A multifunctional hybrid graphitic carbon nitride-based modifier to improve the aging resistance and thermal performance of asphalt binder

Abstract

In one aspect, the disclosure relates to In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to modified asphalt binders comprising an asphalt binder, graphitic carbon nitride, carbon nanofibers, and plastics, asphalts including the same, and roads or pavements including the same. The modified asphalt binders and roads and pavements including the same are resistant to rutting, fatigue, thermal cracking, oxidation, and ultraviolet radiation. Also disclosed are methods of making the modified asphalt binders. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Description

A MULTIFUNCTIONAL HYBRID GRAPHITIC CARBON NITRIDE-BASED MODIFIER TO IMPROVE THE AGING RESISTANCE AND THERMAL PERFORMANCE OF ASPHALT BINDERCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 63 / 558,680, filed February 28, 2024, which is incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with government support under grant number W912HZ21C0040 awarded by the U.S. Army Corps of Engineers. The government has certain rights in the invention.BACKGROUND

[0003] Over the past few decades, asphalt pavements have undergone considerable degradation due to the continuous rise in traffic volume and the influence of climate change. According to the American Society of Civil Engineers’ (ASCE) 2021 Infrastructure Report Card, more than 47% of the nation's roads are in poor to fair condition. Furthermore, an expenditure exceeding 435 billion dollars is required to maintain the current road infrastructure. This highlights the urgent need for improving pavement construction materials with special attention to the asphalt binder. The ability to protect and improve the performance of infrastructures is vital to national security, public health and safety, economic vitality, and way of life. Recent advances in new construction materials allow for the design of durable, resilient, sustainable, and innovative transportation materials.

[0004] Asphalt binder is known for its temperature sensitivity and susceptibility. This susceptibility leads to two main types of distress: rutting when exposed to high temperatures and cracking when subjected to low temperatures. Consequently, there is a pressing need to develop a new generation of modifiers that can efficiently improve the overall performance of the binder by reducing its temperature sensitivity and increasing its stability. The successful implementation of these modifiers has the potential to considerably extend the lifespan of asphalt pavements and significantly reduce maintenance costs during the service period.

[0005] The aging of asphalt binders is recognized as one of the most critical factors that can affect their performance. Aging is a sequence of physical and chemical changes in the binder thatlead to an increase in its viscosity and diminished ductility and flexibility. Consequently, the asphalt becomes more brittle and more susceptible to damage and cracking. One of the primary factors contributing to asphalt binder aging is exposure to environmental conditions such as sunlight (UV radiation) and oxygen. When the binder is subjected to UV rays, it undergoes photochemical reactions that generate free radicals and degrade its molecular structure. Simultaneously, oxygen reacts with the binder, resulting in oxidation and additional degradation.

[0006] Despite advances in asphalt binder research, there is still a scarcity of modifiers that are capable of improving both the anti-aging and temperature resistance properties of the binders. These needs and other needs are satisfied by the present disclosure.SUMMARY

[0007] In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to modified asphalt binders comprising an asphalt binder, graphitic carbon nitride, carbon nanofibers, and plastics, asphalts including the same, and roads or pavements including the same. The modified asphalt binders and roads and pavements including the same are resistant to rutting, fatigue, thermal cracking, oxidation, and ultraviolet radiation. Also disclosed are methods of making the modified asphalt binders.

[0008] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0010] FIG. 1 shows a flow chart including methods useful for assessing temperature resistance and anti-aging properties of the disclosed modified asphalt binders.

[0011] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.DETAILED DESCRIPTION

[0012] Disclosed herein are modified asphalt binders with improved aging resistance and thermal properties. The modified asphalt binders can include a carbon nitride-based hybrid system that functions as a modifier for asphalt binders. In one aspect, the system includes three main components, i.e., graphitic carbon nitride, carbon nanofiber, and plastics. In a further aspect, by combining these elements, the hybrid system acts as a multifunctional modifier capable of improving the high- and low temperature performance of the binder, i.e., enhancing rutting performance and reducing thermal and fatigue cracking. In a further aspect, the hybrid system enhances the anti-aging properties of the binder by reducing the impact of UV light and impeding oxygen diffusion within the asphalt matrix.

[0013] The performances of the modified asphalt binders can be evaluated in accordance with American Association of State Highway and Transportation Officials (AASHTO) standards, considering four specific conditions, i.e., unaged, short-term aged based on the Rolling Thin Film Oven (RTFO) test, long-term aged based on the Pressure Aging Vessel (PA ) test, and UV-aged as described further in the Examples.

[0014] In one aspect, the rheological properties of the modified binders can be evaluated using the Dynamic Shear Rheometer (DSR) following AASHTO T315. Further in this aspect, the rutting parameter (G / sin 5)* is determined to assess the binder’s resistance to permanent deformation under repeated loading at high service temperatures. The rutting parameter is derived from the complex shear modulus (G)**, which quantifies the total resistance of the binder to deformation under shear stress, and the phase angle (5), which indicates the lag between the applied stress and the resulting strain, reflecting the viscoelastic behavior of the binder. Without wishing to be bound by theory, a higher rutting parameter corresponds to increased stiffness and improved rutting resistance, reducing the likelihood of pavement deformation under heavy traffic loads. Ina further aspect, a lower phase angle signifies a more elastic response, enhancing the binder’s ability to recover after deformation and maintain structural integrity. In one aspect, the interaction between G and 5, evaluated according to AASHTO T315, provides a comprehensive assessment of the binder’s ability to balance elasticity and viscosity, which is critical for ensuring long-term performance and durability. In a further aspect, Multiple Stress Creep and Recovery (MSCR) tests can be conducted at various temperatures to investigate the effect of the hybrid system on the rutting performance, following AASHTO T350. In an aspect, two main parameters can be determined by conducting MSCR tests: (1) the non-recoverable creep compliance (Jnr), which can be used as an indicator of permanent deformation, and (2) the percent recovery (R%), which represents the elastic behavior of the modified binder. In another aspect, the intermediatetemperature performance of the modified asphalt binder can be evaluated using the Dynamic Shear Rheometer (DSR) and Linear Amplitude Sweep (LAS) tests to assess the fatigue resistance of the binder. Further in this aspect, the DSR test is conducted on the long-term aged binder following the AASHTO T315 standard to determine the fatigue factor (G*sin 5), which is a key indicator of the binder’s ability to resist fatigue cracking under repeated loading. The LAS test, performed according to AASHTO TP101 , provides further insight into the binder’s fatigue behavior by estimating the predicted fatigue life (Nf) at a specific strain level, allowing for the evaluation of its durability under heavy traffic conditions. Without wishing to be bound by theory, these tests help quantify the impact of the hybrid system on the binder’s resistance to cracking and long-term performance under intermediate service temperatures. In still another aspect, the low- temperature performance of the modified asphalt binder can be evaluated by determining the flexural creep stiffness using the Bending Beam Rheometer (BBR). This test will be conducted for the long-term aged binder following the AASHTO T313 standard. Further details of the tests performed are provided in the Examples. FIG. 1 is a flow chart showing how temperature resistance and anti-aging performance can be evaluated.Modified Asphalt Binders

