AU2020217331B2

AU2020217331B2 - Asphalt recycling

Info

Publication number: AU2020217331B2
Application number: AU2020217331A
Authority: AU
Inventors: Vincent Huang
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-04-28
Filing date: 2020-08-11
Publication date: 2022-04-14
Anticipated expiration: 2040-08-11
Also published as: AU2020217331A1; NZ767000A

Abstract

The present invention relates to the field of recycling, in particular, to a method and apparatus for recycling asphalt pavement.

Description

TITLE ASPHALT RECYCLING FIELD OF THE INVENTION

[0001] The present invention relates to the field of recycling. More particularly, the invention relates to a method and apparatus for recycling asphalt pavement.

BACKGROUND TO THE INVENTION

[0002] Any reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.

[0003] Roads and pavement play an important role in the operation of an economy. Roads are required in the production, distribution, trade and consumption of goods and services.

[0004] Asphalt is typically used in road construction. Asphalt is utilized as a glue or binder with aggregate material to form asphalt pavement. Asphalt typically contains four main elements: saturates, aromatics, resin and asphaltenes. Once cured, the asphalt and aggregate material form asphalt pavement which forms the road. Unfortunately, asphalt pavement is constantly exposed to the elements (sun, rain and wind) and as such ages. Furthermore, the physical strain on asphalt pavement from the loads thereon also contributes to wear.

[0005] Due to this aging, asphalt pavement degrades over time. This degradation can occur over time due to natural factors such as oxidation, changes in temperature, light, and erosion. The reaction of aging asphalt is an irreversible chemical, physical and mechanical reaction.

[0006] The aging process of asphalt results in a change in the relative amounts of constituent elements therein. In this regard, it is believed that as asphalt ages the amount of asphaltenes increases whereas the amount of aromatics decrease. As this occurs, the physical and mechanical properties of the asphalt become harder and more brittle.

[0007] The constant exposure to the elements exacerbates the problem associated with aging. For instance, high temperatures can accelerate the polymerization reaction between oxygen and asphalt molecules. This results in a loss of stickiness in the asphalt. It is postulated that this occurs from the increasing average molecular weight of the asphalt due to polymerization. Furthermore, high temperatures with water bathing the asphalt pavement can also cause the removal of asphalt between the aggregate material. Once the asphalt pavement no longer has the asphalt layer, the surface thereof can be removed.

[0008] Over time, all asphalt ages and will need to be replaced. Currently, aged asphalt pavement is removed from the surface and new asphalt pavement is applied thereon. Current methods of recycling asphalt pavement do not result in constituent parts (such as, asphalt and aggregate material) that are of a sufficiently high quality so that they can be used almost exclusively in the formation of new asphalt pavement. In this regard, there are limitations in the amount of recycled asphalt pavement constituents that can be used.

[0009] It would be advantageous if the aged asphalt pavement could be recycled so as to isolate the constituent elements (asphalt and aggregate material) in a higher quality so that the amount used in asphalt pavement can be increased. It would be advantageous to be able to recycle this material from both an economical and environmental view point.

[0010] It would be advantageous to provide a method of recycling asphalt pavement that alleviates at least one of the above problems, or it would be advantageous to provide a commercial alternative to the prior art methods currently available.

SUMMARY OF THE INVENTION

[0011] In one form, although it need not be the only or indeed the broadest form, the invention resides in a method of isolating constituent materials of asphalt pavement, the method including the steps of:

a. contacting the asphalt pavement with one or more solvents to form a mixture;

b. subjecting the mixture to an elevated temperature;

c. separating the mixture into a solid component and a liquid component,

to thereby isolate the constituent materials of the asphalt pavement.

[0012] In one embodiment, the invention resides in a method of isolating constituent materials of asphalt pavement, the method including the steps of:

a. contacting the asphalt pavement with one or more solvents to form a mixture;

b. subjecting the mixture to an elevated temperature; and

c. separating the mixture into a solid component and a liquid component,

wherein the one or more solvents is selected from the group consisting of benzene, toluene, carbon tetrachloride, N-octane, methanol and isopropanol,

to thereby isolate the constituent materials of the asphalt pavement.

[0012a] In one aspect of the present invention, there is provided a method of isolating constituent materials of asphalt pavement, the method including the steps of:

a. contacting the asphalt pavement with two or more solvents to form a mixture;

b. subjecting the mixture to an elevated temperature of between about 500 C and 100 °C

c. separating the mixture into a solid component and a liquid component,

3a

wherein the three or more solvents comprise n-pentane, cyclohexane and butanol,

to thereby isolate the constituent materials of the asphalt pavement.

