WO2013090283A1 - Rejuvenation of reclaimed asphalt - Google Patents

Abstract

Asphalt compositions comprising reclaimed asphalt and an ester-functional rejuvenating agent are disclosed. Rejuvenated binder compositions are also included. The rejuvenating agents restore to reclaimed asphalt the more desirable properties of virgin asphalt. Reduced glass-transition onset temperatures and improved creep stiffness in the rejuvenated binders translate to improved low-temperature cracking resistance in the asphalt. The rejuvenating agents impart desirable softening at low dosage while also maintaining acceptable penetration values. Dynamic shear rheometry results demonstrate that criteria for asphalt compositions under low, intermediate, and high temperature conditions can be achieved, and the asphalt will have good fatigue cracking resistance and rutting avoidance. The rejuvenating agents reduce the temperature needed to compact or mix asphalt compositions, which conserves energy and reduces cost. The rejuvenated asphalt and binder compositions will enable greater use of reclaimed asphalt, especially RAP, and help the road construction industry reduce its reliance on virgin, non-renewable materials.

Description

REJUVENATION OF RECLAIMED ASPHALT

FIELD OF THE INVENTION

The invention relates to reclaimed asphalt compositions and rejuvenation thereof.

BACKGROUND OF THE INVENTION

Reclaimed asphalt includes reclaimed asphalt pavement (RAP), reclaimed asphalt shingles (RAS), asphalt reclaimed from plant waste, and asphalt recovered from roofing felt, among other sources.

Asphalt pavement is one of the most recycled materials in the world, finding uses in shoulders of paved surfaces and bridge abutments, as gravel substitutes on unpaved roads, and as a replacement for virgin aggregate and binder in asphalt pavements. Recycled asphalt pavement is typically limited, however, to use as sub-surface "black rock" or in limited amounts in asphalt base and surface layers. The usefulness of recycled material in the critical surface layers is limited because asphalt deteriorates with time; it loses flexibility, becomes oxidized and brittle, and tends to crack, particularly under stress or at low temperatures. The effects are due to aging of the organic component of the asphalt, i.e., the bitumen-containing binder, particularly upon exposure to weather. The oxidized binder is also highly viscous. Consequently, reclaimed asphalt pavement has different properties than virgin asphalt and is difficult to process. Untreated RAP can be used only sparingly; generally, an asphalt mixture comprising up to 30 wt.% of RAP can be used as sub-surface black rock. Moreover, because of the higher demands of the pavement surface, untreated RAP use there is generally limited to 15-25%.

Reclaimed asphalt can be blended with virgin asphalt, virgin binder, or both (see, e.g., U.S. Pat. No. 4,549,834). Rejuvenating agents have been developed to increase the amount of reclaimed asphalt that can be incorporated in both the base and surface layers. Rejuvenating agents restore a portion of the asphalt paving properties and binder bitumen physical properties, such as viscoelastic behavior, so that the reclaimed asphalt properties more closely resemble those of virgin asphalt. Improving the properties of recycled asphalt, and particularly the properties of bitumen binder in RAP, allows increased amounts of RAP to be used in asphalt mixtures without compromising the properties and lifetime of the final pavement.

Commonly used rejuvenating agents for RAP include low-viscosity products obtained by crude oil distillation or other hydrocarbon oil-based materials (see, e.g., U.S. Pat. Nos. 5,766,333 or 6,1 17,227).

Rejuvenating agents of plant origin have also been described. See, for example, U.S. Pat. No. 7,81 1 ,372 (rejuvenating agents comprising bitumen and palm oil); U.S. Pat. No. 7,008,670 (soybean oil, alkyl esters from soybean oil, and terpenes used for sealing or rejuvenating); U.S. Pat. Appl. Publ . No. 2010/0034586 (rejuvenating agent based on soybean, sunflower, rapeseed, or other plant-derived oils); and U.S. Pat. Appl. Publ. No. 2008/0041276 (plasticizers for recycled asphalt that may be vegetable oils or alkyl esters made from vegetable oils). U.S. Pat. Appl. Publ. No. 201 1 /0015312 describes a binder composition comprising a resin of vegetable origin, a vegetable oil, and a polymer having anhydride, carboxylic acid, or epoxide functionality, but this binder is not specifically taught for rejuvenation.

More recently introduced are rejuvenating agents derived from cashew nut shell oil, which contain mostly cardanol, a phenolic compound having a Ci₅ unsaturated chain (see, e.g., PCT Internat. Publ. Nos. WO 2010/077141 and WO 2010/1 10651 ). Such products are available commercially from Ventraco Chemie, B.V., such as RheoFalt® HP-EM.

Various fractions isolated from crude tall oil (CTO) distillation have been used in asphalt compositions, although they are not specifically taught for rejuvenation. See, for instance, U.S. Pat. Appl. Publ . No. 2010/0170417 (CTO distillation fractions as cutting solvents use in asphalt compositions); U.S. Pat. Appl. Publ. No. 2010/0147190 (distilled or oxidized tall oil components for use in asphalt compositions); and U.S. Pat. Nos. 4,479,827 and 4,373,960 (patching compositions comprising asphalt, tall oil, and possibly an organopolysiloxane).

Esters made from tall oil fatty acid (TOFA), tall oil rosin, tall oil pitch, or downstream products of CTO, such as Monomer acid (a unique product described, e.g., in U.S. Pat. No. 7,256,162), dimer acids, or the like, are not suggested for use as rejuvenating agents for reclaimed asphalt. Improved rejuvenating agents for reclaimed asphalt are needed. In particular, the industry needs non-crystalline additives for reclaimed asphalt that can improve low- temperature cracking resistance and fatigue cracking resistance while maintaining good rutting resistance. Better rejuvenating agents would reduce the cost of road construction by enabling greater use of RAP in new pavements and reducing reliance on virgin, non-renewable binder and aggregate materials. A preferred rejuvenating agent would reduce the binder viscosity to a level comparable to that of virgin binder and would also lower the glass-transition temperature of the binder to allow for softer, more easily processed asphalt mixtures. Ideally, the rejuvenating agent would derive from renewable resources, would have good thermal stability at the elevated temperatures normally used to mix and lay asphalt, and could restore the original performance grading to the binder.

SUMMARY OF THE INVENTION

In one aspect, our invention relates to an asphalt composition comprising reclaimed asphalt and an ester-functional rejuvenating agent. The reclaimed asphalt comprises aggregate and an oxidized binder. The rejuvenating agent is present in an amount effective to reduce the glass-transition onset temperature of the oxidized binder by at least 5°C compared with the glass-transition onset temperature of the oxidized binder without the rejuvenating agent. Our invention includes binder compositions suitable for use with reclaimed asphalt and methods for making the inventive asphalt and binder compositions.

In another aspect, our invention relates to an asphalt composition comprising 0.01 to 10 wt.% of a rosin ester and at least 15 wt.% of reclaimed asphalt. The rosin ester is a reaction product of tall oil rosin or a tall oil and a polyol selected from diethylene glycol, triethylene glycol, glycerol, pentaerythritol, and mixtures thereof. Our invention includes a method which comprises rejuvenating reclaimed asphalt by mixing it with 0.01 to 10 wt.% of a tall oil ester, a rosin ester, or mixtures thereof.

In yet another aspect, the invention relates to an asphalt composition comprising an ester-functional rejuvenating agent and at least 15 wt.% of reclaimed asphalt comprising oxidized binder. The rejuvenating agent is present in an amount within the range of 1 to 10 wt.% based on the combined amounts of oxidized binder and rejuvenating agent. The oxidized binder and rejuvenating agent mixture form a rejuvenated binder with a ring and ball softening point, by EN 1427, less than 60°C and a penetration value, by EN 1426, greater than 20 dmm.

Our invention also includes paved surfaces comprising the inventive binders and asphalt compositions.

We found, surprisingly, that by incorporating an ester-functional rejuvenating agent we can revitalize the oxidized bitumen binder of reclaimed asphalt and generate rejuvenated bitumen binders with physical properties similar to those of the original performance grade of the bitumen before it was oxidized. The rejuvenated binders demonstrate reduced glass-transition onset temperatures and, by dynamic shear rheometry (DSR), improved creep stiffness. These results translate to improved low- temperature cracking resistance in the rejuvenated asphalt. DSR analysis also reveals that the rejuvenated binders have reduced values of G^* sin δ, which is consistent with improved fatigue cracking resistance. When rejuvenated binders are formed with up to 10 wt.% of the rejuvenating agent, such binders also have good elevated temperature performance, which relates to rutting avoidance. Rutting is a common failure mode for asphalt road surfaces, particularly those that experience high traffic rates or high weight traffic.

We also found that certain rejuvenating agents restore desirable softening at low dosage while also maintaining acceptable penetration values. The rejuvenating agents are valuable for reducing the temperature needed to compact or mix asphalt compositions, which conserves energy and reduces cost. Certain of our rejuvenating agents improve the temperature sensitivity of the rejuvenated binder, so it can be used in hot mix asphalt processes. Reduced temperature sensitivity is an advantage over conventional additives such as vegetable oil, which can degrade at hot mix temperatures of over 150°C. The inventive binders have good ductility, and they lose properties upon aging only sparingly, similar to virgin binder.

In sum, the rejuvenating agents of our invention allow use of higher levels of recovered asphalt in asphalt mixtures, by reducing the glass transition temperature (Tg) of the binder, thereby improving the processability of the recovered asphalt. Incorporating more recovered asphalt in roads lowers costs of both binder and aggregate and helps the road construction industry reduce its reliance on virgin, nonrenewable materials. DETAILED DESCRIPTION OF THE INVENTION

The invention relates to rejuvenation of asphalt compositions with an ester- functional rejuvenating agent. In particular, it relates to renewal of reclaimed asphalt, especially reclaimed asphalt pavement (RAP), which contains aggregate and oxidized asphalt binder.

