The Magazine of the Asphalt Institute

Fall 2005Vol. 20, No. 3

The Magazine of the Asphalt Institute

Fall 2005Vol. 20, No. 3

Tools and Techniques for Pavement Preservation

Tools and Techniques for Pavement Preservation

AM-Fall05 11/1/05 10:22 PM Page FC1

Fall 2005

Proficiency Sample Program for

Roofing Asphalt BindersAsp

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FO R L A B S E RV I C E S CO N TAC T M I K E A N D E R S O N AT M A N D E R S O N @ A S P H A LT I N S T I T U T E . O RG

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F or many years, the AASHTO MaterialsReference Laboratory (AMRL) has conductedproficiency sample programs for a variety of

tests related to highway materials. Using the datagenerated in these programs, the appropriatebetween-lab reproducibility of a specific test could bedetermined. This estimate of variability has helpedtesting labs understand why another lab, such as astate highway agency’s lab, could have a seeminglydifferent, and possibly failing, result even though thetesting lab’s result passed the specification.

Starting in 1999, Paramount Petroleum Corporation

initiated a similar program for roofing asphaltbinders based on the tests in ASTM D312,

Standard Specification for Asphalt Used inRoofing. In 2005, the Asphalt Institute became

involved with the operation of the proficiency sample

program. The price for the 2005 program was estab-lished at $270 for each set of two samples.

This year’s program started in June with each partici-

pating lab receiving two individual pint containers(Sample 01 and 02) of roofing asphalt binder.

Participants were asked to perform four tests – Ringand Ball Softening Point (ASTM D36); ClevelandOpen Cup Flash Point (ASTM D92); Penetration at77ºF (ASTM D5); and Rotational Viscosity at 400ºF(ASTM D4402) – on each sample and provideresults back to AI by the end of July. AI then ana-lyzed the data and returned a report to the partici-pants in early September.

A survey is currently being conducted to providefeedback on the proficiency sample program.Responses to questions regarding the clarity of thedata form and instructions, best and worst time of

year for the program, and participant cost will helpshape the program details for the future. It is expect-ed that the proficiency sample program will betterhelp labs to understand the appropriate testing repro-ducibility of some common tests for roofing asphalts.

For more information on the Asphalt Institute’sProficiency Sample Program for Roofing Asphalts,

please contact either Shay Emmons, Program

Manager (semmons@asphaltinstitute.org) or MikeAnderson (manderson@asphaltinstitute.org).

The Asphalt Institute’s lab is available toperform research,testing andtraining.

This scatter diagram

illustrates the variability

of test results obtained

for the flash point of two

roofing asphalt samples.

42 Asphalt

oF

AM-Fall05 11/1/05 10:24 PM Page 42

Fall 200540 Asphalt

Moisture Sensitivity and Antistrip Compatibility For acidic aggregates such as granite, PPAtypically enhances the moisture resistanceof the asphalt mix, possibly to a level wherean antistrip additive may not be required.When an amine-based antistrip additiveis used, a partial neutralization betweenthe PPA and the antistrip can occur, pos-sibly leading to a partial loss of theincreased binder stiffness (G*/sin δ)achieved from the PPA modification.According to recently published research,this partial neutralization does not affectthe improved binder-aggregate adhesionproperties from the addition of antistrip.

The partial neutralization that may occuris dependent on the nature of theasphalt, aggregate and antistrip, and maybe avoided by correctly formulating themix with a compatible antistrip. Oneclass of antistrip chemicals known asphosphate esters does not react with PPAfunctionality, so they are effective in bothconventional and PPA modified binders.

SummaryPPA modified binder has no additionalsafety issues beyond those of neat asphalt.However, PPA by itself is a corrosiveagent, so the Material Safety Data Sheetinformation should be reviewed carefully.

The improvements realized with the addi-tion of PPA are not the same with allasphalts. As with most modifiers, theinteraction is dependent on the asphalt'schemistry (aromaticity, asphaltene con-tent, etc.). PPA modified mixtures aregenerally resistant to moisture degradationor can be made moisture resistant throughthe use of appropriate antistrip additives.

Good communication between theasphalt supplier, contractor and agencyregarding potential use of amine-basedantistripping agents is necessary. This isbecause under certain conditions, PPA

may react with some liquid amine anti-strips leading to a partial decrease of thePG high temperature improvement real-ized with PPA modification. Correctformulation is required to address theeffects of amines on binder stiffness.Binder testing, especially for stiffness, isrecommended both before and after theaddition of antistrip.

Mark Buncher is Director of Field Engineering for the Asphalt Institute.

OA2027 MrktplcAd4.6x6.875_4c 1 9/27/05 12:05:39 PM

Mixture testing may also be used to eval-uate moisture susceptibility. Tests, such asAASHTO T-283 or any suitable underwater wheel tracking test, can be used asan additional assurance of compatibilityand performance.

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Fall 200538 Asphalt

The Asphalt Institute supports the responsi-ble modification of asphalt materials forimproved performance and better life cyclecosts, without endorsing any specific or pro-prietary form of modification.

Polyphosphoric acid, or PPA, is aliquid mineral polymer and justone of many additives used to

modify and enhance paving gradeasphalts. It is the Asphalt Institute’s posi-tion that the correct use of PPA, in theappropriate amount, can improve thephysical properties of bituminous pavinggrade binders. On the other hand, incor-rect application of PPA technology canresult in construction or performanceproblems.

When used in combination with a poly-mer, PPA provides flexibility in reachingthe requested test specifications(Dynamic Shear Rheometer, ElasticRecovery, etc.) while limiting the increasein asphalt viscosity at 135°C (275°F).

To assist agencies in making informeddecisions, the Asphalt Institute recentlypublished Informational Series (IS) 220,Polyphosphoric Acid Modification ofAsphalt. The purpose of this educationaldocument is to clarify the issues regard-ing acid modification, particularly, PPAmodification. This article provides somehighlights of IS-220.

Orthophosphoric Acid versusPolyphosphoric Acid It is important to understand that thereare major differences between the twogeneric acid types, and how they behave

in asphalt. Orthophosphoric acid, whichincludes purified phosphoric acid, is notrecommended for use in asphalt modifi-cation. Orthophosphoric acid has approx-imately 15 percent free water contentwhich creates poor miscibility in asphaltand leads to separation issues. The freewater also leads to corrosion problemswhen the orthophosphoric acid is blendedin asphalt and stored in steel tanks.

PPA, on the other hand, has no freewater allowing a total miscibility withasphalt. The PPA blended with a neat orpolymer modified asphalt does not createany binder storage issues such as separa-tion or corrosion.

Literature and PresentationsThe first patent describing asphalt modi-fication using PPA was published in1973. Since the early 1990s, PPA hasalso been used in combination with vari-ous polymer modifiers to enhance thequality of paving grade asphalts.

Concerns by some users within the bituminous supply and paving sectorsregarding the performance quality of acidmodified binders have resulted in numer-ous studies by researchers. The process oforthophosphoric and PPA modificationhas been examined as well as their impacton asphalt and hot mix asphalt mixtures.The IS-220 publication summarizes ninetechnical papers that have been publishedsince 2001 on the topic of acid modifica-tion. The Federal Highway Administrationis currently conducting a study at theirTurner Fairbanks Research Center on theuse of PPA and other acids in asphalt.

In addition to the nine published papers,IS-220 also provides a partial listing andsummaries of many recent formal presen-tations at events such as a one-day sympo-sium on acid modification hosted by theRocky Mountain User Producer Group(March 2003), a symposium on predictingpavement performance sponsored by theWestern Research Institute (2004), andthe annual Petersen Conferences.

Effects on High and LowTemperature Performance PPA can be an effective and economicaltool for chemical modification, usedalone or in conjunction with a polymer.PPA can improve the high temperaturePG grade, and with some asphalts mayimprove the low temperature PG grade.This modification does not oxidize theasphalt, thereby avoiding the low m-valueissues that have been associated withbinder brittleness at low temperatures.PPA chemically modifies the asphalt as aresult of irreversible and sometimes par-tially reversible reactions. Two main reac-tions may be considered—phosphate esterformation (irreversible reaction) and acid-basic neutralization (reversible reaction).