[0012b] In another aspect of the present invention, there is provided a method of isolating constituent materials of aged asphalt pavement, the method including the steps of:

a. contacting the aged asphalt pavement with n-pentane, cyclohexane and butanol to form a mixture, wherein the aged asphalt pavement to solvent ratio (asphalt pavement: solvent) is about 1:10

b. subjecting the mixture to an elevated temperature of between 900 C and 95 °C with agitation for about 120 minutes;

c. cooling the mixture for 24 hours and then separating the mixture into a solid component and a liquid component,

to thereby isolate the constituent materials of the asphalt pavement

[0013] The various features and embodiments of the present invention referred to in the individual sections above and in the description which follows apply, as appropriate, to other sections, mutatis mutandis. Consequently, features specified in one section may be combined with features specified in other sections as appropriate.

[0014] Further features and advantages of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect, preferred embodiments of the invention will be described by way of example only with reference to the accompanying drawings, in which:

FIG 1 is a sample of coarse reclaimed asphalt pavement;

FIG 2 is a sample of fine reclaimed asphalt pavement;

FIG 3 is the sample of FIG 1 after treatment with the present invention; and

FIG 4 is the sample of FIG 2 after treatment with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Embodiments of the present invention reside primarily in a method of recycling asphalt pavement. Accordingly, the apparatus and method steps have been illustrated in concise schematic form in the drawings, showing only those specific details that are necessary for understanding the embodiments of the present invention, so as to not obscure the disclosure with excessive detail that will be readily apparent to those of ordinary skill in the art having the benefit of the present description.

[0017] In this specification, adjectives such as first and second, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order.

[0018] As used herein, the terms such as "comprises" or "includes" are intended to define a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed, including elements that are inherent to such a process, method, article, or apparatus.

[0019] As used herein, the term 'about' means the amount is nominally the number following the term 'about' but the actual amount may vary from this precise number to an unimportant degree.

[0020] As used herein, the term 'asphalt pavement' refers to a composite material commonly used to surface roads, parking lots and airports. Asphalt pavement is commonly named asphalt, blacktop, or pavement in North America, and tarmac, bitumen macadam, or rolled asphalt in the United Kingdom. Typically, asphalt pavement is made up of asphalt and aggregate material (stone, sand and gravel).

[0021] As used herein, the term 'reclaimed asphalt pavement' refers to removed pavement materials containing asphalt and aggregates. These materials are generated when asphalt pavements are removed for reconstruction, resurfacing, or to obtain access to buried utilities. The reclaimed asphalt pavement may be referred herein as 'RAP'.

[0022] The present invention is predicated on the finding that asphalt pavement can be readily recycled such that it results in separated asphalt and regenerated aggregate material. This separated asphalt and regenerated aggregate material is typically of such quality that it can be reused in forming asphalt pavement. It will be appreciated this is environmentally and economically advantageous.

[0023] In a first aspect, although it need not necessarily be the broadest aspect, the invention resides in a method of isolating constituent materials of asphalt pavement, the method including the steps of:

a. contacting the asphalt pavement with one or more solvents to form a mixture;

b. subjecting the mixture to an elevated temperature;

c. separating the mixture into a solid component and a liquid component,

to thereby isolate the constituent materials of the asphalt pavement.

[0024] The constituent materials include, but are not limited to, asphalt, aged asphalt and aggregate material.

[0025] The solvent preferably removes the asphalt and aged asphalt from the aggregate material in the asphalt pavement. The solvent is suitably a polar solvent or a non-polar solvent. The solvent may include one or more solvents. In one embodiment, the solvent may include one, two, three, four or five solvents.

[0026] The solvent is suitably selected based on their properties of dissolving asphalt and aged asphalt. In this regard, the solvent may be selected from the group consisting of toluene, carbon tetrachloride, dichloromethane, N-octane, methanol and isopropanol, and mixtures thereof.

[0027] One solvent may be preferred over another in recovering constituent materials of asphalt pavement. In this regard, when isolating asphalt from aged asphalt, two different solvents systems may be used. For instance, re-usable asphalt in reclaimed asphalt pavement may be removed by using a solvent selected from the group consisting of n-pentane, cyclohexane, butanol and mixtures thereof; and aged asphalt in reclaimed asphalt pavement may be removed by using a solvent selected from toluene, tetrachloromethane, dichloromethane and mixtures thereof.

