, the plastic waste aggregate in one portion of the paving composition may contain primarily one type of plastic, while the plastic waste aggregate in another portion of the same paving composition may contain primarily a different type of plastic, or a mixture of different types of plastics. In this way, unsorted plastic waste can be used as aggregate in the paving composition, thus avoiding the cost of sorting. However, in an alternative embodiment, sorted plastic waste may be used.

[0033] Plastic waste used as aggregate may be formed to a desired size, and a wide variety of techniques can be employed to form the aggregate to the desired size. If the plastic waste is too large, it can be reduced in size by shredding, crushing, grinding, or other techniques. If the plastic waste is too small, it can be pelletized or agglomerated by melting, partially melting, or compacting. For example, plastic waste used as aggregate may be formed into a material having an average particle size of about 20 to about 25 mm, although other average particle sizes are possible. In alternative embodiments, the average particle size of the plastic waste may be about 20 mm, or about 10 mm, or about 6 to 7 mm, or other sizes. In some embodiments, the plastic waste may have a wide range of particle sizes, with some particles being larger than others.

[0034] Replacing mineral aggregate with plastic waste has the added benefit of reducing the overall weight of the asphalt composition. For example, a standard paving composition contains approximately 88 weight percent mineral aggregate and approximately 12 weight percent bitumen, based on the total volume of the paving composition. A hypothetical paving composition containing approximately 12 volume percent bitumen and approximately 88 volume percent plastic waste aggregate, based on the total volume of the paving composition, is approximately 62% lighter than the same volume of standard paving composition containing approximately 88 volume percent mineral aggregate. In an exemplary embodiment of the paving composition, coarse mineral aggregate (20 mm, 10 mm, and 6.3 mm) was replaced by plastic waste aggregate (5-6 mm) on a volumetric basis, and the paving composition with plastic waste aggregate was approximately 32% lighter than the standard paving composition with coarse mineral aggregate. In a hypothetical example, by replacing mineral aggregate granules in a building shingle roofing board with plastic waste aggregate granules on a volumetric basis, the weight of the building shingle roofing board could be reduced by approximately 22%. Reducing the weight of the paving composition can help with transportation issues and provide other benefits: Reducing the weight of the shingles reduces the load on roof structuring, and similar benefits can be applied to other waterproofing structures.

[0035] recycled plastic The recycled plastic is melted and incorporated into the binder along with the bitumen. The particle size of the recycled plastic can vary widely due to the particles being melted to incorporate into the binder. Recycled plastics tend to reduce the storage stability of the binder, as determined by ASTM D7173, and testing has shown that some types of recycled plastics reduce binder stability more than others. For example, recycled low-density polyethylene can be incorporated into the binder at concentrations up to about 4 weight percent of the binder, based on the total weight of the binder, to form a stable product. However, polypropylene or other types of plastics may require lower concentrations to form a stable binder, or may not form a stable binder at any concentration. Therefore, the recycled plastic used for melting and incorporation into the binder may be selected so that, in one embodiment, the recycled plastic is about 50 weight percent or more polyethylene, based on the total weight of the recycled plastic. In alternative embodiments, the recycled plastic incorporated into the binder may be 70 weight percent polyethylene, or 80 weight percent polyethylene, or 90 weight percent polyethylene, or 95 weight percent polyethylene, or 98 weight percent polyethylene, or even 100 weight percent polyethylene, based on the total weight of the recycled plastic. Gel permeation chromatography can be effective in distinguishing recycled plastic from performance enhancing additives.

[0036] Performance-enhancing additives A performance-enhancing additive is incorporated into the binder along with the recycled plastic. The performance-enhancing additive is selected from a low molecular weight polyolefin, a glycidyl compound, or a combination thereof. The low molecular weight polyolefin has a weight average molecular weight of about 500 to about 30,000 daltons and can be referred to as a low molecular weight (LMW) polyolefin. "Low molecular weight polyolefin," as that term is used herein, means a polyolefin-containing polymer or a blend of two or more polyolefin-containing polymers, each of which has a weight average molecular weight (M) of about 500 to about 30,000 daltons. w ) and comprises one or more olefinic monomers, the olefinic monomers being selected from ethene, propene, butene, hexene, and octene. Thus, LMW polyolefins may be homopolymers containing only a single type of olefinic monomer, or copolymers containing two or more types of olefinic monomers. Furthermore, LMW polyolefins, as this term is used herein, include, but are not limited to, polyolefin waxes, i.e., polyolefins that are solid at or near room temperature and have low viscosity above their melting point. Some Fischer-Tropsch waxes, i.e., those that meet the above-defined properties of low molecular weight polyolefins but are produced from carbon monoxide and hydrogen, may also be used in the asphalt compositions contemplated and described herein.

[0037] Pyrolytic waxes are also examples of LMW polyolefins, and as noted above, pyrolytic waxes have a weight average molecular weight limit of about 500 to about 30,000 daltons. Pyrolytic waxes can be formed from virgin polymers or recycled polymers, in various embodiments.

[0038] In some embodiments, the low molecular weight polyolefin may be functionalized, in which case the low molecular weight polyolefin may be a functionalized homopolymer or copolymer. In exemplary embodiments, the functionalized low molecular weight polyolefin comprises one or more functional groups, including, but not limited to, acids, esters, amines, amides, ethers, and anhydrides, such as maleic anhydride. Additionally, the low molecular weight polyolefin may be oxidized.

[0039] In an exemplary embodiment, the LMW polyolefin is oxidized high-density polyethylene. High-density polyethylene has a density of about 0.93 to about 0.97 grams per cubic centimeter (g / cc) or greater, and oxidized high-density polyethylene has a density equal to or greater than high-density polyethylene, depending on the degree of oxidation. Exemplary oxidized high-density polyethylenes have densities of at least 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or 1.00 g / cc. In contrast, low-density polyethylenes have densities of about 0.91 to about 0.93 g / cc. Low-density polyethylenes tend to contain multiple branches in the polymer chain, while high-density polyethylenes have minimal polymer branching. Oxidized polyethylene is the reaction product of polyethylene and oxygen and can be produced by a variety of techniques. Oxidized polyolefins have an acid number, defined as the amount of potassium hydroxide in milligrams required to neutralize one gram of polyolefin under specified conditions. One set of fixed conditions is, for example, ASTM 1386-83.

[0040] In exemplary embodiments, the low molecular weight polyolefin has an olefin content of about 50 to about 100 weight percent, based on the total weight of the low molecular weight polyolefin. Exemplary low molecular weight polyolefins have an olefin content, in weight percent, of at least about 55, 60, 65, 70, 75, 80, 85, 90, or 95 weight percent, and independently, up to about 100, 98, 95, 92, 90, 85, 80, or 75 weight percent, based on the total weight of the low molecular weight polyolefin.

[0041] As previously mentioned, in exemplary embodiments, the low molecular weight polyolefin has a weight average molecular weight (M) of about 500 to about 30,000 daltons. w In various embodiments, the low molecular weight polyolefin has an M of at least about 500, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, or 7,000, and independently, no more than about 30,000, 20,000, 15,000, 12,000, or 10,000. w (Daltons). When the low molecular weight polyolefin comprises a combination of two or more types of polyolefins, the M w may individually be within the above range of about 500 to about 30,000 daltons. The weight-average molecular weight of the low molecular weight polyolefins of the present disclosure can be determined by gel permeation chromatography (GPC), a technique commonly known in the art. For GPC, the sample to be measured may be dissolved in 1,2,4-trichlorobenzene at about 140°C and a concentration of about 2.0 mg / mL. The solution (200 microliters (μL)) is injected into a GPC containing two PLgel 5 micrometer (μm) Mixed-D (300 × 7.5 mm) columns held at about 140°C with a flow rate of about 1.0 mL / min. The instrument may be equipped with two detectors, such as a refractive index detector and a viscosity detector. The molecular weight (weight-average molecular weight, Mw) is determined using a calibration curve generated from a set of narrow Mw standards of linear polyethylene.

