This is an international;, Patent Cooperation Treaty application that claims priority to US Provisional application US 60/560,791, filed on 7 April, 2004, hereby incorporated herein by reference.

TECHNICAL FIELD

This inventive technology relates to asphaltic substances generally, and more specifically, certain embodiments relate to enhancing the anti-aging capabilities of substances such as asphalt pavement.

BACKGROUND

Generally embodiments of this invention relates to the use of lignin in asphalt such that it may improve the anti-aging capabilities of asphalt containing materials (e.g., asphalt pavement). Specifically, this invention may involve the use of lignin in an asphalt to prolong or extend the functional life of asphalt pavement (or indeed any material or substance of which the asphalt is a constituent part). This anti-aging (i.e., reduction and or mitigation of the deleterious effects of age) may be the result of anti-oxidation capabilities of lignin.

Asphalt pavements comprise approximately 95% of the paved roads in the United States. Typically, an asphalt pavement is composed of 5% asphalt (also known as asphalt binder) and 95% aggregate (including, but not limited to, rocks or pebbles). The asphalt is essentially the glue that holds the aggregate together. Thirty million tons of asphalt is used each year in the construction or maintenance of pavements in the United States.

The composition of asphalts is quite variable, and the performance of the resultant asphalt pavement is primarily dependent upon the chemical and physical properties of the asphalt and the aggregate. Various AASHTO-approved (AASHTO stands for American Association of State Highway and Transportation Officials) tests are used to qualify or determine the suitability of the asphalt and aggregate that will be used in construction of a pavement. As is well known, after an asphalt pavement has been laid, it starts to age due to the action of traffic and the environment. In general, aging of the asphalt results in various forms of pavement distress, such as fatigue damage, thermal cracks, moisture- related damage, and/or raveling. With regard to the impact of the environment on the pavement, aging (which is primarily caused by oxidation, the result of the reaction of the oxygen in the air with selected compounds in the asphalt) changes the chemical and physical properties of the asphalt, and these changes can be deleterious to the performance of the pavement, resulting in various forms of distress. A process that would mitigate the aging (oxidation) of the asphalt would be a benefit to the highway community (e.g. driving users) by prolonging pavement life resulting, in a significant savings in the cost of maintaining our current highway system. However, effective anti¬ oxidants for asphalts are expensive and consequently not used (or are used only rarely and sparingly). It is of note also that these anti-oxidants are not lignin or lignin-based.

There are various additives or modifiers that have been used in asphalt pavement with the intent of improving asphalt performance. These include: sulfur, glass, polymers, crumb rubber (from tires), lime, etc. Unfortunately, these materials often do not improve the performance of the pavement, the exception being the use of the various polymers, styrene-butadiene and Elvaloy , and, potentially, crumb rubber. In addition, the use of lime in asphalt pavements has had a dramatic effect on the mitigation of moisture damage in asphalt pavements. Laboratory studies have also been conducted to evaluate the impact of lignin as an asphalt modifier [Terrel and Rimsritong 1979; Sundstrom et al. 1983]. Sundstrom and co-workers observed that lignin produced from exploded wood decreased an aging index of asphalt using one particular exposure paradigm. No comment as to asphalt performance was made. Notably, the specification tests used in the early 1980's have recently been supplanted with specification tests that are pavement- performance based. The Superpave specification tests were adopted by AASHTO in 1993.

Lignin can be generated from the biorefining process in addition to being a co- product of the pulp and paper processing industry (e.g., kraft lignin). However, other types of lignin exist and may find novel use in asphalt as an anti-oxidant. It may find use as a fuel for power plants, as a component in the manufacture of lignosulfonates, and in the manufacture of inks. Lignosulfonates are used to stabilize emulsions that are formed when immiscible liquids are mixed together. Such liquids (emulsions) include asphalt emulsions, pigments and dyes, pesticides, and wax emulsions (floor waxes). Asphalt emulsions are used in pavement applications as a preventative maintenance measure. Specifically, asphalt emulsions are used to mitigate crack growth' due to fatigue and low temperatures (thermal cracks).