In the literature, the term "asphalt" is sometimes used to describe the binder, and sometimes used to describe the binder plus the aggregate. In this description, "asphalt" refers to the composite material comprising a bituminous binder and aggregate, which is generally used for paving applications. Such asphalt is also known as "asphalt concrete." Asphalt is commonly graded to qualify it for paving applications. Examples of asphalt grades used in paving applications include dense-graded asphalt, gap- graded asphalt, porous asphalt and mastic asphalt. Typically, the total amount of bituminous binder in asphalt is from 1 to 10 wt.% based on the total weight of the asphalt, in some cases from 2.5 to 8.5 wt.% and in some cases from 4 to 7.5 wt.%.

"Reclaimed asphalt" includes reclaimed asphalt pavement (RAP), reclaimed asphalt shingles (RAS), reclaimed asphalt from plant waste, reclaimed asphalt from roofing felt, and asphalt from other applications.

"Reclaimed asphalt pavement" (RAP) is asphalt that has been used previously as pavement. RAP may be obtained from asphalt that has been removed from a road or other structure, and then has been processed by well-known methods, including milling, ripping, breaking, crushing, and/or pulverizing. Prior to use, the RAP may be inspected, sized and selected, for instance, depending on the final paving application.

"Aggregate" (or "construction aggregate") is particulate mineral material suitable for use in asphalt. It generally comprises sand, gravel, crushed stone, and slag. Any conventional type of aggregate suitable for use in asphalt can be used. Examples of suitable aggregates include granite, limestone, gravel, and mixtures thereof. "Bitumen" refers to a mixture of viscous organic liquids or semi-solids from crude oil that is black, sticky, soluble in carbon disulfide, and composed primarily of condensed polycyclic aromatic hydrocarbons. Alternatively, bitumen refers to a mixture of maltenes and asphaltenes. Bitumen may be any conventional type of bitumen known to the skilled person. The bitumen may be naturally occurring. It may be crude bitumen, or it may be refined bitumen obtained as the bottom residue from vacuum distillation of crude oil, thermal cracking, or hydrocracking. The bitumen contained in or obtained from reclaimed asphalt pavement is further referred to as bitumen of RAP origin.

"Virgin bitumen" (also known as "fresh bitumen") refers to bitumen that has not been used, e.g., bitumen that has not been recovered from road pavement.

"Binder" refers to a combination of bitumen and, optionally, other components. The other components could include elastomers, non-bituminous binders, adhesion promoters, softening agents, additional rejuvenating agents (other than those of the invention), or other suitable additives. Useful elastomers include, for example, ethylene-vinyl acetate copolymers, polybutadienes, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, butadiene-styrene block copolymers, styrene- butadiene-styrene (SBS) block terpolymers, isoprene-styrene block copolymers and styrene-isoprene-styrene (SIS) block terpolymers, or the like. Cured elastomer additives may include ground tire rubber materials. "Virgin binder" is binder that has not been used previously for road paving.

"Oxidized binder" refers to binder that is present in or is recovered from reclaimed asphalt. Normally, the oxidized binder is not isolated from the reclaimed asphalt. Oxidized binder has high viscosity compared with that of virgin bitumen as a result of aging and exposure to outdoor weather.

"Aged binder" refers to virgin binder that has been aged to resemble oxidized binder using the RTFO and PAV laboratory aging test methods described herein.

"Rejuvenating agent" refers to a composition or mixture that is combined with oxidized binder or reclaimed asphalt (or their mixtures with virgin binder and/or virgin asphalt) to revitalize the oxidized binder or reclaimed asphalt and restore some or all of the original properties of virgin binder or virgin asphalt. "Ester-functional" rejuvenating agents have at least one ester group and are further described below.

The bitumen in the binder may be commercially available virgin bitumen such as a paving grade bitumen, i.e. suitable for paving applications. Examples of commercially available paving grade bitumen include, for instance, bitumen which in the penetration grade (PEN) classification system are referred to as PEN 35/50, 40/60 and 70/100 or bitumen which in the performance grade (PG) classification system are referred to as PG 64-22, 58-22, 70-22 and 64-28. Such bitumen is available from, for instance, Shell, Total and British Petroleum (BP). In the PEN classification the numeric designation refers to the penetration range of the bitumen as measured with the ASTM D1586 method, e.g. a 40/60 PEN bitumen corresponds to a bitumen with a penetration which ranges from 40 to 60 decimillimeters (dmm). In the PG classification (AASHTO MP 1 specification) the first value of the numeric designation refers to the high temperature performance and the second value refers to the low temperature performance as measured by a method which is known in the art as the Superpave^SM system.

In one aspect, the invention relates to an asphalt composition. The asphalt composition comprises reclaimed asphalt and an ester-functional rejuvenating agent. The reclaimed asphalt comprises aggregate and an oxidized binder.

In another aspect, the invention relates to a binder composition suitable for use with reclaimed asphalt. The binder composition comprises a combination of oxidized binder and an ester-functional rejuvenating agent. Suitable oxidized binder for use in the inventive compositions is present in or recovered from reclaimed asphalt, which can be RAP. Binder can be recovered from RAP by conventional means such as solvent extraction. Preferably, oxidized binder is not isolated from the reclaimed asphalt. Instead, the reclaimed asphalt is simply combined with a desirable amount of rejuvenating agent. In a preferred approach, the rejuvenating agent is combined and mixed with virgin binder, reclaimed asphalt, and optionally virgin asphalt to give the rejuvenated asphalt product.

The inventive asphalt and binder compositions comprise an ester-functional rejuvenating agent. The binder compositions comprise 0.1 to 15 wt.%, preferably 0.5 to 10 wt.%, of the rejuvenating agent based on the combined amounts of oxidized binder and rejuvenating agent. In both the inventive asphalt and inventive binder compositions, the rejuvenating agent is present in an amount effective to reduce the glass-transition onset temperature of the oxidized binder by at least 5°C compared with the glass-transition onset temperature of the oxidized binder without the rejuvenating agent.

The ester-functional rejuvenating agents preferably derive principally from carboxylic acids (including resin acids) or C8-C20 fatty acids and C1-C18 alcohols. The acid portion can be linear, branched, cyclic, aromatic, or a combination thereof; it can be saturated, unsaturated, or a combination thereof. Resin acids include monocarboxylic acids in the form C19H29COOH with a nucleus of three fused six-carbon rings, and comprise double bonds that vary in number and location. The fatty acid can be in a polymerized form, as in dimerized fatty acid mixtures. The alcohol portion of the ester- functional rejuvenating agent can be primary, secondary, or tertiary; it can be a monol, diol, or polyol. The alcohol can also derive from polyethers such as triethylene glycol or polyethylene glycols. Phenolate esters are also suitable.

Thus, suitable carboxylic resin acids include abietic, neoabietic, dehydroabietic, pimaric, levopimaric, sandaracopimaric, isopimaric, and palustric acids. Suitable C₈-C₂o fatty acids include, for example, benzoic acid, caprylic acid, azeleic acid, ricinoleic acid, 12-hydroxystearic acid, stearic acid, isostearic acid, tall oil fatty acid, oleic acid, linoleic acid, linolenic acid, palmitic acid, Monomer acid (defined below), dimer acids, tall oil heads, and the like, and mixtures thereof. Suitable Ci-Ci₈ alcohols include, for example methanol, ethanol, 1 -propanol, isobutyl alcohol, 2-ethylhexanol, octanol, isodecyl alcohol, benzyl alcohol, cyclohexanol, ethylene glycol monobutyl ether, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, sucrose, and the like, and mixtures thereof.

The ester-functional rejuvenating agents preferably have a flash point greater than 200°C, more preferably greater than 220°C, most preferably greater than 250°C. The rejuvenating agents are preferably non-crystalline, preferably having a melting point or titer at or below 30°C, more preferably below 20°C, and most preferably below 0°C. Since many resin acids are solids, resin acids may be blended with fatty acids, or selected so that they have relatively low softening points, to give preferred rejuvenating agents.

In a preferred aspect, the ester-functional rejuvenating agent derives from tall oil fatty acid (TOFA) or a TOFA derivative (e.g., a TOFA dimer acid). Tall oil fatty acid is isolated from crude tall oil (CTO) by distillation. The CTO is a by-product of the Kraft wood pulping process. Distillation of CTO gives, in addition to tall oil fatty acid, a more volatile, highly saturated fraction of long-chain fatty acids (largely palmitic acid), known as "tall oil heads." Tall oil fatty acid is the next cut, which contains mostly Cis and C20 fatty acids having varying degrees of unsaturation (e.g., oleic acid, linoleic acid, linolenic acid, and various isomers of these). Another cut, known as distilled tall oil or "DTO," is a mixture of mostly tall oil fatty acid and a smaller proportion of tall oil rosin. Tall oil rosin ("TOR"), isolated next, consists largely of a C19-C20 tricyclic monocarboxylic acid. The bottom cut of the distillation is known as "tall oil pitch" or simply "pitch." Generally, any cut that contains at least some tall oil fatty acid is preferred for use in making an ester-functional rejuvenating agent.

As noted earlier, polymerized fatty acids can be used to make the ester- functional rejuvenating agents. Because of its high content of unsaturated fatty acids, TOFA is commonly polymerized using acid clay catalysts. In this high-temperature process, the unsaturated fatty acids undergo intermolecular addition reactions by, e.g., the "ene reaction," to form polymerized fatty acids. The mechanism is complex and not well understood. However, the product comprises mostly dimerized fatty acid and a unique mixture of monomeric fatty acids. Distillation provides a fraction highly enriched in dimerized fatty acid, which is commonly known as "dimer acid." Such dimer acids are suitable for use in making the ester-functional rejuvenating agents.

The distillation of polymerized TOFA also provides a fraction that is highly enriched in monomeric fatty acids and is known as "Monomer" (with a capital "M") or "Monomer acid." Monomer, a unique composition, is a preferred starting material for making ester-functional rejuvenating agents. Whereas natural source-derived TOFA largely consists of linear Ci₈ unsaturated carboxylic acids, principally oleic and linoleic acids, Monomer contains relatively small amounts of oleic and linoleic acids, and instead contains significant amounts of branched and cyclic Cis acids, saturated and unsaturated, as well as elaidic acid. The more diverse and significantly branched composition of Monomer results from the catalytic processing carried out on TOFA during polymerization. The art recognizes that the reaction of Monomer with alcohols to make "Monomerate" esters will yield unique derivatives that differ from the corresponding TOFA-based esters. Monomer has been assigned CAS Registry Number 68955-98-6. Examples of Monomer products are Century^® MO5 and MO6 fatty acids, products of Arizona Chemical Company. For more information about the composition of Monomer and its conversion to various esters, see U.S. Pat. No. 7,256,162, the teachings of which are incorporated herein by reference.