[0042] Generally, suitable low molecular weight polyolefins include, but are not limited to, polyethylene homopolymers, polypropylene homopolymers, copolymers of two or more of ethylene, propylene, butene, hexene, and octene, functionalized derivatives of the aforementioned homopolymers, functionalized derivatives of the aforementioned copolymers, or combinations of unfunctionalized and functionalized low molecular weight polyolefins. Some Fischer-Tropsch waxes, i.e., those that meet the above-defined properties of low molecular weight polyolefins but are produced from carbon monoxide and hydrogen, may also be used in the asphalt compositions contemplated and described herein. Examples of suitable functionalized low molecular weight polyolefins include, but are not limited to, maleated polyethylene, maleated polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, oxidized polypropylene, oxidized polyethylene, including oxidized low molecular weight polyethylene, and combinations thereof.

[0043] In an exemplary embodiment, the low molecular weight polyolefin is selected from the group consisting of polyethylene, oxidized polyethylene having an acid number of about 5 to about 40 milligrams of potassium hydroxide per gram (mg KOH / gm), polypropylene, maleated polypropylene, and combinations thereof. In alternative embodiments, the low molecular weight polyolefin is polyethylene, or oxidized polyethylene, or polypropylene, or maleated polypropylene, a copolymer of ethylene and propylene, or a combination thereof.

[0044] Glycidyl compounds include ethylene glycidyl (meth)acrylate polymers. The term "(meth)acrylate," as used herein, refers to acrylate compounds that may or may not contain methyl groups; thus, the term includes "...acrylate" and "...methacrylate." Ethylene glycidyl (meth)acrylate polymers may contain from about 4 to about 20 weight percent glycidyl (meth)acrylate and from about 80 to about 96 weight percent ethylene in the polymer. However, in alternative embodiments, the ethylene glycidyl (meth)acrylate polymer contains from about 2 to about 30 weight percent glycidyl (meth)acrylate and from about 70 to about 98 weight percent ethylene. The ethylene glycidyl (meth)acrylate polymer has a weight average molecular weight of from about 500 to about 30,000 daltons. Binder compositions containing glycidyl compounds often also contain polyphosphoric acid as a component.

[0045] The glycidyl compound may include an ethylene glycidyl (meth)acrylate copolymer, a terpolymer, a polymer having more than three types of monomers, or a mixture of the above compounds. In exemplary embodiments, the acrylate compound includes a polymer having two or more types of monomers, and the acrylate compound may be free of homopolymers. By "free" of homopolymers, we mean that the glycidyl compound may contain less than about 1 weight percent of homopolymers based on the total weight of the glycidyl compound. Additional monomer(s) in the polymer may include methyl (meth)acrylate, butyl (meth)acrylate, and similar compounds containing combinations thereof. Various glycidyl (meth)acrylate-based polymers may be effective in improving the storage stability of binders. Thus, ethylene glycidyl (meth)acrylate polymers may be formed from two or more monomers selected from the group consisting of ethylene, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate. The low molecular weight of about 500 to about 30,000 daltons is expected to provide improved storage stability compared to other glycidyl compositions, including ethylene glycidyl (meth)acrylate polymers having molecular weights greater than 30,000 daltons.

[0046] In different exemplary embodiments, the performance-enhancing additive includes a glycidyl compound without a polyolefin; a polyolefin without a glycidyl compound; and a combination of a glycidyl compound and a polyolefin. In exemplary embodiments, the combination of a glycidyl compound and a polyolefin more specifically includes a combination of an oxidized low-molecular-weight high-density polyethylene, a glycidyl compound, and polyphosphoric acid; a combination of a low-molecular-weight polypropylene, a glycidyl compound, and polyphosphoric acid; and a combination of a maleated polypropylene, a glycidyl compound, and polyphosphoric acid. Other specific combinations of polyolefins and glycidyl compounds are also possible.

[0047] additives The asphalt compositions described herein may, in some embodiments, include other additives. It is well known in the art that additional additives, such as plastomers, elastomers, or both, are used in asphalt compositions containing binders; these additives can extend the temperature range over which the asphalt composition can be used without serious failure or breakdown. Plastomers and elastomers are generally polymers of one type or another and may be used in asphalt compositions, such as binders in paving compositions, waterproofing compositions, or for other purposes. The asphalt compositions contemplated herein may optionally include one or more polymers other than the performance-enhancing additives, present in a total amount of about 0.5 to about 30 weight percent, based on the total weight of the asphalt composition. Non-limiting examples of polymers suitable for modifying the asphalt compositions contemplated herein include natural or synthetic rubbers, including ground tire rubber (GTR), devulcanized GTR, pulverized GTR, butyl rubber, styrene / butadiene rubber (SBR), styrene / ethylene / butadiene / styrene terpolymer (styrene / ethylene / butadiene / styrene (SEBS)), polybutadiene, polyisoprene, ethylene / propylene / diene (EPDM) terpolymer, and styrene / conjugated diene block or random copolymers, such as styrene / butadiene / styrene copolymer (SBS), styrene / isoprene, styrene / isoprene / styrene (SIS), and styrene / butadiene, including styrene / isoprene-butadiene block copolymers. Block copolymers may be branched or linear, and may be diblock, triblock, tetrablock, or multiblock. In addition to bitumen, performance enhancing additives, and recycled plastics, the binder can optionally include the polymers listed above, as well as other polymers used to improve performance.

[0048] The asphalt compositions contemplated herein may, in some embodiments, contain additional additives. Asphalt compositions include binders for paving compositions and waterproofing compositions, as well as other embodiments not specifically described. Non-exclusive examples of such additives suitable for inclusion in the asphalt compositions contemplated and described herein include, but are not limited to, plastomers, waxes (where waxes can also be polymers), polyphosphates, flux oils, plasticizers, antioxidants, tackifiers, processing aids, UV protection additives, and the like. Exemplary non-exclusive waxes include ethylene bis-stearamide wax (EBS), Fischer-Tropsch wax (FT) (not included in the definition of "polyolefin" provided herein), oxidized Fischer-Tropsch wax (FTO) (not included in the definition of "polyolefin" provided herein), alcohol waxes, silicone waxes, petroleum waxes, such as microcrystalline wax or paraffin, natural waxes, and other synthetic waxes. Exemplary plasticizers include hydrocarbon oils (e.g., paraffin, aromatic oils, and naphthenic oils), long-chain alkyl diesters (e.g., phthalates such as dioctyl phthalate and adipates such as dioctyl adipate), sebacates, glycols, fatty acids, phosphorus and stearates, epoxy plasticizers (e.g., epoxidized soybean oil), polyether and polyester plasticizers (which may be polymeric), alkyl monoesters (e.g., butyl oleate), long-chain partial ether esters (e.g., butyl oleate cellosolve), and others. Exemplary tackifiers include rosins and their derivatives; terpenes and modified terpenes; aliphatic, cycloaliphatic, and aromatic resins (C5 aliphatic resins, C9 aromatic resins, and C5 / C9 aliphatic / aromatic resins); hydrogenated hydrocarbon resins; terpene-phenolic resins; and combinations thereof.Exemplary oils include flax oils (e.g., paraffinic oils, aromatic oils, and naphthenic oils), bio-oils, corn oil, soybean oil, tall oil, reclaimed oil, remanufactured engine oil, recycled engine oil bottoms (REOB), and combinations thereof.