[0015] In one aspect, disclosed herein is a modified asphalt binder including at least the following components: an asphalt binder, a nanofiller comprising graphitic carbon nitride, carbon nanofibers (CNFs), or both, and plastics. The plastics can be any plastics, including, but not limited to, waste plastics. In an aspect, the CNFs have a diameter of from about 10 nm to about 500 nm, or from about 20 nm to about 200 nm, and a length of from about 20 to about 200 pm. In a further aspect, the graphitic carbon nitride is present at from about 0.1 % by weight to about 4% by weight, from about 1% by weight to about 4% by weight, or at about 2% by weight in the modified asphaltbinder. In another aspect, the CNFs are present at from about 0.1% by weight to about 4% by weight, from about 1% by weight to about 4% by weight, or at about 2% by weight in the modified asphalt binder . In still another aspect, the plastics can be present at from about 2% to about 6% by weight, or at from about 2% to about 4% by weight, in the modified asphalt binder. In a further aspect, the graphitic carbon nitride and CNFs are present in a combined amount of from about 0.4% to about 3% by weight of the modified asphalt binder in 1 : 1 ratio.

[0016] In some aspects, amounts of components can be provided in parts per hundred rubber (phr) instead of, or in addition to, weight percent. Thus in one aspect, the graphitic carbon nitride can be present at from about 0.5 to about 3 phr in the modified asphalt binder, or at about 0.5, 1 , 1.5, 2, 2.5, or about 3 phr. In another aspect, the carbon nanofibers can be present at from about 0.5 to about 3 phr in the modified asphalt binder, or at about 0.5, 1 , 1.5, 2, 2.5, or about 3 phr.

[0017] In one aspect, the one or more plastics can be present at from about 3 to about 5 phr in the modified asphalt binder, or can be about 3, 3.5, 4, 4.5, or about 5 phr. In another aspect, plastic can include high-density polyethylene (HDPE), low-density polyethylene (LDPE), ethylene vinyl acetate (EVA), or any combination thereof. In a further aspect, the polymeric component (i.e., the plastic) can be any individual polymer or combination of polymers chosen to optimize elasticity and / or stiffness. In another aspect, the plastic can be post-consumer waste, manufacturing waste, virgin plastic, recycled plastics, or any combination thereof.

[0018] In one non-limiting aspect, the one or more plastics can be HDPE and the nanofiller can be present at from about 2.5 to about 3 phr, while the HDPE can be present at about 3 to about 4 phr in the modified asphalt binder. In another non-limiting aspect, the one or more plastics can be EVA and the nanofiller can be present at from about 0.5 to about 1 phr, while the EVA can be present at about 4 to about 5 phr in the modified asphalt binder.

[0019] Also disclosed herein is an asphalt including the disclosed modified asphalt binder. In one aspect, the asphalt, the modified asphalt is present at from about 2% to about 6% by weight, or at about 5% by weight. Furthermore, disclosed herein is a road, pavement, or shingles including the asphalt disclosed herein.

[0020] In one aspect, the modified asphalt binder is resistant to rutting, fatigue, thermal cracking, oxidation, ultraviolet radiation, or any combination thereof relative to asphalt not including the disclosed modified asphalt binders.Methods for Making the Modified Asphalt Binders

[0021] In one aspect, disclosed herein is a method for making an asphalt binder including at least the following steps:(a) heating an asphalt binder in an oven;(b) admixing a plastic with the binder to produce a polymer-modified binder;(c) admixing a graphitic carbon nitride and carbon nanofibers with the polymer-modified binder to produce the modified asphalt binder.

[0022] In a further aspect, the asphalt binder is heated for from about 60 min to about 120 min at from about 135 °C to about 180 °C, or from about 160 °C to about 180 °C, or at 135, 140, 145, 150, 155, 160, 165, 170, 175, or 180 °C, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.

[0023] In another aspect, step (b) can be conducted by any means known in the art, such as, for example, use of a high-speed shear mixer. In a further aspect, step (b) can be conducted at from about 4500 rpm to about 6000 rpm for from about 30 minutes to about 50 minutes. In an aspect, step (c) can be carried out at from about 7500 rpm to about 8500 rpm, or at about 8000 rpm for from about 30 minutes to about 40 minutes. In any of these aspects, steps (b) and (c) can be conducted at from about 160 °C to about 180 °C, or at 160, 165, 170, 175, or 180 °C, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.

[0024] In another aspect, disclosed herein is a method for making the graphitic carbon nitride useful here, the method including at least the following steps:(a) heating a precursor compound to a first temperature for a first period of time to form a crude graphitic carbon nitride;(b) washing the crude graphitic carbon nitride to remove residual compounds adsorbed on a surface of the crude graphitic carbon nitride to produce a washed carbon nitride; and(c) drying the washed carbon nitride to produce the graphitic carbon nitride.

