Anti-aging agents for asphalt binders

Abstract

The invention relates to an anti-aging agent for an asphalt binder. Specifically, the present application provides an asphalt mixture comprising an asphalt binder wherein the asphalt binder comprises at least one of a raw asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising asphalt shingle; and an anti-aging agent having a hydroxyl number greater than about 25 mg KOH / g.

Description

[0001] This application is a divisional application with application date of July 15, 2020, application number 202080057248.5, and title “Anti-aging agent for asphalt binder”. Background Art

[0002] Asphalt pavement is one of the most recycled materials in the world and, when recovered in the shoulders and abutments of paved roads, can be used as a gravel substitute for unpaved roads and as a replacement for virgin aggregate and binder in new asphalt pavements. Typically, the use of recycled asphalt pavement is limited to the pavement sublayer or to controlled amounts in the asphalt base and surface layers. This use is limited in part because asphalt deteriorates over time, loses its elasticity, becomes oxidized and brittle, and tends to crack, especially under stress or low temperatures. These effects are primarily due to aging of the organic components of the asphalt (e.g., the binder containing earth asphalt), especially when exposed to weather. Aged binders are also highly viscous. As a result, recycled asphalt pavement has different properties than virgin asphalt and is difficult to process. Summary of the invention

[0003] Disclosed are compositions and methods that can delay, reduce or otherwise overcome the aging effects in original or aged asphalt to maintain or restore some or all of the original properties of the original binder or original asphalt used. In some embodiments, the disclosed compositions and methods can change the aging rate of the total binder present in an asphalt mixture, the asphalt mixture comprising original asphalt, and reclaimed asphalt binder material comprising asphalt pavement (RAP), asphalt shingle (RAS) or both. The disclosed compositions and methods use a modified asphalt anti-aging agent that is modified to contain a high level of free hydroxyl groups. This modified anti-aging agent can improve processing and performance characteristics in original asphalt, reclaimed asphalt and highly oxidized asphalt. In addition, the incorporation of this anti-aging agent can slow down the harmful effects of aging on original asphalt, allowing the use of a larger amount of recycled asphalt materials, or both.

[0004] In some embodiments, the present disclosure describes an asphalt mixture comprising an asphalt binder, wherein the asphalt binder includes at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle; and a modified anti-aging agent having a hydroxyl value greater than about 25 mgKOH / g.

[0005] In some embodiments, the present disclosure describes an asphalt mixture comprising an asphalt binder, wherein the asphalt binder includes at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle; and a novel anti-aging agent having a hydroxyl value greater than about 25 mg KOH / g, greater than 35 mg KOH / g, greater than 40 mg KOH / g, or greater than 50 mg KOH / g.

[0006] In some embodiments, the present disclosure describes an asphalt mixture comprising an asphalt binder, wherein the asphalt binder includes at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle; and a modified anti-aging agent, wherein the modified anti-aging agent is derived from reacting an asphalt additive with one or more polyols or amino alcohols to increase the hydroxyl value of the additive, wherein after PAV aging at 100 degrees Celsius for 40 hours, the modified anti-aging agent provides less negative ΔTc in an aged asphalt containing the modified anti-aging agent than a similarly aged binder with an unmodified asphalt additive.

[0007] In another embodiment, the present disclosure describes a method for improving the effectiveness of an antioxidant on an asphalt mixture, the method comprising reacting the antioxidant with one or more polyols or amino alcohols to increase the hydroxyl value of the antioxidant and form a modified antioxidant, wherein after PAV aging for 40 hours at 100 degrees Celsius, the modified antioxidant provides less negative ΔTc in aged asphalt containing the modified antioxidant compared to a similar aged binder with unmodified antioxidant.

[0008] In another embodiment, the present disclosure describes a method of forming a modified antioxidant for an asphalt mixture, the method comprising reacting one or more of tall oil, fatty acids, or vegetable oils with one or more polyols or amino alcohols at a temperature of less than about 200 degrees Celsius to increase the hydroxyl value of the tall oil to at least 25 mg KOH / g.

[0009] In another embodiment, the present disclosure describes a method for slowing down aging or restoring an aged asphalt binder, the method comprising adding a modified anti-aging agent to the asphalt binder, wherein the asphalt binder comprises at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle; and wherein the hydroxyl value of the modified anti-aging agent is greater than about 25 mg KOH / g.

[0010] In another embodiment, the present disclosure describes a method for improving the effectiveness of an asphalt additive as an anti-aging agent for an asphalt mixture, the method comprising reacting an asphalt additive comprising one or more carbonyl groups with one or more polyols or amino alcohols to form a modified anti-aging agent having a hydroxyl value greater than about 25 mg KOH / g, and adding the modified anti-aging agent to an asphalt binder to form an asphalt mixture, wherein the asphalt binder comprises at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle.

[0011] The above summary of the present disclosure is not intended to describe every embodiment or every specific implementation of the present invention. The following description more specifically illustrates illustrative embodiments. In many places throughout the application, guidance is provided by example lists, which can be used in various combinations. In each case, the narrated list is used only as a representative group and should not be interpreted as an exclusive list.

[0012] Abbreviations, Acronyms and Definitions

[0013] "Aged" refers to asphalt or binder present in or recovered from regenerated asphalt. Due to aging and exposure to outdoor weather, the aged binder has a high viscosity compared to the original asphalt or original binder. The term "aged" also refers to the original asphalt or original binder that has been aged using the laboratory aging test methods described herein (such as RTFO and PAV). "Aged" may also refer to hard, poor quality or non-standard original asphalt or original binder, in particular, original binders with a ring softening point and a ball softening point greater than 65°C according to EN 1427 and a needle penetration value of less than or equal to 12 dmm at 25°C according to EN 1426.

[0014] “Aggregate” and “construction aggregate” refer to particulate mineral materials useful in paving and pavement applications, such as limestone, granite, trap rock, gravel, crushed gravel sand, crushed stone, crushed rock, and slag.

[0015] "Anti-aging agent" refers to an asphalt additive that can be combined with an aged asphalt binder or an original asphalt binder to retard the aging rate of the asphalt or binder, or to restore or renew the aged asphalt or the aged binder, thereby providing some or all of the original properties of the original asphalt or the original binder. In some embodiments, the anti-aging agent may include additives known to those skilled in the art. In other embodiments, the anti-aging agent may include novel compounds that have met the standards disclosed herein. The effectiveness of an asphalt additive as an anti-aging agent can be checked by comparing the ΔTc value of a binder mixture containing the anti-aging agent after 40 hours of PAV aging at 100 degrees Celsius with a similarly aged binder that does not contain the anti-aging agent, or in an example where the asphalt has undergone the disclosed modification to increase its hydroxyl value, with a similarly aged binder containing an unmodified asphalt additive.

[0016] "Asphalt" refers to a binder and aggregate and optionally other components suitable for mixing with the aggregate and binder. Depending on local usage, the term "asphalt mix" or "mixture" may be used interchangeably with the term "bitumen".

[0017] “Asphalt pavement” means compacted asphalt.

[0018] "Binder" refers to a highly viscous liquid or semi-solid form of petroleum. "Binder" may include, for example, asphalt. The term "asphalt binder" may be used interchangeably with the term "binder."

[0019] "Bitumen" refers to a class of black or dark-colored (solid, semisolid or viscous) cementitious materials, either natural or manufactured, composed primarily of high molecular weight hydrocarbons, of which the products asphalts, tars, coal tar pitches and asphaltenes are typical.

[0020] "M-critical" or "creep critical" rating refers to the low temperature relaxation rating of the adhesive. The creep critical temperature is the temperature at which the absolute value of the slope of the flexural creep stiffness versus creep time according to ASTM D6648 is 0.300. Alternatively, the stiffness and creep critical temperature can be determined by a 4 mm Dynamic Shear Rheometer (DSR) test or a Bending Beam Rheometer (BBR).