[0049] In exemplary embodiments, asphalt compositions, including paving compositions, waterproofing compositions, and other compositions, are cement-free. "Cement-free" means that the asphalt composition contains less than about 0.1 weight percent cement, based on the total weight of the asphalt composition. This means that the binder also contains less than about 0.1 weight percent cement. As used herein, cement includes, but is not limited to, normal Portland cement, high-early-strength Portland cement, extra-high-early-strength Portland cement, moderate-heat Portland cement, white Portland cement, blast-furnace cement, silica cement, alumina cement, expansive cement, blast-furnace colloidal cement, colloidal cement, ultra-rapid-setting cement, white cement, fly ash cement, sulfate-resistant cement, jet cement, and combinations thereof.

[0050] binder The binder includes bitumen, a performance-enhancing additive, and recycled plastic, as described above. In an exemplary embodiment, the binder includes the performance-enhancing additive in an amount of about 0.1 to about 5 weight percent and the recycled plastic in an amount of about 1 to about 20 weight percent, based on the total weight of the binder, as described above. For example, the binder may include about 0.1 to about 5 weight percent low molecular weight polyolefin and / or about 0.1 to about 5 weight percent glycidyl compound and about 0.1 to about 1 weight percent polyphosphoric acid, all based on the total weight of the binder. In alternative embodiments, the binder may include about 0.5 to about 5 weight percent low molecular weight polyolefin, or about 0.5 to about 3 weight percent low molecular weight polyolefin, based on the total weight of the binder. While the binder may be free of either the low molecular weight polyolefin or the glycidyl compound in various embodiments, the binder does not necessarily simultaneously include both the low molecular weight polyolefin and the glycidyl compound when used.

[0051] In exemplary embodiments, the low molecular weight polyolefin and / or glycidyl compound may be combined with the aggregate, and thus the binder may be free of both the low molecular weight polyolefin and the glycidyl compound before being mixed with the aggregate. However, at least a portion of the low molecular weight polyolefin and / or glycidyl compound then melts and dissolves in the aggregate in the final paving composition. Because some of the low molecular weight polyolefin and / or glycidyl compound may not dissolve in the binder and thus remain with the aggregate, the amount of the low molecular weight polyolefin and / or glycidyl compound may be increased to ensure sufficient dissolution into the binder for desired performance. The low molecular weight polyolefin may be functionalized in some embodiments, as described above. The binder may also optionally contain additives other than performance-enhancing additives and recycled plastics. Other optional additives may be included in amounts of 0 to about 30 weight percent based on the total weight of the binder. The binder includes bitumen in an amount of about 25 to about 99.9 weight percent based on the total weight of the binder. Recycled plastics can also be added to aggregate as reclaimed plastics to form part of the reinforcing aggregate. A portion of the reclaimed plastics may then be dissolved in the binder, in which case the reclaimed plastic dissolved in the binder is referred to herein as "recycled plastic," as described above. Any reclaimed plastics that do not dissolve in the binder remain with the aggregate as plastic waste and form part of the aggregate in the final paving composition. "Plastic waste," as described above, is the term used for reclaimed plastics that do not dissolve in the binder and function as aggregate in the paving composition.

[0052] Binders containing recycled plastic but without performance-enhancing additives tend to be unstable unless the binder contains very low concentrations of recycled plastic based on the total weight of the binder. For the low-density polyethylene recycled plastic used in this work, 4 weight percent low-density polyethylene, based on the total weight of the binder, forms a stable binder. If the recycled plastic contains polypropylene or other types of plastics other than low-density polyethylene, the binder tends to be unstable at even lower concentrations of recycled plastic, or may be unstable at all concentrations. Performance-enhancing additives increase the amount of recycled plastic that can be incorporated into a stable binder composition. Thus, in an exemplary embodiment, the binder may contain greater than 4 weight percent low-density polyethylene based on the total weight of the binder, and the binder also includes a performance-enhancing additive. For example, the binder may contain from about 4 to about 20 weight percent low-density polyethylene, in which case the polyethylene is recycled plastic. In another embodiment, the binder contains from about 4 to about 8 weight percent low-density polyethylene from recycled plastic.

[0053] Paving composition The paving composition is intended for use in roads, parking lots, driveways, and other similar structures. The paving composition is suitable for maintaining vehicular traffic. The paving composition includes a binder and aggregate, as described above. The binder is present in the paving composition in an amount of about 1 to about 15 weight percent, and the aggregate is present in an amount of about 85 to about 99 weight percent, based on the total weight of the paving composition.

[0054] The binder is stable, and a stable binder indicates that the top and bottom portions of the binder have approximately the same softening point. As used herein, a "stable binder" is defined by top and bottom samples having a softening point difference (absolute value) of 5°C or less. If the softening points of the top and bottom binder samples are within 5°C of each other, the binder is considered stable, regardless of which of the top and bottom samples has the higher softening point. Top and bottom binder samples are obtained using a separation test such as that described by ASTM D7173. The softening points of the top and bottom samples are then determined using a ring and ball softening point test. The ring and ball softening point test is described by ASTM D36. The ASTM D7173 separation test, or "Standard Practice for Determining the Separation Tendency of Polymer from Polymer Modified Asphalt," provides consistent sampling of the top and bottom portions of an asphalt composition, such as a binder. The Ring and Ball Softening Point Test, or ASTM D36, is a consistent method for measuring the softening point of asphalt compositions, such as binders. Other countries / regions use the complex modulus, G, to determine storage stability. * For example, the Qatar national specification may use Delta G. * <20%. However, for the purposes of this description, the definitions provided above will be used. A stable binder is important for producing paving compositions that provide consistent quality for the construction of roads, parking lots, and other structures intended to support automobiles.

[0055] Another important parameter of a binder is its workability, processability, or pumpability, which is determined by the binder's viscosity at or near about 135°C according to ASTM D4402. It is widely accepted by the global paving industry that the viscosity of a binder at or near 135°C should be less than about 3000 centipoise (cPs) to have acceptable workability, processability, or pumpability. Viscosities above about 3,000 cPs produce binders with poor workability, processability, and / or pumpability.

[0056] In an alternative embodiment, the paving composition includes aggregate, which includes plastic waste in an amount of up to 100 weight percent based on the total weight of the aggregate. For example, the aggregate in the paving composition may include about 1 to 100 weight percent plastic waste. The paving composition also includes a binder, which includes bitumen and a low molecular weight polyolefin performance-enhancing additive, although the binder may be free of recycled plastic. The binder may be free of glycidyl compounds. The binder may also include other additives, as described above. It has been found that a binder combined with a low molecular weight polyolefin provides better coverage of both the plastic waste aggregate and the mineral aggregate, producing a denser paving composition, compared to the same binder without the low molecular weight polyolefin described in the performance-enhancing additive.