[0028] It will be appreciated that benzene, toluene, tetrachloromethane and dichloromethane will dissolve both aged asphalt and asphalt, whereas n-pentane, cyclohexane and butanol will preferentially if not selectively dissolve reusable asphalt. As such, the method may include the step of first treating the asphalt pavement with one or more of n-pentane, cyclohexane, and butanol to first dissolve the reusable asphalt; and the method may include a further step of treating the remaining solid with one or more of benzene, toluene, tetrachloromethane, and dichloromethane to dissolve the aged asphalt. In one embodiment, the method may include simply dissolving the aged asphalt and reusable asphalt by using one or more solvents selected from benzene, toluene, tetrachloromethane and dichloromethane, to provide re-usable aggregate material.

[0029] The elevated temperature is suitably greater than 250 C, greater than 500 C, greater than 750C, or greater than 950 C. In one embodiment, the elevated temperature is between about 250 C and about 1250 C, between about 500 C and 1000 C, between about 750 and 950, between about 850 C and 950, or between about 900 C and 950 C.

[0030] The time required for the aged asphalt and/or asphalt to dissolve in the solvent may vary depending on solvent. Suitably, step b. occurs for greater than about minutes, greater than about 20 minutes, greater than about 40 minutes, greater than about 60 minutes, greater than about 90 minutes or greater than about 120 minutes. Preferably, the time required for step b. is about 40 minutes.

[0031] The method may further include the step of cooling the mixture. The mixture is suitable cooled to room temperature. The step of cooling the mixture may include assisted cooling, such as subjecting the mixture to a temperature that is lower than room temperature. Alternatively, the step of cooling the mixture may be allowed to cool in ambient temperatures over time. Preferably, the mixture is cooled to ambient temperatures. Preferably, the mixture is cooled to about 300 C, about 250 C, about 200 C, about 15 0C or about 100 C. Most preferably, the mixture is cooled to about 250 C.

[0032] The step of cooling the mixture is suitably greater than about 1 hour, greater than about 2 hours, greater than about 4 hours, greater than about 6 hours, greater than about 9 hours, greater than about 12 hours, greater than about 18 hours, or greater than about 24 hours. The step of cooling the mixture is suitably between about 2 hours to 24 hours.

[0033] The asphalt pavement to solvent ratio (asphalt pavement: solvent) is between about 1:0.05 to about 1:2, between about 1:0.1 to about 1:1, between about 1:0.14 to about 1:0.6, between about 1:0.2 to about 1:0.6, or between about 1:0.4 to about 1:0.6. The solvent ratio (asphalt pavement: solvent) may suitable be selected from the group consisting of about 1.0:0.4; about 1.0:0.6, about 1.0:0.14; and about 1.0:0.2

[0034] The step in which the mixture of asphalt pavement is contacted to the solvent may further include the step of agitating the mixture. In this regard, the step of agitating the mixture may include, but are not limited to, mechanical agitation, centrifuge and/or ultrasonic vibration. Alternatively, the asphalt pavement may be soaked in the solvent.

[0035] As mentioned above, the solvent may either be used to separate the asphalt and/or aged asphalt from the aggregate material in the asphalt pavement. In one embodiment, the asphalt pavement may be treated with a first solvent that preferentially dissolves re-usable asphalt. The re-usable asphalt may be isolated by removing the solvent. This asphalt is of sufficient quality that it can be reused in asphalt pavement. The remaining solvent can then be treated with a second solvent that dissolves the aged asphalt.

[0036] The removal of aged asphalt results in an aggregate material that can be reused in asphalt pavement. It will be appreciated that a solvent can be utilized to dissolve both the aged asphalt and asphalt to afford re-usable aggregate material in one step. These solvents include, but are not limited to, benzene, toluene, tetrachlorocarbon, dichloromethane, and mixtures thereof.

[0037] The method may further include the step of filtering the mixture to separate the solid material from the liquid material.

[0038] The method may further include the step of filtering the asphalt pavement and/or aggregate material. This step will separate the particle size of the aggregate material so that the amounts of said particle size of aggregate material can be utilized in asphalt pavement. This step can be completed before step a. or after step c.

[0039] The method may further include repeating steps of contacting and agitating the isolated solid in/with a solvent.

[0040] The ratio of isolated solid material and solvent may be different to the preceding step. In this regard, the ratio of solid material and solvent may be 1:0.05 to about 1:2, between about 1:0.1 to about 1:1, between about 1:0.1 to about 1:0.6; between about 1:0.14 to about 1:0.6, or between about 1:0.14 to about 1:0.2. Preferably, the ratio is selected from about 1:0.6, about 1:0.2 and about 1:0.14.