Suitable rejuvenating agents include, for example, ethylene glycol tallate (i.e., ethylene glycol ester of tall oil fatty acid), propylene glycol tallate, trimethylolpropane tallate, neopentyl glycol tallate, methyl tallate, ethyl tallate, glycerol tallate, oleyl tallate, octyl tallate, benzyl tallate, 2-ethylhexyl tallate, polyethylene glycol tallates, tall oil pitch esters, ethylene glycol Monomerate, glycerol Monomerate, trimethylolpropane Monomerate, neopentyl glycol Monomerate, 2-ethylhexyl Monomerate, ethylene glycol dimerate, 2-ethylhexyl dimerate, 2-ethylhexyl trimerate, trimethylolpropane isostearate, benzyl 12-hydroxystearate, benzyl ricinoleate, octyl caprylate, octyl azelate, octyl benzoate, and the like. Particularly preferred rejuvenating agents are tallates and Monomerates, especially trimethylolpropane tallate, ethylene glycol Monomerate, and glycerol Monomerate.

The ester-functional rejuvenating agents can be used in combination with other rejuvenating agents or adjuvants. For instance, they can be used in combination with tall oil rosin esters, terpene phenols, polyterpenes, alkylated phenols, or the like. The examples below illustrate combinations of tall oil fatty esters and a rosin ester (Example 38, trimethylolpropane ester from a mixture of rosin acid and TOFA) or a terpene phenol (Example 47, ethylene glycol Monomerate combined with Sylvares^® TP 96).

In the inventive asphalt and binder compositions, the rejuvenating agent is present in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 5°C, preferably by at least 10°C, compared with the glass-transition onset temperature of the oxidized asphalt binder without the rejuvenating agent. The glass-transition onset temperature can be determined by any desired method, but it is conveniently measured by differential scanning calorimetry (DSC). Transitions in the DSC curve are noted as samples are cycled through a programmed increase and/or decrease of temperatures. In plots of heat flow (W/g) versus temperature, inflection points denote the onset of glass transition and the endpoint. The temperature range between the onset temperature and the endpoint is the "spread." A desirable rejuvenating agent will lower the onset temperature of glass transition and will also narrow the spread. DSC has been used previously as a diagnostic tool for evaluating asphalt compositions; see, e.g., R.F. Turner and J. F. Branthaven, "DSC Studies of Asphalts and Asphalt Components" in Asphalt Science and Technology. A.M. Usnami, ed., Marcel Dekker, Inc., NY (1997), pp. 59-101 .

We surprisingly found that ester-functional rejuvenating agents, when introduced at low to modest levels, can be effective in reducing the glass-transition onset temperature of oxidized asphalt binders by at least 5°C. The reduction is important because it correlates with an anticipated improvement in low-temperature cracking resistance in asphalt pavement. As the results in Tables 1 and 2 (below) suggest, a wide variety of ester derivatives, when used at 2.5 to 10 wt.% with oxidized asphalt binder, are effective in reducing the onset temperature of glass transition by at least 5°C. Many of the ester-functional rejuvenating agents reduce the onset temperature of glass transition by at least 10°C, and some can reduce that temperature by as much as 20°C. On the other hand, other tested compositions are not effective in reducing the Tg onset temperature by at least 5°C at the 10 wt.% level. For instance, as shown in Table 1 , high-hydroxyl rosin ester (C16), terpene phenols (C18), polyterpenes (C23), and phenolic rosin esters (C24), among other classes, are ineffective in reducing the Tg onset temperature (see "Δ onset" column). Note that Tudalen^® 65, a hydrocarbon flux oil currently used to rejuvenate reclaimed asphalt pavement, does not give the desired 5°C reduction in Tg onset at the 10% additive level. Cardanol, the active component of another commercial rejuvenating agent (RheoFalt^® HP-EM, product of Ventraco Chemie, B.V.), effectively reduces the Tg onset temperature, but cardanol is a long- chain unsaturated alkylate of a phenol and has no ester functionality.

In preferred asphalt and binder compositions of the invention, the ester-functional rejuvenating agent is present in an amount effective to reduce the glass-transition temperature spread (or melting range) by at least 5°C, preferably by at least 10°C. As shown in Tables 1 and 2 (see "Δ spread" column), there are numerous examples of ester-functional rejuvenating agents that have this capability including, for example, trimethylolpropane tallate, ethylene glycol Monomerate, glycerol Monomerate, oleyl tallate, neopentyl glycol Monomerate, and others. Although somewhat less diagnostic than the reduction in Tg onset temperature, a narrower Tg spread for the binder generally indicates greater homogeneity, which can translate to better fatigue cracking resistance at ambient temperature for the asphalt compositions.

The asphalt and binder compositions can be made by combining components in any desired order. In one convenient approach, an asphalt composition is made by combining rejuvenating agent with virgin binder, then blending the resulting mixture with RAP. In another approach, the asphalt composition is made by combining rejuvenating agent with RAP, optionally with virgin asphalt.

Asphalt compositions of the invention preferably contain rejuvenating agent, 5 to 95 wt.% RAP, and at least some virgin binder. More preferred asphalt compositions contain 10 to 90 wt.% RAP, most preferably 30 to 70% RAP. Other preferred compositions comprise 1 to 99 wt.%, preferably 10 to 90 wt.%, more preferably 30 to 70 wt.% of virgin binder.

Depending on the source, age, history, any pretreatment, and other factors, RAP will normally contain from 2 to 8 wt.%, more typically 3 to 6 wt.%, of oxidized asphalt binder. Therefore, the effective amount of rejuvenating agent can vary by asphalt source. In general, the rejuvenating agent is preferably used at 0.1 to 15 wt.%, more preferably 0.5 to 10 wt.%, even more preferably 2 to 8 wt.%, most preferably 3 to 6 wt.%, based on the amount of oxidized asphalt binder.

Further evidence of the value of ester-functional rejuvenating agents comes from dynamic shear rheometry (DSR) data. Table 3 shows the improvement in low- temperature performance, particularly m-value and creep stiffness at -15°C. EG Monomerate, trimethylolpropane tallate, and glycerol Monomerate, for example, all perform well when compared with terpene phenols and other neutral additives. At ambient temperatures, the ester-functional rejuvenating agents provide a palpable reduction in G^* sin δ of RAP binder, an indication of improved fatigue cracking properties in the ultimate asphalt composition. The benefits for low- and ambient- temperature performance are significant, but too often such benefits are obtained only by sacrificing elevated temperature properties such as resistance to rutting. As shown in Table 3, however, the low values (versus the control) of G7sin δ determined at 70°C indicate that binders containing the ester-functional rejuvenating agents will likely also perform well at elevated temperature. The test results are used to predict the amount of rut formation to be expected from use of a particular binder. The results in Table 3 suggest that softening of the binder by the rejuvenating agent will not create a rutting problem for the ultimate asphalt compositions, even on hot summer days.

In one aspect, the invention relates to a rejuvenation method. The method comprises rejuvenating reclaimed asphalt by mixing the reclaimed asphalt with 0.01 to 10 wt.%, preferably 0.025 to 5 wt.%, more preferably 0.05 to 2 wt.%, of a rosin ester. Suitable rosin esters are made by este fying at least one rosin acid with at least one alcohol.

Suitable alcohols for esterification include mono-alcohols, such as methanol, ethanol, butanol, Cs-Cn isoalcohols (such as isodecylalcohol and 2-ethylhexanol), and polyols such as diethylene glycol, triethylene glycol, glycerol, pentaerythritol, sorbitol, neopentyl glycol and trimethylolpropane. Easily obtained, useful alcohols include diethylene glycol, triethylene glycol and pentaerythritol.

Rosin acids include mono-carboxylic acids with the general formula

C19H29COOH, with a nucleus of three fused six-carbon rings and comprise double bonds that vary in number and location. Examples of rosin acids include abietic acid, neoabietic acid, dehydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid and palustric acid.

The rosin acid may be used in isolated form, or as part of a composition which may comprise a plurality of rosin acids. In particular, rosin may be used as a source of rosin acid. Rosin is a hydrocarbon secretion of many plants, particularly coniferous trees such as Pinus palustris and Pinus caribaea. Natural rosin typically consists of a mixture of seven or eight rosin acids, and other minor components. Rosin is commercially available and can be obtained from pine trees by distillation of oleoresin (gum rosin being the residue of distillation), by extraction of pine stumps (wood rosin) or by fractionation of tall oil (tall oil rosin). Any type of rosin may be used, including tall oil rosin, gum rosin and wood rosin. Tall oil rosin is typically used because of its availability. Examples of suitable commercially available rosins include tall oil rosins (e.g. Sylvaros^® 85, Sylvaros^® 90 or Sylvaros^® 95 from Arizona Chemical).

The rosin acid may be modified prior to esterification, by, for instance, hydrogenation, dismutation, oligomerization, Diels-Alder reaction, isomerization or combinations thereof. Rosin esters may also be modified to form disproportionated rosin esters. For example, dehydroabietic acid may be useful.

Rosin esters may be obtained from rosin acids and alcohols by methods known in the art (see, e.g., US 5,504,152, the teachings of which are incorporated herein by reference). In general, rosins may be esterified by a thermal reaction of the rosin acid with the alcohol. In order to drive the esterification reaction to completion water may be removed from the reactor, by methods, such as distilling, application of vacuum, and others known to the skilled person.