[0057] waterproof composition Many different waterproofing compositions incorporating recycled plastic are possible. These include roofing membranes, shingles, and other waterproofing structures. Waterproofing compositions include a waterproof binder, sometimes a substrate, a facing layer, a backing layer, and other optional components. The substrate may be polyester mat, fiberglass mat, fiberglass-reinforced polyester mat, or other materials. The facing layer may be a granular material made from one or more of mineral grains, recycled plastic, sand, talc, paint, plastic film, metal film, etc. The backing layer may be sand, talc, plastic film, metal film, etc. Waterproofing compositions include a waterproof binder, which includes bitumen, recycled plastic, performance-enhancing additives, optional fillers, and optional other compounds. The waterproof binder includes recycled plastic in an amount of about 1 to about 20 weight percent, performance-enhancing additives in an amount of about 1 to about 10 weight percent, and fillers in an amount of 0 to 70 weight percent, based on the total weight of the waterproof binder. The waterproof binder may also include additional additives other than the recycled plastic and performance-enhancing additives in an amount of about 0 to about 40 weight percent based on the total weight of the waterproof binder. The waterproof composition may include other ingredients as well. For example, the shingles include at least one adhesive. The filler, in various embodiments, may be limestone, stone dust, fly ash, other materials, or combinations thereof.

[0058] Method for producing paving composition The paving composition is prepared by mixing the components of the binder to form the binder and then mixing the binder with aggregate to form the paving composition. Specifically, the binder can be prepared by mixing the above-described bitumen, the above-described performance-improving additive, and the above-described recycled plastic in a molten state to form the binder. In various embodiments, other additives (other than the performance-improving additive and recycled plastic) can optionally be mixed with the binder and / or aggregate. The binder can be mixed at a temperature of from about 90°C to about 220°C; in other embodiments, the binder can be mixed at a temperature of from about 100°C to about 190°C. In a "wet" process, the performance-improving additive and recycled plastic are dissolved into the binder. The binder can then be mixed with aggregate to form the paving composition.

[0059] In a "dry" process, performance-enhancing additives and / or plastic waste can be mixed with aggregate to form a reinforcing aggregate, which can then be mixed with a binder to form the paving composition. However, in alternative embodiments, the plastic waste and / or performance-enhancing additives can be mixed with the binder before the binder and aggregate are mixed together. In such cases, the recycled plastic is incorporated into the paving composition, either with the aggregate, the binder, or separately, and a portion of the plastic waste is incorporated into the binder, referred to herein as "recycled plastic" as described above. A portion of the recycled plastic remains separate and distinguishable from the binder, functions as aggregate, and is referred to herein as "waste plastic" as described above. While the performance-enhancing additives can be mixed with the binder before being mixed with the aggregate, in other embodiments, the performance-enhancing additives can be included in the reinforcing aggregate and then mixed with the binder when the binder and aggregate are combined. Thus, some of the performance-enhancing additive may be incorporated into the binder, while some may remain separate from the binder and still function to stabilize and enhance the performance of paving compositions having plastic waste as a component of the aggregate. Depending on the type of equipment utilized, it may be easier for some manufacturers to mix the reclaimed plastic and / or performance-enhancing additive with the aggregate before combining it with the binder.

[0060] The aggregate described above is mixed with a binder to produce a paving composition. In embodiments in which the aggregate comprises plastic waste, the aggregate may be mixed with the binder in a manner that prevents or minimizes melting of the plastic waste in the aggregate. This can be achieved by mixing the aggregate and binder at a temperature below the melting point of the plastic waste, or by rapidly mixing the aggregate and binder and then cooling the paving composition so that the plastic waste is not exposed to temperatures above the melting point of the plastic waste for extended periods of time. Also, during or after mixing the aggregate and binder, some of the plastic waste may melt, as the binder may be able to incorporate some additional plastic material from the plastic waste. Alternatively, some of the molten plastic waste may remain separated from the binder in the mixture around the edges of the solid plastic waste particles, and the molten plastic waste may then resolidify as solid aggregate that can be distinguished from the binder by inspection as the paving composition cools. In an exemplary embodiment, the binder and plastic waste are mixed at a temperature of from about 90°C to about 220°C, while in an alternative embodiment, the binder and aggregate are mixed at a temperature of from about 100°C to about 190°C.

[0061] In an alternative embodiment, the method includes mixing plastic waste with mineral aggregate at a temperature above the melting point of the plastic waste. The plastic waste and mineral aggregate are mixed under conditions effective to coat the mineral aggregate with the plastic waste, such that the plastic waste essentially encases the mineral aggregate to form an encased aggregate. The encased aggregate can then be mixed with a binder to form a paving composition. In some embodiments, the mineral aggregate may be completely encased in the plastic waste, although in alternative embodiments, the mineral may be partially encased. In an exemplary embodiment, approximately 20 to 100 percent of the surface area of ​​the mineral aggregate may be encased in the plastic waste. However, in alternative embodiments, approximately 50 to 100 percent or approximately 75 to 100 percent of the surface area of ​​the mineral aggregate is encased in the plastic waste. [Example]

[0062] Several experiments were performed as follows:

[0063] Table 1 provides 21 binders prepared and tested as described below. These tests demonstrate that storage stability is improved when the performance-enhancing additive includes (1) low molecular weight oxidized polyethylene homopolymer, (2) a glycidyl compound, (3) a low molecular weight polyethylene homopolymer, (4) a glycidyl compound in combination with polyphosphoric acid and Fischer-Tropsch wax, and / or (5) a pyrolysis wax. Table 1 provides examples of a "wet" process in which recycled plastic is incorporated into the binder. The recycled plastic in the examples listed in Table 1 was low-density polyethylene. Storage stability is clearly indicated by the absolute value (ABS) of the dropping point difference (highest value in °C - lowest value in °C), with a difference of more than 5 °C being considered unstable. Experiment No. 14 exhibits acceptable storage stability when high molecular weight glycidyl compound No. 2 is used, but the viscosity at 135 °C of 9360 cPs is much higher than the maximum value of 3000 cPs. Experiment No. 20 shows that glycidyl compounds and polyphosphoric acid do not produce stable products when the low-density polyethylene recycled plastic concentration reaches 8 weight percent, while Experiments Nos. 5, 6, and 7 show that glycidyl compounds and polyphosphoric acid effectively produce stable products at a low-density polyethylene recycled plastic concentration of 7 weight percent.

[0064] Blends Nos. 1, 2, 4, and 8 produced in Table 1 were prepared by adding recycled plastic to molten bitumen at 180°C and mixing in a high-shear mixer at approximately 3500 rpm for 4 hours. Blends Nos. 9, 16, 17, and 21 were prepared by adding recycled plastic and LMW polyethylene homopolymer to molten bitumen at 180°C and mixing in a high-shear mixer at approximately 3500 rpm for 4 hours, following the blending procedure described above. Blend No. 12 was prepared by adding recycled plastic and Fischer-Tropsch wax to molten bitumen at 180°C and mixing in a high-shear mixer at approximately 3500 rpm for 4 hours, following the blending procedure described above. Blends Nos. 3, 5, 6, and 10 were prepared by adding recycled plastic, LMW polyethylene oxide homopolymer, and glycidyl compound to molten bitumen at 180°C, mixing in a high shear mixer at approximately 3500 rpm for 2 hours, adding PPA (polyphosphoric acid) after 2 hours of mixing, and mixing for an additional 2 hours, according to the blending procedure described above. Blend No. 11 was prepared by adding recycled plastic, Fischer-Tropsch wax, and glycidyl compound to molten bitumen at 180°C, mixing in a high shear mixer at approximately 3500 rpm for 2 hours, adding PPA (polyphosphoric acid) after 2 hours of mixing, and mixing for an additional 2 hours, according to the blending procedure described above. Blends Nos. 7, 13, 14, 15, and 20 were prepared by adding recycled plastic and glycidyl compound (high or low molecular weight) to molten bitumen at 180°C, mixing in a high shear mixer at approximately 3500 rpm for two hours, and adding PPA (polyphosphoric acid) after two hours of mixing was completed and mixing for an additional two hours, according to the blending procedure described above. Blends Nos. 18 and 19 were prepared by adding recycled plastic and pyrolysis wax to molten bitumen at 180°C, mixing in a high shear mixer at approximately 3500 rpm for four hours, according to the blending procedure described above.