[0041] The time required for contact and agitating the isolated solid in/with a solvent is suitably greater than about 1 minute, greater than about 5 minutes, greater than about 10 minutes, greater than about 20 minutes, greater than about 30 minutes, greater than about 40 minutes, greater than about 50 minutes, or greater than about minutes. Preferably, the time required for contact and agitating the isolated solid in/with a solvent is about 10 minutes.

[0042] The method may include the step of contacting and agitating the isolated solid in/with a solvent repeated multiple times. This step may be repeated 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more times. Suitably, this step is repeated 1, 2, 3, 4, or 5 times. Preferably, this step is repeated 4 or 5 times.

Examples

Example method that utilizes soaking

[0043] The following steps were completed to isolate constituent materials from reclaimed asphalt pavement:

- soaking RAP in a solvent (ratio of 1.0:0.4; RAP: solvent) in a suitably sized container for 40 minutes;

- filtering the solution with a 1000m/m sieve;

- re-soaking the isolated solid in the solvent (ratio of 1.0:0.14; isolated solid: solvent) for 10 minutes; and

- repeating the preceding step until the filtered solution is clear

[0044] The amount of solvent used and operation times were recorded.

Example method that utilizes mechanical agitation

[0045] The following steps were completed to isolate constituent materials from reclaimed asphalt pavement:

- soaking RAP in a solvent (ratio of 1.0:0.6; RAP: solvent) in a suitably sized container, and agitating for 40 minutes;

- filtering the solution with a 1OOOm/m sieve;

- re-soaking and re-agitating the isolated solid in the solvent (ratio of 1.0:0.14; isolated solid: solvent) for 10 minutes; and

- repeating the preceding step until the filtered solution is clear.

[0046] The amount of solvent used and operation times were recorded.

Example method that utilizes centrifuge

[0047] The following steps were completed to isolate constituent materials from reclaimed asphalt pavement:

- soaking RAP in a solvent (ratio of 1.0:0.6; RAP: solvent) in a centrifuge device, and centrifuging for 40 minutes;

- filtering the solution with a 1OOOm/m sieve to separate solids from liquid;

- re soaking and re-centrifuging the isolated solid in the solvent (ratio of 1.0:0.6; isolated solid: solvent) for 10 minutes, and the centrifugal solution was then removed; and

- repeating the preceding step until the filtered solution is clear.

[0048] The amount of solvent used and operation times were recorded.

Example method that utilizes ultrasonic vibration

[0049] The following steps were completed to isolate constituent materials from reclaimed asphalt pavement:

- soaking and ultrasonic vibrating RAP in a solvent (ratio of 1.0:0.6; RAP: solvent) in a suitably sized ultrasonic vibration device for 40 minutes.

- filtering the solution with a 1OOOm/m sieve;

- re-soaking and re-ultrasonic vibrating the isolated solid in the solvent (ratio of 1.0:0.2; isolated solid: solvent) for 10 minutes, and the solution was removed; and

- repeating the preceding step until the filtered solution is clear.

[0050] The amount of solvent used and operation times were recorded.

Results from the methods that utilize soaking, mechanical agitation, centrifuge and ultrasonic vibration

[0051] The results of each of the above methods were compared based on the solvent usage, operation time, and the efficiency as shown in Table 1 (below). The centrifugal method and mechanical agitation method seem promising since the disappearance of the asphalt on the surface of the RAP is observed. The centrifugal method is the preferred separation method when comparing solvent usage and operation time. The soaking method and ultrasonic vibration method still showed good results but were not as good as the centrifuged method.

Method Centrifuge Mechanical Ultrasonic Pure Soaking Separation Agitation Vibration

Ratio of RAP and 1:1 1:1.2 1:1.2 1:1 solvent Operation time 80 100 70 80 (mins)

The photo of the result 3

Table 1 -The comparison of the example methods

Example method utilizing centrifuge with sieving the RAP

[0052] The following steps were completed to isolate constituent materials from reclaimed asphalt pavement:

- sieving RAP into a coarse RAP sample (particle size>1.41mm) and a fine RAP sample (particle size<1.41mm) through a sieve (NO. 14 sieve, pore size: 1.41mm);

- centrifuging the coarse RAP sample and fine RAP samples separately in a solvent (ratio of 1.0:0.6; RAP: solvent) in a centrifuge device for 40 minutes;

- removing the solution;

- re-centrifuging the isolated solid in the solvent (ratio of 1.0:0.6; isolated solid: solvent) for 10 minutes, and removing the solution; and

- repeating the preceding step until the filtered solution is clear.