Commercially available rosin esters may also be used, as for example Sylvatac^®

RE103, Sylvatac^® RE55, Sylvatac^® RE85, Sylvatac^® RE12 and Sylvatac^® RE5 all from Arizona Chemical; Eastman^® ester Gum 15 D-M, Permalyn^® 3100, Permalyn^® 51 10-C and Staybelite™ ester 3-E all from Eastman; Dertoline^® G2L, Dertoline^® SG2, Dertoline^® P105, Dertoline^® P1 10, Dertoline^® P2L, Dertoline^® PL5, Dertopoline P125, Granolite SG, Granolite P, Granolite P1 18 and Granolite TEG all from DRT (les Derives Resiniques & Terpeniques); and NovaRes^® 1 100 from Georgia Pacific.

The rosin ester may comprise some residual, unreacted acid and alcohol. Typically, the rosin ester has an acid number below 20 mg KOH/g, in particular below 15 mg KOH/g. The acid number may be determined by methods known to the skilled person, such as the standard method ASTM D974 which uses a color-indicator titration.

Suitable rosin esters are liquid rosin esters or may be solid rosin esters having a softening point of between 30 and 120°C, between 30 and 80°C, or between 40 and 60°C. The softening point may be determined by methods known to the skilled person, for instance, according to the standard method ASTM 28-99, which uses a method known as "ring and ball" method. Suitable rosin esters include esters of tall oil rosin, esters of gum rosin, and esters of wood rosin. Several alcohols and glycols are suitable for reacting with one or more rosins, including C₈-C alkyl and isoalkyl alcohols and glycols, pentaerythntol, glycerol, triethylene glycol, diethylene glycol. Suitable rosin esters that result include, for example, from at least one of pentaerythntol rosin esters, glycerol rosin esters, triethylene glycol, diethylene glycol rosin ester and Cs-Cn isoalkyl rosin esters and mixtures thereof. In particular, the rosin ester may be a mixture of diethylene glycol rosin ester, triethylene glycol rosin ester and pentaerythntol rosin ester.

The amount of rosin ester in the asphalt composition may be adjusted relative to the amount of binder present in the reclaimed asphalt. The amount of rosin ester may be, for instance, from 1 to 10 wt.% of the total amount of binder present in the reclaimed asphalt, or from 2.5 to 7.5 wt.% or from 3 to 6 wt.%. Higher or lower amounts of rosin ester relative to the amount of binder present in the RAP may also be used. Generally, relative amounts lower than 1 wt.% may still provide a rejuvenating effect, even if to a lesser extent. On the other hand, the use of relative amounts higher than 10 wt.% does not negatively affect the performance of the final RAP-containing asphalt composition, even if the use of such higher amounts do not significantly increase rejuvenation.

The amount of binder in a reclaimed asphalt composition is generally known from the supplier, but may also be determined by methods known to the skilled person. For instance, a known amount of RAP may be treated with a suitable solvent, e.g. dichloromethane to extract the binder. The weight amount of binder in the extracted fraction may be measured, thereby determining the content of binder in the RAP. The amount of binder in the RAP typically may range from 1 to 10 wt.% based on the total weight of the RAP, in particular from 2.5 to 8.5 wt.% and more particularly from 4 to 7.5 wt.%.

In one aspect, the invention relates to an asphalt composition comprising 0.01 to

10 wt.%, preferably 0.025 to 5 wt.%, of a rosin ester and at least 15 wt.% of reclaimed asphalt. The rosin ester is a reaction product of tall oil rosin and a polyol selected from the group consisting of diethylene glycol, triethylene glycol, glycerol, pentaerythntol, and mixtures thereof. Preferably, the asphalt composition further comprises additional binder and/or aggregate. Preferably, the reclaimed asphalt is RAP. We found that the rosin esters, made from tall oil rosin and a combination of polyols, have a favorable overall balance of properties. See especially Rosin ester L, Ex. 64 in Table 7, below. When used as a rejuvenating agent, this product favorably impacts ring and ball softening point and glass-transition temperature of the binder as well as rheological properties, including storage modulus and loss modulus.

In another aspect, the invention relates to an asphalt composition comprising an ester-functional rejuvenating agent and at least 15 wt.% of reclaimed asphalt comprising oxidized binder. The rejuvenating agent is present in an amount within the range of 1 to 10 wt.%, preferably from 3 to 8 wt.%, more preferably from 4 to 6 wt.%, based on the combined amounts of oxidized binder and rejuvenating agent. In addition, the oxidized binder and rejuvenating agent mixture forms a rejuvenated binder having a ring and ball softening point by EN 1427 less than 60°C and a penetration value by EN 1426 greater than 20 dmm.

Suitable ester-functional rejuvenating agents have already been described. Particularly preferred rejuvenating agents are trimethylolpropane tallates, ethylene glycol Monomerates, neopentyl glycol Monomerates, 2-ethylhexyl Monomerates, and glycerol Monomerates. Ethylene glycol Monomerate and trimethylolpropane (TMP) tallate are especially preferred (see Tables 8-18 below).

Certain rosin esters, rosin acids, or mixtures thereof are also suitable. In one aspect, the rejuvenating agent comprises a rosin ester having a ring and ball softening point by EN 1427 less than 50°C. In other aspects, the rejuvenating agent comprises, in addition to the rosin ester, rosin acid, or mixtures thereof, a fatty ester, a vegetable oil, or a petroleum flux oil (see Tables 13-14 below). We surprisingly found that rejuvenated binders comprising rosin esters, rosin acids, or their mixtures may have reduced temperature sensitivity compared with that of a similar rejuvenated binder made without the rosin acid, rosin ester, or mixture thereof (see Table 14).

Inclusion of the rejuvenating agent in reclaimed asphalt can facilitate handling of the asphalt composition in one or more plant operations. Thus, in one aspect, the rejuvenating agent reduces the temperature required for mixing, at viscosities less than or equal to 200 mPa/s, by at least 5°C, preferably by at least 10°C. When high temperatures are needed to reach a viscosity of 200 mPa/s, the process can consume too much energy to be cost-effective. Thus, any reduction in the temperature needed to reach a reasonable viscosity for mixing is valuable. In another aspect, the rejuvenating agent reduces the temperature required for compaction, at viscosities less than or equal to 3000 mPa/s, by at least 5°C, preferably by at least 10°C. When high temperatures are needed to reach a viscosity of 3000 mPa/s, the process can consume too much energy to be cost-effective. Thus, any reduction in the temperature needed to reach a reasonable viscosity for compaction is valuable. As shown in Table 10, ester-functional rejuvenating agents are effective in reducing the minimum temperature required for both mixing and compaction.

In another aspect, the invention relates to a rejuvenated binder. The rejuvenated binder comprises oxidized binder and an ester-functional rejuvenating agent. The rejuvenating agent is present in an amount within the range of 1 to 10 wt.% based on the combined amounts of oxidized binder and rejuvenating agent. The rejuvenated binder has a ring and ball softening point by EN 1427 less than 60°C and a penetration value by EN 1426 greater than 20 dmm. Suitable rejuvenating agents have already been described. Particularly preferred rejuvenating agents are trimethylolpropane tallates, ethylene glycol Monomerates, neopentyl glycol Monomerates, 2-ethylhexyl Monomerates, and glycerol Monomerates, especially ethylene glycol Monomerate and trimethylolpropane (TMP) tallate.

Preferred rejuvenated binders reach a force ductility, when measured by AASHTO T-300, of 1 .0 J/cm² at some temperature within the range of 15°C to 25°C. Particularly preferred are rejuvenated binders that also have a ring and ball softening point less than 60°C (see Table 15 and further discussion below).

Preferred binders demonstrate stability when the binder is subjected to short- term aging by the rolling thin-film oven (RTFO) test according to EN 12607-1 and long- term aging by the pressure aging vessel (PAV) test according to EN 14769. As shown in Table 18, rejuvenated binders of the invention are stable when exposed to laboratory conditions designed to simulate short-term or long-term aging of asphalt compositions.

The invention includes uses for the asphalt compositions or binders of the invention. The asphalt compositions and binders can be used, e.g., for paved surfaces, road surfaces and subsurfaces, shoulders, bridges, bridge abutments, gravel substitutes for unpaved roads, and the like. In one aspect, the invention relates to a paved surface comprising an asphalt or binder composition of the invention.

The following examples merely illustrate the invention; the skilled person will recognize many variations that are within the spirit of the invention and scope of the claims.

PART 1: Evaluation of Ester-Functional Rejuvenating Agents in Reclaimed Asphalt Pavement: Reduction of Tg Onset Temperature in Oxidized Binders

Method for Preparing RAP Binder with Rejuvenating Agents

RAP is received in 40-lb. bags. Material is removed from the bag and allowed to air dry until no visible moisture remains. A sieve table with multiple gauge wire is utilized to separate the material into different sizes: large, medium, and fines.

The material classified as "large" is placed into a large fritted column with glass wool used as the primary filtration. Toluene/ethanol (85:15) is poured over the RAP and allowed to stand until gravity filtration is complete. The process is repeated multiple times until the solvent blend is almost void of coloration and clear. The "medium" and "fines" material is placed into a large Erlenmeyer flask, after which the same solvent blend is added to level. The material is agitated and the resultant solvent/asphalt mix is decanted. This process is also repeated to the same target.

The combined extracts are charged to a 5-gal. container and allowed to sit for 24 h to allow any dirt/rock fines to settle. The material is carefully decanted through a medium grade filter (Whatman #4). The filtrate is charged in batches to a 5-L flask, and the solvent is stripped under vacuum while warming to 40-50°C. Concentration continues until the material reaches a solids target of -20-25%. All concentrated material is combined into a single container and the solvent is recovered and recycled.

Using the solids content as a guideline, concentrated material is charged to a 50- ml_ round-bottom flask based on a 2 g target. Additives to be evaluated are diluted to a minimum of 50% with toluene and charged to the same round bottom targeting a total addition of 0.2 g. The solution is then stripped under vacuum using a 150°C oil bath for 0.5 h. The concentrated product remains under a nitrogen purge until it cools.

Differential Scanning Calo metry (DSC) Analysis of Samples

Differential scanning calorimetry analysis is performed using a Thermal Analysis

Inc. model Q2000 instrument using the following conditions: sample weight: 4-6 mg RAP; sample containment: TA Inc. standard aluminum pans and lids (TA Inc. part numbers 900786.901 and 900779.901 ); instrument purge: nitrogen, 50 mL/min.