[0065] [Table 1]

[0066] [Table 2]

[0067] [Table 3-1]

[0068] [Table 3-2] The compositions are listed in weight percent based on the total weight of the binder composition. The low molecular weight, high density oxidized polyethylene homopolymer had a weight average molecular weight of 8,000-9,000 daltons using the conditions above. LMW Oxidized PE Homopolymer Number 1: Honeywell Titan® 7686. LMW Oxidized PE Homopolymer No. 2: EPOLENE® EE-2 from Westlake Chemical. LMW PE Homopolymer Number 1: Honeywell Titan® 7205. LMW PE Homopolymer No. 2: Honeywell Titan® 7467. LMW PE Homopolymer No. 3: Honeywell Titan® 7287. High molecular weight glycidyl composition number 1 is Elvaloy® 4170. High molecular weight glycidyl composition number 2 is Lotader® AX 8900. Pyrolytic Wax Number 1: AW115.91 from GreenMantra Technologies. Pyrolysis wax No. 2: 104N manufactured by Lion Chemtech Co., Ltd. Brookfield Viscosity: ASTM D4402, Standard Test Method for Determining the Viscosity of Asphalt at Elevated Temperatures Using a Rotational Viscometer. G *(Complex Modulus), Delta (Phase Angle): From ADTM D7175, Standard Test Method for Determining the Rheological Properties of Asphalt Binders Using a Dynamic Shear Rheometer. G * / sin(delta) is G * and Delta. A value of 1.00 kilopascals (kPa) or greater at both 70°C and 76°C is considered a passing value. RTFO (Rolling Thin Film Oven) Test: ASTM D2872, Standard Test Method for the Effects of Heat and Air on Transfer Films of Asphalt (Rolling Thin Film Oven Test). A value of 2.20 kPa or greater at both 70°C and 76°C is considered a passing value. MSCR (Multiple Stress Creep and Recovery) Test: ASTM D7405, Standard Test Method for Multiple Stress Creep and Recovery (MSCR) of Asphalt Binders Using a Dynamic Shear Rheometer. R3.2: Average recovery rate at 3.2 kPa. Jnr 3.2: Non-recoverable creep compliance at 3.2 kPa. A value of 4.50 kPa or less is considered a passing value at both 70°C and 76°C. Jnr difference: The difference in irrecoverable creep compliance between 0.100 kPa and 3.200 kPa. Multiple stress creep recovery (MSCR) testing according to the methodology described in AASHTO T350-14 and specifications of AASHTO M332-14. Segregation Test: ASTM D7173, Standard Practice for Determining the Tendency of Polymer to Segregate from Polymer-Modified Asphalt. Softening Point Test: ASTM D36, Standard Test Method for Softening Point of Bitumen (Ring and Ball Apparatus). ABS (difference (top - bottom)), unit: °C. A value of 5 °C or less is considered a pass. PG: Performance Grade, AASHTO M320, Standard Specification for Performance-Grade Asphalt Binders. Notes: A. The columns titled (Low Molecular Weight Polyethylene Homopolymer No. 2; Low Molecular Weight Polyethylene Homopolymer No. 3; Pyrolysis Wax No. 1; and Pyrolysis Wax No. 2) that are present in Table 1, Part 3, all have a value of zero (0) in Table 1, Part 1 and Part 2. B. Elvaloy® 4170 has a melt flow index (MFI) of 8, and Lotader® AX8900 has an MFI of 6. Lotader® AX8840 has an MFI of 5 and a molecular weight of 105,000. MFI is often used to estimate molecular weight. Lotader® AX8840 is an ethylene and glycidyl methacrylate copolymer, similar to Elvaloy® 4170 and Lotader® AX8900. Therefore, based on the MFI values, it is clear that Elvaloy® 4170 (High Molecular Weight Glycidyl Composition No. 1) and Lotader® AX 8900 (High Molecular Weight Glycidyl Composition No. 2) have higher molecular weights than the glycidyl methacrylate copolymers used in the above examples. Elvaloy® 4710 has a reported molecular weight of 68,205 daltons, and Lotader® AX8840 has a reported molecular weight of 71,190 daltons.

[0069] The above examples demonstrate that the binder can contain recycled plastic in an amount of about 4 to about 8 weight percent based on the total weight of the binder, although the upper limit is unclear. The use of performance-enhancing additives allows for the incorporation of recycled plastic in amounts greater than 4 weight percent, where unstable binders have been found at 4 weight percent or more recycled plastic without the performance-enhancing additive.

[0070] Table 2 shows five paving compositions containing bitumen and high-density polyethylene (HDPE), where the high-density polyethylene is a recycled plastic dissolved in a binder. The results show that HDPE and bitumen are unstable when the HDPE concentration alone is 4 weight percent or greater (based on the total weight of the binder), as indicated by the ABS difference (top vs. bottom), with HDPE concentrations of 4 weight percent or greater having a top vs. bottom softening point difference of greater than 5°C. These tests show that storage stability is improved when the performance-enhancing additive includes (1) a low molecular weight oxidized polyethylene homopolymer, (2) a glycidyl compound, and (3) polyphosphoric acid.

[0071] [Table 4] Compositions are listed in weight percent based on the total weight of the binder composition. Brookfield Viscosity: ASTM D4402, Standard Test Method for Measurement of Viscosity of Asphalt at Elevated Temperatures Using a Rotational Viscometer. G * (Complex Modulus), Delta (Phase Angle): From ADTM D7175, Standard Test Method for Determining the Rheological Properties of Asphalt Binders Using a Dynamic Shear Rheometer. G * / sin(delta) is G * and delta. A value of 1.00 kilopascals (kPa) or greater is considered a passing value. RTFO (Rolling Thin Film Oven) Test: ASTM D2872, Standard Test Method for the Effects of Heat and Air on Transfer Films of Asphalt (Rolling Thin Film Oven Test). A value of 2.20 kPa or greater is considered a passing value. MSCR (Multiple Stress Creep and Recovery) Test: ASTM D7405, Standard Test Method for Multiple Stress Creep and Recovery (MSCR) of Asphalt Binders Using a Dynamic Shear Rheometer. R3.2: Average recovery rate at 3.2 kPa. Jnr 3.2: Non-recoverable creep compliance at 3.2 kPa. A value of 4.50 kPa or less is considered a passing value at both 70°C and 76°C. Jnr difference: The difference in irrecoverable creep compliance between 0.100 kPa and 3.200 kPa. Multiple stress creep recovery (MSCR) testing according to the methodology described in AASHTO M350-14 and specifications of AASHTO M332-14. Segregation Test: ASTM D7173, Standard Practice for Determining the Tendency of Polymer to Segregate from Polymer-Modified Asphalt. Softening Point Test: ASTM D36, Standard Test Method for Softening Point of Bitumen (Ring and Ball Apparatus). ABS (difference (top - bottom)), unit: °C. A value of 5 °C or less is considered a pass. PG: Performance Grade, AASHTO M320, Standard Specification for Performance-Grade Asphalt Binders.