[0021] "Modified antioxidant" is used to refer to a compound that has undergone a process for increasing the hydroxyl value of the compound. In some embodiments, the modified antioxidant may include an antioxidant known to those skilled in the art that has undergone a disclosed process for increasing the hydroxyl value of the compound. In other embodiments, the modified antioxidant may include a novel compound that has not been previously used in an asphalt mixture, which has undergone a process for producing the hydroxyl value of the disclosed compound. In yet another embodiment, the modified antioxidant may include a combination of known compounds and novel compounds. The reference to "modified antioxidant" does not mean that the starting material must be a recognized or commercially available antioxidant or asphalt additive before the disclosed modification is performed.

[0022] "Pure" or "virgin" binder is a binder that has not been used in or recovered from asphalt pavement or asphalt shingles, and may include Performance Grade binders.

[0023] "PAV" means Pressurized Aging Vessel. PAV is used to simulate accelerated aging of asphalt or binder as described in ASTM D6521-13, Standard Practice for Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV).

[0024] “Recycled asphalt” and “recycled asphalt” refer to RAP, RAS, and recycled binders recovered from old pavement, shingle manufacturing waste, roofing felt, and other products or applications.

[0025] "Reclaimed Asphalt Pavement" and "RAP" refer to asphalt that has been removed or excavated from a previously used road or pavement or other similar structure and processed for reuse by various well-known methods, including grinding, tearing, breaking, crushing, or pulverizing.

[0026] "Recycled asphalt shingles" and "RAS" refer to asphalt shingles from sources including roof tear-offs, manufacturers' discarded asphalt shingles, and post-consumer waste.

[0027] "RTFO" refers to Rolling Thin Film Oven. RFTO is used to simulate short-term aging of adhesives as described in ASTM D2872-12e1, Standard Test Method for Effect of Heat and Air on a Moving Film of Asphalt (Rolling Thin-Film Oven Test).

[0028] "S critical" or "stiffness critical" rating refers to the low temperature stiffness rating of the adhesive. The stiffness critical temperature is the temperature at which an adhesive tested according to ASTM D6648 has a flexural creep stiffness value of 300 MPa as determined by the bending beam rheometer test or the 4 mm DSR test as described in ΔTc.

[0029] SHRP refers to the Strategic Highway Research Program, which developed the new adhesive specification in 1993.

[0030] "Softener" refers to a low viscosity additive that facilitates (or promotes) the mixing and incorporation of recycled binder into virgin binder during the asphalt production process.

[0031] “Temp” is used as an abbreviation for the word “Temperature” in tables and graphs.

[0032] "ΔTc" refers to the value obtained when the low temperature creep or m-value critical temperature is subtracted from the low temperature stiffness critical temperature.

[0033] The 4 mm dynamic shear rheometer (DSR) test and analysis procedure is described by Sui, C., Farrar, M., Tuminello, W., Turner, T., A New Technique for Measuring low-temperature Properties of Asphalt Binders with Small Amounts of Material, Transportation Research Record: No 1681, TRB 2010. See also Sui, C., Farrar, MJ, Harnsberger, PM, Tuminello, WH, Turner, TF, New Low Temperature Performance Grading Method Using 4mm ParallelPlates on a Dynamic Shear Rheometer. TRB Preprint CD, 2011, and Farrar, M. et al., (2012), Thin Film Oxidative Aging and Low Temperature Performance Grading Using Small Plate Dynamic Shear Rheometry:An Alternative to Standard RTFO,PAV and BBR.Eurasphalt&Eurobitume 5th E&E Congress-2012Istanbul(Page Paper O5ee-467).Istanbul:Foundation Euraspalt.

[0034] Unless otherwise indicated, all weights, parts and percentages are by weight. DETAILED DESCRIPTION

[0035] In one aspect, the present disclosure provides an asphalt mixture comprising an asphalt binder and a modified anti-aging agent having a hydroxyl value greater than about 25 mg KOH / g. The asphalt binder may include virgin asphalt binder, recycled asphalt binder material (RAP) comprising asphalt pavement, or recycled asphalt binder material (RAS) comprising asphalt shingles, or a combination thereof.

[0036] As asphalt ages, the binder in the asphalt oxidizes, which negatively affects the properties of the asphalt. For example, the aged binder will generally become more brittle, especially at low temperatures, resulting in cracking of the asphalt. In addition, the penetration index of the asphalt will generally increase. The properties of the binder containing earth asphalt in the recycled asphalt source relative to the original binder used in the asphalt mixture are shown in Table 1.

[0037] Table 1

[0038]

[0039] Table 2 shows the high and low temperature properties of samples produced using virgin binder and earth asphalt recycled from post-consumer waste tiles after various aging periods. Table 2 also shows the high and low temperature properties of mixes containing RAP and RAS. Some of these mixes have been subjected to long-term laboratory aging, and some are from field cores.

[0040] Table 2

[0041]

[0042]

[0043] The last three rows of Table 2 show that the effect of aging on the ΔTc parameter decreases the further away from the air mixture interface. This parameter can be used to assess the effect of aging on the properties of the binder, and more specifically, the effect of aging on the relaxation properties of the binder; the relaxation properties are characterized by a property called "low temperature creep grade".

[0044] Research published in 2011 showed that based on recovered binder data from field cores, ΔTc can be used to identify when a pavement has reached a point where there is a risk of non-load related mix cracking, and also when potential failure limits have been reached. In that study, the authors subtracted the stiffness critical temperature from the creep or m critical temperature, and thus binders with poor performance characteristics had calculated positive ΔTc values.

[0045] Since 2011, industry researchers have agreed to reverse the order of subtraction, and so adhesives that exhibit poor performance characteristics are calculated as negative ΔTc values ​​when the mThreshold Temperature is subtracted from the StiffnessThreshold Temperature. It is generally accepted in the industry that it makes more sense for poor performing adhesives to become more negative as performance decreases. Therefore, today in the industry and as used in the application, the ΔTc warning limit value is -3°C, and the potential damage value is -5°C.

[0046] Reports at two Federal Highway Administration Expert Task Group meetings have shown a correlation between ΔTc values ​​of binders recovered from field test projects and the severity of pavement damage associated with fatigue cracking. In addition, it has been shown that when the binders used to construct these field test projects were subjected to 40 hours of PAV aging, the ΔTc values ​​showed a correlation with pavement damage associated with fatigue cracking, especially top-down fatigue cracking, which is generally considered to be the result of binder relaxation loss at the surface of the soil-asphalt mixture. It is therefore desirable to obtain an asphalt mixture whose soil-asphalt material has a reduced susceptibility to developing excessively negative ΔTc values ​​with aging.

[0047] The data in Table 1 show that a typical virgin binder produced by a refinery can maintain a ΔTc greater than -3°C after 40 hours of PAV aging. Furthermore, the data in Table 1 show that the ΔTc values ​​of binders recovered from RAP can be less than -4°C, and the impact of high RAP levels in new soil-asphalt blends can further reduce the ΔTc values. Furthermore, the extremely negative values ​​of ΔTc for RAS-recovered binders require additional detailed examination of the overall impact of RAS incorporated into soil-asphalt blends.

[0048] Table 2 shows that soil asphalt mixtures can be aged under laboratory aging conditions, after which the binder is recovered from the mixture and the ΔTc of the recovered binder is determined. The long-term aging protocol for soil asphalt mixtures in AASHTO R30 specifies aging the compacted mixture at 85°C for five days. Some studies have extended the aging time to ten days to investigate the effects of more severe aging. Recently, aging loose soil asphalt mixtures at 135°C for 12 hours and 24 hours, and in some cases for even longer periods of time, has been proposed as an alternative to aging compacted mixtures. The goal of these aging protocols is to produce rapid binder aging similar to field aging representative of use longer than 5 years, and more ideally 8 to 10 years. For example, it has been shown that for a mixture that is approximately eight years old, the ΔTc of reclaimed or recycled asphalt from the top 1 / 2 inch of the pavement is more severe than aging at 135°C for 12 hours, but not as severe as aging at 135°C for 24 hours.