[0025] In an aspect, the first temperature is from about 450 °C to about 650 °C, or is about 450, 475, 500, 525, 550, 575, 600, 625, or about 650 °C, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In a further aspect, the first period of time can be from about 2 to about 4 h, or can be about 2, 2.5, 3, 3.5, or about 4 hours, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.ln a further aspect, step (a) can be conducted under an air atmosphere and washing can be performed using distilled water.

[0026] In one aspect, the precursor compound can include both carbon and nitrogen atoms and can be selected from melamine, thiourea, urea, dicyandiamide, a similar compound, or any combination thereof.

[0027] Also disclosed are modified asphalt binders produced by the disclosed method. In one aspect, the modified asphalt binders are resistant to rutting, fatigue, thermal cracking, oxidation, ultraviolet radiation, or any combination thereof. In another aspect, the modified asphalt binders show a high-temperature failure temperature of from about 10% to about 15% above an otherwise identical but unmodified asphalt binder. In still another aspect, the modified asphalt binders show a rutting parameter at 70° C of from about 195% to about 295% above an otherwise identical but unmodified asphalt binder. In still another aspect, the modified asphalt binders show a non- recoverable creep compliance at 70° C of from about 70% to about 80% above an otherwise identical but unmodified asphalt binder.

[0028] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0029] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0030] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

[0031] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in aspecific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0032] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

[0033] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class.

[0034] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0035] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.Definitions

[0036] As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence oraddition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.

[0037] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a carbon nanofiber,” “a plastic,” or “an asphalt binder,” include, but are not limited to, mixtures or combinations of two or more such carbon nanofibers, plastics, or asphalt binders, and the like.

[0038] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.

[0039] When a range is expressed, a further aspect includes from the one particular value and / or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g. 'about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”.

[0040] It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or subranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1 % to 5%” should be interpreted to include not only the explicitly recited values of about 0.1 % to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.

[0041] As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that “about” and “at or about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0042] As used herein, the term “effective amount” refers to an amount that is sufficient to achieve the desired modification of a physical property of the composition or material. For example, an “effective amount” of a plastic refers to an amount that is sufficient to achieve the desired improvement in the property modulated by the formulation component, e.g. achieving the effective mixing and binding of graphitic carbon nitride and carbon nanofibers. The specific level in terms of wt% in a composition required as an effective amount will depend upon a variety of factors including the amount and type of plastic, properties of the carbon nanofibers, amount of graphitic carbon nitride, and end location of installation of the asphalt binder, including consideration of local temperature and precipitation conditions.

[0043] As used herein, the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0044] Unless otherwise specified, temperatures referred to herein are based on atmospheric pressure (i.e. one atmosphere).Testing Procedures

[0045] In some aspects, short-term aging of asphalt binders can be assessed using the rolling thin film oven (RTFO) test. In an aspect, the properties of the binder in asphalt change and can undergo aging during handling, mixing, and / or paving; thus, the asphalt binder should be evaluated to assess whether it still meets performance requirements when installed.

[0046] In an aspect, the role of the RTFO test is primarily to simulate short-term aging in asphalt. Further in this aspect, the change in mass of the asphalt before and after the RTFO simulation is of particular importance in the disclosed methods. In one aspect, according to the AASHTO standard (AASHTO T-240), this mass change should be less than 1 %.

[0047] In a further aspect, in addition to measuring weight change, the disclosed simulations are useful for producing enough short-term aged asphalt to conduct further testing. Thus, in yet another aspect, the aged asphalt can then undergo additional testing using various techniques. In one aspect, for example, the rheological behavior of unaged (fresh) asphalt can be assessed. Further in this aspect, following assessment of fresh asphalt, RTFO testing can be used to simulate short-term aging, the aged binder can be collected, and the rheological properties can be evaluated.

[0048] The RTFO test measures the effects of heat and air on a moving film of asphalt binder. In an aspect, the RTFO test simulates short-term aging that occurs during asphalt processing. In the RTFO test, asphalt binder is heated and dispensed into a specimen bottle, which is mounted in a carousel in an oven. The specimen bottle is rotated at 15 rpm for 85 min while a jet of 163 °C air is directed into the bottle. Following completion of the test, mass change and rheological properties are measured and compared to values from untreated samples. The RTFO test is more fully described in AASHTO T 240 and / or ASTM D 2872.

[0049] In an aspect, asphalt oxidation and aging can be measured using the pressure aging vessel (PAV) test. In a further aspect, the PAV test can be used to simulate long-term aging. In one aspect, oxidation can change the rheological properties of asphalt binders, which can in turnimpact the long term performance of pavements. When an asphalt binder is exposed to oxygen, it can stiffen, which can lead to cracking through fatigue, low-temperatures, and other means. The RTFO test may first be performed and samples can then be recovered from RTFO sample bottles; samples are mixed thoroughly after recovery. The PAV can be heated to from about 90 °C to about 110 °C. Asphalt binder is poured into sample pans and the pans are loaded into the PAV. The PAV is closed and bolts are tightened with a torque wrench. A pressure of 2.1 MPa can be applied and is maintained for about 21 hours. Depressurization is then performed over a period of from about 8 to about 15 minutes. Samples are removed from the PAV and transferred to a warming oven, then to a vacuum degassing oven, after which properties of the samples are assessed. In a further aspect, in addition to measuring weight change, the disclosed PAV simulations are useful for producing enough long-term aged asphalt to conduct further testing. The PAV test is more fully described in ASTM D6373 and AASHTO M 320.

[0050] In an aspect, the dynamic shear rheometer (DSR) test is useful for characterizing viscous and elastic behavior of asphalt binders at elevated temperatures. In a further aspect, temperatures anticipated in the location of asphalt binder placement can be used to determine the test temperatures. A thin asphalt binder sample is placed between two circular plates, the lower of which is fixed. The upper plate oscillates across the sample at 1.59 Hz to create a shearing action. Properties measured in the DSR include complex shear modulus (G*), or the samples resistance to deformation when repeatedly sheared, and phase angle (5), or the lag between applied shear stress and resulting shear strain. Larger 5 values correspond to more viscous materials. Sample thickness corresponds to testing temperatures. DSR testing can be conducted on unaged, RTFO aged, UV aged, and PAV aged samples. Tests on unaged binder and RTFO samples are primarily concerned with rutting, while tests on PAV samples are primarily concerned with fatigue cracking. The DSR test is more fully described in AASHTO T 315.