[0072] Table 3 shows five paving compositions containing bitumen and linear low-density polyethylene (LLDPE), where LLDPE is a recycled plastic dissolved in the binder. The results indicate that LLDPE and bitumen are unstable at LLDPE concentrations alone of 2 weight percent or greater (based on the total weight of the binder), as indicated by the ABS difference (top vs. bottom); LLDPE concentrations of 2 weight percent or greater have a top-to-bottom softening point difference of greater than 5°C. Furthermore, Brookfield viscosity and RTFO residual values ​​are too low at concentrations below 2 weight percent. Therefore, the binder may be essentially free of LLDPE in exemplary embodiments, such as having a concentration of about 1 weight percent or less, or about 0.5 weight percent or less, or about 0.1 weight percent or less in various embodiments. However, combinations of LLDPE with other types of recycled plastic dissolved in the binder can produce promising products.

[0073] [Table 5] The compositions are listed in weight percent based on the total weight of the binder composition. Brookfield Viscosity: ASTM D4402, Standard Test Method for Determining the Viscosity of Asphalt at Elevated Temperatures Using a Rotational Viscometer. G * (Complex Modulus), Delta (Phase Angle): From ADTM D7175, Standard Test Method for Determining the Rheological Properties of Asphalt Binders Using a Dynamic Shear Rheometer. G * / sin(delta) is G * and delta. A value of 1.00 kilopascals (kPa) or greater is considered a passing value. RTFO (Rolling Thin Film Oven) Test: ASTM D2872, Standard Test Method for the Effects of Heat and Air on Transfer Films of Asphalt (Rolling Thin Film Oven Test). A value of 2.20 kPa or greater is considered a passing value. MSCR (Multiple Stress Creep and Recovery) Test: ASTM D7405, Standard Test Method for Multiple Stress Creep and Recovery (MSCR) of Asphalt Binders Using a Dynamic Shear Rheometer. R3.2: Average recovery rate at 3.2 kPa. Jnr 3.2: Non-recoverable creep compliance at 3.2 kPa. A value of 4.50 kPa or less is considered a passing value at both 70°C and 76°C. Jnr difference: The difference in irrecoverable creep compliance between 0.100 kPa and 3.200 kPa. Multiple stress creep recovery (MSCR) testing according to the methodology described in AASHTO M350-14 and specifications of AASHTO M332-14. Segregation Test: ASTM D7173, Standard Practice for Determining the Tendency of Polymer to Segregate from Polymer-Modified Asphalt. Softening Point Test: ASTM D36, Standard Test Method for Softening Point of Bitumen (Ring and Ball Apparatus). ABS (difference (top - bottom)), unit: °C. A value of 5 °C or less is considered a pass. PG: Performance Grade, AASHTO M320, Standard Specification for Performance-Grade Asphalt Binders.

[0074] Table 4 shows nine paving compositions demonstrating the benefits of using plastic waste to replace mineral aggregate, with or without low-molecular-weight oxidized polyethylene homopolymer. The aggregate gradation and mix design are described above and shown in these tables. The "Control" is a typical gradation and mix design using 100% mineral aggregate. For Experiments 1 and 2, typically used large mineral aggregate sizes (20 mm, 10 mm, and 6.3 mm) were replaced with an equal volume of high-density waste polyethylene pellets (5-6 mm). In these mixtures, the fine aggregate, high-density waste polyethylene aggregate, and filler were heated at 120°C for 2 hours, and then the desired amount of bitumen was added to the mixture, which was mixed with a trowel until the entire mixture was homogeneous (approximately 20 minutes). For Experiments 3 and 4, the typically used 20 mm mineral aggregate and half of the typically used 10 mm mineral aggregate were replaced with an equal volume of high-density waste polyethylene pellets (5-6 mm). The remaining 10 mm mineral aggregate, 6.3 mm aggregate, high-density waste polyethylene aggregate, and filler were heated at 120°C for 2 hours, and then the desired amount of bitumen was added to the mixture and mixed with a trowel until the entire mixture was homogeneous (approximately 20 minutes). In Experiments 7 and 8, the 6.3 mm aggregate was replaced with an equal volume of high-density waste polyethylene pellets (5-6 mm). The 20 mm mineral aggregate, 10 mm aggregate, high-density waste polyethylene aggregate, and filler were heated at 120°C for 2 hours, and then the desired amount of bitumen was added to the mixture and mixed with a trowel until the entire mixture was homogeneous (approximately 20 minutes). In Experiments 9 and 10, the 10 mm aggregate was replaced with an equal volume of high-density waste polyethylene pellets (5-6 mm). The 20 mm mineral aggregate, 6.3 mm aggregate, high-density waste polyethylene aggregate, and filler were heated at 120°C for 2 hours, and then the desired amount of bitumen was added to the mixture, which was mixed with a trowel until the entire mixture was homogeneous (approximately 20 minutes).

[0075] All bitumen mixtures were compacted using a Marshall compactor with 75 blows on each side. Compared to the "control" paving composition, all paving compositions containing plastic waste pellets as aggregate had lower densities, which helps produce lighter building materials with multiple advantages, including: 1) less load demand on the base layer to support paving materials made with these paving compositions, and 2) less fuel consumption when transporting paving materials made with these paving compositions. In addition, because mineral aggregate was replaced by plastic waste pellets on a volumetric basis, and mineral aggregate has a much higher density, the amount of bitumen used in the experiments using plastic waste was much less than that used in the control. Overall, reductions in bitumen, the most expensive ingredient in the control paving composition, ranged from 38% (no polyolefin) to 45% (polyolefin) for Experiments 1 and 2; from 17% (no polyolefin) to 25% (polyolefin) for Experiments 3 and 4; from 17% (no polyolefin) to 26% (polyolefin) for Experiments 7 and 8; and from 12% (no polyolefin) to 21% (polyolefin) for Experiments 9 and 10. Without being bound by theory, it is possible that because plastic waste aggregates are less porous than mineral aggregates, the bitumen that is normally absorbed into the pores of mineral aggregates is not absorbed into the pores of the replacement plastic waste aggregates. Therefore, the bitumen that is not absorbed into the pores is available to provide the structure and function of the bitumen in the paving composition. Furthermore, even though the density and amount of bitumen in paving compositions containing plastic waste pellets as aggregate is lower, the paving compositions with plastic waste have comparable or even better performance than all mineral aggregate paving compositions, as shown by Marshall stability data.

[0076] The binder was the same for all experiments except that Runs 2, 4, 8, and 10 contained 2 weight percent low molecular weight oxidized polyethylene homopolymer, based on the weight of bitumen, and Runs 1, 3, 7, and 9 contained no low molecular weight oxidized polyethylene homopolymer. Runs 2, 4, 8, and 10 had higher densities and higher Marshall stability than Runs 1, 3, 7, and 9, respectively, which would result in better lifespans for roads produced using bitumen mixes with low molecular weight oxidized polyethylene homopolymer. As can be seen from Runs 2, 4, 8, and 10, the use of low molecular weight oxidized polyolefin results in paving compositions with better properties and reduced bitumen content.

[0077] [Table 6] Density is determined by ASTM D2726, Standard Test Method for Bulk Gravity and Density of Nonabsorbent Compacted Bituminous Mixtures. Marshall Stability: ASTM D6927; Standard Test Method for Marshall Stability and Flowability of Asphalt Mixtures.