[0049] The data in the first two rows of Table 2 show why long-term aging of mixtures containing recycled products is important. The binder recovered from the unaged mixture (row 1) exhibited a ΔTc of -1.7°C, while the binder recovered from the 5-day aged mixture exhibited a ΔTc of -4.6°C.

[0050] Tables 1 and 2 show the impact of incorporating recycled materials at high binder replacement levels, particularly those derived from post-consumer waste shingles. While it is desirable to use such recycled materials, the effects of aged binders on the properties of such asphalt mixtures have limited the incorporation of RAP and RAS materials. In some cases, government agencies have even placed restrictions on the amount of RAP and RAS materials that may be used in asphalt mixtures. Current asphalt paving practices involve the use of high percentages of RAP and RAS as components in the asphalt being laid. In some cases, RAP concentrations may be as high as 50% by weight of the asphalt paving mixture, and RAS concentrations may be as high as 6% by weight of the asphalt paving mixture. Typical binder contents for RAP are in the range of 5-6% by weight, and typical binder contents for RAS are in the range of 20-25% by weight. Thus, a binder containing 50% by weight RAP will contain 2.5% to 3% RAP binder of the final binder mixture, while a binder mixture containing 6% by weight RAS will contain 1.2% to 1.5% RAS binder of the final binder mixture. In many cases, RAP and RAS are combined in the binder mixture; for example, 20% to 30% RAP and 5% to 6% RAS can be incorporated into the binder mixture. Based on typical asphalt binder contents of RAP and RAS, an asphalt binder containing 20% ​​to 30% RAP and 5% to 6% RAS can result in 2% of the binder coming from the combination of RAP and RAS up to as much as 3.3% of the binder coming from the combination of RAP and RAS. Since a typical asphalt paving will contain about 5.5% total soil asphalt, about 36% to as much as 60% of the total soil asphalt in the soil asphalt mixture can come from these recycled sources.

[0051] In order to reduce or delay the impact of asphalt aging on the long-term performance of asphalt mixture, people have carried out research of different success degrees to many materials.A class of materials is called anti-aging agent or rejuvenator.These materials are often sold with the narrative target of reversing the aging that has occurred in the raw materials (such as RAP and RAS) of recovery or slowing down the aging effect in the original binder.In some embodiments, anti-aging agent can help to recover the rheological properties of aging asphalt binder, thereby allowing the asphalt mixture of greater percentage to be formed by RAP material or RAS material.For example, modified anti-aging agent can be partially helped in the following ways: softening aging binder to produce processable asphalt mixture, which then makes this mixture easy to prepare, lay and compact.Additionally or alternatively, modified anti-aging agent can help slow down or prevent the aging effect to the original binder, thereby allowing the original binder to use a longer service life.

[0052] One group of antioxidants that have been developed includes sterols. Sterols, also known as steroid alcohols, are a group of organic molecules that are generally derived from natural sources such as plants, animals, fungi, or bacteria. It has been found that sterols help to increase the ΔTc of an aged binder, thereby allowing the binder to maintain its performance characteristics over a longer life of the material. Although sterols have shown promise as asphalt antioxidants, the costs associated with producing such materials can be relatively high.

[0053] Another group of asphalt antioxidants include those obtained from bio-based sources, including, for example, castor oil, cashew nut shell liquid, rapeseed oil, soybean oil, sunflower oil, tall oil, vegetable oils and other plant-based oils. Some of these materials can be relatively cheap and easily available compared to sterols, however, many of these materials have been found to be poor antioxidants or have other disadvantages. For example, it has been found that vegetable oils help soften the binder, but are easily leached from the renewed asphalt, thereby causing the binder to revert to its aged state and, over time, to cause rutting in the asphalt.

[0054] PCT International Patent Application Publication No. WO2013\163463A1 (Grady), entitled "REJUVENATION OF RECLAIMED ASPHALT," explores the use of ester-functional antioxidants, such as those derived from tall oil. Grady states that by incorporating ester functional groups into the antioxidant, the glass transition onset temperature of the binder can be lowered, thereby improving the low temperature and fatigue cracking resistance of the asphalt, among other properties. However, we have discovered that the high ester-functional tall oil derivatives disclosed by Grady have adverse effects on asphalt and tend to exhibit poorer performance characteristics over time than the unmodified tall oil material from which the high ester-functional derivatives are prepared. The low performance characteristics of the derivatives disclosed by Grady are believed to be due to the low hydroxyl content (e.g., low hydroxyl value) in the material produced under the reaction parameters disclosed by Grady.

[0055] Modified anti-aging agents disclosed at present include carbonyl-containing materials, such as tall oil, other plant-based materials (e.g., raw materials or extracts derived from plants), or other anti-aging agents modified to contain high levels of free hydroxyl groups (e.g., hydroxyl values ​​of at least about 25 mg KOH / g) as discussed in more detail below. Without being bound by theory, it is believed that increasing the number of free hydroxyl groups in such agents, such as by increasing the number of free hydroxyl groups in tall oil materials, increases the polarity of such anti-aging agents, thereby making them more compatible and therefore more suitable for helping to soften and mix with aging binders and other materials. For example, asphalt binders are a complex mixture of materials, and although the mechanism of aging is not yet fully understood, due to oxidation, the relative amount of aliphatic groups or segments in the binder material generally tends to shift to a more polar structure, including, for example, forming ethers, peroxides, and alcohol groups in the aging binder material. With aging, this shift can cause the binder to become harder and more polar. We have discovered that increasing the polarity of antioxidants (e.g., tall oil or other carbonyl-containing agents) by increasing the relative number of free hydroxyl groups within such compounds can significantly improve their efficacy as antioxidants. Such modified antioxidants appear to be more compatible with aged binders and can help solvate and soften the aged binder to reduce both the M critical level and the S critical level of the material and increase the Tc.

[0056] The disclosed modified anti-aging agents preferably can change (e.g., reduce or slow) the aging rate of asphalt binders, or can renew, restore or recover aged or recycled binders to provide some or all of the properties of the original asphalt binder. The disclosed asphalt mixtures containing such modified anti-aging agents can also improve the processing and performance characteristics of original, regenerated and highly oxidized asphalt, which helps in the preservation, recovery and reuse of asphalt or asphalt binders. In some embodiments, the disclosed modified anti-aging agents can change or improve the physical and rheological properties of asphalt mixtures, such as stiffness, effective temperature range and low temperature properties.

[0057] The starting material that can be used for the modified anti-aging agent disclosed in the derivatization preferably comprises the obtainable or obtainable carbonyl group that can react with one or more hydroxyl groups of polyol.Such starting material can include the starting material containing carboxylic acid group, and the carboxylic acid group reacts with polyol to form ester bond, or reacts with the amine group of amino alcohol to form amide bond.Exemplary carbonyl-containing compounds can include but are not limited to triglyceride, such as various plants and natural oil, various tall oil, vegetable oil or natural fatty acid, tall oil and gum rosin acid (gum rosin acid), monoacid, diacid, triacid, ester, polyester and various amides.Although the following embodiment mainly focuses on using tall oil as starting material, the concept disclosed herein does not need to be limited to tall oil.