[0051] In another aspect, the multiple stress creep and recovery (MSCR) can be used to assess rutting performance of an asphalt binder. The MSCR can be conducted on a dynamic shear rheometer. In the MSCR test, a creep load (1 s) is applied to a sample and then removed. The sample is allowed to recover for a period of time (9 s). A low stress is typically applied for 10 cycles (about 0.1 kPa) and then stress is increased for an additional 10 cycles (3.2 kPa). The MSCR test is more fully described in AASHTO TP70, AASHTO MP19, AASHTO T 350, and AASHTO T 332.

[0052] In another aspect, the bending beam rheometer (BBR) test can measure low temperature stiffness and relaxation properties of an asphalt binder, which can in turn provide information about low-temperature cracking resistance of an asphalt binder. Testing temperatures can differ based on anticipated temperatures in the area where the asphalt would be installed. An asphalt beam is submerged in a liquid bath (typically ethanol, distilled water, and / or a glycol-methanol mixture) and a load is applied to the beam. Deflection of the beam is measured over time and stiffness is calculated based on that deflection. BBR tests are typically conducted on PA asphalt binder samples. The BBR test is described in AASHTO T 313 and AASHTO PP 42.

[0053] Any of the above tests can be modified as described herein in the Examples based on available equipment, specific desired properties of the binders, or the like.

[0054] Now having described the aspects of the present disclosure, in general, the following Examples describe some additional aspects of the present disclosure. While aspects of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure.ASPECTS

[0055] The present disclosure can be described in accordance with the following numbered aspects, which should not be confused with the claims.

[0056] Aspect 1. A modified asphalt binder comprising an asphalt binder, one or more plastics, and a nanofiller comprising graphitic carbon nitride, carbon nanofibers (CNFs), or both graphitic carbon nitride and CNFs.

[0057] Aspect 2. The modified asphalt binder of aspect 1 , wherein the carbon nanofibers comprise a diameter of from about 10 nm to about 500 nm.

[0058] Aspect 3. The modified asphalt binder of aspect 1 or 2, wherein the carbon nanofibers comprise a length of from about 20 to about 200 pm.

[0059] Aspect 4. The modified asphalt binder of any one of aspects 1-3, wherein the one or more plastics comprise high-density polyethylene (HDPE), low-density polyethylene (LDPE), ethylene vinyl acetate (EVA), or any combination thereof.

[0060] Aspect 5. The modified asphalt binder of any one of aspects 1-4, wherein the one or more plastics comprise post-consumer waste, manufacturing waste, virgin plastics, recycled plastics, or any combination thereof.

[0061] Aspect 6. The modified asphalt binder of any one of aspects 1-5, wherein the graphitic carbon nitride is present at from about 0.5 to about 3 phr in the modified asphalt binder.

[0062] Aspect 7. The modified asphalt binder of any one of aspects 1-6, wherein the carbon nanofibers are present at from about 0.5 to about 3 phr in the modified asphalt binder.

[0063] Aspect 8. The modified asphalt binder of any one of aspects 1-7, wherein the graphitic carbon nitride and the carbon nanofibers are present in a 1 :1 ratio by weight.

[0064] Aspect 9. The modified asphalt binder of any one of aspects 1-8, wherein the one or more plastics are present at from about 3 to about 5 phr in the modified asphalt binder.

[0065] Aspect 10. The modified asphalt binder of any one of aspects 1-9, wherein the one or more plastics comprises HDPE and wherein the nanofiller is present at from about 2.5 to about 3 phr in the modified asphalt binder.

[0066] Aspect 11. The modified asphalt binder of aspect 10, wherein the H DPE is present at from about 3 to about 4 phr in the modified asphalt binder.

[0067] Aspect 12. The modified asphalt binder of any one of aspects 1-9, wherein the one or more plastics comprises EVA and wherein the nanofiller is present at from about 0.5 to about 1 phr in the modified asphalt binder.

[0068] Aspect 13. The modified asphalt binder of aspect 12, wherein the EVA is present at from about 4 to about 5 phr in the modified asphalt binder.

[0069] Aspect 14. A road, pavement, or shingles comprising the modified asphalt binder of any one of aspects 1-13.

[0070] Aspect 15. A method for making a modified asphalt binder, the method comprising:(a) heating an asphalt binder in an oven;(b) admixing one or more plastics with the binder to produce a polymer-modified binder;(c) admixing a graphitic carbon nitride, carbon nanofibers, or a combination thereof with the polymer-modified binder to produce the modified asphalt binder.

[0071] Aspect 16. The method of aspect 15, wherein the asphalt binder is heated at from about 135 °C to about 180 °C in step (a).

[0072] Aspect 17. The method of aspect 15 or 16, wherein the asphalt binder is heated for from about 60 min to about 120 min in step (a).

[0073] Aspect 18. The method of any one of aspects 15-17, wherein step (b) is conducted using a high-speed shear mixer.

[0074] Aspect 19. The method of any one of aspects 15-18, wherein admixing in step (b) is conducted for from about 30 minutes to about 50 minutes.

[0075] Aspect 20. The method of any one of aspects 15-19, wherein admixing in step (b) is conducted at from about 4500 rpm to about 6000 rpm.

[0076] Aspect 21. The method of any one of aspects 15-20, wherein admixing in step (c) is carried out for from about 30 minutes to about 40 minutes.

[0077] Aspect 22. The method of any one of aspects 15-21 , wherein admixing in step (c) is carried out at from about 7500 rpm to about 8500 rpm.

[0078] Aspect 23. The method of any one of aspects 15-22, wherein steps (b) and (c) are conducted at from about 160 °C to about 180 °C.