Although the oxidation of some petrole-um compounds is known to be catalyzedby strong acids, such mechanisms havenot been found for PPA modified bitu-mens. Comparison of Dynamic ShearRheometer measurements after short-term and long-term lab aging, chro-matography results and infrared data allindicate there is no accelerated aging ofPPA modified asphalt as compared to theneat asphalt.

www.astaris.com • 800-244-6169

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IN A RUTASK ASTARISAmerica’s roadways and runways take a beating every dayfrom harsh natural elements and increased traffic loads. Hotweather and heavy loading can cause pavement to developrutting. Cold weather can lead to thermal cracking and fatigue.

Astaris’ polyphosphoric acid can significantly improve thethermal-mechanical properties of asphalt cement and prolong pavement life. Proven in testing and in use, our high-quality polyphosphoric acid increases the high-temperature performance grade rating of asphalt and delivers improved resistance to rutting and adhesion to moisture-sensitive aggregates – with no loss of low-temperature properties and performance.

STAY OUT OF THE RUT –

ADD POLYPHOSPHORIC ACID

FROM ASTARIS AND ADD LIFE

TO YOUR PAVEMENT.

Polyphosphoric AcidModification of Asphalt

Polyphosphoric AcidModification of Asphalt

By Mark Buncher, Ph.D., P.E.

AM-Fall05 11/1/05 10:24 PM Page 38

both at the plant as well as at the pavingsite, and analysis tools helped reduce cycletimes and minimize truck usage.

Plant to Office CommunicationUp to this point, plant to office communi-cation had been limited to crude fileexchanges in which most systems weremerely capable of sending a file of ticketsback to the office at the end of the day.Some systems could also accept replace-ments of entire data files from the office.But, in 1997, the first online gatewaybetween office and plants was introducedto provide seamless, real-time integration ofplant production data with office account-ing and management information systems.

Multiple plants could all be in sync withthe headquarters. Office personnel hadthe ability to access company-wide pro-duction and operational data to managelogistics, answer customer questions andplan production.

The New Millennium and Beyond…In 2002, the first asphalt automation sys-tem with highly configurable software wasintroduced to the industry. For years, cus-tom requests meant custom programmingat the producer’s expense. Now, softwarehas been introduced that can be configuredto meet the exacting requirements of theusers without programmer involvement.Producers have the ability to mold the sys-tem to their unique business processes. Thisincludes the ability to add data fields, layout printing on delivery tickets, add ormodify reports, add special logic, createtheir own pricing schemes, etc.

Whereas custom software had the effectof locking producers out of new versions,the configurable and modular design oftoday’s software allows users to receivenew releases and features.

New office software utilizes open database architecture, such as open

database connectivity, to allow seamlessintegration with virtually any officeapplication. Customer and job changesare automatically broadcast to all plantsand transactions are automaticallyretrieved and invoiced.

The technological advancements inautomation and plant to office integra-tion have brought about many changesto our industry. Thankfully, they have allbeen integral in helping producers toimprove quality, maximize productivity,provide valuable management informa-tion and realize greater profits.

Kenneth Cardy is president of

Libra Systems Corporation,

based in Harleysville, Pennsylvania,

www.librasystems.com.

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Fall 200536 Asphalt

and smaller, dedicated systems addedmore and more capacity without increas-ing the physical size of the controls.

The 1980sThe ’80s brought about the personalcomputer revolution, and in 1984 thefirst PC was used to control an asphaltplant. Computers were everywhere andthe ability to interface the office with theplant was a logical step to eliminatehandwritten administrative functions.Prior to building the communicationinterface between office and plant com-puters, information generated at theplant had to be re-entered into the officecomputer. This was often time-consum-ing, expensive and prone to error.

Background communications to theplants were introduced in 1989.Background means that another task canbe occurring and be invisible to the plantoperator. More specifically, the plant

operator could be running the asphaltplant with all of its requirements, and atthe same time the office could call in andupdate files, retrieve data or generatereports. Office tasks became completelyinvisible to the plant operators and didnot interfere with their work.

Multi-tasking environments were alsointroduced to the industry during this peri-od. This technique allows many tasks tooccur virtually simultaneously. For exam-ple, operators could simultaneously mixmaterial in the batch tower, load materialout of the silos and access the database fileswithout performance degradation.

The 1990sMemory constraints were no longer aconcern in the early ’90s. With the rapidtechnology advancements in the PCindustry, producers could easily storeinformation about customers, productsand thousands of trucks.

Microsoft Windows® paved the way forthe first graphical user interface to be intro-duced for control of an asphalt plant. Theuse of animated pictures and “live” graphsto depict real-time trends aided operators inquick problem detection and response.

While radio frequency identification tech-nology had been around for some time, themid-’90s saw the asphalt industry utilizethis technology to solve truck managementissues. Truck waiting times were monitored,

Graphical user interface (GUI)for control of an asphalt plant

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T oday, plant automation playsmany roles in a hot mix asphalt

producer’s enterprise. Plantautomation must support real-time man-agement decisions by providing up-to-the-minute company-wide data, accessi-ble from anywhere.

Plant automation must allowmanagement personnel tocontrol business data in real

time, while allowing operatorsto concentrate on running

plants. It must mold itself tofit the unique businessprocesses of the producerwithout requiring the customprogramming that has stunted

the agility of past systems.

Prior to 1970Early asphalt plant automa-tion was entirely electro-mechanical. This meant thecontrols for the plant were based on whatis known as relay logic.

These controls were composed of relayswitches which, being mechanical, woreout quickly. The switches were very sus-ceptible to heat, dust, moisture and othernatural elements, making them unreli-

Asphalt 35Fall 2005

able. Early controls were very large andrequired a lot of control-room space.They were extremely heavy and notportable. Although these machines werecumbersome by today’s standards, theydid increase productivity by speeding upthe mixing/loading process.

The 1970sWith the advent of transistor and inte-grated circuit technology, controlsbecame entirely electronic instead ofelectromechanical. Physically, integrated

circuits were much smaller than relay

switches. The integrated circuits were

also faster, but the biggest advantage wastheir reliability. They used no movingparts and were therefore immune to themechanical (moving) problems encoun-tered with relay switches.

During this time, memory in the con-trols became economically feasible.Cassette tapes became a popular choicefor memory because of their capability tostore information indefinitely. However,the tapes were very susceptible to dust,dirt and moisture.

In 1974, the first microprocessor-basedcontrol was installed on an asphalt plant.This year also marked the first time thatcassette tapes were bypassed in favor ofanother type of memory storage— floppydisks. The disks were much faster than

tapes but, liketapes, they were

susceptible to envi-ronmental damage.

EPROMIn 1977, two newtypes of memory,known as ErasableProgrammable

Read OnlyMemory (EPROM)

and Read Only

Memory (ROM),were introduced.These types ofmemory wereimpervious to dust,

dirt, heat and even coffee spills. EPROMs

were also extremely fast.

In this era, control systems also becamemuch smaller and could fit on a tabletopdesk. As integrated circuits grew smaller

Evolution ofAsphalt Plant AutomationEvolution ofAsphalt Plant Automation

BY KEN CARDY

EPROM-Based Asphalt Batching System, circa 1977

AM-Fall05 11/1/05 10:23 PM Page 35

Roadtec’s SP-200 Asphalt Spray Paver allows asphalt cementor emulsion (tack) to be sprayed directly in front of the asphaltmix before it is laid. Spraying the tack only seconds before theasphalt is laid provides a strong bond between the existing sur-face and the new pavement, which is especially important withthin overlays. The SP-200 also eliminates the need for separatetack trucks and does away with the inconvenience of tackadhering to tires of other construction vehicles.

For more information, phone (423) 265-0600 or visit www.roadtec.com.

Sakai America’s Vibratory Rubber Tire Roller, the GW750, hasa 77 inch rolling width, over 13,000 pounds centrifugal force peraxle and a total force equal to that of a 55,000 pound pneumat-ic roller. Like double drum steel vibratories, the new roller offersfour different amplitude settings to suit the application. Theroller can also run static, like a conventional pneumatic roller.The machine itself weighs just over 20,000 pounds, providing aconsiderable amount of force from a relatively small package.

For more information, phone (800) 323-0535 or email d-brown@sakaiamerica.com.