Temperature program: Metrics for Tg are applied to data from segment (23) of the following method log: (1 ) Sampling interval 0.60 sec/pt; (2) zero heat flow at 0.0°C; (3) equilibrate at 165.00°C; (4) data storage off; (5) isothermal for 5.00 min; (6) mark end of cycle 1 ; (7) data storage on; (8) ramp 5.00°C/min to -45.00°C; (9) data storage off; (10) isothermal for 5.00 min; (1 1 ) mark end of cycle 2; (12) data storage on; (13) ramp 10.00°C/min to 165.00°C; (14) data storage off; (15) isothermal for 5.00 min; (16) mark end of cycle 3; (17) data storage on; (18) ramp 5.00°C/min to -85.00°C; (19) data storage off; (20) isothermal for 5.00 min; (21 ) mark end of cycle 4; (22) data storage on; (23) ramp 10.00°C/min to 165.00°C; (24) mark end of cycle 5; (25) end of method.

Curves are generated by plotting heat flow (W/g) as a function of temperature (°C) over the range of -80°C to 80°C. Inflection points representing the onset of glass transition and the end of glass transition are noted, and a midpoint is determined. The "spread" is the difference between the temperature at the end of glass transition and the glass transition onset temperature. Thus, for a sample having an onset Tg at -36°C and an endpoint at 10°C, the spread is reported as 46°C. The values of Δ onset and Δ spread (each in °C) for each sample are reported in comparison to the average values obtained for multiple runs of the control sample of oxidized asphalt binder. The tested samples contain 90 wt.% of oxidized asphalt binder and 10 wt.% of potential rejuvenating agent additive unless otherwise noted in Tables 1 and 2.

A measurable impact on low-temperature properties of the RAP is expected if the onset of glass transition can be reduced by at least 5°C, and each of Examples 1 -12 (Table 1 ) and Examples 27-63 (Table 2) satisfies this requirement. Rheofalt^® distillate (cardanol), a long-chain alkylated phenol that is the principal component of a commercial rejuvenating agent, is provided for comparison.

Reduced fatigue cracking is normally inferred from improved homogeneity, which correlates with a narrower spread of the glass-transition temperature. Thus, an improvement in fatigue cracking may result from narrowing of the Tg spread by at least 5°C relative to the control sample. Many of the samples reported in Tables 1 and 2 also meet this test and are considered more preferred.

Evaluation of Low, Intermediate, and High Temperature Performance of RAP Binder Rejuvenating Agents by Dynamic Shear Rheometry (DSR)

Samples of RAP binder containing 10 wt.% of rejuvenating agents A-G prepared as described above are submitted to an independent laboratory for evaluation of low, intermediate, and high-temperature properties using dynamic shear rheometry (DSR). Each of the samples, except for sample E, is found to be softened significantly by the rejuvenating agent. The rheological properties are used to assess rejuvenation products for use in high-RAP, hot and warm mix asphalt.

Dynamic shear moduli are measured using 4-mm diameter parallel plate geometry with a Malvern Kinexus^® rotational dynamic shear rheometer. Frequency sweeps are performed at 15°C intervals over a temperature range of -30 to 60°C and an angular frequency range of 0.1 to 100 rad/sec (in some cases 0.1 to 50 rad/sec is used).

The control sample is an extracted binder without added rejuvenating agent. Stress sweeps are performed before each frequency sweep to ensure a low strain level and that the test results would be in the linear viscoelastic range.

High (70°C) and in some cases low (-15°C) performance parameters, such as G7sin δ, master curves are extrapolated using the Christensen Anderson (CA) model (D.W. Christensen et al., J. Assoc. Asphalt Paving Technologists. 61 (1992) 67). The CA model relates the frequency dependence of the complex modulus to the glassy modulus (G_g), the cross-over frequency (ω₀) and the rheological index (R). The form of the mathematical function is

The G(t) master curves are generated by interconverting the storage modulus (G'(CJO)) using Christensen's approximate method (see Christensen, R.M., Theory of Viscoelasticity (1971 ) Academic Press, New York).

1 . Low temperature properties

Low-temperature properties are measured with 4-mm plate rheometry. Bending beam rheometer (BBR) m-value and creep stiffness (S(t)) are estimated through a correlation developed by Sui et al ("A New Low-temperature Performance Grading Method using 4-mm Parallel Plates on a DSR," Transportation Research Record 2207 (201 1 ) 43-48.).

M-value is the slope of the creep stiffness curve at the performance grade temperature plus 10°C at 60 seconds. It is an indication of the asphalt's ability to relax stress. A minimum m-value of 0.3 is typically specified for laboratory RTFO/PAV (rolling thin film oven/ pressure aging vessel) aged asphalts. Creep stiffness is used to evaluate the potential for high thermal stress development. A higher creep stiffness value indicates higher potential thermal stress development in the pavement, a maximum value of 300 MPa is typically specified. Creep stiffness is measured at the same time and temperature as m-value. Results of testing samples A-G appear in Table 3. 2. Intermediate temperature properties

Fatigue cracking resistance of an RTFO/PAV aged asphalt binder is typically evaluated using G^* sin δ (a fatigue factor). G^* represents the binder complex shear modulus and δ represents the phase angle. G^* approximates stiffness and δ approximates the viscoelastic response of the binder. Binder purchase specifications typically require the factor to be less than 5 MPa. The factor is considered a measure of energy dissipation which is related to fatigue damage. The critical temperature range for fatigue damage is near the midpoint between the highest and lowest service temperatures. A test temperature of 25°C is used. Results of testing samples A-G appear in Table 3. 3. High-temperature properties

High-temperature mechanical properties are evaluated by the parameter G7 sin δ. The factor is an indication of a binder's resistance to rutting. Binder purchase specifications typically require the factor to be greater than 2.2 kPa for RTFO aged asphalt. In all of the tested samples, G7sin δ decreases significantly with addition of the rejuvenating agent.

As shown in Table 3, samples A, B, C, and F show the most improvement in m- value, which directly relates to improvement in the ability of the material to relax and avoid thermal stress development that could lead to thermal cracking. G^* sin δ provides an indication of fatigue performance. Samples F (glycerol Monomerate) and A (EG Monomerate) stand out as the highest ranked in terms of both (m-value) and (G^* sin δ) improvement. Samples B, C, and D are somewhat effective. Comparative samples G (returned neutrals from sterols) and E (terpene phenol) rank last, with E being particularly ineffective.

Table 1 . Effect of Rejuvenating Agents on RAP Binders: DSC Analysis

Ex Description Tg onset, Tg Δ onset, Δ spread,

°C spread, °C °C °C

Controls, ave. of 13 experiments -36.7 47.5 — —

1 EG Monomerate, 2.5% -41.4 46.2 -4.7 -1 .3

2 EG Monomerate, 5% -47.8 47.0 -1 1.1 -0.5

3 EG Monomerate, 10% -50.9 41 .4 -14.2 -6.1

4 TMP tallate, 2.5% -43.4 56.8 -6.7 9.3

5 TMP tallate, 5% -50.1 36.6 -13.4 -10.9

6 TMP tallate, 10% -53.9 32.6 -17.2 -14.9

7 NPG Monomerate, 2.5% -49.7 48.3 -13.0 0.8

8 NPG Monomerate, 5% -49.4 43.0 -12.7 -4.5

9 NPG Monomerate, 10% -52.6 42.3 -15.9 -5.2

10 Sylfat^® DP-6 tall oil pitch residue -47.3 52.5 -10.6 5.0

1 1 Sylfat^® DP-8 tall oil pitch residue -49.6 58.9 -12.9 1 1 .4

12 EG ester of heads -56.3 47.8 -19.6 0.3

C13 Rheofalt^® distillate (cardanol) -47.3 38.2 -10.6 -9.3

C14 Virgin asphalt, 100% -37.9 42.4 -1.2 -5.1

C15 Palm oil -51.0 54.1 -14.3 6.6

C16 High-hydroxyl rosin ester -31.6 46.8 5.1 -0.7

C17 Nonyl phenol -41.0 49.2 -4.3 1.7

C18 Sylvares^® TP 96 -29.8 36.5 6.9 -1 1 .0

C19 Tergitol^® NP-40 nonylphenol ethoxylate -39.4 43.8 -2.7 -3.7

C20 Crude sterols -33.4 38.9 3.3 -8.6

C21 Heavy neutrals from sterols -37.0 45.0 -0.3 -2.5

C22 Returned neutrals from sterols -33.0 36.8 3.7 -10.7

C23 TRA 25 polyterpene -31.6 37.3 5.1 -10.2

C24 Sylvaprint^® 9205 phenolic rosin ester -29.4 39.5 7.3 -8.0

C25 Cenwax^® G hydrogenated castor oil -34.8 51 .4 1 .9 3.9

C26 Tudalen^® 65 hydrocarbon flux oil -37.5 40.3 -1 .6 -6.6

Sylfat®, Sylvaprint®, Sylvares®, Sylvatol®, Cenwax®, and Uniflex® are trademarks of Arizona Chemical Company.

RheoFalt® is a trademark of Ventraco, B.V.

Tudalen® is a trademark of H&R Group.

Tergitol® is a trademark of Dow Chemical. Table 2. Effect of Rejuvenating Agents on RAP Binders: DSC Analysis

ARZ-040000PCT 127-018PCT

Table 3. Evaluation of Low, Internnediate, and High Temperature Performance of RAP Binder Rejuvenating Agents by Dynamic Shear Rheometry (DSR)

^* Comparative examples

A=EG Monomerate; B=TMP tallate; C=Cardanol; D=50/50 blend of A and E; E= Syl

TP-96 terpene phenol; F=glycerol Monomerate; G=returned neutrals from sterols

PART 2: Evaluation of Rosin Esters as Rejuvenating Agents Preparation of Rosin Ester H

A 1 -L flask equipped with thermometer, overhead stirrer, nitrogen purge line, Dean-Stark trap, condenser, collecting vessel, and sampling port is charged with a combination of pentaerythritol monoester of rosin and glycerol monoester of rosin (acid value: 107 mg KOH/g, 83.5 g total). The two mono-esters are heated to 200°C. 4,4'- Thiobis(2-t-butyl-5-methylphenol) (0.1 g) and magnesium acetate (0.2 g) are added at a rate slow enough to ensure that the temperature does not drop more than about 3°C. Triethylene glycol (16.2 g) is then added at a rate slow enough to ensure that the temperature does not drop more than about 3°C. The temperature is increased at a rate of 10-15°C per hour to a temperature between 270 and 280°C. The acid value is checked as a control measurement. The reaction continues until an acid value specification of 20 mg KOH/g is met. Vacuum is applied to remove light oils, i.e. monoesterified by-product. Rosin ester H is obtained after removal of the light oils and has a maximum viscosity at 40°C of 6000 mPa-s.