[0079] Aspect 24. The method of any one of aspects 15-23, further comprising synthesizing the graphitic carbon nitride prior to step (a) using a method comprising:(a) heating a precursor compound to a first temperature for a first period of time to form a crude graphitic carbon nitride;(b) washing the crude graphitic carbon nitride to remove residual compounds adsorbed on a surface of the crude graphitic carbon nitride to produce a washed carbon nitride; and(c) drying the washed carbon nitride to produce the graphitic carbon nitride.

[0080] Aspect 25. The method of aspect 24, wherein the first temperature is from about 450 °C to about 650 °C.

[0081] Aspect 26. The method of aspect 24 or 25, wherein the first period of time is from about 2 h to about 4 h.

[0082] Aspect 27. The method of any one of aspects 24-26, wherein step (a) is conducted under an air atmosphere.

[0083] Aspect 28. The method of any one of aspects 24-27, wherein washing is performed using distilled water.

[0084] Aspect 29. The method of any one of aspects 24-28, wherein the precursor compound comprises melamine, thiourea, urea, dicyandiamide, or any combination thereof.

[0085] Aspect 30. A modified asphalt binder produced by the method of any one of aspects 15- 29.

[0086] Aspect 31. The modified asphalt binder of any one of aspects 1-13 or 30, wherein the modified asphalt binder is resistant to rutting, fatigue, thermal cracking, oxidation, ultraviolet radiation, or any combination thereof.

[0087] Aspect 32. The modified asphalt binder of any one of aspects 1-13, 30, or 31, wherein the modified asphalt binder shows a high-temperature failure temperature of from about 10% to about 15% above an otherwise identical but unmodified asphalt binder.

[0088] Aspect 33. The modified asphalt binder of any one of aspects 1-13 or 30-32, wherein the modified asphalt binder shows a rutting parameter at 70° C of from about 195% to about 295% above an otherwise identical but unmodified asphalt binder.

[0089] Aspect 34. The modified asphalt binder of any one of aspects 1-13 or 30-33, wherein the modified asphalt binder shows a non-recoverable creep compliance at 70° C of from about 70% to about 80% above an otherwise identical but unmodified asphalt binder.EXAMPLES

[0090] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and / or methods claimed herein are made and evaluated, and are intended to be purely exemplary of the disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric.Example 1 : Materials and MethodsMaterials

[0091] The modified binder specimens will be prepared using an asphalt binder with a PG 67-22 performance grade (Ergon, Inc., Jackson, MS, USA). In some experiments, other grades of asphalt binders can also be used. The graphitic carbon nitride (g-CsN4) will be synthesized using a variety of precursors including melamine, thiourea, urea, and dicyandiamide (Sigma-Aldrich, Inc., St. Louis, MO, USA). Carbon nanofibers (CNFs) with a diameter of 200 nm and lengths ranging from 20 to 200 mm (also from Sigma-Aldrich, Inc.) will be utilized for the development of a hybrid system. Three different polymer types (Scientific Polymer Products, Inc., Ontario, New York, USA) will be employed in the initial phase to determine the most suitable candidate. Then, the optimal choice among these three polymers, high-density polyethylene (HOPE), low-density polyethylene (LDPE), and ethylene / vinyl acetate (EVA), will be selected for further examination.Sample Preparation

[0092] Graphitic carbon nitride (g-CsNj) The bulk g-C3N4synthesis procedure using a thermalpolymerization approach will be as follows: an appropriate amount of the chosen precursor will be placed in a covered crucible, then heated for 2-4 h at 450-650 °C at a heating rate range between 2.5 and 5 °C / min, under static air atmosphere. The resulting yellowish product will be washed with distilled water to remove any residual alkaline species (i.e., ammonia) adsorbed on the sample’s surface and further dried in a vacuum oven at 60 °C. The as-obtained bulk g-C3N4powder will be re-dispersed in distilled water and then exfoliated to generate graphitic carbon nitride nanosheets by ultrasonication. Finally, the product will be centrifuged and washed with distilled water and dried at 60 °C.

[0093] Modified asphalt samples: The following procedures will be used to prepare the samples of the modified asphalt binder: (1) the binders will be placed in an oven and exposed to a temperature ranging from 160 to 180 °C for 60 minutes. Then, (2) the polymer will be added to the binder and combined using a high-speed shear mixer for 50 minutes at 6000 RPM. After that, (3) the nanofillers (g-C3N4and CNFs) will be added to the polymer-modified binder and combined for another 40 minutes at 8000 RPM. A temperature of 160-180 °C will be maintained throughout the mixing process.Methodology

[0094] A comprehensive characterization program was systematically executed to examine the influence of the hybrid system on the high and low-temperature performance of the modified asphalt samples. The methodological framework of the experimental program is illustrated in FIG. 1.

[0095] Aging procedures: The performance of the modified asphalt binders will be evaluated in accordance with the AASHTO standards, considering four specific conditions: unaged, short-term aged (RTFO), UV aged, and long-term aged (PAV). The short-term aging process for the binders followed the AASHTO T-240 standards using the rolling thin film oven (RTFO) method. Each binder specimen, with a mass of 35.0 ± 0.5 g, was placed within a glass bottle and exposed to a temperature of 163 °C for a duration of 85 minutes. During this interval, the bottles were rotated at a rate of 15 RPM, and heated air was directed onto them. The resulting mass alterations attributed to the lost volatiles will be quantified, and the short-term aged binders will be subsequently collected for subsequent analyses. The long-term aged binders will be achieved by subjecting the RTFO binders to the pressure aging vessel (PAV) at a pressure of 2.1 MPa for a duration of 21 hours, following the AASHTO R28 standard. On the other side, an additional group of asphalt binder samples will be exposed to a UV light source immediately after the RTFO test, with the purpose of simulating ultraviolet aging.High and Low-Temperature Performance

[0096] Rotational viscosity: The rotational viscosity measurements will be conducted at a temperature of 135 °C to assess the workability of the binder. The test will be conducted using FGB EVO-Series rotational viscometers (New South Wales, Australia) in accordance with the AASHTO T-316 standards.