[0058] Preferred starting materials include starting materials (e.g., carboxylic acids, esters, etc.) with one or more reactive carbonyl groups, and are relatively cheap to obtain. Such starting additives may include, but are not limited to, plant-based materials, such as castor oil, cashew nut shell oil, cottonseed oil, corn oil, peanut oil, rapeseed oil, rice bran oil, safflower oil, sarsaparilla root oil, soybean oil, sunflower oil, vegetable oil, wheat germ oil, and other plant-based oils; rosin and rosin acid; fatty acids; mixtures thereof, etc. Additionally or alternatively, the starting material may include one or more coal or petroleum-based materials, including but not limited to coal tar pitch, coal extracts, engine oil or lubricating oil, paraffin or naphthenic oil, their derivatives or mixtures, etc. In some embodiments, when other commercially available anti-aging agents and commercially available asphalt additives are capable of reacting with one or more hydroxyl groups of polyols or the amine groups of amino alcohols to provide reagents or additives that will impart improved anti-aging properties to asphalt mixtures, the disclosed modification techniques may also be applied to such reagents and additives. In some embodiments, the carbonyl groups available in the starting material may be increased by oxidation processes or other synthetic techniques.

[0059] Can use multiple technology to increase the relative quantity of free hydroxyl group in the parent material.In some embodiments, can increase the quantity of free hydroxyl group by making this anti-aging agent react with one or more polyols or amino alcohol, at the same time control reaction conditions and the stoichiometric ratio of material to be conducive to adding such polyols or amino alcohol, and can not significantly consume available hydroxyl group.Additionally or alternatively, the hydroxyl value of parent material can be increased by transesterification reaction or by using different reaction mechanisms, catalyst or with different reactants.

[0060] The availability of free hydroxyl groups can be measured based on the hydroxyl value of the resulting compound, for example by using ASTM method D1957-86 (1995). The disclosed modified antioxidant should have a final hydroxyl value of at least about 25 mg KOH / g, more preferably at least about 35 mg KOH / g, and most preferably at least about 50 mg KOH / g after reaction with a polyol or amino alcohol. In comparison, the hydroxyl values ​​of commercially available fatty acid esters and rosin acid esters are typically in the range of 0-5 mg KOH / g and 5-12 mg KOH / g. The hydroxyl value of crude tall oil is on the order of about 1 mg KOH / g.

[0061] Additionally or alternatively, the final hydroxyl value may be adjusted to even higher or lower values ​​as needed to obtain the desired adjustment to ΔTc. In some embodiments, the modified antioxidant may have a sufficient hydroxyl value to provide a less negative ΔTc in an aged asphalt containing the modified antioxidant after 40 hours of PAV aging at 100 degrees Celsius, compared to a similarly aged binder with an unmodified antioxidant. In some embodiments, the final hydroxyl value may be adjusted based on the acid value of the starting material, the number of acid groups available in the starting molecule, the number of hydroxyl groups in the selected polyol or amino alcohol, the initial polarity of the reactants, etc.

[0062] In some embodiments, the disclosed modification method can reduce the acid value of the starting material. For example, reacting the fatty acid material with one or more polyols or amino alcohols can result in at least some carboxyl groups in the carboxyl group of the fatty acid reacting with polyols (e.g., by esterification) or amino alcohols (e.g., by amide formation) and reducing the final acid value of the material. In some embodiments, the modified anti-aging agent can have an acid value less than about 100, less than about 70, less than about 30 or even lower.

[0063] In some embodiments, the acid value of the starting material can be initially increased to provide more reactive acid groups in the starting material for combining with the disclosed polyols or amino alcohols. A variety of techniques can be used to improve the acid value of the starting material. For example, the starting material can react with an acid or anhydride (e.g., acrylic acid, adipic acid, fumaric acid, maleic acid, maleic anhydride, succinic acid, other diacids, etc.) to increase the number of carboxylic acid groups in the molecule by, for example, Diels-Alder addition or ester addition. The increase in available carboxylic acid groups can allow additional bonding between polyols or amino alcohols. Additionally or alternatively, at least some of the available carboxylic acid groups in the available carboxylic acid groups in the starting material can be retained in the resulting modified antiaging agent, for example, for other functions in an asphalt mixture. For example, carboxylic acid groups can help asphalt binders to bond to aggregate.

[0064] In some embodiments, the disclosed modification method may include an ester exchange method to increase the hydroxyl value. For example, a starting material (such as soybean oil or other plant-based oils) containing one or more ester bonds can be reacted with a polyol using an ester exchange catalyst. A polyol with more than two hydroxyls can replace the organic group at the ester bond. One of the hydroxyl groups in the polyol will be provided to the removed organic group to form new alcohol in the process. A polyol (lacking one of its hydroxyl groups) will be attached to the ester bond of the modified starting material to provide one or more free hydroxyl groups.

[0065] In some embodiments, the disclosed modified anti-aging agent may include modified tall oil. Traditional tall oil is a byproduct of paper mills and includes a complex mixture of different compounds, including various rosin and fatty acid materials, including resin acids, such as abietic acid and its isomers; various fatty acids, including palmitic acid, oleic acid and linoleic acid, fatty alcohols; sterols; and other alkyl hydrocarbon derivatives. The composition of tall oil varies greatly, depending on the source of supply, refining level, etc. A typical technique for quantifying the quality or refining degree of tall oil is to refer to the acid value, fatty acid content level, or both. Traditionally, tall oil with an acid value in the range of about 100-200, or about 125-165, can be purchased. Tall oil is available in a variety of forms, including, for example, crude tall oil and distilled or refined crude tall oil. The distillation of crude tall oil provides fatty acids in various isolated forms, including highly saturated and volatile long-chain fatty acids known as tall oil heads, tall oil fatty acids including C8-C12 fatty acids with different degrees of unsaturation, tall oil rosin, or coal tar pitch mainly including C18-C20 tricyclic monocarboxylic acids. Commercially distilled tall oil includes a mixture of most tall oil fatty acids and tall oil rosin in different proportions. In some embodiments, the modified antioxidant can be derived from crude tall oil, distilled tall oil, tall oil heads, tall oil coal tar pitch, or mixtures thereof.

[0066] The hydroxyl value of tall oil, particularly such fatty acids, resin acids and similar compounds present in tall oil, can be increased by reacting the tall oil with a polyol or amino alcohol at a relatively low temperature. The hydroxyl groups or amine groups can react with one or more carbonyl groups (e.g., carboxylic acid groups) of the fatty acids and resin acids of the tall oil to form ester bonds or amide bonds. Although the reaction conditions, time and stoichiometry can be unique to the individual carbonyl compounds and polyols used in the reaction, the reaction kinetics can be controlled to favor the addition of such polyols or amino alcohols, while at the same time promoting the retention of a large number of residual hydroxyl groups by the reaction temperature and stoichiometric ratio. The disclosed reaction can be carried out at relatively low temperatures and without the use of an ester catalyst to help ensure that the available hydroxyl groups are not consumed by subsequent side reaction crosslinking, thereby providing a high hydroxyl value in the resulting compound.

[0067] For reactions using polyols and fatty acids, the reaction temperature may be below 200° C. Temperatures exceeding 200° C. may promote the formation of ester groups and will significantly reduce the hydroxyl value of the resulting compound.

[0068] For reactions using amino alcohols and fatty acids, the reaction temperature can be high enough to favor amide reactions (e.g., about 150° C.), but is generally lower than the reaction temperature that favors esterification (e.g., above about 180° C.) Temperatures in excess of 200° C. can promote the formation of ester groups and will significantly reduce the hydroxyl value of the resulting compound.

[0069] Compared to the lower molecular weight fatty acids discussed above, larger molecular weight starting materials (e.g., rosin acids and high molecular weight acids) and ester-based starting materials (e.g., polyesters, vegetable oil triglycerides, etc.) may require higher reaction temperatures, longer reaction times, or reaction catalysts to react with the disclosed polyols or amino alcohols.

[0070] Suitable polyols and amino alcohols that can be used in the disclosed reactions can include polyols containing two or more free hydroxyl groups or amines containing one or more hydroxyl groups, including but not limited to ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dimethylol propionic acid, glycerol, trimethylol propane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sucrose, polyethylene glycol, polypropylene glycol, methanolamine, dimethylethanolamine, ethanolamine, aminomethyl propanol, propanolamine, mixtures thereof, etc. In some embodiments, the source of hydroxyl groups can include polyethylene polyols, such as polyethylene glycol (PEG), polypropylene glycol, or other polyalkylene glycols having multiple available and preferably terminal hydroxyl groups.