[0053] The amount of solvent used and operation times were recorded.

[0054] Shown in FIG 1 is a coarse RAP sample, and shown in FIG 2 is the fine RAP sample (both pre-treatment). As can be seen in FIGs 1 and 2, the untreated RAP samples have a dark outer surface which is believed to be the asphalt and aged asphalt. The course RAP sample of FIG 1 and the fine RAP sample of FIG 2 were treated according to the above example method utilizing centrifuging.

[0055] The performance of this method on the coarse RAP sample and the fine RAP sample was monitored, and the resultant samples are shown in FIG 3 (coarse RAP sample after treatment) and FIG 4 (fine RAP sample after treatment). As can be seen in FIGs 3 and 4, the treated RAP samples (both fine and coarse samples) exhibited a lighter appearance which indicates that the asphalt in both these samples had been substantially removed therefrom.

[0056] The operating process of the two samples (course and fine RAP samples) are shown in Table 2 (below). Based on these results, the coarse RAP sample requires up to four times of 10 minutes centrifuging. This indicates that solvent usage and operation time is about 20% and 10 minutes less than the fine RAP sample. Therefore, this suggests that the RAP should be sieved prior to treatment.

Initial (40 minutes soaking and centrifuge) V V

1" 10 minutes soaking and centrifuge V V

2 nd 10 minutes soaking and centrifuge V V

3 rd 10 minutes soaking and centrifuge V V

4 th 10 minutes soaking and centrifuge Clear solution V

5 h 10 minutes soaking and centrifuge --- Clear solution

Ratio of RAP: Solvent (total usage) 1:1 1:1.2

Total operation time 80 minutes 90 minutes

Table 2 - Comparison of the coarse RAP sample and the fine RAP sample Further testing of the recovered aggregates was completed by CNS15308 (Standard Specification for Coarse Aggregate for Bituminous Paving Mixtures) and CNS1240 (Standard Specification for Concrete aggregates). The recovered aggregates had only 18% of the wear rate and this is lower than both CNS methods. This indicates that the recovered aggregates are not likely to have further fretting. The soundness of coarse particles in sodium sulfate and magnesium sulfate solutions was 2.2% and 1.6% respectively, and are superior to the standard in both cases. This indicates that the recovered aggregate has an advantage in the tolerance to chemical corrosion. The detection of the Toxicity Characteristic Leaching Procedure (TCLP) shows no sign of toxicity. The test for organic impurities in fine aggregates presents a mark in the No.2 organic color palette which passes the standard since the color palette should not be above No.3 organic color palette. The further details of the analysis are shown in Table 3 below.

Coarse particles' surface course <40% 50% 18% wear rate base course <50%

Mass loss rate in sodium Mass loss rate in sodium sulfate <12% Mass loss rate in sulfate: 2.2% Coarse particles' Mass loss rate in magnesium sulfate Mass loss rate in soundness magnesium sulfate <18% <18% magnesium sulfate: 1.6%

Fine particles' moisture content <4% NA moisture content 2.2% plasticity Refer to hazardous TCLP test NA industrial waste undetected regulation Coarse particles' fragmentation (up to NA >90% 99% No. 4 sieve) The test of organic Below No.3 organic Up to No.2 organic color impurities in fine NA color palette palette aggregates

Table 3 - Comparison of the regenerated aggregates with the two CNS standards

Example method of separating regenerated asphalt from aged asphalt

[0059] The following steps were completed to isolate usable asphalt from aged asphalt in reclaimed asphalt pavement:

- RAP and solvent (n-pentane, cyclohexane and butanol mixture(s)) in a ratio of 1:10 (RAP: solvent) were added a flask equipped with a stirrer and reflux condenser;

- heating the mixture to approximately 90-95°C and mix for 2 hours;

- cooling mixture for 24 hours;

- filtering the solution; and

- washing the filter cake with the solvent until clear.

[0060] The usable asphalt is suspended in the filtrate. The solvent may be removed, such as via rotary evaporation. The remaining substance is regenerated usable asphalt. The percentage recovery is about 68%.

[0061] The following steps were completed to isolate the remaining asphalt (aged asphalt) from the filter cake:

- washing the filter cake with a second solvent (toluene, tetrachloromethaneand/ordichloromethane);

- washing the filter cake with the solvent until clear.