[0097] Rheological behavior. The rheological properties of the binders will be assessed using a dynamic shear rheometer (DSR) test conducted with a DSR RN 4.3 instrument from Rheotest, Germany, following the guidelines of AASHTO T-315 standards. This test method provided data on the complex shear modulus (G*) and phase angle (5) for both the unaged and short-term aged binders at temperatures of 64, 70, 76, and 80 °C. For this evaluation, a parallel plate with a diameter of 25 mm was employed to measure the rutting parameter (G* / sin(5)) and the failure temperature (Tf) of the binders in both conditions. The assessment was initiated at a temperature of 64 °C, and subsequently, the temperature was incrementally raised by 6 °C until the rutting parameter value fell below 1.00 kPa for the unaged binders and 2.20 kPa for the binders subjected to the rolling thin film oven (RTFO) aging process.

[0098] Multiple stress creep and recovery (MSCR): To evaluate the resistance to rutting, the Multiple Stress Creep and Recovery (MSCR) test will be applied in order to analyze the creep and recovery characteristics of both the unmodified and the modified asphalt binders. The testing protocol will be conducted on RTFO binders at a temperatures of 70 °C following the AASHTO T-350 standard. During the MSCR test, a cyclic constant creep stress regime will be applied to the specimens, involving two distinct stress levels: 0.1 kPa and 3.2 kPa. Each stress level will be maintained for a duration of 1 second, followed by a subsequent recovery interval for another 9 seconds. The outcomes garnered from the dynamic shear rheometer (DSR) will be used to calculate the non-recoverable creep compliance (Jnr) and the percentage recovery (R%) at each of the designated stress levels.

[0099] Linear amplitude sweep test (LAS): The LAS test will be used to evaluate the anti-fatigue properties of the asphalt binder. First, the viscoelastic parameters will be obtained from the frequency sweep test at a frequency range of 0.1 to 30 Hz and 5% strain. Then, the linear strain amplitude sweep test will be employed using a constant frequency of 10 Hz in order to determine the damage parameter of the modified binder as described in the AASHTO TP 101 standard.

[0100] Bending beam rheometer (BBR): The long-term aged (PAV) binder will be subjected to the bending beam rheometer (BBR) test following the AASHTO T 313 standard. The outcomes data from the BBR will be used to calculate the creep stiffness at -12 °C in order to evaluate the low-temperature performance of the modified binder.Anti-Aging Performance

[0101] Viscosity aging index (VAI): Considering that aging typically increases the viscosity of the binder, the viscosity aging index (VAI) will be employed as a parameter to evaluate the anti-aging resistance of the modified asphalt binder. By comparing the viscosity values before and after aging, this index provides valuable insights into the ability of the hybrid system to enhance the anti-aging properties of the modified binder. The following equation will be used to calculate the VAI:where HRTFO and QRTFO are the viscosity for the RTFO binder and the unaged binder respectively.

[0102] Rheological aging index (RAI): The complex shear modulus (G*) and the phase angle (6) will be determined for the modified binder under unaged and RTFO-aged conditions. Then, the anti-aging properties of the modified binder will be evaluated using the rheological aging index (RAI). The RAI will be calculated using the following equation:

[0103] Where; Gaged* and Gunaged* are the complex shear modulus of the RTFO aged binder and the unaged binder respectively, while the baged and bunaged are the phase angle of the RTFO aged binder and unaged binder respectively.Sample Mix Design

[0104] A parametric study will be performed using response surface methodology (RSM) to investigate the effects of nanofiller (1:1 g-C3N4 / CNF hybrid nanofiller system) content (0.5-3.0 phr), polymer type (EVA, LDPE, and HDPE), and polymer content (2.0-5.0 phr) on the low temperature, high temperature, and anti-aging properties of the modified asphalt binders. These responses are summarized in Table 1. A preliminary D-optimal design with an anticipated quadratic model yields 22 experimental runs (including five lack-of-fit and five replicate points on the design space). Once these runs are complete and all responses are measured, a numerical multi-response optimization will be performed to identify the modified asphalt binder compositions that would yield desirable low and / or high temperature, and / or anti-aging properties. These properties of the optimal binders will then be compared to those of the corresponding control binders (neat asphalt binder, asphalt binder + nanofiller only, and asphalt binder + polymer only at the optimal nanofiller and polymer contents). Overall, the developed predictive model will be validated with additional experimental runs and used to suggest binder compositions based on select target criteria for performance.Results

[0105] Sample A: A polymer-modified asphalt binder containing 96.3% by weight of asphalt binder (PG 67-22) and 1.93% by weight of EVA was mixed with 1.69% by weight of a nanofiller composition comprising carbon nanofibers (CNF) and graphitic carbon nitride (GCN) in a 1 :1 ratio to obtain a modified asphalt binder. The Fresh viscosity of the modified asphalt binder was measured in accordance with AASHTO T316. The modified asphalt binder underwent short-term aging using the Rolling Thin Film Oven Test (RTFOT) as per AASHTO T240, resulting in the RTFO-modified asphalt binder. For the RTFO-modified binder, the high-temperature performance failure temperature (°C) and rutting parameter at 70 °C (kPa) were determined using the Dynamic Shear Rheometer (DSR) for RTFO-aged binder, following AASHTO T315. Additionally, the non-recoverable creep compliance at 70 °C (1 / kPa) and percent recoverable strain at 70 °C (%) were assessed through the Multiple Stress Creep Recovery (MSCR) test at a 3.2 kPa stress level, performed in accordance with AASHTO T350.The RTFO-modified asphalt binder underwent long term-aging using the Pressure Aging Vessel (PAV) as per AASHTO R28, yielding the PAV-modified asphalt binder. For the PAV-modified binder, the intermediate-temperature failure temperature (°C) and fatigue factor at 22 °C (kPa) were evaluated using the Dynamic Shear Rheometer (DSR) for PAV-aged binder, following AASHTO T315. The predicted fatigue life at 25 °C under 5% strain (heavy traffic conditions) was determined using the Linear Amplitude Sweep (LAS) test, conducted according to AASHTO TP101.The low-temperature performance of the PAV- modified asphalt binder was assessed by measuring the creep stiffness at -12 °C (MPa) and m-value at -12 °C using the Bending Beam Rheometer (BBR) test, performed in accordance with AASHTO T313.