[0071] Exemplary polyalkylene glycols are miscible, soluble or dispersible in the starting materials and contain repeating units of oxyethyl, oxypropyl and / or oxybutyl groups of low to high molecular weight (e.g., number average molecular weight of about 190 g / mol to about 8000 g / mol, preferably greater than about 190 g / mol). Such polyalkylene glycols may include liquids supplied, for example, as CARBOWAX, POLY(R), HYDROXY ... TM PEG 300 and PEG 400 obtained from PEG 300 and CARBOWAX PEG 400; wax; solid; or a combination thereof. Polyethylene polyols represent a class of preferred polyols that, when reacted with a starting material such as tall oil, provide modifiers that exhibit comparable renewal properties at lower hydroxyl values ​​than other tested polyols. Without being bound by theory, it is believed that the long-chain polyether bonds of such materials may also help increase the polarity of the resulting antioxidant, thereby making the modified antioxidant more compatible with the aged asphalt component and slowing down the aggregation of oxidized molecules in the aged binder.

[0072] In some embodiments, the disclosed modified anti-aging agents can maintain a ΔTc value greater than or equal to -5°C when the asphalt or asphalt pavement is aged. In some embodiments, the disclosed modified anti-aging agents can provide an asphalt binder with a ΔTc greater than or equal to -5°C, or more preferably a ΔTc greater than or equal to -3°C after PAV aging for 40 hours at 100°C. In some embodiments, the disclosed modified anti-aging agents provide an asphalt binder with a more corrected ΔTc value and a reduced R value after aging when compared to a similar aged asphalt binder without the disclosed modified anti-aging agent or an aged binder made using a similar but unmodified anti-aging agent or an anti-aging agent with a lower hydroxyl value.

[0073] Additionally or alternatively, the disclosed modified anti-aging agent can change, reduce or delay the degradation of the rheological properties of the binder containing recycled soil asphalt materials such as RAS and RAP. The disclosed modified anti-aging agent can be added to the asphalt mixture in an amount of about 0.5% by weight to about 15% by weight, about 1% by weight to about 10% by weight, or about 1% by weight to about 3% by weight relative to the amount of the original binder in the asphalt. The amount used in the asphalt mixture may depend in part on the target specifications of the asphalt material, the amount of RAS or RAP contained, or the requirements set by government regulations.

[0074] In some embodiments, the modified anti-aging agent of the present disclosure can be provided by a novel agent that has not been previously used as an anti-aging agent in the asphalt industry, but is manufactured to have a disclosed high hydroxyl value (e.g., greater than about 25 mg KOH / g, greater than 35 mg KOH / g, greater than 40 mg KOH / g, or greater than 50 mg KOH / g) and provide the desired ΔTc disclosed herein. Such novel compounds may include polyols, aliphatic modified polyols, polyester polyols, polycarbonate polyols, and the like.

[0075] In one embodiment, the disclosed asphalt mixture may include a blend of a binder and a modified anti-aging agent. In certain embodiments, the binder blend includes an original binder and a binder extracted from recycled asphalt. For example, the binder extracted from the RAS material can be extracted from manufacturer asphalt shingle waste, from consumer asphalt shingle waste, or from a mixture of binders extracted from manufacturer and consumer asphalt shingle waste. In certain embodiments, the binder blend may include about 60% by weight to about 95% by weight of the original binder and about 5% by weight to about 40% by weight of the binder extracted from recycled asphalt such as RAS. In certain embodiments, the binder blend includes a modified anti-aging agent added to about 0.5% by weight to about 15.0% by weight of the original asphalt. In certain embodiments, the binder blend may include a modified anti-aging agent added to about 0.2% by weight to about 1.0% by weight. The disclosed modified anti-aging agent has been shown to improve the high and low temperature properties of the asphalt binder blend containing RAS and the PG classification of both the low temperature and high temperature ends.

[0076] The disclosed asphalt mixture can be prepared by mixing or blending the disclosed modified anti-aging agent and the original binder to form a mixture or blend. The mixture or blend can be added to the recycled asphalt material (e.g., RAS and / or RAP) and aggregate. Those skilled in the art will recognize that many orders of adding and mixing components are possible. In addition, asphalt can be prepared by applying mechanical or thermal convection. In one aspect, a method for preparing asphalt involves mixing or blending the disclosed modified anti-aging agent with the original asphalt at a temperature of about 100°C to about 250°C. In some embodiments, the disclosed modified anti-aging agent is mixed with the original asphalt at a temperature of about 125°C to about 175°C, or 180°C to 205°C. In some embodiments, asphalt is mixed with asphalt, RAS, RAP, or a combination of RAS and RAP, the disclosed modified anti-aging agent and aggregate.

[0077] In addition to a number of standard tests, the disclosed asphalts can also be characterized according to ASTM specifications and test methods. For example, the disclosed asphalts and binders can be characterized using rheological tests (ie, dynamic shear rheometer, rotational viscosity, and bending beam).

[0078] At low temperatures (e.g., -10°C), pavements need to resist cracking. At ambient conditions, stiffness and fatigue properties are important. At high temperatures, roads need to resist rutting when the asphalt becomes too soft. The asphalt industry has established standards to identify the rheological properties of binders that are related to the performance of pavements that may be laid under three common sets of temperature conditions.

[0079] In order to determine the ΔTc parameter, a 4 mm dynamic shear rheometer (DSR) test procedure and data analysis methodology as described above can be used. The ΔTc parameter can also be determined using a BBR test procedure based on AASHTO T313 or ASTM D6648. It is important that when using the BBR test procedure, the test is performed at a sufficient number of temperatures to obtain a result with a stiffness failure standard of 300 MPa and a creep or m-value failure standard of 0.300, one of which is below the failure standard and one of which is above the failure standard. In some cases, for adhesives with ΔTc values ​​less than -5°C, this may require performing BBR tests at three or more test temperatures. When the BBR standard requirements mentioned above are not met, the ΔTc value calculated from the data may be inaccurate.

[0080] The present application is further illustrated in the following non-limiting examples, in which all parts and percentages are by weight unless otherwise indicated.

[0081] Example 1

[0082] Preparation of crude tall oil modified antioxidants: Two representative modified antioxidants were prepared using crude tall oil and glycerol or polyethylene glycol 400 as sources of hydroxyl groups.

[0083] Sample No. 1 was prepared with 680 grams of crude tall oil having an acid value of about 160 and a hydroxyl number of about 1 mg KOH / g as determined by ASTM D1957-86 (1995). The crude tall oil was heated to about 70°C to facilitate mixing, after which about 320 grams of PEG 400 (a polyethylene glycol ether having a molecular weight of 400 g / mol) was added. The contents of the flask were heated to an elevated temperature of 180°C to initiate a minor level of esterification reaction, thereby joining the PEG to the tall oil compounds, but preventing the hydroxyl groups from being completely consumed in the reaction. In addition, no esterification catalyst was used in the reaction in order to limit the extent to which esterification occurred. The reaction was maintained at elevated temperature until an acid value of 65-85 was obtained. The hydroxyl value of the resulting sample modified anti-aging agent was about 35-60 mg KOH / g sample.

[0084] Sample No. 2 was prepared with 785 grams of crude tall oil having an acid value of about 160 and a hydroxyl number of about 1 mg KOH / g as determined by ASTM D1957-86 (1995). The crude tall oil was heated to about 70°C to facilitate mixing, after which about 215 grams of glycerol was added. The contents of the flask were heated to an elevated temperature of 180°C to initiate a minor level of esterification reaction, thereby joining the glycerol to the tall oil compound. No esterification catalyst was used in the reaction in order to limit the extent to which esterification occurred. The reaction was maintained at elevated temperature until an acid value of 50-70 was obtained. Based on stoichiometry and reaction conditions, it is expected that glycerol will combine with the tall oil so that only about 1-1.25 of the 3 glycerol hydroxyl groups react, thereby leaving about 1.75-2.0 of the hydroxyl groups free. The resulting modified anti-aging agent has a hydroxyl value of about 45-75 mg KOH / g.