Preparation of Rosin Ester J

The apparatus described above is charged with tall oil rosin (Sylvaros^® 90 from Arizona Chemical, softening point of 66°C, acid number 171 mg KOH/g, 1 1 .3 g). The rosin is heated to 160°C and agitated when the rosin is molten enough for the stirrer to turn. Fumaric acid (5 g) is added at a slow enough rate to ensure that the temperature does not drop more than about 3°C. The reactor temperature is then raised to 200°C, and the reactor is held at this temperature for 3 hours. The reactor is cooled to 160°C. Iodine (0.38 g) is added at a rate to ensure that the temperature does not drop more than 3°C. The temperature is maintained at 160°C for one hour. Pentaerythritol (5 g) is added, and the temperature is increased at a rate of 10-15°C per hour to 250°C. The reactor temperature is maintained at 250°C for 4 hours. After two hours, the temperature drops to 220°C and triethanolamine (1 .22 g) is added. The temperature is maintained for 1 hour at 220°C. The reaction continues until the product, Rosin ester J, has an acid value of 120 mg KOH/g and a softening point of 53°C. Preparation of Rosin Ester K

The usual apparatus is charged with tall oil rosin (Sylvaros^® 90, 95 g). The reactor is heated to 180°C until the rosin is sufficiently is molten to allow agitation. 4,4'- Thiobis(2-t-butyl-5-methylphenol (0.1 g) and magnesium acetate (0.13 g) are added at a slow enough rate to ensure that the temperature does not drop more than 3°C. Triethylene glycol (12.8 g) and diethylene glycol (13.7 g) are added at a rate to ensure that the temperature does not drop more than 3°C. The reactor temperature is maintained at about 160°C for one hour, and then the temperature is increased at a rate of 10-15°C per hour to a temperature between 270 and 280°C. The reaction continues until the product, Rosin ester K, has an acid value < 25 mg KOH/g and a maximum viscosity at 60°C of 2000 mPa-s.

Preparation of Rosin Ester L

The usual apparatus is charged with Rosin ester J (10.5 g), Rosin ester K (8.4 g), and triethylene glycol dibenzoate (2.1 g). The mixture is agitated and heated to 160°C. When temperature is reached it is maintained for 2 hours prior to cooling. The final rosin ester blend, Rosin ester L, has an acid value of 70 mg KOH/g and a viscosity at 60°C of 2500 mPa-s.

The acid number is measured according to ASTM D465. A sample of a known weight is dissolved in isopropyl alcohol. The solution is then titrated with an alcoholic solution of potassium hydroxide. The acid values correspond to the amount of potassium hydroxide used to neutralize the measured amount of sample (generally expressed in milligrams of potassium hydroxide per gram of sample: mg KOH/g).

Viscosity is measured according to ASTM D2196, which uses Brookfield equipment and provides a rotational viscosity measurement.

Softening point is measured according to the ring and ball method (ASTM E28- 99). A sample of the product is poured, when still warm, into a metal ring and then cooled. The ring is cleaned in such a way that the material fits the ring, and a steel ball is placed resting on top of the ring. The ring and ball are lowered into a beaker containing water, and the water is heated at 5°C per minute while being stirred. When the ball drops completely through the ring, the temperature of the water is recorded. The temperature value is reported in as the ring and ball softening point. Preparation of Test Samples

Bitumen of RAP origin is prepared by washing RAP (from BAM Wegen, The Netherlands) with dichloromethane. The extracted bitumen is dried by evaporation of the dichloromethane.

The compositions of Examples 64-67 and Comparative Examples 70 and 71 of Table 4 are prepared as follows: bitumen of RAP origin (19.95 g) and virgin bitumen (PEN 40/60 from Total, The Netherlands, 9 g) are combined and heated to 100°C in a 50-mL beaker. The additive (1 .05 g) is then mixed in thoroughly. The temperature is maintained at 100°C for 30 minutes and then the mixture is cooled.

Reference compositions, without additives, are prepared similarly from PEN 40/60 (30 g) for Comparative Example 68, and a mixture of bitumen of RAP origin (21 g) and PEN 40/60 (9 g) for Comparative Example 69.

Measurements and Results

A sample of each bitumen composition is taken for measuring the ring & ball softening point, the glass transition temperature and the rheological profile (Tables 4, 5 and 6).

The ring and ball softening point is measured in water according to the ring and ball method (ASTM E28-99) as described above for the rosin esters. The temperature value is reported in Table 4 as the ring and ball softening point. The ring and ball softening point of bitumen is an indicator of stiffness of asphalt wherein the bitumen is used.

The glass transition temperature (Tg) is measured with a differential scanning calorimetry (DSC) apparatus from Mettler with the following parameters:

- Gas: Nitrogen 65 mL/min.

- Cup: Standard aluminum 40 μΙ_ cup with small hole on the lid

- Temperature: from 25.0°C to -60.0°C at a rate of 10°C per minute, and from -60.0°C to 25.0°C at a rate of 10°C per minute.

The glass transition temperature of bitumen is an indicator of brittleness of the asphalt wherein the bitumen is used.

Storage modulus and loss modulus of the bitumen samples are measured with an Anton Paar physical rheometer, MCR 101 . A temperature profile from -20°C to 80°C at a rate of 5°C per minute is used. The strain is set at 0.1 % with a frequency of 1 .592 s^~1. The spindle used is a PP25 mm with a 1 mm gap and a peltier plate. The normal force is set at 0 N.

Viscoelastic behavior of the bitumen at temperatures below 15°C is an indicator of the tendency to crack at low temperatures of the asphalt comprising the bitumen. The viscoelastic behavior may be expressed in terms of the storage modulus and the loss modulus. The lower the storage modulus and the loss modulus, the lower is the tendency to crack.

Table 5. Storage Modulus v. Temperature for Bitumen Samples

Temperature, °C

-20 -15 -10 -5 0 5 10 15 20 25

Additive Storage Modulus, MPa

Comp. Ex. 68 2.68 2.76 3.1 1 3.88 5.09 6.73 8.99 9.93 4.88 1.65

Comp. Ex. 69 5.59 5.48 6.45 8.09 10.4 13.4 15.3 14.1 9.38 4.49

Comp. Ex. 70 (palm oil) 6.27 6.73 8.14 10.2 12.6 15.5 16.9 15.1 9.22 4.19

Comp. Ex. 71 (C15 alkyl m- 0 0 0 1 .26 9.05 16.8 19.4 12.2 6.07 2.59 substituted phenol)

Ex. 64 (Rosin ester L) 1 .61 2.22 2.96 5.05 7.44 10.3 12.2 12.1 7.19 3.14

Ex. 67 (Rosin ester K) 0 0 0 0 0 4.64 15.2 19.9 1 1 .7 5.29

Table 7 presents an overview of the performance of each of the additives used with respect to virgin bitumen (Comp. Ex. 68), i.e. sample with the target performance, and with respect to a mixture of virgin bitumen and bitumen of RAP origin (Comp. Ex. 69), i.e. sample with the performance to be improved. A negative sign (-) indicates no improvement or no significant improvement with respect to Comparative Example 69 and a positive sign (+) indicates an improvement. The higher the number of positive signs the higher the improvement. N.a. indicates that the corresponding data is not available.

As can be seen from the results presented in Tables 4-7, rosin esters (Examples 64-67) act as rejuvenating agents restoring at least some of the properties lost with the aging process. In particular all of them modify the softening point and the glass transition temperature. Rosin ester L (Ex. 64) also modifies the storage modulus and the loss modulus at most of the temperatures measured (see Tables 5 and 6).

Palm oil has been described in US 2010/0041798 to act as a rejuvenating agent. However, no significant modification was observed for compositions comprising palm oil as additive (Comp. Ex. 70).

Alkyl-substituted phenols have been described in WO 2010/077141 to act as rejuvenating agents. The Ci₅-alkyl m-substituted phenol of Comparative Example 71 , i.e. a phenol with an alkyl group with 15 carbon atoms on the meta position with respect to the hydroxyl group which is commercially available, for instance, under the name of Rheofalt™ HCP-22 (from Ventraco, The Netherlands), presents improved softening point and glass transition temperature. This additive also appears to improve the loss modulus and storage modulus for some tested temperatures.

PART 3: Additional Evaluation of Ester-Functional Rejuvenating Agents

Several ester-functional rejuvenating agents are further evaluated, particularly ethylene glycol (EG) Monomerate, trimethylolpropane (TMP) tallate, and Sylvatac^® rosin esters RE5, RE25, RE40, and RE55, products of Arizona Chemical, which have ring and ball softening points of about 5, 25, 40, and 55°C, respectively.

The binders tested are oxidized binder ("RA"), which is recovered from reclaimed asphalt, or laboratory aged binder ("AB").

Aged binder is prepared in two steps. The first step is the rolling thin film oven (RTFO) test, which is performed in accord with EN 12607-1 . This reflects short-term aging that normally occurs during manufacture, transport, and laying of asphalt. The RTFO test involves heating binder in glass cylinders on a rotating carousel in an air- blown oven at 163°C for 50 min. After the test, mass loss is recorded and binder properties are measured.

The second step is pressure aging vessel (PAV) testing in accord with EN 14769. In the PAV test, binder samples are heated in an oven at 90 to 1 10°C under 2.07 MPa of pressure for 20 h. After the test, mass loss is recorded and binder properties are measured.