Bioprocessing is the conversion of low- value biomass and biowastes into higher- value fuels, fibers, energy and specialty chemicals. Bioprocessing takes place in biorefineries, where biomass can be separated into its constituent products streams (i.e., cellulose, hemicellulose and lignin). The lignin content of biomass is typically approximately 20%. It is currently used as a low-value fuel for industrial plant power, process heat and electricity. However, for biorefining to achieve its full potential, new higher-value markets for lignin must be identified and developed. One such new, higher- value market for lignin may be as an anti-aging modifier (specifically as an anti-oxidant) in asphalt.

DISCLOSURE OF INVENTION

The present invention includes a variety of aspects which may be selected in different combinations based upon the particular application or needs to be addressed. Generally this invention relates to the use of lignin in asphalt such that it may improve the anti-aging capabilities of asphalt comprising materials or substances (e.g., asphalt pavement). An aspect of the inventive technology may involve the use of lignin (e.g., non-derivative lignin) in an asphalt binder to prolong the life of asphalt pavement or other asphalt comprising materials in which the binder is used. Certain lignins (e.g., those that are more polar than others, kraft lignins, and/or non-derivative lignins), and/or certain amounts of lignin in the asphaltic composition (binder or asphalt pavement, as but two examples) may better inhibit aging of asphalt than others due, e.g., to their enhanced capability to act as an anti-oxidant. Carbonyl content of a lignin modified asphalt (a type of asphaltic composition) may correspond to the anti-aging effect of the lignin; particularly, those amounts of lignin which yield (or result in) lower (e.g., minimal) carbonyl contents of the asphaltic composition may effect better anti-aging capabilities than observed in asphaltic compositions having higher carbonyl contents. The underlying chemical reason for this anti-aging effect afforded by the lignin may relate to lignin's ability to act as an anti-oxidant.

Objects of the invention include a significant reduction in highway maintenance costs to taxpayers, an improvement in highway safety, especially for those traveling on older roads, the creation of an impetus for the further development of biorefining due to the enhancement of the value of lignin, and the provision of a valuable new market for agricultural producers. Naturally, further objects of the invention are disclosed throughout other areas of the specification, and claims when presented.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a graph showing results of accelerated aging tests for West Texas asphalt modified with lignin as compared with an unmodified version of that asphalt.

MODESFORCARRYINGOUTTHEINVENTION

As mentioned earlier, the present invention includes a variety of aspects, which may be combined in different ways. The following descriptions are provided to list elements and describe some of the embodiments of the present invention. These elements are listed with initial embodiments, however it should be understood that they may be combined in any manner and in any number to create additional embodiments. The variously described examples and preferred embodiments should not be construed to limit the present invention to only the explicitly described systems, techniques, and applications. Further, this description should further be understood to support and encompass descriptions and claims, when presented, of all the various embodiments, systems, techniques, methods, devices, and applications with any number of the disclosed elements, with each element alone, and also with any and all various permutations and combinations of all elements in this or any subsequent application.

A study was conducted to evaluate the impact of lignin on the rheological and chemical properties of two different asphalts. The asphalts were modified by the preparation of asphalt samples that contained 3, 5, and 7 weight percent lignin. The rheological properties of the samples were then determined using the AASHTO-approved specification tests. During the conduct of these tests asphalt samples are aged using widely accepted accelerated aging tests. The results indicated that, at the level of modification tested, the performance grade of the asphalts had not changed (e.g., adding as much as 7% lignin has no detrimental effect on the high- and low-temperature performance grade of the lignin modified asphalt. However, a spectroscopic analysis of the aged samples using Fourier transform infrared spectroscopy revealed that the concentration of the carbonyl-containing compounds was affected. In particular, as the concentration of the lignin was increased in West Texas Intermediate asphalt, the amount of carbonyl-containing compounds decreased compared to the unmodified asphalt (see Table 1 below), until an apparent minimum carbonyl content was observed at approximately 5% by weight of lignin in asphalt. Among the four percentage by weight amounts of lignin in California Coastal asphalt that were tested (including 0% lignin), the 5% by weight amount of lignin (relative to the weight of the total composition) yielded the smallest value. TABLE 1