The Rosco RA-300 Spray Injection Patcher, with its one-person,from-the-cab operation makes safely and effectively repairingpotholes a year-round activity. The RA-300 features its in-cabcontrols, full-function spray nozzle with joystick control andfront-mounted patching boom and rear-mounted arrowboard formaximum simplicity, effectiveness and safety. Its hydraulic“Patch-on-the-Go” feature allows for patching on the move withno auxiliary power.

For additional information, phone (704) 966-3358or email ssimons@leeboy.com.

Asphalt 33Fall 2005

The Wirtgen W 2000 from Wirtgen America is a high-perform-ance, large-volume, compact milling machine with broad cuttingwidth for removing deteriorated asphalt pavement or completeroadway structures down to 13 inches in a single pass. The W2000 boasts a 565 hp engine and features front loading of RAPfor ease of operations. It has a base cutting width of 79 or 87inches, can operate at speeds up to 180 fpm, and has an operat-ing weight of approximately 64,000 pounds.

For more information, phone (615) 501-0600 or visit www.wirtgenamerica.com.

AsphaltProduct ShowcaseProduct Showcase

AM-Fall05 11/1/05 10:23 PM Page 33

The Bearcat 501 Asphalt Distributor features several innova-tions. The internal poppet spray valves are immersed in hotasphalt, providing instant spray when valves open. Uniformspray patterns are assured and clogs are eliminated. The wingsbreak away both forward and backward to prevent damage.Limit switches prevent accidental spray when wings are in theupright position. The Computer Rate Control system controls theasphalt pump and monitors truck speed, distance traveled, flowrate and spray bar width.

For additional information, phone (520) 684-7851 or email bearcat@primenet.com.

Etnyre Chip Spreaders are designed to spread aggregate in thechip seal process. The spreaders feature controlled applicationrates and have individual one foot wide power gates across theentire spreader width. Engine options range from 200 to 240 hpand the chip spreaders are available in front wheel or four wheeldrive models.

For more information, phone (800) 995-2116 or email sales@etnyre.com.

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RoadArmor High Performance Chip Seal is a single pass sur-face treatment developed for cost-effective pavement preserva-tion with low user delays. It is designed for high traffic roads ingood condition but with minor surface distresses. A new ultra-fast setting polymer modified emulsion is used with a single-sized aggregate in a continuous synchronized application.RoadArmor surfacing means quick traffic return, reliable per-formance, and low risk of vehicle damage.

For additional information, phone (918) 388-8100 or email info@semgrouplp.com.

The patented Ray-Tech Joint Heating System effectively elimi-nates longitudinal cold joint failure by providing 98-100 percentdensity at the joint. The infrared heating system is capable of in-depth heating of longitudinal joints without burning or damagingthe asphalt. This complete system is a proven, effectivemethod of eliminating joint failure.

For additional information, phone (800) 884-2072 or email info@raytechinfrared.com.

32 Asphalt Fall 2005

AM-Fall05 11/1/05 10:23 PM Page 32

Asphalt 29Fall 2005

chairman of numerous subcommittees. Hewas chairman of the Use of Waste Materialsin Hot Mix Asphalt Symposium, for whichhe received the Award of Merit and the

2003 ASTM Charles B. Dudley Award.

Fred is a lifetime member of theAssociation of Asphalt PavingTechnologists and served as its Presidentin 1994. He has also been an active par-ticipant in the Transportation ResearchBoard for 35 years.

How did AI most help the asphalt industry?After working in the asphalt industry for50 years, Fred has some perspective on itsachievements and also on its currentneeds. And he has a good fix on AI’s con-

tributions. “I think the Institute has con-tributed significantly to the developmentof good pavements and to long-termpavement performance,” stated Fred.“And more than any other organization, I

believe AI deserves credit for developingand promoting Superpave.”

As for the current needs of the industry,

Fred believes that “long-term pavementperformance is still the biggest challenge.

Fifteen or twenty years ago, we built

asphalt pavements that would last 8 to12 years, now we need to build them tolast 15 to 20 years.”

What are you doing nowadays?“I just finished overseeing the construc-

tion of a 110-space parking lot for a U.S.

Post Office facility,” says Fred. “We usedthe right mix, the right structural designand it turned out to be one of the mostsuccessful jobs I have seen.”

Several years ago, Fred spent 15 months asthe volunteer construction supervisor forhis new Baptist church building. Uponcompletion, the congregation grew so fast

that another building was built to accom-modate the rapid growth. Fred oversawthe construction of that building too.

“A few years ago, I had the pleasure ofoverseeing the design and paving of anew parking lot for our church.” saidFred. “We built it right. We specified 6

inches of aggregate base course and 2inches of I-2 hot mix asphalt. The onlymaintenance expense on that lot has beenfor re-striping.”

Even at age 78, Fred has really notretired from his asphalt career.

“The first six years afterretiring from the Institute,

I worked 60 hours aweek,” says Fred.“Now I’ve slacked offto about 40 hours a

week. But nextyear, as I told

my wife Phyllis,I think I reallymight retire.”

A s p h a l t E n g i n e e r P a r E x c e l l e n c eAsphalt 29

AM-Fall05 11/1/05 10:23 PM Page 29

F red Waller’s long, distinguishedcareer with the asphalt industrybegan when he enrolled at

North Carolina State University (NC

State) at the age of 16. “I was first intro-duced to asphalt right in the middle ofWorld War II,” said Fred. “I wanted toenlist the day I turned 17.” He hoped tobe a fighter pilot but ended up at bootcamp and aerial gunnery school.

When the war ended, Fred went back toNC State and graduated with a B.S. inCivil Engineering and an officer’s com-mission in the U.S. Air Force. TheNorth Carolina DOT hired him andasked him to start an asphalt laboratory.At the time there were very few asphaltlabs. Most mixes were put together based

simply on experience.

Fred created an asphalt laboratory andNCDOT hired Bruce Marshall ofMarshall Mix Design fame to train him.

The Marshall procedure at that time used50 hammer blows and a manual hammer.

The Waller I-2 Mix“I was developing NCDOT’s lab aboutthe same time the Interstate program

began,” says Fred. “We were experienc-

ing a lot of failures with our Interstatesurface mix because of increasing trafficand heavier loads. It was obvious weneeded a better mix. My boss called me

in and told me that I had one week todesign a new surface mix or I was fired.

“Well, I had been working on a new sur-face mix, so when the boss called meback in after a week, I was ready. Helooked it over, tested it, and said, ‘We’regoing to accept this mix and use it.’ ”Fred traveled all over the state for

NCDOT working with contractors toget them familiar with the new mix.

NCDOT later gave Fred a special awardfor his work on that mix. The agency

used it for 40 years, until they startedusing Superpave. Even now, the I-2 mixis used for many local applications.

Humble OilAfter 11 years with NCDOT, Fred joinedthe Asphalt Division of Humble Oil(later Exxon), serving Virginia and WestVirginia. Fred did such a good job thatHumble offered him a job in a big officein the Humble building on Times Squarein New York City. “Only thing was,” saidFred, “I would have had to travel all overthe U.S. and I had three little boys athome that I wanted to see grow up. Ididn’t take that New York City job but Idid go to work as an asphalt consultantfor Miller-Warden when they movedtheir office to Raleigh, North Carolina.”

Asphalt ConsultantWhile Fred was with Miller-Warden, heled five key projects with the NationalCooperative Highway Research Program

(NCHRP). The projects involved theproper use of aggregates and aggregatestockpiling. The purpose of one NCHRP

contract was to find the most efficientmethod of building an aggregate stockpileand feeding the aggregate into the hot

mix plant. Fred took 3,000 pounds of

aggregate, colored it and screened it intofour different sizes, then photographicallytraced the colored aggregate to show howit would flow down the stockpile.

“Even back in the 1960s, we were trying

to build stockpiles to avoid segregation.

The NCHRP study was the first to meas-ure and demonstrate how to minimizesegregation. We found out it was betterto use a system that built stockpiles in

layers rather than building them with aconveyor,” explained Fred. While atMiller-Warden, Fred also helped rewritethe pavement specifications for the

District of Columbia.