[0062] The aged asphalt is suspended in this filtrate. The solvent was removed by evaporation, such as via rotary evaporation. The remaining substance is aged asphalt. The percentage recovery is about 28%.

Properties of the usable asphalt

[0063] As mentioned in the background section, asphalt typically contains four organic compounds: saturates, aromatics, resin, and asphaltenes. The percentages of the aromatics and asphaltenes in fresh or new asphalt are 42% and 24%, respectively; whereas aged asphalt has a dramatic decrease in aromatics (27%) and an increase in asphaltenes (36%).

[0064] TLC analysis on the recovered usable asphalt promisingly showed that the percentage of aromatics and asphaltenes were 55% and 3%, respectively. The analysis shows that the recovered usable asphalt has a decrease in asphaltenes, but also an increase in aromatics. The significant increase in the percentage of aromatics is in part due to the increase in relative aromatics content per unit weight of asphalt due to removal of aged asphaltenes.

[0065] The result of the CNS15073 shows the viscosity of the regenerated asphalt is 1,085 poise; this indicates that the removal of aged asphalt can significantly decrease the viscosity of the asphalt. Moreover, the penetration improves from 26 to 73 compared to the aged asphalt. Furthermore, the flash point and solubility of trichloroethylene are within standards.

[0066] The thin film oven test on the recovered reusable asphalt shows a viscosity of 4,841 poise and ductility of 100 cm; whereas the aged asphalt, with the same test, shows a viscosity of 250,000 poise and ductility of 7cm. These findings suggest that the performance of recovered usable asphalt using the present method is superior to fresh or new asphalt (e.g., the ductility). A possible reason for this ductility is the percentage of the aromatics and asphaltenes in the recovered reusable asphalt is 55% and 3%, respectively; whereas fresh or new asphalt has aromatics and asphaltenes in an amount of 42% and 24%, respectively.

[0067] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this invention is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.

Claims

1. A method of isolating constituent materials of asphalt pavement, the method including the steps of:

a. contacting the asphalt pavement with three or more solvents to form a mixture;

b. subjecting the mixture to an elevated temperature of between about 500 C and 100 °C; and

c. separating the mixture into a solid component and a liquid component,

wherein the three or more solvents comprise n-pentane, cyclohexane and butanol,

to thereby isolate the constituent materials of the asphalt pavement.

2. The method of claim 1, wherein the constituent materials is asphalt and/or aggregate material.

3. The method of claim 1 or 2, wherein the elevated temperature is between about 75 0C and about950 C.

4. The method of claim 3, wherein the elevated temperature is between about 850 C and 950 C.

5. The method of claim 4, wherein the elevated temperature is between 900 C and 95 0C.

6. The method of any one of the preceding claims, wherein step b. occurs for greater than 10 minutes, greater than 20 minutes, greater than 40 minutes, greater than 90 minutes or greater than 120 minutes.

7. The method of claim 6, wherein step b. occurs for about 120 minutes.

8. The method of any one of the preceding claims, wherein the asphalt pavement to solvent ratio (asphalt pavement: solvent) is between about 1:0.05 to about 1:10, between about 1:0.05 to about 1:1, between about 1:0.1 to about 1:0.75, between about 1:0.14 to about 1:0.6, between about 1:0.2 to about 1:0.6, or between about 1:0.4 to about 1:0.6.

9. The method of claim 8, wherein the asphalt pavement to solvent ratio (asphalt pavement: solvent) is about 1:10.

10.The method of any one of the preceding claims, wherein step b. further includes the step of agitating the mixture.

11.The method of claim 10, wherein the step of agitating the mixture comprises mechanical agitation, centrifuge and/or ultrasonic vibration.

12. A method of isolating constituent materials of aged asphalt pavement, the method including the steps of:

a. contacting the aged asphalt pavement with n-pentane, cyclohexane and butanol to form a mixture, wherein the aged asphalt pavement to solvent ratio (asphalt pavement: solvent) is about 1:10;

to thereby isolate the constituent materials of the asphalt pavement.

13.The method of any one of the preceding claims, further includes the step of contacting and agitating the solid component with a solvent.

14.The method of claim 13, wherein the step of contacting and agitating the solid component with a solvent is repeated one, two, three, four, five, six, seven or more times.

15.Isolated constituent materials produced by the method of any one of the preceding claims.

16.The isolated constituent material of claim 15, wherein the isolated constituent material is asphalt and/or aggregate material.

Vincent Huang Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON

FIGURES 1/4

Figure 1