Carbonyl Content (in Absorbance Units) of Unmodified and Lignin-Modified Asphalts (Aged for 20 hours at 1000C in a Pressure Vessel)

Effective ranges of lignin (in % weight relative to the weight of an asphaltic composition created by admixing asphalt with lignin) may include, but are not limited to: 6 - 9, 7 - 8, 4 - 6.5, 6.5 - 9, 3 - 7, 4 - 8, 4.7 - 5.3, 6.8 - 7.4, and 3 - 9; specific values of lignin (in weight percentage) such as 5, 7 and 8 (as but as few examples) may also serve to characterize the makeup of asphaltic compositions that yield improved aging qualities as desired. Specific ranges may or may not correspond to a specific type of asphalt, whether California Coastal, West Texas Intermediate, or other, or may simply relate to lignin in general. Of course, other ranges may indeed be effective in prolonging the life of the asphaltic composition.

Aspects of the inventive technology may relate to admixing lignin with asphalt to form an asphaltic composition, and in substantially a relative amount (e.g., weight lignin/weight asphaltic composition expressed in a percentage) which yields a desired carbonyl content (in absorbance units) of the asphaltic composition; the desired carbonyl content may be a minimal carbonyl content (e.g., the lowest measured carbonyl content); a relatively low carbonyl content (e.g., a range defined by the lowest 25%, 10%, or 5% carbonyl content values); a minimal range of carbonyl content (e.g., 10%, 5%, or 2% on either side of the minimal carbonyl content); and a specific range of carbonyl content, as but a few examples. Ranges (in absorbance units) include, but are not limited to: 0.05- 0.075; 0.06-0.07; 0.10-0.13; 0.105-0.110; specific values of carbonyl content that may effect an improvement in response to aging include, but are not limited to: 0.11; 0.107; 0.108; 0.106; 0.066; 0.067; 0.068; 0.069; 0.070; 0.071; 0.072; 0.073; 0.065; 0.064; 0.063; 0.062; 0.061. Such ranges or specific values may correspond to a specific type of asphalt, or may relate to asphalt in general (i.e., may relate to any type of asphalt). It is of note that any value (whether as part of a value or not; and whether defining an amount of lignin or other parameter), may be characterized in some fashion with the term "substantial" (or a variant thereof). Such term indicates that slight variations from the value as presented are deemed to still fit within the description. For example, a 10% variation is not so large that it is not "substantially" the specific value that the term "substantial" (or its variant) relates to.

Typically, as a consequence of aging, the carbonyl content of an asphalt increases, and this increase in carbonyl content results in an asphalt that is more viscous or stiffer. Thus, the presence or modification of the asphalt with lignin in appropriate amounts results in an asphalt that ages at a slower rate than the unmodified asphalt. The lignin is acting as an anti-oxidant or an oxidation inhibitor. Accelerated aging tests suggest that lignin-modified asphalt (West Texas Asphalt) may take 40% longer to harden to a given stiffness (see Fig. 1). A decrease in the aging rate of an asphalt implies that a reduced level of effort will be required in the preventative maintenance of our highway system and a significant cost savings to the state Departments of Transportation. Not only could the use of lignin in asphalt pavement (a type of aggregated asphaltic composition) significantly reduce costs to taxpayers by extending the functional life of asphalt pavement, but it could also improve highway safety, create an impetus for the further development of biorefming, and provide a valuable new market for agricultural producers.