After seven years with Miller-Warden,Fred was called back into active duty forthe U.S. Air Force during the Korean War.After 6 and a half years with the Air Forceand reaching the rank of Colonel, Fredwent to work for Troxler, developing andpromoting soil testing equipment. Later,Gerry Triplett, then president of theAsphalt Institute (AI), talked him intocoming to work for the Institute.

Asphalt Institute“I worked for the Asphalt Institute for 19

and a half years,” said Fred, “and Ienjoyed every week of it.” One of the sig-nificant contributions Fred made whilehe was there was writing the AsphaltEmulsion Manual. Fred researched and

wrote the entire manual with the help ofthe Asphalt Emulsion ManufacturingAssociation and FHWA. After writing

the manual, Fred went all over the U.S.,

developing emulsion seminars.

While Fred was at the Institute he saw a

need for practical guidelines for repairingutility cuts with asphalt, so he developedan extensive slide show training programfor AI field engineers.

During his career with the Institute, Fred

was active with a host of asphalt industry

organizations. He is still an active partici-pant in ASTM Committee D-4 on Roadand Paving Material. During his 45 yearsof membership with ASTM, he served as

Fall 200528 Asphalt

AM-Fall05 11/1/05 10:23 PM Page 28

Asphalt 25Fall 2005

situations and is more cost-effective,

making it a good choice, so long as quali-ty materials are used.

Rejuvenating PavementsPavement rejuvenators are applied to

existing aged or oxidized HMA pave-ments in order to restore pavement sur-face flexibility and to retard block crack-

ing. Emulsified sealers, binders and reju-

venators are used in pavement preserva-tion to protect oxidized asphalt surfaces

or actually penetrate and rejuvenate them.

The oxidative aging of pavements beginsat the time of construction and continuesthroughout a pavement’s life. However,

most aging occurs within the first two tofour years of service life. This results in

the top half-inch or so of the pavement

surface becoming more brittle than theunderlying material due to the actions ofwater and environment. This can resultin raveling and/or premature cracking,which begins at the pavement surface.

Rejuvenators are formulated to penetrateinto the pavement and then enhance theproperties of the asphalt binder of theexisting pavement. These treatments aremost commonly used in the western

states where ultraviolet exposure appearsto promote greater oxidation. Treatmentscan begin immediately after construction

but more typically occur many years laterwhen some form of distress is observed.

Slurry SurfacingsA slurry surfacing, also known as a slurry

seal, is not the same as a chip seal.Instead, it is a mixture of aggregates dis-persed in an asphalt emulsion andapplied in a slurry state. It is usually a

mix of polymer-modified emulsion andfine crushed aggregate that is spread

simultaneously in one pass over the street

at a particular thickness. The slurry curesas the water evaporates, leaving only theasphalt to coat the aggregate.

Slurry surfacings are designed in a lab,are proportioned by a slurry machine,

and laid down and cured so the asphalt-

to-aggregate ratio is maintained at theoptimum value to assure uniform aggre-gate coating and adhesion. Such frictioncourses use very large fractions of finematerial, giving a very high surface areaand a lot of microstructure, leading to a

sandpaper surface and a high skid resist-ance while maintaining a smooth finish.

A variant of the slurry surfacing is micro-surfacing, which is a mix of polymer-

modified asphalt emulsion, mineralaggregate, mineral filler, water, and otheradditives, which is proportioned, mixed,and spread on a paved surface.

Microsurfacing differs from slurry seal inthat it can be used on high volume road-ways to correct wheel path rutting andprovide a skid-resistant pavement surface.

HMA as a Preservation TreatmentFor severely distressed surfaces, thinHMA overlays will provide a like-newsurface, prolong pavement structure life,and make a pavement stronger for onlyan incrementally higher expenditure thancompeting surface treatments like chipseals or slurry surfacings.

For many roads and streets the best pre-

ventive maintenance strategy may be athin HMA overlay. This thin (0.5 to 1.5inch) surfacing combines the best attrib-utes of HMA’s strength and smoothnesswith a low cost that makes maintenancedollars go farther. Aesthetically, the over-all impression is of a brand-new road, atthe price of a thin overlay. Other benefits

include HMA’s trademark quiet pave-

ment and smooth ride.

Crack sealing prior to applying a surfacetreatment reduces moisture damage.

Pavement preservation is promoted by theNational Center for Pavement Preservation(NCPP) at Michigan State University, and theFoundation for Pavement Preservation (FP2),both of which maintain that the key to opti-mized pavement life is the application of the“right treatment, to the right pavement, at theright time”. NCPP and FP2 are allied with theOffice of Asset Management of the FederalHighway Administration in expanding pave-ment preservation and transportation assetmanagement among state, county and munic-ipal road agencies.

This article covers some of the basic techniquesfor pavement preservation. However, space didnot allow for inclusion of all of the preservationoptions. Future articles will cover such tech-niques as hot-in-place recycling and cold-in-place recycling.

Tom Kuennen is principal ofExpresswaysOnline.com,

Buffalo Grove, Illinois.

AM-Fall05 11/1/05 10:23 PM Page 25

surface treatment in which the pavementis sprayed with asphalt and then immedi-ately covered with aggregate and rolled.Chip seals are used primarily to seal apavement with non-load-associatedcracks, and to improve surface friction.They also are common as a wearingcourse on low volume roads.

The asphalt binder can be modified with ablend of ground tire or latex rubber, orpolymer modifiers, to enhance the elasticity

Fall 200524 Asphalt

and adhesion characteristics of the binder.A variant of the chip seal is the fog seal, alight application of slow-setting asphaltemulsion diluted with water, and withoutthe addition of any aggregate applied tothe surface of an asphalt pavement. Fogseals are used to renew aged asphalt sur-faces, seal small cracks and surface voids,or adjust the quality of binder in newlyapplied chip seals.

A cape seal is a combination of a chip

seal and a slurry surfacing or seal. Forpaved roads, the chip seal is applied firstand, between four and 10 days later, theslurry seal is applied. For unsurfacedroads, an application of MC-70 or SC-70 cutback asphalt is applied first as aprime coat, followed about two days laterby a chip seal and about two weeks laterby a slurry seal.

Joints, Cracks and PotholesIn advance of any surface treatment,pavements are prepared by sweeping andsealing the joints and cracks. “It is criticalthat all necessary preparation work suchas crack filling, pothole repair, patching,leveling, and dig-outs be done prior tosurface treatments being placed,” reportsthe California Department ofTransportation (Caltrans).

Caltrans says crack filling and sealing isits first line of defense in roadway main-tenance. Caltrans urges that cracks 1/4inch or wider be filled or sealed beforerainy seasons or before the application ofmaintenance surface treatments such asfog seals, sand seals, slurry seals, chipseals or maintenance overlays.

Potholes are bowl-shaped holes of varioussizes which are associated with pavementfatigue and poor drainage. Highwaydepartments can minimize potholes bykeeping water out of the base material.Water weakens pavement support andcontributes to frost heave and cracking.

A long-term study that began under theStrategic Highway Research Program,and continued under FHWA’s Long-termPavement Performance program, foundthat for patching potholes, quality ofmaterials is more important than methodor machine. The use of quality, even pre-mium, materials is the utmost variable ineffective pothole patching. The throw-and-roll technique proved as effective asthe semipermanent procedure in most

AM-Fall05 11/1/05 10:23 PM Page 24

Three varieties of liquid asphalts are used

in conventional surface treatments.• Liquid asphalt cement is used to

construct chip seals in regions thathave very hot weather. The asphalt

cement is shot at high temperatureswhere it flows well and accepts chips

readily. A fairly warm pavement sur-

face is required so the asphalt doesnot cool off too quickly beforeplacement of the chips.

• Cutback asphalts are blends ofasphalt cement with solvents, whichmake the asphalt cement fluid for

spraying or mixing. The solventsthen evaporate, leaving the baseasphalt cement in place to bind therock. Solvents used include gasolinefor rapid-curing, kerosene for medi-

Asphalt 23Fall 2005

um-curing, and diesel fuel for slow-curing cutbacks. The use of cutbackasphalts, once common for chipseals, has declined considerablybecause of environmental restrictions

on hydrocarbon emissions fromevaporating solvents in specific

regions around the country.