[0078] [Table 7] Density is determined by ASTM D2726, Standard Test Method for Bulk Gravity and Density of Nonabsorbent Compacted Bituminous Mixtures. Marshall Stability: ASTM D6927; Standard Test Method for Marshall Stability and Flowability of Asphalt Mixtures.

[0079] The formulation designs for Experiments No. 5 and No. 6 are shown in Table 5.

[0080] [Table 8]

[0081] Table 6 shows the Marshall stability and voids filled with bitumen (VFB) for samples with and without low molecular weight oxidized polyethylene homopolymer used as a performance enhancing additive when using the same formulation design as in Table 5.

[0082] Experiment 5 in Table 6 was prepared by heating coarse mineral aggregates (20 mm, 10 mm, and 6.3 mm) at 150–160°C for 2 hours, then adding the desired amount of shredded plastic waste and low molecular weight oxidized polyethylene (LMWPE) to coat the heated aggregate. Filler and fine aggregate were then added to the mixture and mixed until the entire mixture reached 150–160°C. Bitumen at 160°C was then added to the mixture and mixed until the mixture was homogeneous. The mixture was then transferred to a Marshall mold and compacted using a Marshall compactor with 75 blows on each side. Experiment 6 used the same process, but without the LMWPE.

[0083] [Table 9] LMWPE - Low Molecular Weight Oxidized Polyethylene. Stability: ASTM D6927; Standard Test Method for Marshall Stability and Flowability of Asphalt Mixtures. VFB (Voids Filled with Bitumen): ASTM D3203 / AASHTO &269;Standard Test Method for Percent Air Voids in Compacted Dense and Open Bituminous Pavement Mixtures.

[0084] Table 7 shows the test results when polyethylene terephthalate (PET) was used as the plastic waste. The "Control" was a typical gradation and mix design using 100% mineral aggregate, as described and exemplified above. In Experiments 11 and 12, the 6.3 mm aggregate was replaced with an equal volume of recycled PET pellets (5-6 mm). The 20 mm mineral aggregate, 10 mm aggregate, recycled PET aggregate, and filler were heated at 120°C for 2 hours, and then the desired amount of bitumen was added to the mixture, which was then mixed with a trowel until the entire mixture was homogeneous (approximately 20 minutes). Similar to the high-density recycled polyethylene plastic described above, recycled PET plastic allowed for the use of reduced bitumen with acceptable Marshall stability results. Furthermore, the use of low-molecular-weight oxidized polyethylene homopolymer in the binder allowed for further bitumen reduction and improved Marshall stability compared to Experiment 11, which had the same amount of recycled PET but no low-molecular-weight oxidized polyethylene homopolymer in the binder.

[0085] [Table 10] Density is determined by ASTM D2726, Standard Test Method for Bulk Gravity and Density of Nonabsorbent Compacted Bituminous Mixtures. Marshall Stability: ASTM D6927; Standard Test Method for Marshall Stability and Flowability of Asphalt Mixtures.

[0086] Table 8 shows the test results for polystyrene (PS) as the plastic waste. The "Control" was a typical gradation and mix design using 100% mineral aggregate, as described and exemplified above. In Experiments 13 and 14, the 6.3 mm aggregate was replaced with an equal volume of waste PS pellets (5-6 mm). The 20 mm mineral aggregate, 10 mm aggregate, waste PS aggregate, and filler were heated at 120°C for 2 hours, and then the desired amount of bitumen was added to the mixture, which was then mixed with a trowel until the entire mixture was homogeneous (approximately 20 minutes). Similar to the high-density waste polyethylene plastic described above, waste PS plastic allowed for the use of reduced bitumen with acceptable Marshall stability results. Furthermore, the use of low-molecular-weight oxidized polyethylene homopolymer in the binder allowed for further bitumen reduction and improved Marshall stability compared to Experiment 13, which had the same amount of waste PS but no low-molecular-weight oxidized polyethylene homopolymer in the binder. The use of low molecular weight oxidized polyethylene homopolymer in the binder resulted in a highly significant improvement in Marshall stability when waste PS plastic was utilized.

[0087] [Table 11] Density is determined by ASTM D2726, Standard Test Method for Bulk Gravity and Density of Nonabsorbent Compacted Bituminous Mixtures. Marshall Stability: ASTM D6927; Standard Test Method for Marshall Stability and Flowability of Asphalt Mixtures.

[0088] As can be seen in the examples, the use of low molecular weight oxidized polyethylene homopolymer allows for a reduction in the amount of bitumen in the paving composition. By adding low molecular weight oxidized polyethylene homopolymer in an amount of about 1 to about 3 weight percent based on the total weight of the binder, the amount of binder in the paving composition can be reduced to about 5.5 weight percent of the paving composition, or about 5.1 weight percent of the paving composition, while still providing comparable performance compared to an equivalent paving composition without the low molecular weight oxidized polyethylene homopolymer. The above examples also demonstrate that plastic waste can be incorporated into aggregate in amounts from about 1 to at least about 13.5 weight percent based on the total weight of the paving composition and still provide an effective product. For example, a paving composition can contain plastic waste in amounts from about 1 to about 15 weight percent and still provide an effective product. In exemplary embodiments, the plastic waste utilized as aggregate may include one or more of high-density polyethylene, polyethylene terephthalate, and / or polystyrene.

[0089] Figures 1-4 are photographs of mineral aggregate mixed with 10 weight percent plastic waste (based on the weight of the aggregate) coated with a binder. In Figures 1 and 2, the binder was 100 weight percent bitumen, while in Figures 3 and 4, 3 weight percent low-molecular-weight oxidized polyethylene (LOE) based on the total weight of the binder was also added to the aggregate-plastic waste mixture. The aggregate was heated at 150°C for 2 hours, after which 10 weight percent crushed plastic waste (based on the weight of the aggregate) was added to the heated aggregate so that the crushed plastic waste effectively coated the aggregate. If low-molecular-weight oxidized polyethylene was used, it was then added to the aggregate-plastic waste mixture. Five weight percent bitumen (based on the total weight of the asphalt composition) was then heated to 160°C to achieve the desired fluidity, added to the aggregate / crushed plastic waste / LOE composition, and mixed to coat the aggregate with bitumen. The coated aggregate was then allowed to equilibrate to room temperature, after which deionized water was added and it was kept in a water bath at 40°C for 24 hours. Figures 1 and 3 show the results for samples without and with low molecular weight polyethylene oxide, respectively. Close inspection of Figures 1 and 3 reveals that the aggregate in Figure 1 is not completely coated with bituminous binder, while the aggregate in Figure 3 is completely coated with bituminous binder.

[0090] Both samples (numbers 2 and 4) were evaluated for the boiling water test according to ASTM D3625. In the boiling water test, the specimens were kept in boiling water for 10 minutes and then observed. Figures 2 and 4 show the aggregates after the boiling water test for aggregates without and with low molecular weight polyethylene oxide, respectively. Close inspection of Figures 2 and 4 reveals that the aggregate in Figure 2 has a significant portion not covered by bitumen, while the aggregate in Figure 4 is completely covered by bitumen.

[0091] These tests show that the low molecular weight polyethylene oxide increases the coverage of the aggregate by the binder compared to a binder without the low molecular weight polyethylene oxide.

[0092] While several embodiments have been presented in the foregoing detailed description, it should be understood that numerous variations exist. It should also be understood that the embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description provides those skilled in the art with convenient guidance for implementing various embodiments of the asphalt composition, and it will be understood that various changes can be made in the function and arrangement of the elements described without departing from the scope set forth in the appended claims and their legal equivalents.