Lignins may be classified relative to polarity - one lignin may be more polar than the other. The more polar lignins may have better anti-oxidant properties and thus may reduce or inhibit aging of asphalt pavement more than lignins that are less polar. It should also be noted that under one system of classification, lignins may be classified as either analytical lignin preparations and industrial lignin preparations. Analytical lignin preparations include brauns lignin, cellulolytic enzyme lignin, dioxane acidolysis lignin, milled wood lignin, klason lignin and periodate lignin. Industrial lignins (e.g., highly modified lignin materials produced using various industrial procedures) include hydrolysis lignin, kraft lignin, lignosulfonates (whether from acid sulfite pulping, bisulfite pulping, the neutral sulfite semi chemical process or from alkaline sulfite-anthraquinone pulping), organosolv lignin, or steam explosion lignin. Any of these may be used as anti¬ oxidants to inhibit or reduce aging of asphalt pavement. Certain of these types may better inhibit aging of asphalt pavement than others. The dielectric constant of phenol, which is the simplest form of lignin, is 12.4 at 30°C and decreases as the temperature decreases. The dielectric constant of substituted or, more importantly, hindered phenols is less than this value. Those certain types of lignin having higher dielectric constants (than perhaps an average dielectric constant of all or most lignins) may be more polar and thus, because of enhanced abilities to act as an anti-oxidant, may inhibit aging other than less polar lignins.

Certain inventive methods may relate to the admixture of that specific amount of lignin (e.g., in % by weight relative to an asphaltic composition) to asphalt to create an asphaltic composition that has a certain aging propensity (which may or may not be the best possible). Especially where additional amounts of lignin and/or the labor associated with admixing it result in additional costs, or where certain amounts of lignin (e.g., higher percentages by weight) compromise a performance quality of the asphalt (e.g., malleability under high temperature conditions) which takes priority over anti-aging effects, it may be desired to not use that specific amount of lignin that effects the best anti-aging effect. Thus, a correlation between the anti-aging effect and the amount of lignin added to the asphalt, and/or a correlation between the anti-aging effect, at least one performance parameter, and the amount of lignin added to the asphalt, may be used to determine that specific amount of lignin that creates an asphaltic composition (and an aggregated asphaltic composition) that reflects a desired compromise between anti-aging and at least one other asphaltic performance parameter.

As is understood, there may be several different classifications of lignin (as but one example, derivative lignin vs. non-derivative lignin). Aspects of the inventive technology may focus on the use of one type of lignin as an anti-oxidant in asphalt so as to reduce aging because this certain type of lignin has a longer or better anti-aging effect.

It is also important to understand that the inventive technology is not limited in application to asphalt pavement. Indeed, any substance or material of which asphalt is a constituent (e.g., binders, roofing materials or substances, chip seal materials or substances, glues and glue seal materials or substances, to name a few) may find useful application of the inventive technology disclosed and claimed herein. Asphalt itself (i.e., where asphalt is not admixed with another material) may find use in certain applications and may benefit from the anti-oxidation properties of lignin. It is of note that as any asphaltic composition (i.e., any asphalt to which a substance such as lignin has been added) is deemed to have had that substance admixed with asphalt, the term admixed is to be accorded a broad meaning and is not limited to physical blending or physical mixing.

It should also be noted that lignin may be added to asphalt (whether before that asphalt is added to another ingredient or not) in any number of ways, including but not limited to mechanical mixing. Any manner in which lignin is incorporated with asphalt to form an asphaltic composition is deemed admixing.

Further, it should be understood that any application where the anti-oxidant capabilities of lignin effect an increase in the functional life of a substance or material after lignin is added to it may be within the scope of the inventive technology. As can be easily understood from the foregoing, the basic concepts of the present invention may be embodied in a variety of ways. It involves both anti-aging or functional life-extension techniques as well as devices to accomplish the appropriate anti-aging. In this application, the functional life extending techniques are disclosed as part of the results shown to be achieved by the various devices described and as steps which are inherent to utilization. They are simply the natural result of utilizing the devices as intended and described. In addition, while some devices are disclosed, it should be understood that these not only accomplish certain methods but also can be varied in a number of ways. Importantly, as to all of the foregoing, all of these facets should be understood to be encompassed by this disclosure.