• Emulsified asphalts are an emulsionof very small asphalt cement parti-cles held in suspension in water withthe use of an emulsifying agent. Likecutback asphalts, emulsified asphaltscome in rapid-, medium-, and slow-

setting grades for different uses. Thevarious grades are developed throughthe use of different emulsifyingagents and the addition of some sol-vents. These asphalt particles are

either anionic (negatively charged)or cationic (positively charged).

The rapid-setting emulsions are used most-

ly for chip sealing, while the medium andslow setting grades are used for emulsionmixes or recycling and fog or tack seals.The emulsified asphalt ‘sets’ or ‘breaks’when the asphalt particles precipitate orfall out of the water suspension and coatthe aggregates. The emulsion changes color

from brown to black during this process.

Ever Popular Chip SealsChip seals have been used for decades topreserve riding surfaces. A chip seal is a

Chip seals have been used fordecades to preserve riding surfaces.

AM-Fall05 11/1/05 10:23 PM Page 23

B Y T O M K U E N N E N

Preservation with Asphalt TreatmentsAs NCPP’s Galehouse implied, a big partof pavement preservation is keepingwater out of pavements, and the water-proofing properties of asphalt surfacetreatments and liquid asphalt mean theytake top billing in pavement preservationtechniques.

Such pavement preservation practicesinclude crack sealing, patching, fog seals(a combination of mixing-type emulsionand approximately 50 percent water, usedto seal shoulders and patches), rejuvena-tion (application of a rejuvenator agentin a procedure similar to fog sealing), andchip seals (surface treatment in which thepavement is sprayed with asphalt emul-sion and then immediately covered withaggregate and rolled).

Also included are slurry seals (an applica-tion of mixing-type asphalt emulsion,sometimes with additives, mineral aggre-gate and proportioned water, mixed andspread on clean pavement free of dirt andloose gravel); microsurfacing (polymer-modified asphalt emulsion, mineralaggregate, mineral filler, water, and otheradditives, properly proportioned, mixed,and spread on a pavement); cape seals(application of slurry seal to a newly con-structed surface treatment or chip seal);and thin and ultrathin hot mix asphaltoverlays (HMA overlay with one lift ofsurface course, generally with a thicknessof 1.5 inches or less).

Fall 200522 Asphalt

P avement preservation is a plannedsystem of treating pavements atthe optimum time to maximize

their useful life, thus enhancing pavementlongevity at the lowest cost.

Typically, pavements perform well underloads until a particular point in their lifespans, at which time they deteriorate pre-cipitously and rapidly to failure.Experience shows that spending $1 onpavement preservation before that pointeliminates or delays spending $6 to $10dollars on future rehabilitation or recon-struction costs.

Ideally, pavement preservation can meanmaintenance of a pavement even whenthere is nothing apparently wrong withit. “The number one fault of agencies isthat they wait until a problem developsbefore they address it,” said LarryGalehouse, P.E., executive director of theNational Center for PavementPreservation (NCPP) at Michigan StateUniversity. “Instead, successful pavementpreservation demands a pavement that’snot in bad shape to start. If the structureis good, we can keep water out of thepavement, prevent oxidation of theasphalt, and maintain good skid resist-ance. With pavement preservation tech-niques, we will improve their perform-ance and extend their life.”

That approach is directly opposed to thepolitically popular road managementmethod of “worst-first”, in which scarce

maintenance dollars are used to provideband-aid repairs to pavements whichhave gone too far and are failing. Soonafter repairs are made, base or pavementfailures are reflected through to the sur-face and the effort has been wasted.

Strong FHWA SupportIn May 2005, the FHWA came outstrongly in support of pavement preser-vation. “Each highway agency faces dif-ferent challenges in applying pavementpreservation treatments and establishingan effective preservation program,” saidDavid R. Geiger, P.E., director, FHWAOffice of Asset Management.“Preservation involves a paradigm shiftfrom worst-first to optimum timing.Preservation programs must focus ondemonstrating benefit, securing commit-ment of top agency management, con-vincing the public, and selecting the righttreatment for the right pavement at theright time.”

According to Tom Deddens of theFHWA’s Construction and SystemPreservation Team, “The goal is to helpstates assess where they are and providecomments and recommendations on whatthey can do to further develop andenhance their pavement preservation pro-grams.” Those preventive maintenancetreatments include crack sealing, chipseals, slurry surfacings and hot mix asphalt(HMA) thin overlays that will bolster ridequality, provide surface drainage and fric-tion, and correct surface irregularities.

Techniques for Making Roads Last

PAVEMENT PRESERVATION:

AM-Fall05 11/1/05 10:23 PM Page 22

Right turn ad AM.indd 1 9/26/2005 1:18:15 PM

Fall 200520 Asphalt

the MTAG. Upon completing a module,the student will be tested on his under-standing of the subject material. A pass orfail grade will be issued based on the testscores. If the student passes, a verificationnotice will be issued to his employer. Ifthe student fails, he will be instructed toretake the module and repeat the test.

National Center for PavementPreservationIn August of 2004, the National Centerfor Pavement Preservation (NCPP) wascreated through the partnership of theFHWA, private industry and MichiganState University. The purposes of theNCPP are to:

• Provide technical training related topavement preservation and management

• Reach out to state agencies and pro-vide assistance in development of spec-ifications and be a repository for tech-nical research related to pavementpreservation issues

• Coordinate the research activities ofregional or national pooled-fund studiesand those research activities undertakenby other regional pavement preservationcenters as they develop.

The website of the NCPP is www.pave-mentpreservation.org. Presently theNCPP is available to teach two courses,Chip Seal Design and PavementPreservation: Applied Asset Management.

Voluntary Assessment ProgramThe most recent FHWA activity isdirected toward assisting the states byproviding a voluntary assessment of anagency’s pavement preservation program.This assessment program is being imple-mented through a contract between theFHWA Office of Asset Management andthe NCPP. Representatives from NCPPand/or FHWA will meet with the various

components of a highway agency—uppermanagement, contract administration,asset management, maintenance, materi-als and construction—involved withimplementation of maintenance of theroadway system.

The assessments will be guided by a setof standard questions regarding theimplementation of pavement preserva-tion practices and policies within thatstate. A report will then be preparedbased on the responses to these standardquestions. The report will also includegeneral suggestions for improvement, inparticular, noting the best practices effec-tively used in other states. The informa-tion obtained from this study will becompiled and placed in a large databasethat can be accessed by the agencies.Each agency will be assigned a uniqueidentifier that will permit anonymousviewing of the data for purposes of com-parison with their peer agencies.

ConclusionInterpretations of the various FHWAmemorandums can lead to significant dif-

The pavement preservation concept is that an agency can apply a relatively low cost treatmentto a pavement surface while it is still “good.” After treatment, the pavement will be improved andits life extended for some period of time. Pavement preservation requires a commitment by theagency to apply the preservation activities before significant pavement failure occurs.

ferences in the manner in which programsare administered among the various agen-cies. In order to mitigate some confusion,the FHWA has just finalized a documentstandardizing the use of the various cate-gories of roadway maintenance. It isFHWA’s intent to have this “DefinitionsStatement” endorsed by the AASHTO’sStanding Committee on Construction.

The intent of all this activity is to firmlyestablish pavement preservation as thoseactivities focusing on maintenance offunctional surface characteristics of a pave-ment. The preventive maintenance pro-gram is intended to complement expendi-tures made for capital improvements byproviding a strategy to cost effectively pro-long the life of pavement systems of theNational Highway System. As the mantrasays, pavement preservation is about plac-ing the right treatment on the right pave-ment at the right time.

PAVEMENT PRESERVATION CONCEPT

Tom Deddens is the Pavement Preservation

and Construction Engineer in FHWA’s

Office of Asset Management.

AM-Fall05 11/1/05 10:23 PM Page 20

Asphalt 19Fall 2005

thin surface treatments that extend thelife of a road, such as crack and jointsealing, chip seals, slurry seals, microsur-facing and thin and ultrathin hot mixasphalt overlays for flexible pavements,and partial and full depth repairs, dowelbar retrofits, and surface grinding of rigidpavements. To be effective, these treat-ments must be selected carefully andapplied before the pavement sustains anystructural damage.