In one study, basic properties of the rejuvenated binder are investigated. Ring and ball softening point of the binder, measured according to EN 1427, reflects the consistency of the binder at high temperature. The higher the softening point, the more heat required to soften it or induce flow. Penetration values at 25°C of the binder, measured according to EN 1426, reflect the consistency of the binder at ambient temperature. Higher values correspond to softer binders. Viscosities at 90, 135, 150, and 180°C are measured in accord with EN 13302. The results indicate how easy it will be to store, pump, mix, compact, lay, or otherwise handle the asphalt in day-to-day operations. Penetration index (PI) quantifies the way that the asphalt consistency varies with temperature. It is calculated from:

PI = 20- (500Γ2.903 - loa(PenW(T-25½

{50 [2.903 - log(Pen)]/(T-25)} +1 where Pen is the penetration value at 25°C and T is the ring and ball softening temperature (in °C). Virgin binder typically has a negative PI, while oxidation tends to push the PI into positive values. Thus, a negative value of PI is more desirable.

Table 8 summarizes the results from this study. Ideally, the rejuvenating agent restores the properties of the oxidized binder to make it perform more like virgin binder. Thus, the softening point of the rejuvenated binder should be less than 60°C, and its penetration value at 25°C should be at least 20 dmm. As shown in the table, TMP tallate effectively achieves those results with as little as 5 wt.% based on the combined amounts of aged binder and TMP tallate. The liquid or lower melting rosin esters, Sylvatac^® RE5 and Sylvatac^® RE25, also have a rejuvenating impact, although somewhat higher levels (about 10 wt.%) are needed to get optimal results. Interestingly, Sylvatac^® RE55, a rosin ester with a higher softening point, is ineffective in restoring basic properties of the aged binder to those found in virgin binder.

Table 9 summarizes results of experiments performed to determine the amount of rejuvenating agent needed to achieve desirable softening while maintaining an acceptably low penetration value. With EG Monomerate and TMP tallate, softening point reaches the desired value of < 60°C with about 4-5 wt.% of rejuvenating agent while maintaining a penetration value at 25°C that matches that of virgin binder 35/50. In contrast, Sylvatac^® RE55 does not restore these properties to the oxidized binder even at 10 wt.% additive.

Viscosity curves for rejuvenated binders help to identify the ability of rejuvenating agents to facilitate asphalt compaction, mixing, and other handling properties. Table 10 shows that the minimum temperature at which viscosity is suitable for compaction (< 3000 mPa-s) can be reduced by as much as 20°C by combining oxidized binder with an ester-functional rejuvenating agent. Moreover, the minimum temperature at which viscosity is suitable for mixing (< 200 mPa-s) can also be reduced by as much as 20°C. ARZ-040000PCT 127-018PCT

Table 9. Impact of Dosage of Rejuvenating Additive on

Ring and Ball Softening Point and Penetration Values

Pen R&B

Oxidized binder (RA) 13 67

Virgin binder, 35/50 35 58

Virgin binder, 50/70 50 54

EG Monomerate TMP tallate Sylvatac® RE55^*

Pen R&B Pen R&B Pen R&B

RA + 1 % additive — — 17 65 — —

RA + 3% additive 23 62 24 63 13 65

RA + 5% additive 34 58 32 58 13 65

RA + 10% additive 87 48 72 49 14 62

^* Comparative example

Particularly in the United States, dynamic shear rheometry (DSR) is used to evaluate asphalt products to assess their likely performance at low, ambient, and elevated temperatures. At low temperatures (e.g., -10°C), road surfaces need cracking resistance. Under ambient conditions, stiffness and fatigue properties are important. At elevated temperature, roads need to resist rutting when the asphalt becomes too soft. Criteria have been established by the asphalt industry to identify rheological properties of a binder that correlate with likely paved road surface performance over the three common sets of temperature conditions.

Thus, for low temperatures, the complex modulus (G^*) of the rejuvenated binder measured at -10°C should be less than or equal to the value for virgin binder. For 30/50 grade virgin binder, G^* at -10°C is ideally at or below 2.8 x 10⁸ Pa (see Table 1 1 ). Oxidized binder is not dramatically different from virgin binder in this property, and the low-temperature criteria is satisfied with 1 wt.% of EG Monomerate or TMP tallate (but see results with Sylvatac^® RE55, which does not improve this parameter even at 10 wt.%).

At ambient temperatures, the complex modulus of the rejuvenated binder should be less than or equal to the value for virgin binder. For 30/50 grade virgin binder, G^* at 20°C is ideally at or below 6.0 x 10⁶ Pa. This stiffness criteria can be satisfied with about 4 wt.% of EG Monomerate or TMP tallate (Table 1 1 ). Again, Sylvatac^® RE55 does not improve this property at 10 wt.%.

Fatigue criteria also relates to ambient temperature performance. The product of the complex modulus (G^*) and the sine of the phase angle (δ) measured at 10 rad/s is determined. The temperature at which the value of G^*sin δ at 10 rad/s equals 5000 MPa should be less than or equal to 20°C for rejuvenated binders comparable to 35/50 grade virgin binder. As shown in Table 12, the fatigue criteria can be met when at least about 4 wt.% of EG Monomerate or TMP tallate is used, while Sylvatac^® RE55 shows no improvement relative to oxidized binder.

At high temperatures, the quotient G7sin δ is of interest. The temperature at which the value of G7sin δ at 10 rad/s equals 1000 Pa should be reduced for rejuvenated binders compared with that of aged binder. For 30/50 grade virgin binder, the temperature at which G7sin δ at 10 rad/s equals 1000 Pa is about 70°C (see Table 12). The high-temperature criteria is generally satisfied with up to about 10 wt.% of ester-functional rejuvenating agent.

In another rheology study, we generated master curves of G^* generated at 20°C from isothermal frequency sweeps (Table 13). When we compared results from testing binders rejuvenated with petroleum flux oil, vegetable oils, fatty esters, cardanol, and rosin esters, particularly when analyzing the data to compare high-temperature and fatigue criteria, we noticed some interesting behavior. All of these rejuvenating agents soften aged binder to some degree, and some more so than others at the same dosage. Thus, vegetable oil and fatty esters provide a high degree of softening, while petroleum flux oil and cardanol do so to a lesser degree. In contrast, cyclic esters, such as rosin esters, do not soften as effectively.

Moreover, although oxidized binders and virgin binders have fatigue characteristics that are relatively insensitive to temperature, most of the rejuvenating agents tend to make the rejuvenated binder more temperature sensitive. Ideally, the rejuvenated binder would behave more like virgin binder, i.e., it would preferably be less sensitive to temperature.

Surprisingly, we found that rejuvenated binders containing cyclic compounds such as rosin esters, rosin acids, or their mixtures have fatigue properties that are relatively resistant to temperature change, similar to oxidized binder or virgin binder. Because the cyclic compounds usually lack the ability to impart adequate softening, however, it is preferred to combine them with other rejuvenating agents, such as fatty esters or vegetable oils. Thus, the use of rosin esters, rosin acids, or their mixtures in combination with other rejuvenators can soften the binder while maintaining a desirably low temperature sensitivity. See Table 14.

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Table 15 summarizes the results of a ductility study. In general, force ductility relates to the energy needed to stretch a binder sample 200 or 400 mm at a given temperature, and is a measure of strength and flexibility. Lower energies correspond to more flexible samples. Ductility relates to elongation at rupture for a given temperature, typically 5°C (for softer binders) or 15°C. Higher elongations are usually better. In these experiments, TMP tallate, Sylvatac^® RE5 (liquid), and Sylvatac^® RE40 (softening point about 40°C) are compared. Force ductility is measured at three temperatures for each sample. The test method used is AASHTO T-300.

In general, the rejuvenating agents restore at least some of the ductility that the virgin binder loses during aging. Comparing the results in Table 15, TMP tallate (5 wt.%) and Sylvatac^® RE5 (10 wt.%) perform better than Sylvatac^® RE5 (5 wt.%), which is better than Sylvatac^® RE40 (5 wt.%). It is helpful to compare the results at a baseline energy level, such as 1 J/cm² and ask at what temperature this force ductility value is achieved. As shown in the table, this value is 28°C for aged binder and 17°C for virgin binder. Rejuvenating agent helps the binder rival the targeted value of 17°C.

Table 16 provides results of a gyratory compaction study (by EN 12697-31 ) in which 75 wt.% of reclaimed asphalt pavement (RAP) is combined with virgin binder and aggregate, with or without rejuvenating agent. TMP tallate is used at 6 wt.% based on the amount of oxidized binder present in the RAP. The results after 10 gyrations indicate how well mixing is occurring. The void content after 60 or 100 gyrations is also of interest. The compaction study is complete after 200 gyrations. In general, we found that, compared with a control mixture with no RAP, the use of RAP makes it easier to achieve a low void content. Additionally, void content remains desirably low when TMP tallate is included as a rejuvenating agent. ASTM D6925 can also be used.

Water sensitivity by EN 12697-12 is also evaluated for asphalt mixtures containing 75 wt.% RAP, and those results appear in Table 17. Compared with a control mixture, the ratio of wet to dry indirect tensile strength (wet ITS/dry ITS) decreases with RAP, indicating significant water sensitivity. However, inclusion of 6 wt.% TMP tallate makes the RAP-containing mixture behave more like the control, i.e., it reduces the water sensitivity of the asphalt mixture. ARZ-040000PCT 127-018PCT

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Table 18. Effect of Aging on Binder Properties

Fresh After RTFO After RTFO and PAV

Pen R&B, Pen R&B, Mass Ret. Δ Pen R&B, Mass Ret. Δ

°C °C loss, Pen, R&B, °C loss, Pen. R&B

% % °C % % °C

Oxidized binder (RA) 21 66

Virgin binder, 70/100 75 47

Virgin binder, 40/60 47 52 35 57 -0.36 76 6 28 64 -0.47 60 12

70/100 + 5% TMP tallate 176 37 109 43 -0.32 62 7 55 51 -0.50 31 15

RA + 70/100 35 56 32 60 -0.43 91 4 26 65 -0.42 75 8

RA + 70/100 + TMP tallate 37 58 33 61 -0.60 90 3 26 65 -0.43 71 8

RA + 40/60 + TMP tallate 41 56 35 58 -0.55 84 2 29 64 -0.46 71 8

RA + 5% TMP tallate 42 56 36 59 -0.62 86 2 30 64 -0.47 71 7

RA + 70/100 + TMP tallate^* 36 58 30 60 -0.55 84 3 26 66 -0.43 73 8

RA + 70/100 + cardanol 39 56 36 59 -0.60 94 3 29 65 -0.46 75 8

RA + 70/100 + veg. oil 38 55 33 59 -0.62 86 4 27 66 -0.47 70 10

^*EU sourced. Pen = penetration at 25°C in dmm. R&B = ring and ball softening point. Ret. Pen. is the % of penetration value retained after the aging step. Δ R&B is the change in softening point after aging. RTFOT is the rolling thin-film oven test; PAV is the pressure aging vessel test.