The discussion included in this application is intended to serve as a basic description. The reader should be aware that the specific discussion may not explicitly describe all embodiments possible; many alternatives are implicit. It also may not fully explain the generic nature of the invention and may not explicitly show how each feature or element can actually be representative of a broader function or of a great variety of alternative or equivalent elements. Again, these are implicitly included in this disclosure. Where the invention is described" in device-oriented terminology, each element of the device implicitly performs a function. Apparatus claims may not only be included for the device described, but also method or process claims may be included to address the functions the invention and each element performs. Neither the description nor the terminology is intended to limit the scope of the claims that will be included in any subsequent patent application.

It should also be understood that a variety of changes may be made without departing from the essence of the invention. Such changes are also implicitly included in the description. They still fall within the scope of this invention. A broad disclosure encompassing both the explicit embodiment(s) shown, the great variety of implicit alternative embodiments, and the broad methods or processes and the like are encompassed by this disclosure and may be relied upon when drafting the claims for any subsequent patent application. It should be understood that such language changes and broader or more detailed claiming may be accomplished at a later date (such as by any required deadline) or in the event the applicant subsequently seeks a patent filing based on this filing. With this understanding, the reader should be aware that this disclosure is to be understood to support any subsequently filed patent application that may seek examination of as broad a base of claims as deemed within the applicant's right and may be designed to yield a patent covering numerous aspects of the invention both independently and as an overall system.

Further, each of the various elements of the invention and claims may also be achieved in a variety of manners. Additionally, when used or implied, an element is to be understood as encompassing individual as well as plural structures that may or may not be physically connected. This disclosure should be understood to encompass each such variation, be it a variation of an embodiment of any apparatus embodiment, a method or process embodiment, or even merely a variation of any element of these. Particularly, it should be understood that as the disclosure relates to elements of the invention, the words for each element may be expressed by equivalent apparatus terms or method terms ~ even if only the function or result is the same. Such equivalent, broader, or even more generic terms should be considered to be encompassed in the description of each element or action. Such terms can be substituted where desired to make explicit the implicitly broad coverage to which this invention is entitled. As but one example, it should be understood that all actions may be expressed as a means for taking that action or as an element which causes that action. Similarly, each physical element disclosed should be understood to encompass a disclosure of the action which that physical element facilitates. Regarding this last aspect, as but one example, the disclosure of a "modifier" should be understood to encompass disclosure of the act of "modifying" ~ whether explicitly discussed or not ~ and, conversely, were there effectively disclosure of the act of "modifying", such a disclosure should be understood to encompass disclosure of a "modifier" and even a "means for modifying" Such changes and alternative terms are to be understood to be explicitly included in the description.

Any acts of law, statutes, regulations, or rules mentioned in this application for patent; or patents, publications, or other references mentioned in this application for patent are hereby incorporated by reference. In addition, as to each term used it should be understood that unless its utilization in this application is inconsistent with such interpretation, common dictionary definitions should be understood as incorporated for each term and all definitions, alternative terms, and synonyms such as contained in the Random House Webster's Unabridged Dictionary, second edition are hereby incorporated by reference. Finally, all references listed in the information statement filed

with the application are hereby appended and hereby incorporated by reference, however,

as to each of the above, to the extent that such information or statements incorporated by

reference might be considered inconsistent with the patenting of this/these invention(s)

such statements are expressly not to be considered as made by the applicant(s).