Available ResourcesThe FHWA’s shift to an emphasis onpreservation motivated the Office ofAsset Management to reach out to thestate DOTs and the highway industrythrough a number of activities. Theavailable research and “conventional wis-dom” was previously collected andassembled in a “toolbox” by theFoundation for Pavement Preservation(FP2). The Foundation collected itsindustry members’ technical manuals,brochures, and pamphlets that describedthe “best practices” for the variouspreservation techniques. About this time,FHWA and FP2 produced two videosaddressing pavement preservation enti-tled: Protecting Our Pavement: PreventiveMaintenance and PreventiveMaintenance: Project Selection. The con-tent of these videos were consolidatedlater onto a single DVD.

Next, a Compendium on PavementPreservation was compiled and is present-ly available on the FHWA’s PavementPreservation website,www.fhwa.dot.gov/preservation/. In2003, a sequel to the toolbox entitledPavement Preservation State of the PracticeVolume 2 was produced and distributedon CD by FP2.

Due to the popularity of these resources,all the information was compiled on aCD, which is now available from theFoundation for Pavement Preservation.

Training Efforts Training is another significant part of thistransition. Four courses specifically address-ing pavement preservation issues have beendeveloped and are available through theNational Highway Institute (NHI).

131054A Pavement Preservation:The Preventive Maintenance Concept

131058A Pavement Preservation: Selecting Pavements for Preventive Maintenance

131103A Pavement Preservation: Design & Constructionof Quality PreventiveMaintenance Treatments

131104A Pavement Preservation:Integrating PavementPreservation Practices &Pavement Management

A listing of these courses can be found on the NHI’s website,www.nhi.fhwa.dot.gov/coursec.asp, under Pavements and Materials.

Interactive ManualThe FHWA’s Office of Asset Managementand the Pavement Preservation ExpertTask Group are in the process of develop-ing an interactive, online version of amanual originally developed by theCalifornia Department of Transportationentitled Maintenance Technical AdvisoryGuide (MTAG). The training will includemodules on crack sealing, patching andedge repairs, chip seals, slurry seals,microseals, ultrathin bonded asphalt over-lays, and thin overlays. When this projectis complete in January 2006, an individualrequiring training will be able to access thespecific technique at his convenience.

Modules will be taught by referring thestudents to the corresponding section of

AM-Fall05 11/1/05 10:23 PM Page 19

Fall 200518 Asphalt

O ver the years, the Federal HighwayAdministration (FHWA) has

changed its emphasis from con-struction to preservation of the NationalHighway System (NHS). FHWA is now

providing assistance to the state DOTs

and the highway industry through anumber of new programs.

HistoryHistorically, preventive maintenanceactivities have been excluded from feder-al-aid funding. When President

Eisenhower initiated the construction ofthe Interstate System in 1956, he left the

maintenance responsibility of the newly

constructed roadway system squarely onthe shoulders of the individual statetransportation agencies. As the interstatesystem aged, Congress initiated the 4RProgram (resurfacing, restoration, reha-bilitation and reconstruction) which

funded the activities to maintain theserviceability of the Interstate system. The passage of the Intermodal SurfaceTransportation Efficiency Act of 1991created the Interstate Maintenance pro-

gram and provided funds using the exist-ing 4R equation. A 1993 FHWA memo-

randum identified any work which pro-vided additional structural capacity, pre-vented the intrusion of water into the

pavement, or any other work that

extended the life of the highway, as beingeligible for federal funding.

A 1998 memorandum gave state DOTsmore flexibility in managing their federal-aid highway program. This memorandumpermitted the use of “planned staged con-

struction” for the completion of surfacepaving independent of other required

project modifications. The memorandum

simultaneously placed added emphasis ontransportation systems preservation andencouraged the state DOTs to properlyfund preservation programs without anyadditional federal assistance.

New DefinitionIn October of 2004, a memorandumissued by the Office of Infrastructurenow makes preventive maintenance activ-ities eligible for federal-aid funding based

on a definition of pavement preservationwhich was consistent with the AASHTOdefinition: “… The planned strategy ofcost effective treatments to an existingroadway system and its appurtances that

preserves the system, retards future dete-

rioration, and maintains or improves thefunctional condition of the system with-out increasing structural capacity.”

The memorandum explains that “…projects that address deficiencies in thepavement structure or increase the capac-

ity of the facility are not considered pre-ventive maintenance and should be

designed using appropriate 3R standards.

Functionally, federal-aid eligibility pre-ventive maintenance activities are thosethat address aging, oxidation, surfacedeterioration and normal wear and tearfrom day-to-day performance and envi-ronmental conditions.”

FHWA now accepts that pavementpreservation is a proactive, long-termstrategy to improve pavement perform-ance through a variety of cost effective,

By Tom Deddens, P.E.

AM-Fall05 11/1/05 10:22 PM Page 18

Fall 200516 Asphalt

AM-Fall05 11/1/05 10:22 PM Page 16

Is It Durable?Shively adds that so far his company hasnot seen any problems with Smoothseal onany of the projects. “We are usingSmoothseal in both rural and urban areas.We did a few jobs in southern Ohio, butmost of the jobs we’ve done are in themiddle of the state. Some jobs are fiveyears old; some are only two years old. Sofar we have not heard anything negative.”

Finally, Shively and other contractors expectgood durability from Smoothseal. “If weuse it for its proper purpose, for pavementpreservation, to prolong the surface life ofroads that are not in need of extensiverepair, then we can expect good durability.”

Durability is a big question in the mindsof city street engineers, says Eric Smith,City Manager of Englewood, Ohio. “Webegan using Smoothseal and found it wasnot only more durable, but was also more

economically viable. The Smoothseal islasting ten years, while the slurry was last-ing only five. The Smoothseal is thickenough and tough enough to resist reflec-tive cracking. We also found thatSmoothseal was less expensive than a con-ventional HMA overlay.

“We used the Smoothseal on residentialstreets, usually two-lane residential streets,with an average daily traffic between 200and 500. Sometimes we used it on collec-tors, but mostly on residential streets. Weput down a 3/4-inch or 1-inch overlay overthe entire roadway. We don’t useSmoothseal on state roads or interstates. Weuse a 1 1/2-inch HMA overlay on those.”

Smith says Englewood uses Type BSmoothseal exclusively. “We found itworks better for our purposes than TypeA. Type B takes only two hours to set up,then you can drive on it.”

Problems with Smoothseal?Smith doesn’t see any critical problemswith Smoothseal, but he has found themodified mix is highly susceptible to cooltemperatures. “When the weather is hot,Type B works well,” says Smith. “Whenthe weather gets cooler, like late October,it is hard to work with—it won’t com-pact easily.”

Smith says that after paving and rolling,Type B looks as smooth as a billiardtable. He adds that even though it lookssmooth, there is no problem with skidresistance, even when it rains.

Future ApplicationsSmith says that quite a few communitiesin Ohio are beginning to use Smoothseal.Although community engineers are oftenreluctant to try new things, Smoothseal isstarting to have a wider and widerappeal.

Asphalt 15Fall 2005

last between 10 and 15 years. ODOT alsois placing Type B on the Ohio Test Road(concrete on one side, asphalt on the other)to test its use as an impermeable surfacemix that can provide long pavement life.

Both types of Smoothseal can be used asa viable alternative to a conventionalHMA overlay. The Ohio AsphaltPavement Alliance has promoted Type Brather than Type A because it requiresless asphalt binder content and is a coars-er mix, which improves rutting resist-ance. Some local agencies that previouslydidn’t consider using Smoothseal are nowlooking at Type B.

ODOT ExperienceODOT has had good experience withboth types. “I’ve had more experiencewith Type A than Type B,” says JimMarszal, ODOT Pavement Engineer inthe Cleveland area. “We cover threecounties and many of our roads areurban and suburban, and some are rural.In this District, we use Smoothseal pri-marily as an overlay to restore rideability.As far as performance and durability, weexpect the Type A sections to last 8, 10or 12 years, or longer. So far I’ve doneone project using Type B, although I amconsidering several others.

“In Type A,” says Marszal, “there is a lit-tle more asphalt binder along withstyrene butadiene rubber or styrene buta-diene styrene, and it pays off in durabili-ty. In the Type B, we use slightly largeraggregate and less modified asphaltbinder in the mix. This provides someadditional structure or strength for use inheavier traffic applications.”