The laboratory methods used to age binder to make it behave more like the oxidized binders found in reclaimed asphalt have already been discussed. As noted, the RTFO test, or rolling thin film oven test, is used to assess short-term aging effects, while the PAV (pressure aging vessel) test assesses long-term aging.

Table 18 compares basic properties of rejuvenated binders before and after aging using first the RTFO test and then the PAV test. In all cases with rejuvenated binder, the cumulative mass loss is about 1 wt.% or less, which is consistent with the results seen using virgin binder. Thus, there is no adverse impact on mass loss when a rejuvenating agent is used.

Following the aging steps, the ring and ball softening point of all of the tested binders increases somewhat. However, the overall increase (see far right column, Δ R&B) is in line with the increase seen with virgin binder. In other words, the ester- functional rejuvenating agent does not appear to accelerate short- or long-term aging of the binder. Similarly, the penetration values are not adversely impacted by aging. If anything, when compared with virgin binder, a higher proportion of the original penetration value of the binder is maintained when the rejuvenating agent is present (compare the Ret. Pen.% values at the far right of Table 18).

The preceding examples are meant only as illustrations; the following claims define the scope of the invention.

Claims

We claim:

1. An asphalt composition comprising reclaimed asphalt and an ester-functional rejuvenating agent, wherein the reclaimed asphalt comprises aggregate and an oxidized asphalt binder, and wherein the rejuvenating agent is present in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 5°C compared with the glass-transition onset temperature of the oxidized asphalt binder without the rejuvenating agent.

2. The composition of claim 1 further comprising 1 to 99 wt.% of virgin binder based on the combined amounts of virgin binder and oxidized asphalt binder.

3. The composition of claim 1 comprising 0.1 to 15 wt.% of the rejuvenating agent based on the combined amounts of oxidized asphalt binder and rejuvenating agent.

4. The composition of claim 1 wherein the rejuvenating agent derives from a C Ci8 monol, diol, or triol and a C8-C20 fatty acid or a dimer acid thereof.

5. The composition of claim 1 wherein the rejuvenating agent is present in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 10°C.

6. The composition of claim 1 wherein the rejuvenating agent is present in an amount effective to narrow the glass-transition temperature spread of the oxidized asphalt binder by at least 5°C compared with the glass-transition temperature spread without the rejuvenating agent.

7. The composition of claim 1 wherein the rejuvenating agent is selected from the group consisting of trimethylolpropane tallates, ethylene glycol Monomerates, neopentyl glycol Monomerates, 2-ethylhexyl Monomerates, and glycerol Monomerates.

8. The composition of claim 1 wherein the rejuvenating agent is an ester derived from tall oil fatty acid, Monomer acid, dimer acids, stearic acid, isostearic acid, 12- hydroxystearic acid, ricinoleic acid, azeleic acid, caprylic acid, or benzoic acid.

9. A rejuvenated binder suitable for use with reclaimed asphalt, comprising:

(a) oxidized asphalt binder; and

(b) 0.1 to 15 wt.% of an ester-functional rejuvenating agent, based on the combined amounts of oxidized asphalt binder and rejuvenating agent; wherein the rejuvenating agent is present in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 5°C compared with the glass-transition onset temperature of the oxidized asphalt binder without the rejuvenating agent.

10. The binder of claim 9 further comprising 1 to 99 wt.% of virgin binder based on the combined amounts of virgin binder and oxidized asphalt binder.

11. The binder of claim 9 comprising 0.5 to 10 wt.% of the rejuvenating agent.

12. The binder of claim 9 wherein the rejuvenating agent derives from a C1 -C18 monol, diol, or triol and a C₈-C₂o fatty acid or a dimer acid thereof.

13. A method which comprises combining reclaimed asphalt with an ester- functional rejuvenating agent, wherein the reclaimed asphalt comprises aggregate and an oxidized asphalt binder, and wherein the rejuvenating agent is used in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 5°C compared with the glass-transition onset temperature of the oxidized asphalt binder without the rejuvenating agent.

14. The method of claim 13 wherein the reclaimed asphalt, the rejuvenating agent, or a mixture thereof is combined with 1 to 99 wt.% of virgin binder based on the combined amounts of virgin binder and oxidized asphalt binder.

15. The method of claim 13 wherein the reclaimed asphalt, the rejuvenating agent, or a mixture thereof is combined with 30 to 70 wt.% of virgin binder based on the combined amounts of virgin binder and oxidized asphalt binder.

16. The method of claim 13 wherein 0.1 to 15 wt.% of the rejuvenating agent is used based on the combined amounts of oxidized asphalt binder and rejuvenating agent.

17. The method of claim 13 wherein the rejuvenating agent is used in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 10°C.

18. The method of claim 13 wherein the rejuvenating agent is used in an amount effective to narrow the glass-transition temperature spread of the oxidized asphalt binder by at least 5°C.

19. The method of claim 13 wherein the rejuvenating agent is selected from the group consisting of trimethylolpropane tallates, ethylene glycol Monomerates, neopentyl glycol Monomerates, 2-ethylhexyl Monomerates, and glycerol Monomerates.

20. A method which comprises combining a binder composition comprising an oxidized asphalt binder with an ester-functional rejuvenating agent, wherein the rejuvenating agent is used in an amount effective to reduce the glass-transition onset temperature of the oxidized asphalt binder by at least 5°C compared with the glass- transition onset temperature of the oxidized asphalt binder without the rejuvenating agent.

21. An asphalt composition comprising 0.01 to 10 wt.% of a rosin ester and at least 15 wt.% of reclaimed asphalt, wherein the rosin ester is a reaction product of tall oil rosin or a tall oil and a polyol selected from the group consisting of diethylene glycol, triethylene glycol, glycerol, pentaerythritol, and mixtures thereof.

22. The composition of claim 21 further comprising binder and/or aggregate.

23. The composition of claim 21 wherein the reclaimed asphalt is reclaimed asphalt pavement.

24. A method comprising rejuvenating reclaimed asphalt by mixing the reclaimed asphalt with 0.01 to 10 wt.% of a tall oil ester, a rosin ester, or mixtures thereof.

25. The method of claim 24 wherein the rosin ester is a reaction product of tall oil rosin and a polyol selected from the group consisting of diethylene glycol, triethylene glycol, glycerol, pentaerythritol, and mixtures thereof.

26. An asphalt composition comprising:

(a) at least 15 wt.% of reclaimed asphalt comprising oxidized binder; and

(b) an ester-functional rejuvenating agent;

wherein the rejuvenating agent is present in an amount within the range of 1 to 10 wt.% based on the combined amounts of oxidized binder and rejuvenating agent; and

wherein the rejuvenating agent and the oxidized binder form a rejuvenated binder having a ring and ball softening point by EN 1427 less than 60°C and a penetration value by EN 1426 greater than 20 dmm.

27. The composition of claim 26 further comprising additional aggregate and/or binder.

28. The composition of claim 26 wherein the rejuvenating agent is selected from the group consisting of trimethylolpropane tallates, ethylene glycol Monomerates, neopentyl glycol Monomerates, 2-ethylhexyl Monomerates, and glycerol Monomerates.

29. The composition of claim 26 wherein the rejuvenating agent comprises a rosin ester having a ring and ball softening point by EN 1427 less than 50°C.

30. The composition of claim 26 wherein the rejuvenating agent comprises a rosin ester, a rosin acid, or a mixture thereof.

31. The composition of claim 30 wherein the rejuvenating agent further comprises a fatty ester, a vegetable oil, or a petroleum flux oil.

32. The composition of claim 30 wherein the rejuvenated binder has reduced temperature sensitivity compared with that of a similar rejuvenated binder made without the rosin acid, rosin ester, or mixture thereof.

33. The composition of claim 26 wherein the rejuvenating agent reduces the temperature required for mixing, at viscosities less than or equal to 200 mPa-s, by at least 5°C.

34. The composition of claim 26 wherein the rejuvenating agent reduces the temperature required for compaction, at viscosities less than or equal to 3000 mPa-s, by at least 5°C.

35. A rejuvenated binder comprising:

(a) oxidized binder; and

(b) an ester-functional rejuvenating agent;

wherein the rejuvenating agent is present in an amount within the range of 1 to 10 wt.% based on the combined amounts of oxidized binder and rejuvenating agent; and

wherein the rejuvenated binder has a ring and ball softening point by EN 1427 less than 60°C and a penetration value by EN 1426 greater than 20 dmm.

36. The binder of claim 35 wherein the force ductility, when measured by AASHTO T-300, is 1 .0 J/cm² at a temperature within the range of 15°C to 25°C.

37. The binder of claim 35 wherein the rejuvenating agent is selected from the group consisting of trimethylolpropane tallates, ethylene glycol Monomerates, neopentyl glycol Monomerates, 2-ethylhexyl Monomerates, and glycerol Monomerates.

38. The binder of claim 35 that demonstrates stability when the binder is subjected to short-term aging by the rolling thin-film oven test according to EN 12607-1 and long-term aging by the pressure aging vessel test according to EN 14769.

39. A paved surface comprising the asphalt composition of claim 1.

40. A paved surface comprising the binder of claim 9.

41. A paved surface comprising the asphalt composition of claim 21.

42. A paved surface comprising the asphalt composition of claim 26.

43. A paved surface comprising the binder of claim 35.