I. U.S. PATENT DOCUMENTS

II. FOREIGN PATENT DOCUMENTS

III. OTHER DOCUMENTS (Including Author, title, Date, Pertinent Pages, Etc.)

Sangita and I. R. Arya; R. Chandra and Sandeep, "Development and Characterization of Asphalt Modifiers from Agrobased Resin", Asphalt Science and Technology. 1997, 349-368. Donald W. Sundstrom, Herbert E. Klei, Timothy H. Daubenspeck, "Use of Byproduct Lignins as Extenders in Asphalt", Ind. Eng. Chem. Prod. Res. Dev.. vol. 22 #3, 1983, 496-500. "Biorefining", Western Research Institute - BioRefining Utilization, www. westernresearch. org. , 04/07/2004, 1 p. "Lignin", www.eng.φi.edu/dept/chem-eng/Biotech-Environ/FUNDAMNT/ligni n.htm, 1

"Lignin and Its Properties", More About Lignin, www.lignin.info, 04/07/2004, 4 pp. "Lignins - Products with Many Uses", What is Lignin, www.lignin.info, 04/07/2004, 2 pp. Terrel, Ronald L. and Rimsitong, Sveng"Wood Lignins Used as Extenders for asphalt in Bituminous Pavements"

Thus, the applicant(s) should be understood to have support to claim and make a

statement of invention to at least: i) each of the anti-aging devices or methods as herein

disclosed and described, ii) the related methods disclosed and described, iii) similar,

equivalent, and even implicit variations of each of these devices and methods, iv) those alternative designs which accomplish each of the functions shown as are disclosed and described, v) those alternative designs and methods which accomplish each of the functions shown as are implicit to accomplish that which is disclosed and described, vi) each feature, component, and step shown as separate and independent inventions, vii) the applications enhanced by the various systems or components disclosed, viii) the resulting products produced by such systems or components, ix) each system, method, and element shown or described as now applied to any specific field or devices mentioned, x) methods and apparatuses substantially as described hereinbefore and with reference to any of the accompanying examples, xi) the various combinations and permutations of each of the elements disclosed, and xii) each potentially dependent claim or concept as a dependency on each and every one of the independent claims or concepts presented.

With regard to claims whether now or later presented for examination, it should be understood that for practical reasons and so as to avoid great expansion of the examination burden, the applicant may at any time present only initial claims or perhaps only initial claims with only initial dependencies. Support should be understood to exist to the degree required under new matter laws ~ including but not limited to European Patent Convention Article 123(2) and United States Patent Law 35 USC 132 or other such laws— to permit the addition of any of the various dependencies or other elements presented under one independent claim or concept as dependencies or elements under any other independent claim or concept. In drafting any claims at any time whether in this application or in any subsequent application, it should also be understood that the applicant has intended to capture as full and broad a scope of coverage as legally available. To the extent that insubstantial substitutes are made, to the extent that the applicant did not in fact draft any claim so as to literally encompass any particular embodiment, and to the extent otherwise applicable, the applicant should not be understood to have in any way intended to or actually relinquished such coverage as the applicant simply may not have been able to anticipate all eventualities; one skilled in the art, should not be reasonably expected to have drafted a claim that would have literally encompassed such alternative embodiments.

Further, if or when used, the use of the transitional phrase "comprising" is used to maintain the "open-end" claims herein, according to traditional claim interpretation. Thus, unless the context requires otherwise, it should be understood that the term "comprise" or variations such as "comprises" or "comprising", are intended to imply the inclusion of a stated element or step or group of elements or steps but not the exclusion of any other element or step or group of elements or steps. Such terms should be interpreted in their most expansive form so as to afford the applicant the broadest coverage legally permissible.

Finally, any claims set forth at any time are hereby incorporated by reference as part of this description of the invention, and the applicant expressly reserves the right to use all of or a portion of such incorporated content of such claims as additional description to support any of or all of the claims or any element or component thereof, and the applicant further expressly reserves the right to move any portion of or all of the incorporated content of such claims or any element or component thereof from the description into the claims or vice-versa as necessary to define the matter for which protection is sought by this application or by any subsequent continuation, division, or continuation-in-part application thereof, or to obtain any benefit of, reduction in fees pursuant to, or to comply with the patent laws, rules, or regulations of any country or treaty, and such content incorporated by reference shall survive during the entire pendency of this application including any subsequent continuation, division, or continuation-in-part application thereof or any reissue or extension thereon.