Smoothseal or HMA?Ohio contractors think that Smoothsealcompares favorably with traditionalHMA overlays. “If it is the proper thick-ness, and under proper conditions, yes,Smoothseal can compete,” says Larry

Shively of the Shelly Company. “If it isplaced over a roadway in need of exten-sive surface repair, then Smoothseal is notas effective as a regular HMA overlay.

“Type B has more aggregate matrix thanType A,” says Shively. “Type A is com-posed of natural sands, but Type Brequires crushed faces and limestonecoarse aggregate for heavier traffic. Type Bcan take the place of a traditional HMA

overlay if it contains the proper aggregategradation. Traditional overlays are usually1 1/4 to 1 1/2 inches in thickness.”

Shively says that Smoothseal roads aregetting good density, “but ODOT givesus a method specification to go by. Weuse a specific type of roller and a speci-fied rolling pattern. We don’t oftencheck density because we are followingthe ODOT specification.”

AM-Fall05 11/1/05 10:22 PM Page 15

Fall 200514 Asphalt

Local and state transportation agen-

cies in Ohio started to useSmoothseal™ in the early 1990s

because they were looking for a hot mixasphalt (HMA) alternative pavementpreservation option. They were looking for

a speedy, effective, durable method of resur-facing their roads and streets other than tra-ditional microsurfacing or chip seals.

Seeing the need for a thin-lift hot mixpavement preservation option, represen-

tatives of Flexible Pavements of Ohio

(FPO), the state hot mix paving associa-tion, developed what is known today asSmoothseal. Smoothseal is a heavily poly-mer-modified hot mix that incorporates

styrene butadiene latex. The mixture hasa fine gradation comprised of a sprin-kling of coarse aggregate — 8s and 9s —

with mostly natural and manufacturedsand. The Marshall Method was used fordeveloping the mix design.

In recent years pavement preservationtechniques have seen renewed interest in

Ohio. Like many departments of trans-portation, the Ohio DOT is seeking tobe fiscally prudent with its resources. Inthese later years, when the ODOT re-ini-tiated pavement preservation measures

throughout the state, they reverted to the

use of traditional micro-surfacing andchip seals. So, FPO reminded them,“Wait, you have specifications for HMAmicrosurfacing called Smoothseal.” SoODOT agreed to do some Smoothseal

projects. And they are still using it.

Type A and Type BODOT adopted two versions of

Smoothseal, Type A and Type B. Type A isan all sand mix using 8.5 percent asphalt

binder. It was first used by ODOT in the

Akron, Canton and Cleveland areas.

Type A has been used on non-high-speedroads and four lane boulevards by a

number of urban communities. It has

been used for rural roads and park roads

and calls for a 5/8 to 3/4-inch thickness.

Smoothseal Type B, with about 6.5 to7.0 percent asphalt binder content and a5 percent polymer loading, has per-

formed well on the Georgia Wheel Tester(a rut-testing device) while being com-pactable during construction. ODOT’s

Toledo district was an early user of Type

B, and its use has been spreading aroundthe state. It is typically placed in a 3/4-

to 1 1/2-inch thickness.

Type B has been used on both residentialroads and streets and also on interstatepavements. Asphalt industry designers

expect the various Smoothseal projects to

SEIVE TYPE A TYPE B

1/2 inch (12.5mm) 100

3/8 inch (9.5mm) 100 95 — 100

No. 4 (4.75mm) 95 — 100 85 — 95

No. 8 (2.36mm) 90 — 100 53 — 63

No. 16 (1.18mm) 80 — 100 37 — 47

No. 30 (0.600mm) 60 — 90 25 — 35

No. 50 (0.300mm) 30 — 65 9 — 19

No. 100 (0.150mm) 10 — 30

No. 200 (0.075mm) 3 — 10 3 — 8

Ohio SmoothsealH M A P A V E M E N T P R E S E R V A T I O N O P T I O N

SMOOTHSEAL AGGREGATE GRADATION REQUIREMENTS

AM-Fall05 11/1/05 10:22 PM Page 14

est d2s values, Apr 2002 and Apr 2004,occurred when polymer modified sam-ples were tested.)

For other tests, such as penetration, thed2s calculated for each program (Figure3) is much closer to the ASTM D5 limit.The average d2s limit for penetration forthe round robin programs conductedfrom 1999 to 2004 was 7.9 dmm com-pared to the ASTM limit of 7.1 dmm.

The calculated d2s limits from the 1999-2004 round robin programs are shown inTable 1 along with the average d2s value(calculated from all 9 programs) and theASTM d2s value. The higher variabilityindicates that some work is still neededwithin the participating labs to tighten

down the between-lab variability of com-mon tests for roofing asphalts. It is alsoworthwhile continuing the programs andanalyses to determine if the testing vari-ability is higher because of the materialproperties being tested (i.e., stiffer roof-ing asphalt binders compared to softerpaving asphalt binders). If so, then a sep-

arate set of d2s limits for roofing asphalts

may eventually be determined.

Raise the RoofBeginning in 2005, the Asphalt Institute,with the cooperation of ParamountPetroleum, has taken the reins of the pro-ficiency sample program. This year’s pro-

gram was started in June with reportsbeing sent to the participants in earlySeptember (see Lab Corner on page 42for more details). It is expected that theprogram will continue either annually orbiannually depending on the interests ofthe participating labs.

Through increased knowledge of testing

variability and its causes, we anticipatethat the between-lab reproducibility willimprove for the common roofing asphaltbinder tests, as well as any future teststhat may be used in characterizing the

Asphalt 13Fall 2005

FIGURE 3: REPRODUCIBILITY LIMITS (d2s) FOR PENETRATION AT 77ºF (25ºC)

TABLE 1: MULTILABORATORY d2s LIMITS FOR ROOFING ASPHALT TESTS

1 The d2s limits for Rotational Viscosity come from the recently completed NCHRP 9-26 report, Web

Document 71, entitled “Precision Estimates for AASHTO Test Method T308 and the Test Methods for

Performance-Graded Asphalt Binder in AASHTO Specification M320”.

2 Highlighted rows indicate polymer modified binder samples.

PeriodSoftening Point,

ºFFlash Point, ºF

Penetration @77ºF, dmm

Rot. Viscosity @400ºF, cp

Rot. Viscosity

Apr-2004 22.7 52.2 9.8 131.2 42.9%

Nov-2003 16.6 58.3 8.0 171.1 45.2%

Apr-2003 11.9 69.4 10.7 68.1 40.9%

Nov-2002 11.1 90.8 8.0 131.9 43.0%

Apr-2002 34.5 51.7 6.4 45.4 23.4%

Oct-2001 11.0 66.4 7.1 95.7 38.2%

Nov-2000 13.9 55.0 6.7 124.3 65.7%

Jun-2000 17.2 50.5 6.2 210.0 74.3%

Dec-1999 7.7 66.5 8.6 90.8 44.0%

Average 16.3 62.3 7.9 118.7 46.4%

ASTM1 3.5 32.0 7.1 12.1%

Mike Anderson is Director of Research andLaboratory Services for the Asphalt Institute.

Steve Burhans is the Asphalt TechnicalServices Director for Paramount Petroleum.

physical properties of roofing asphalts. To this end, we believe that the contin-ued success of the Proficiency SampleProgram for Roofing Asphalts will play akey role.

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AM-Fall05 11/1/05 10:22 PM Page 13

In 1999, Paramount supplied samples ofa roofing asphalt binder (Type III) to 20labs, with 18 labs supplying test data onseven tests in ASTM D312 and an addi-tional test on rotational viscosity. In thefirst round robin, tests included:

ASTM Test MethodD36 Softening Point

(Ring and Ball)

D92 Flash Point (Cleveland Open Cup)

D5 Penetration @ 32ºF, 77ºF,and 115ºF

D113 Ductility @ 77ºF

D4402 Viscosity Determination using a Rotational Viscometer@ 400ºF

In later programs after 1999, the ductili-ty test and penetration tests at 32ºF and115ºF were discontinued because of poor

response from the initial round robinlabs. Less than half of the 1999 partici-pants conducted these tests.