[0106] The RTFO-modified asphalt binder was further subjected to long-term UV aging following UV Protocol 1 mentioned above. The UV aging process was applied to the RTFO- modified binder to obtain the UV-modified asphalt binder. After UV aging, the high- temperature performance failure temperature (°C) and rutting parameter at 70 °C (kPa) were reassessed using the Dynamic Shear Rheometer (DSR), following AASHTO T315. The non- recoverable creep compliance at 70 °C (1 / kPa) and percent recoverable strain at 70 °C (%) were evaluated again using the Multiple Stress Creep Recovery (MSCR) test at a 3.2 kPa stress level, performed in accordance with AASHTO T350. For intermediate-temperature performance, the intermediate-temperature performance failure temperature (°C) and fatigue factor at 22 °C (kPa) were re-evaluated using the Dynamic Shear Rheometer (DSR),following AASHTO T315. The predicted fatigue life at 25 °C under 5% strain (heavy traffic conditions) was determined again using the Linear Amplitude Sweep (LAS) test, conducted according to AASHTO TP101. The results obtained from the UV-modified asphalt binder were compared to the results from the UV-unmodified asphalt binder (PG 67-22) to evaluate the impact of UV exposure. Aging indices were calculated for each test, quantifying the changes induced by UV aging relative to the UV-unmodified asphalt binder (PG 67-22). The results for UV-aged Sample A and other exemplary compositions and property ranges for the same are shown in Tables 2-6 below.

[0107] Viscosity. The viscosity measurements at 135°C for the fresh and RTFO-aged asphalt binders modified with a combination of polymers and nanofillers are presented in Tables 2-6. The results indicate that viscosity increases as the nanofiller and polymer percentages increase in the binder. Specifically, the fresh viscosity of the hybrid-modified binders ranged from 732.73 Pa s to 1584.88 Pa s, while the RTFO-aged viscosities were observed between 1170.35 Pa s and 2142.79 Pa s. The highest viscosity values were recorded for the sample containing 2.804 wt.% nanofiller and 3.738 wt.% polymer, which exhibited an increase of approximately 206% compared to the neat binder. A similar trend was observed after RTFO aging, where the viscosity increased further, demonstrating improved resistance to oxidative aging.

[0108] Despite the viscosity increment with higher nanofiller and polymer contents, all modified binders remained workable and within the acceptable range specified by AASHTO T-316, which sets a maximum viscosity limit of 3000 Pa s at 135 °C for proper handling, pumping, and mixing. The viscosity aging index (VAI) values showed that the incorporation of nanofillers contributed to reducing the rate of viscosity increase post-aging, thereby improving the durability of the binder. These findings confirm that while the addition of nanofillers and polymers enhances the high- temperature performance and aging resistance of asphalt binders, the mixture remains within the required workability standards, making it suitable for practical paving applications.

[0109] Rutting Parameters-. The rutting resistance of the modified asphalt binders was evaluated using the rutting parameter (G / sin6)* at 64°C and 70°C for both fresh and RTFO-aged samples, as shown in Tables 2-6. The results indicate that the addition of nanofillers and polymers significantly improves the rutting resistance of the asphalt binder, with the rutting parameter increasing as the nanofiller and polymer percentages increase. The neat binder exhibited the lowest rutting resistance, with *G / sin6 values of 1.93 kPa and 0.966 kPa at 64 °C and 70 °C, respectively, in the fresh state. In contrast, the modified binders demonstrated substantialimprovements, with the highest increase observed for the sample containing 2.804 wt.% nanofiller and 3.738 wt.% polymer, which achieved *G / sin5 values of 7.591 kPa and 4.014 kPa at 64 °C and 70 °C, respectively.

[0110] Following RTFO aging, the rutting resistance continued to improve, indicating enhanced stiffness and reduced susceptibility to permanent deformation. The *G / sinb values of the neat binder increased to 5.107 kPa and 2.437 kPa at 64°C and 70 °C, respectively, while the modified binders exhibited significantly higher values, with the most resistant sample reaching 20.797 kPa and 9.574 kPa at 64 °C and 70 °C, respectively. This substantial increase suggests that the hybrid polymer-nanofiller system enhances the binder's ability to withstand high temperatures and traffic loading. The overall trend confirms that higher nanofiller and polymer contents contribute to increased stiffness and improved rutting resistance, making the modified binders more durable and suitable for high-temperature applications.Table 2: Compositions and PropertiesTable 6: UV Resistance Improvement Data for Optimal Mixes

[0111] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the abovedescribed embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.REFERENCES1. American Society of Civil Engineers, “Report Card for America’s Infrastructure,” 2021 , <https: / / infrastructurereportcard.org / cat-item / roads-infrastructure / >, accessed October 30, 2023.American Association of State Highway and Transportation Officials. "Standard Method of Test for Effect of Heat and Air on a Moving Film of Asphalt Binder (Rolling Thin-Film Oven Test)." AASHTO T 240 (2013). AASHTO T-316. "Standard method of test for viscosity determination of asphalt binder using rotational viscometer." (2019). AASHTO T 315-12. "Determining the rheological properties of asphalt binder using a dynamic shear rheometer (DSR)." AASHTO Provisional Standards (2016). AASHTO (2014) AASHTO T350 - Standard Method of Test for Multiple Stress Creep Recovery (MSCR) Test of Asphalt Binder Using a Dynamic Shear Rheometer (DSR). American Association of State Highway and Transportation Officials, Washington, DC. American Association of State Highway and Transportation Officials. (2012). Standard practice for accelerated aging of asphalt binder using a pressurized aging vessel (PAV). Standard specifications for transportation materials and methods of sampling and testing. R 28 (pp. 8-9). Washington DC, USA: AASHT AASHTO T 313. "Standard method of test for determining the flexural creep stiffness of asphalt Binder using the bending beam rheometer (BBR). standard specifications for transportation materials and methods of sampling and testing." (2019). Pang, Ling, et al. "Effect of LDHs on the aging resistance of crumb rubber modified asphalt." Construction and Building Materials 67 (2014): 239-243. Wang, Riran, et al. "Evaluation of aging resistance of asphalt binder modified with graphene oxide and carbon nanotubes." Journal of Materials in Civil Engineering 31 , no. 11 (2019): 04019274. AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications. Washington, D.C. :American Association of State Highway and Transportation Officials, 2016. Fini, Ellie H., et al. "Physiochemical, rheological, and oxidative aging characteristics of asphalt binder in the presence of mesoporous silica nanoparticles." Journal of Materials in Civil Engineering 28, no. 2 (2016): 04015133.