Claims

1. A paving composition comprising:

1. A paving composition comprising: a binder, the binder comprising bitumen, recycled plastic, and a performance-enhancing additive, the performance-enhancing additive being selected from the group consisting of a low molecular weight polyolefin, a glycidyl compound, and combinations thereof, the low molecular weight polyolefin having a weight average molecular weight of from about 500 to about 30,000 Daltons, the glycidyl compound comprising an ethylene glycidyl (meth)acrylate polymer, the ethylene glycidyl (meth)acrylate polymer having a weight average molecular weight of from about 500 to about 30,000 Daltons.

2. the paving composition comprises the binder in an amount of from about 1 to about 15 weight percent, based on the total weight of the paving composition; 10. The paving composition of claim 1, wherein the paving composition further comprises aggregate in an amount of from about 85 weight percent to about 99 weight percent, based on the total weight of the paving composition, the aggregate being a solid material that can be distinguished from the binder by inspection.

3. 3. The paving composition of claim 2, wherein the aggregate comprises about 1 to 100 weight percent plastic waste, based on the total weight of the aggregate, and the plastic waste comprises one or more of polystyrene, polyolefins, polyethylene terephthalate, polyvinyl chloride, polymers made from ethylene propylene diene monomer, ethylene vinyl acetate, polyester, polytetrafluoroethylene, polyurethane, polycarbonate, polyamide, polyacrylamide, and polymethacrylamide.

4. 3. The paving composition of claim 2, wherein said paving composition comprises said binder in an amount of less than or equal to about 5.5 weight percent, based on the total weight of said paving composition.

5. 10. The paving composition of claim 1, wherein said binder comprises said recycled plastic in an amount of from about 1 weight percent to about 20 weight percent, based on the total weight of said binder.

6. 10. The paving composition of claim 1, wherein the recycled plastic comprises about 90 weight percent to 100 weight percent polyethylene, based on the total weight of the recycled plastic.

7. 10. The paving composition of claim 1, wherein the low molecular weight polyolefin is selected from the group consisting of polyethylene, oxidized polyethylene having an acid number of from about 5 to about 40 mg KOH / gm, polypropylene, pyrolysis wax, Fischer-Tropsch wax, and combinations thereof, and the low molecular weight polyolefin is present in the binder in an amount of from 0.5 to about 5 weight percent, based on the total weight of the binder.

8. 10. The paving composition of claim 1, wherein the performance-enhancing additive comprises the glycidyl compound in an amount of about 0.1 to about 5 weight percent based on the total weight of the binder, and the paving composition further comprises polyphosphoric acid in an amount of about 0.1 to about 1 weight percent based on the total weight of the binder.

9. 2. The paving composition of claim 1, wherein the recycled plastic comprises linear low density polyethylene in an amount of about 2 to about 4 weight percent based on the total weight of the binder, and the performance enhancing additive comprises the glycidyl compound and the polyphosphoric acid.

10. 2. The paving composition of claim 1, wherein said recycled plastic comprises high density polyethylene in an amount of 4 to about 6 weight percent based on the total weight of said binder, and said performance enhancing additive comprises said glycidyl compound and said polyphosphoric acid.

11. 1. A method for preparing a paving composition, comprising: preparing a binder comprising bitumen, a performance enhancing additive, and recycled plastic, wherein the performance enhancing additive is dissolved in the binder, the performance enhancing additive being selected from the group consisting of a low molecular weight polyolefin, a glycidyl compound, and combinations thereof, the low molecular weight polyolefin having a weight average molecular weight of about 500 to about 30,000 Daltons, the glycidyl compound comprising an ethylene glycidyl (meth)acrylate polymer having a weight average molecular weight of about 500 to about 30,000 Daltons, and the recycled plastic is dissolved in the binder; mixing said binder with aggregate to form said paving composition, wherein said aggregate is a solid material that can be distinguished from said binder by inspection.

12. 12. The method of claim 11, wherein the aggregate comprises about 1 to 100 weight percent plastic waste based on the total weight of the aggregate, the plastic waste comprising one or more of polystyrene, polyolefins, polyvinyl chloride, polymers made from ethylene propylene diene monomer, ethylene vinyl acetate, polyester, polytetrafluoroethylene, polyurethane, polycarbonate, polyamide, polyacrylamide, and polymethacrylamide.

13. 12. The method of claim 11, wherein the recycled plastic comprises low density polyethylene, such that the binder comprises about 4 to about 8 weight percent low density polyethylene, based on the total weight of the binder.

14. 12. The method of claim 11, wherein the performance enhancing additive is selected from the group consisting of low molecular weight polyethylene, low molecular weight oxidized polyethylene having an acid number of from about 5 to about 40 mg KOH / gm, low molecular weight polypropylene, Fischer-Tropsch wax, pyrolysis wax, maleated polypropylene, maleated polyethylene, ethylene vinyl acetate, ethylene acrylic acid, the glycidyl compounds, polyphosphoric acid, and combinations thereof, and wherein the performance enhancing additive is added to the binder in an amount of 0.1 to about 5 weight percent based on the total weight of the binder.

15. 12. The method of claim 11, wherein the binder has an upper sample and a lower sample, the upper sample and the lower sample of the binder are provided by a separate test described by ASTM D7173, and the softening point of the upper sample and the softening point of the lower sample differ by less than 5°C when determined by the Ring and Ball Softening Point Test described by ASTM D36.

16. A paving composition comprising: a binder in an amount of about 1 to about 15 weight percent based on the total weight of the paving composition, the binder comprising bitumen; aggregate in an amount of about 85 weight percent to about 99 weight percent, based on the total weight of the paving composition, wherein the aggregate is a solid material that can be distinguished from the binder by inspection, and the aggregate comprises about 1 to 100 weight percent plastic waste, based on the total weight of the aggregate; a performance-enhancing additive selected from the group consisting of low molecular weight polyolefins, glycidyl compounds, and combinations thereof, wherein the low molecular weight polyolefins have a weight average molecular weight of from about 500 to about 30,000 Daltons, and the glycidyl compound comprises an ethylene glycidyl (meth)acrylate polymer, wherein the ethylene glycidyl (meth)acrylate polymer has a weight average molecular weight of from about 500 to about 30,000 Daltons.

17. 17. The paving composition of claim 16, wherein the binder comprises recycled plastic in an amount of about 1 weight percent to about 15 weight percent based on the total weight of the binder, and the recycled plastic comprises about 90 weight percent to 100 weight percent polyethylene based on the total weight of the recycled plastic.

18. 17. The paving composition of claim 16, wherein said paving composition comprises said binder in an amount of less than or equal to about 5.5 weight percent, based on the total weight of said paving composition.

19. 17. The paving composition of claim 16, wherein the low molecular weight polyolefin is selected from the group consisting of low molecular weight polyethylene, oxidized polyethylene having an acid number of from about 5 to about 40 mg KOH / gm, polypropylene, pyrolytic wax, pyrolytic wax, Fischer-Tropsch wax, maleated polyethylene, maleated polypropylene, ethylene vinyl acetate, ethylene acrylic acid, and combinations thereof, and the low molecular weight polyolefin is present in the binder in an amount of from 0.5 to about 5 weight percent, based on the total weight of the binder.

20. 17. The paving composition of claim 16, wherein the plastic waste comprises high density polyethylene, polyethylene terephthalate, polystyrene, or combinations thereof.

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