[0085] Example 2

[0086] To investigate the efficacy of the modified anti-aging agent of Example 1, five adhesives were produced and subjected to aging tests under various conditions. The adhesives were produced by mixing the components in a 1-gallon jar at a temperature of 187.8°C-204°C (370-400°F) using a low shear Lightning mixer for approximately 30 minutes.

[0087] Binder No. 1 consisted only of the original binder PG64-22.

[0088] Binder No. 2 contained 96% PG64-22 blended with 4% of the Sample No. 1 modified antioxidant.

[0089] Binder No. 3 contained 92% PG64-22 blended with 8% of the Sample No. 1 modified antioxidant.

[0090] Binder No. 4 contained 96% PG64-22 blended with 4% of the Sample No. 2 modified antioxidant.

[0091] Binder No. 5 contained 92% PG64-22 blended with 8% of the Sample No. 2 modified antioxidant.

[0092] The high and low temperature properties of the resulting adhesive were measured using the 4 mm DSR test procedure for unaged samples, samples aged by RTFO according to AASHTO T-240, and PAV aged samples aged at 100° C. for 20 hours according to AASHTO R28. The results are shown in Table 3.

[0093] Table 3.

[0094]

[0095]

[0096] The P / F temperature of the binder heated under unaged conditions is when tested according to AASHTO T-315, the temperature at which the binder stiffness is equal to about 1 kilopascal (kPa). The P / F temperature of the binder under RFTO aging conditions is when tested according to AASHTO T-315, the heating temperature at which the binder stiffness is equal to about 2.2kPa. The P / F temperature of the binder under RFTO aging conditions is when tested according to AASHTO T-315, the low temperature at which the binder stiffness is equal to about 5000kPa. This convention meets typical SHRP PG grading practices. The results in Table 3 show that when there is no antioxidant in the sample, the P / F temperature increases at a faster rate than when there is a modified antioxidant.

[0097] The ΔTc values ​​of PAV aged samples aged at 100° C. for 20 hours and 40 hours according to AASHTO T-313 were also measured using the low temperature BBR test. The results for the samples aged for 20 hours and 40 hours are shown in Tables 4 and 5, respectively.

[0098] Table 4.

[0099]

[0100] Table 5.

[0101]

[0102] For the binder number 1 that does not contain the presence of anti-aging agent, the low temperature ΔTc under the BBR test is relatively lower than any sample binder containing sample number 1 or number 2 modified anti-aging agent. All binder samples containing the modified anti-aging agent tested show more corrected ΔTc, which meets most government regulations. Compared with the pure PG64-22 showing a ΔTc of -1.1, all ΔTc values ​​of the binder samples containing modified anti-aging agents after 20 hours of PAV aging are positive. The ΔTc values ​​of the binder samples containing modified anti-aging agents after 40 hours of PAV aging are also shown to be better than pure PG64-22, and the ΔTc of pure PG64-22 is -3.9, while the lowest ΔTc of the binder samples containing modified anti-aging agents is -1.8.

[0103] The data summarized in Tables 3 to 5 show that for aged binder samples, modified antioxidants with high hydroxyl values ​​have a significant effect on both softness and critical relaxation properties related to the m-value.

[0104] Example 3

[0105] Preparation of soybean oil as a modified antioxidant by transesterification: About 800 grams of soybean oil were added to a laboratory flask. The flask was heated to about 70°C to facilitate mixing. About 100 grams of glycerol and 5 grams of transesterification catalyst (lithium ricinoleate) were then added to the flask. The contents of the flask were heated to about 250°C for 2 hours, then heated to about 270°C and held for 10 hours. The material was then steam sparged to remove any unreacted glycerol. The hydroxyl value of the resulting compound was greater than 100 mgKOH / g sample.

[0106] Example 4

[0107] Preparation of tall oil modified antioxidant with amino alcohol: About 800 grams of sample No. 2 material with a hydroxyl value of 45-75 mg KOH / g was added to a laboratory flask and heated to about 70°C to promote mixing. About 20 grams of monoethanolamine was added to the flask. The contents of the flask were heated to about 140°C and maintained for 2 hours to promote amide formation. The resulting material was then steam sparged to remove any unreacted monoethanolamine. The lower reaction temperature promotes amide formation while minimizing ester formation and thereby retaining hydroxyl groups. The hydroxyl value of the resulting compound is greater than 50 mg KOH / g.

[0108] Example 5

[0109] Preparation of tall oil modified antioxidant with amino alcohol: About 800 grams of crude tall oil with an acid value of about 160 was added to a laboratory flask. The flask was heated to 70°C to promote mixing, after which about 100 grams of monoethanolamine was added. The contents of the flask were heated to 140°C and maintained for 3 hours to promote amide formation. The material was then steam sparged to remove any unreacted monoethanolamine. The lower reaction temperature promotes amide formation while minimizing ester formation and thereby retaining hydroxyl groups. The acid value of the resulting compound was about 60-90, and the hydroxyl value was greater than 65 mg KOH / g.

[0110] Example 6

[0111] Preparation of tall oil modified antioxidant with polyols: About 785 grams of crude tall oil with an acid value of about 160 and a hydroxyl value of about 1 was added to a laboratory flask and heated to about 70°C to facilitate mixing. About 24 grams of maleic anhydride was added to the flask. The contents of the flask were heated to about 205°C and maintained for 2.5 hours to promote the formation of Diels-Alder adducts. The contents of the flask were then cooled to about 180°C, after which about 235 grams of glycerol were added to induce a small level of esterification reaction, thereby joining glycerol to the tall oil adduct, but preventing the hydroxyl groups from being completely consumed in the reaction. This temperature will induce a small level of esterification while maintaining the final hydroxyl content. In addition, no esterification catalyst was used in the reaction in order to limit the extent to which esterification occurred. The reaction was kept at high temperature until an acid value of 70-90 was obtained. The hydroxyl value of the resulting sample modified antioxidant was about 60-95 mg KOH / g sample.

[0112] Example 7

[0113] Preparation of tall oil modified anti-aging agent with polyol: About 785 grams of crude tall oil with an acid value of about 160 and a hydroxyl value of about 1 was added to a laboratory flask and heated to about 70°C to facilitate mixing. About 315 grams of glycerol was added. The contents of the flask were heated to a high temperature of 180°C and maintained for about 1.5 hours. The reaction mass was then heated to about 235°C and maintained for 1 hour. The reaction mass was then heated to 270°C and maintained until the acid value was less than about 10. The hydroxyl value of the resulting sample modified anti-aging agent was about 60-100 mg KOH / g sample.

[0114] The starting materials, polyols and amino alcohols of any of the above modified anti-aging agent embodiments can be replaced to include any materials according to the technology disclosed herein. In addition, any of the above exemplary technologies can be changed or combined with other embodiments or technologies described herein.

[0115] Comparative Example 1

[0116] Tall Oil Coal Tar Pitch: Experiments have been conducted with PG 64-22 blends containing 5% or 10% unmodified tall oil coal tar pitch. This tall oil coal tar pitch was obtained from Union Camp under the trade name Tallex, which is no longer commercially available. Sample blends were produced and aged in PAV according to ASTM D65217 for 20 hours and 40 hours.

[0117] Binder No. 6 contained 95% PG 64-22 plus 5% tall oil coal tar pitch.

[0118] Binder No. 7 contained 90% PG 64-22 plus 10% tall oil coal tar pitch.