Claims

CLAIMSWhat is claimed is:

1. A modified asphalt binder comprising an asphalt binder, one or more plastics, and a nanofiller comprising graphitic carbon nitride, carbon nanofibers (CNFs), or both graphitic carbon nitride and CNFs.

2. The modified asphalt binder of claim 1 , wherein the carbon nanofibers comprise a diameter of from about 10 nm to about 500 nm.

3. The modified asphalt binder of claim 1 , wherein the carbon nanofibers comprise a length of from about 20 to about 200 pm.

4. The modified asphalt binder of claim 1 , wherein the one or more plastics comprise high-density polyethylene (HDPE), low-density polyethylene (LDPE), ethylene vinyl acetate (EVA), or any combination thereof.

5. The modified asphalt binder of claim 1 , wherein the one or more plastics comprise postconsumer waste, manufacturing waste, virgin plastics, recycled plastics, or any combination thereof.

6. The modified asphalt binder of claim 1 , wherein the graphitic carbon nitride is present at from about 0.5 to about 3 phr in the modified asphalt binder.

7. The modified asphalt binder of claim 1 , wherein the carbon nanofibers are present at from about 0.5 to about 3 phr in the modified asphalt binder.

8. The modified asphalt binder of claim 1 , wherein the graphitic carbon nitride and the carbon nanofibers are present in a 1 :1 ratio by weight.

9. The modified asphalt binder of claim 1 , wherein the one or more plastics are present at from about 3 to about 5 phr in the modified asphalt binder.

10. The modified asphalt binder of claim 1 , wherein the one or more plastics comprises HDPE and wherein the nanofiller is present at from about 2.5 to about 3 phr in the modified asphalt binder.

11. The modified asphalt binder of claim 10, wherein the HDPE is present at from about 3 to about 4 phr in the modified asphalt binder.

12. The modified asphalt binder of claim 1, wherein the one or more plastics comprises EVA and wherein the nanofiller is present at from about 0.5 to about 1 phr in the modified asphalt binder.

13. The modified asphalt binder of claim 12, wherein the EVA is present at from about 4 to about 5 phr in the modified asphalt binder.

14. A road, pavement, or shingles comprising the modified asphalt binder of any one of claims 1- 13.

15. A method for making a modified asphalt binder, the method comprising:(a) heating an asphalt binder in an oven;(b) admixing one or more plastics with the binder to produce a polymer-modified binder;(c) admixing a graphitic carbon nitride, carbon nanofibers, or a combination thereof with the polymer-modified binder to produce the modified asphalt binder.

16. The method of claim 15, wherein the asphalt binder is heated at from about 135 °C to about 180 °C in step (a).

17. The method of claim 15, wherein the asphalt binder is heated for from about 60 min to about 120 min in step (a).

18. The method of claim 15, wherein step (b) is conducted using a high-speed shear mixer.

19. The method of claim 15, wherein admixing in step (b) is conducted for from about 30 minutes to about 50 minutes.

20. The method of claim 15, wherein admixing in step (b) is conducted at from about 4500 rpm to about 6000 rpm.

21. The method of claim 15, wherein admixing in step (c) is carried out for from about 30 minutes to about 40 minutes.

22. The method of claim 15, wherein admixing in step (c) is carried out at from about 7500 rpm to about 8500 rpm.

23. The method of claim 15, wherein steps (b) and (c) are conducted at from about 160 °C to about 180 °C.

24. The method of claim 15, further comprising synthesizing the graphitic carbon nitride prior to step (a) using a method comprising:(a) heating a precursor compound to a first temperature for a first period of time to form a crude graphitic carbon nitride;(b) washing the crude graphitic carbon nitride to remove residual compounds adsorbed on a surface of the crude graphitic carbon nitride to produce a washed carbon nitride; and(c) drying the washed carbon nitride to produce the graphitic carbon nitride.

25. The method of claim 24, wherein the first temperature is from about 450 °C to about 650 °C.

26. The method of claim 24, wherein the first period of time is from about 2 h to about 4 h.

27. The method of claim 24, wherein step (a) is conducted under an air atmosphere.

28. The method of claim 24, wherein washing is performed using distilled water.

29. The method of claim 24, wherein the precursor compound comprises melamine, thiourea, urea, dicyandiamide, or any combination thereof.

30. A modified asphalt binder produced by the method of any one of claims 15-29.

31. The modified asphalt binder of any one of claims 1-13, wherein the modified asphalt binder is resistant to rutting, fatigue, thermal cracking, oxidation, ultraviolet radiation, or any combination thereof.

32. The modified asphalt binder of any one of claims 1-13,, wherein the modified asphalt binder shows a high-temperature failure temperature of from about 10% to about 15% above an otherwise identical but unmodified asphalt binder.

33. The modified asphalt binder of any one of claims 1-13, wherein the modified asphalt binder shows a rutting parameter at 70° C of from about 195% to about 295% above an otherwise identical but unmodified asphalt binder.

34. The modified asphalt binder of any one of claims 1-13, wherein the modified asphalt binder shows a non-recoverable creep compliance at 70° C of from about 70% to about 80% above an otherwise identical but unmodified asphalt binder.

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