[0119] The binder blend was produced by mixing the components in a 1 gallon jar at a temperature of 187.8°C-204°C (370-400°F) for approximately 30 minutes using a low shear illuminated mixer.

[0120] 4 mm DSR tests were performed under aged conditions to determine the S critical and M critical low temperature ratings of the blends under different aged conditions. The ΔTc obtained by subtracting the M critical low temperature value from the S critical low temperature value was determined at each aged condition.

[0121] Table 5

[0122]

[0123] The data from Table 5 show that the unmodified tall oil coal tar pitch in Binder Nos. 6 and 7 failed to increase the ΔTc (eg, provide a more positive ΔTc) for the 40 hour PAV aged samples compared to PG 64-22 without the additive.

[0124] The present invention also includes the following exemplary embodiments:

[0125] Embodiment 1. An asphalt mixture, comprising:

[0126] an asphalt binder, wherein the asphalt binder comprises at least one of virgin asphalt binder, a recycled asphalt binder material (RAP) comprising asphalt pavement, or a recycled asphalt binder material (RAS) comprising asphalt shingles; and

[0127] A modified antioxidant having a hydroxyl value greater than about 25 mg KOH / g.

[0128] Embodiment 2. An asphalt mixture, comprising:

[0129] an asphalt binder, wherein the asphalt binder comprises at least one of virgin asphalt binder, a recycled asphalt binder material (RAP) comprising asphalt pavement, or a recycled asphalt binder material (RAS) comprising asphalt shingles; and

[0130] A modified antioxidant derived from reacting an asphalt additive with one or more polyols or amino alcohols to increase the hydroxyl value of the additive, wherein after PAV aging at 100 degrees Celsius for 40 hours, the modified antioxidant provides less negative ΔTc in an aged asphalt containing the modified antioxidant than a similar aged binder with an unmodified asphalt additive.

[0131] Embodiment 3. A method for slowing down or restoring an aged asphalt binder, the method comprising:

[0132] A modified anti-aging agent is added to an asphalt binder, wherein the asphalt binder comprises at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle; and wherein the modified anti-aging agent has a hydroxyl value greater than about 25 mg KOH / g.

[0133] Embodiment 4. A method for improving the effectiveness of an anti-aging agent on an asphalt mixture, the method comprising reacting the anti-aging agent with one or more polyols or amino alcohols to increase the hydroxyl value of the anti-aging agent and form a modified anti-aging agent, wherein after PAV aging for 40 hours at 100 degrees Celsius, the modified anti-aging agent provides less negative ΔTc in aged asphalt containing the modified anti-aging agent than a similar aged binder with unmodified anti-aging agent.

[0134] Embodiment 5. A method for improving the efficacy of an asphalt additive as an anti-aging agent for an asphalt mixture, the method comprising reacting a compound containing one or more carbonyl groups with one or more polyols or amino alcohols to form a modified anti-aging agent having a hydroxyl value greater than about 25 mg KOH / g, and

[0135] The modified anti-aging agent is added to an asphalt binder to form an asphalt mixture, wherein the asphalt binder includes at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising asphalt pavement, or a recycled asphalt binder material (RAS) comprising asphalt shingles.

[0136] Embodiment 6. The asphalt mixture or method according to any one of the preceding embodiments, wherein the modified anti-aging agent has a hydroxyl value greater than about 35 mg KOH / g.

[0137] Embodiment 7. The asphalt mixture or method according to any one of the preceding embodiments, wherein the modified anti-aging agent has a hydroxyl value greater than about 50 mg KOH / g.

[0138] Embodiment 8. The asphalt mixture or method according to any one of the preceding embodiments, wherein the acid value of the modified anti-aging agent is less than about 100.

[0139] Embodiment 9. An asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and one or more polyols or amino alcohols.

[0140] Embodiment 10. An asphalt mixture or method according to embodiment 9, wherein the one or more polyols or amino alcohols include one or more of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dimethylolpropionic acid, glycerol, trimethylolpropane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sucrose, polyethylene glycol, polypropylene glycol, methanolamine, dimethylethanolamine, ethanolamine, aminomethylpropanol or propanolamine.

[0141] Embodiment 11. The asphalt mixture or method of embodiment 9, wherein the compound is reacted with an acid or anhydride to form a Diels-Alder adduct prior to reacting with the one or more polyols or amino alcohols.

[0142] Embodiment 12. The asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and one or more polyalkylene polyols.

[0143] Embodiment 13. The asphalt mixture or method of embodiment 12, wherein the polyol comprises at least one of polyethylene glycol, polyalkylene glycol, or polypropylene glycol.

[0144] Embodiment 14. The asphalt mixture or method of embodiment 12, wherein the polyol comprises polyethylene glycol or polypropylene glycol.

[0145] Embodiment 15. The asphalt mixture or method of Embodiment 13, wherein the polyethylene glycol comprises liquid polyethylene glycol.

[0146] Embodiment 16. The asphalt mixture or method of embodiment 13, wherein the polyethylene glycol comprises wax or solid polyethylene glycol.

[0147] Embodiment 17. The asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and one or more amino alcohols.

[0148] Embodiment 18. The asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent is derived from one or more plant-based materials, rosin acid, or fatty acid.

[0149] Embodiment 19. An asphalt mixture or method according to any one of the preceding embodiments, wherein the modified anti-aging agent is derived from one or more of castor oil, cashew nut shell oil, cottonseed oil, corn oil, peanut oil, rapeseed oil, rice bran oil, safflower oil, sarsaparilla root oil, soybean oil, sunflower oil, tall oil, vegetable oil, and wheat germ oil.

[0150] Embodiment 20. The asphalt mixture or method according to any one of the preceding embodiments, wherein the modified anti-aging agent is derived from at least one of tall oil, resin acid, or fatty acid.

[0151] Embodiment 21. The asphalt mixture or method according to any one of the preceding embodiments, wherein the modified anti-aging agent is derived from at least one of crude tall oil or tall oil asphalt.

[0152] Embodiment 22. The asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent comprises a compound derived from a coal-based material.

[0153] Embodiment 23. The asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent comprises a compound derived from a petroleum-based material.

[0154] Embodiment 24. An asphalt mixture or method according to any of the preceding embodiments, wherein the asphalt binder is mixed with the modified anti-aging agent to provide a ΔTc greater than or equal to -5.0°C after PAV aging for 40 hours at 100 degrees Celsius.

[0155] Embodiment 25. An asphalt mixture or method according to any of the preceding embodiments, wherein the asphalt binder is mixed with the modified anti-aging agent to provide a ΔTc greater than or equal to -3.0°C after PAV aging for 40 hours at 100 degrees Celsius.

[0156] Embodiment 26. An asphalt mixture or method according to any of the preceding embodiments, wherein the modified anti-aging agent is present in an effective amount to provide a more positive ΔTc value after PAV aging at 100 degrees Celsius for 40 hours compared to a similarly aged binder without the modified anti-aging agent.

[0157] Embodiment 27. An asphalt mixture or method according to any of the preceding embodiments, wherein the asphalt mixture comprises from about 0.5 weight percent (wt%) to about 15 wt% of the modified anti-aging agent relative to the asphalt binder.

[0158] Embodiment 28. The asphalt mixture or method according to any of the preceding embodiments, wherein the asphalt binder comprises the recycled asphalt binder material comprising a reclaimed asphalt pavement.

[0159] Embodiment 29. The asphalt mixture or method of any of the preceding embodiments, wherein the asphalt binder comprises the recycled asphalt binder material comprising recycled asphalt shingles.

[0160] Embodiment 30. The asphalt mixture or method according to any one of the preceding embodiments, further comprising aggregate.

[0161] Embodiment 31. A method for paving a road surface using an asphalt mixture according to any of the preceding embodiments, wherein the asphalt mixture according to any of the preceding embodiments is prepared, mixed, laid onto a base surface and compacted.

[0162] Embodiment 32. A method of forming a modified antioxidant for an asphalt mixture, the method comprising reacting tall oil with one or more polyols or amino alcohols at a temperature below about 200 degrees Celsius to increase the hydroxyl value of the tall oil to at least 25 mg KOH / g.

[0163] Embodiment 33. The modified anti-aging agent according to any one of the preceding embodiments.

Claims

1. An asphalt mixture, comprising: an asphalt binder, wherein the asphalt binder comprises at least one of virgin asphalt binder, a recycled asphalt binder material (RAP) comprising asphalt pavement, or a recycled asphalt binder material (RAS) comprising asphalt shingles; and A modified anti-aging agent, wherein the modified anti-aging agent is derived from reacting an asphalt additive containing one or more carbonyl groups with one or more polyols or with one or more amino alcohols to increase the hydroxyl value of the additive to greater than 25 mg KOH / g, wherein the one or more polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dimethylol propionic acid, glycerol, trimethylol propane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sucrose, polyethylene glycol, polypropylene glycol or polybutylene glycol, Wherein after PAV aging at 100 degrees Celsius for 40 hours, the modified antioxidant provides less negative ΔTc in aged asphalt containing the modified antioxidant than in a similar aged binder with an unmodified asphalt additive.

2. A method for slowing down or restoring an aged asphalt binder, the method comprising: adding a modified anti-aging agent to the asphalt binder, wherein the asphalt binder comprises at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising asphalt pavement, or a recycled asphalt binder material (RAS) comprising asphalt shingles; and The modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and one or more polyols or one or more amino alcohols, wherein the one or more polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dimethylol propionic acid, glycerol, trimethylol propane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sucrose, polyethylene glycol, polypropylene glycol or polybutylene glycol, and the hydroxyl value of the modified anti-aging agent is greater than 25 mg KOH / g, and Wherein after PAV aging at 100 degrees Celsius for 40 hours, the modified antioxidant provides less negative ΔTc in aged asphalt containing the modified antioxidant than in a similar aged binder with an unmodified asphalt additive.

3. A method for improving the efficacy of an asphalt additive as an antioxidant for an asphalt mixture, the method comprising reacting a compound containing one or more carbonyl groups with one or more polyols or with one or more amino alcohols to form a modified antioxidant having a hydroxyl value greater than 25 mg KOH / g, the one or more polyols comprising ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dimethylolpropionic acid, glycerol, trimethylolpropane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sucrose, polyethylene glycol, polypropylene glycol or polybutylene glycol, and adding the modified anti-aging agent to an asphalt binder to form the asphalt mixture, wherein the asphalt binder comprises at least one of a virgin asphalt binder, a recycled asphalt binder material (RAP) comprising an asphalt pavement, or a recycled asphalt binder material (RAS) comprising an asphalt shingle, Wherein after PAV aging at 100 degrees Celsius for 40 hours, the modified antioxidant provides less negative ΔTc in aged asphalt containing the modified antioxidant than in a similar aged binder with an unmodified asphalt additive.

4. The asphalt mixture according to claim 1, or the method according to claim 2 or 3, wherein: The modified anti-aging agent is present in an amount of 0.2 wt % to less than 1 wt % relative to the weight of the asphalt binder.

5. The asphalt mixture according to claim 1, or the method according to claim 2 or 3, wherein the hydroxyl value of the modified anti-aging agent is greater than 35 mg KOH / g.

6. The asphalt mixture according to claim 1, or the method according to claim 2 or 3, wherein the hydroxyl value of the modified anti-aging agent is greater than 50 mg KOH / g.

7. The asphalt mixture according to claim 1, or the method according to claim 2 or 3, wherein the acid value of the modified anti-aging agent is less than 100.

8. An asphalt mixture according to claim 1, or a method according to claim 2 or 3, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and the one or more polyols, and the one or more polyols comprise ethylene glycol, diethylene glycol, glycerol, trimethylolpropane, pentaerythritol or a mixture thereof.

9. An asphalt mixture according to claim 1, or a method according to claim 2 or 3, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and the one or more amino alcohols, and the one or more amino alcohols include methanolamine, dimethylethanolamine, ethanolamine, aminomethylpropanol, propanolamine or a mixture thereof.

10. An asphalt mixture according to claim 1, or a method according to claim 2 or 3, wherein the compound containing one or more hydroxyl groups is reacted with an acid or anhydride to form a Diels-Alder adduct prior to reacting with the one or more polyols or amino alcohols.

11. An asphalt mixture according to claim 1, or a method according to claim 2 or 3, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and one or more polyalkylene polyols, wherein the one or more polyalkylene polyols include polyethylene glycol, polypropylene glycol or polybutylene glycol.

12. The asphalt mixture or the method or the modified anti-aging agent according to claim 10, wherein the polyalkylene polyol comprises polypropylene glycol.

13. The asphalt mixture or the method or the modified anti-aging agent according to claim 10, wherein the polyalkylene polyol comprises polyethylene glycol.

14. The asphalt mixture or method or modified anti-aging agent according to claim 10, wherein the polyalkylene polyol comprises liquid polyethylene glycol.

15. The asphalt mixture or method or modified anti-aging agent according to claim 10, wherein the polyalkylene polyol comprises wax or solid polyethylene glycol.

16. The asphalt mixture according to claim 1, or the method according to claim 2 or 3, wherein the modified anti-aging agent is derived from the reaction product of a compound containing one or more carbonyl groups and one or more amino alcohols.

17. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the modified anti-aging agent is derived from one or more plant-based materials, or fatty acids.

18. The asphalt mixture according to claim 1, or the method of claim 2 or 3, wherein the modified antioxidant is derived from one or more of castor oil, cashew nut shell liquid, cottonseed oil, corn oil, peanut oil, rapeseed oil, rice bran oil, safflower oil, sarsaparilla root oil, soybean oil, sunflower oil, tall oil, vegetable oil, and wheat germ oil.

19. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the modified antioxidant is derived from at least one of tall oil, rosin acid, resin acid, or fatty acid.

20. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the modified antioxidant is derived from at least one of crude tall oil, distilled tall oil, or tall oil pitch.

21. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the modified anti-aging agent comprises a compound derived from a coal-based material.

22. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the modified anti-aging agent comprises a compound derived from a petroleum-based material.

23. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the asphalt binder is mixed with the modified anti-aging agent to provide a ΔTc greater than or equal to -5.0°C after PAV aging at 100 degrees Celsius for 40 hours.

24. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the asphalt binder is mixed with the modified anti-aging agent to provide a ΔTc greater than or equal to -3.0°C after PAV aging at 100 degrees Celsius for 40 hours.

25. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the modified anti-aging agent is present in an amount that provides a more corrected ΔTc value and a reduced R-value after PAV aging at 100 degrees Celsius for 40 hours compared to a similarly aged asphalt binder without the modified anti-aging agent, wherein the R-value is determined according to AASHTO T190 or ASTM D 2844.

26. Asphalt mixture according to claim 1, or method according to claim 2 or 3, wherein said asphalt mixture comprises 1% to 15% by weight of said modified anti-aging agent relative to the weight of said asphalt binder.

27. Asphalt mixture according to claim 1 or method according to claim 2 or 3, wherein said asphalt mixture comprises 1% to 10% by weight of said modified anti-aging agent relative to the weight of said asphalt binder.

28. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the asphalt binder comprises recycled asphalt binder from reclaimed asphalt pavement.

29. The asphalt mixture of claim 1, or the method of claim 2 or 3, wherein the asphalt binder comprises recycled asphalt binder from recycled asphalt shingles.

30. The asphalt mixture according to claim 1 or the method according to claim 2 or 3, further comprising aggregate.

31. A method for paving a road surface using the asphalt mixture according to claim 1, wherein the asphalt mixture is laid onto a base surface and compacted.

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