From its inception, the program continuedto grow as samples were supplied and ana-

lyzed by Paramount Petroleum on approxi-

mately a six-month schedule. Figure 1shows the participation in the program.

The program also provided some inter-esting data regarding the reproducibilityof the test results for the participating

labs. While the results were, in general,more variable for all tests than the ASTMd2s limits, the variability was higher forsome tests than others. For example, theASTM d2s limit for the Ring and Ball

Asphalt 11Fall 2005

Softening Point test is 3.5ºF. The averaged2s limit for softening point for theround robin programs conducted from1999 to 2004 was approximately four to

five times greater (16.3ºF). The varyingd2s calculated for each program is shownin Figure 2 along with the ASTM D36limit. (It is interesting that the two high-

FIGURE 1: NUMBER OF PARTICIPATING LABS (PENETRATION TEST)

FIGURE 2: REPRODUCIBILITY LIMITS (d2s) FOR RING AND BALL SOFTENING POINT

BINDERS By R. Michael Anderson, P.E. and Steve Burhans

AM-Fall05 11/1/05 10:22 PM Page 11

Fall 200510 Asphalt

If you’re like me, at one time or anoth-er you’ve made a New Year’s resolutionto lose weight. The process for me

begins on January 1st when I step on thescales to establish my baseline weight.Every week, I then return to the scales todetermine my new weight and am some-times confused by the results. Someweeks my weight will not have changedor I may have gained a pound or two,even though I worked out diligently and

generally ate healthy foods. Other weeks,I’m traveling and have eaten poorly andnot exercised, and yet my weight will staythe same or even drop by a pound.

Why does this happen? Well, fortunatelyas someone familiar with science, I knowthat each time I get on the scales consti-tutes a single test, the purpose of which isto generate a result (weight). Each testresult (weight) is affected by a number of

factors including whether or nor I’ve left

my shoes on, or how much pizza I ate thenight before. These are all examples ofmaterial variability, or variability that isinherent to the material (me) being tested.

A second source of variability may occur as

a result of the equipment. Manufacturing

tolerances for the load cell (or springs) ofthe scales can affect the measured result, ascan the calibration of the scales. Anotherpotential factor is the time of day when Iget on the scales. I may have a differentresult if I weigh myself in the morning or

in the evening. These are examples of test-ing variability. If I tightly control my testconditions (weigh immediately after get-ting out of bed in the morning and ensurethat the scales have been recently calibrated

within the expected weight range), then Ican reduce the variability but not com-pletely eliminate it.

Precisely SpeakingThe American Society for Testing andMaterials (ASTM) defines a test methodas “…a definitive procedure for the iden-tification, measurement, and evaluationof one or more qualities, characteristics,or properties of a material…that pro-

duces a test result.” For any test method,we want to know how closely test resultscompare when repeated tests are con-ducted on the same material. Within-lab-oratory precision, which is often referred

to as repeatability, is a comparison of testresults conducted at separate times on thesame material in the same lab. In our

above example, this would be me step-

ping on the scales, obtaining a reading,and then repeating the process in a few

minutes after I’ve brushed my teeth.

Between-laboratory precision, which isoften referred to as reproducibility, is acomparison of test results conducted atseparate times on the same material in a

different lab. This would be exemplifiedby me stepping on the scales, obtaining areading at my house, driving to the gym,

and then stepping on the scales at thegym and obtaining a reading.

For testing laboratories, we are concernednot only about repeatability within ourlab, but also our reproducibility with

other labs. In this instance, a statisticalterm called the difference two-sigmalimit, or d2s for short, is used to providean estimate of the acceptable range of testresults from two labs that can be expect-

ed as a result of normal testing variability.It is determined by multiplying the cal-culated standard deviation (s) by 2√2 or2.83. In cases where the standard devia-tion is proportional to the average fordifferent levels of the measured property,the d2s% is calculated as the d2s dividedby the average of the two test results.

The d2s and d2s% limits are useful inevaluating test results because it lets us

know how to respond to a set of test datain our lab compared to another lab. Ifthe difference between the test results inLab A and Lab B are within the d2s lim-its, then both results could be considered

“correct” and the “actual” value could besomewhere between the two results. If,however, the difference between the test

results in Lab A and Lab B exceeds the

d2s limits, then a retest, and possibly re-evaluation of test equipment and proce-

dures, may be needed. Needless to say,

the smaller the d2s or d2s%, the morereproducible the test result.

Testing Variability of Roofing AsphaltsIn 1999, Paramount Petroleum

Corporation started a round robin pro-

gram for evaluating the variability insome of the most common tests used inthe Standard Specification for AsphaltUsed in Roofing (ASTM D312). Thepurpose was to allow roofing asphalt sup-pliers and other testing labs the opportu-

nity to compare their lab results to theaverage results from a larger group of labs.A repeated high variation from the aver-age could be an indication of equipmentor procedural problems within a lab.

PPrreecciissiioonn ooff TTeessttss ffoorrROOFING ASPHALT

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Fall 20058 Asphalt

According to the 1993 AASHTO Pavement Design Guide methodol-ogy, the pavement needed to be 23 inches thick to carry the designtraffic volume. Using the PerRoad Perpetual Pavement design soft-ware, the design thickness was 14 inches.

Layer ConsiderationsIn addition to thickness considerations, the various layers within aPerpetual Pavement need to satisfy materials concerns. The base layeris made more resistant to fatigue cracking from bending under trafficloads by increasing the asphalt content to provide increased flexibility.Typically, an asphalt binder content which corresponds to 3 percentair voids in the mix is used.

The intermediate layer of a Perpetual Pavement has to be both stableand durable. This layer must provide rutting resistance. This is accom-plished by achieving stone-to-stone contact in the coarse aggregateand using an asphalt binder with sufficient stiffness to meet the hightemperature needs.

Marshall Thompson, Professor Emeritus at the University of Illinois,indicated that achieving rutting resistance should not be an issue—given current asphalt technology.

If the Perpetual Pavement is designed and built correctly, any distress-es are limited to the surface course and can be readily fixed. The nec-essary wearing course properties depend on traffic, weather conditionsand economics. Particular requirements include resistance to ruttingand cracking, skid resistance and noise mitigation. The wide range ofavailable types of HMA mixes allows the surface mix to be customizedto fit the specific application.

Kansas ApproachThe Kansas project evaluated several pavement cross-sections. Thethickness of the base layer varied from about 7.5 inches to 11.8 inch-es. The intermediate layer (about 2.5 inches) and the surface course(about 1.5 inches) were constant for all sections.

The Perpetual Pavement design approach is based upon providingenough thickness to limit the bending strain at the bottom of theHMA layer to less than the strains associated with fatigue damage, aconcept known as the fatigue limit. Kansas installed instruments atthe test site to measure the strains that occurred at the bottom of theasphalt layer when a load moves over the pavement. Information andexperience gained from this project will be used to build longer lastingasphalt pavements.

For more information on Perpetual Pavements,

visit the Asphalt Pavement Alliance’s website,

www.AsphaltAlliance.com.

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Fall 20056 Asphalt

The Asphalt Pavement Alliance defines aPerpetual Pavement as an asphalt pavementdesigned and built to last longer than 50 yearswithout requiring structural rehabilitation orreconstruction, and needing only periodic surface renewal in response to distresses confined to the top of the pavement.

P erpetual Pavements are not new.Some of them were constructedin the 1960s or even earlier.

Pavements that were well designed andwell constructed have performed withoutstructural failures for many years—evenunder heavy traffic.

Kansas is one of the latest states to evaluatePerpetual Pavement technology. TheKansas Department of Transportation andthe Asphalt Pavement Associations of

Kansas, Arkansas, Missouri and

Oklahoma, along with Dobson BrothersConstruction Company and the FederalHighway Administration, hosted an openhouse in July 2005 to showcase a Perpetual

Pavement installation. The pavement wasconstructed on U.S. 75 about 50 milesnorth of Topeka, Kansas, near Sabetha.

Design ObjectivesWorkshop participants learned the basics ofproducing a long-lasting asphalt pavement.According to David Newcomb, VicePresident for Research and Technology ofthe National Asphalt Pavement Association,a Perpetual Pavement is designed and builtfrom the bottom up to eliminate structuralfailures. A Perpetual Pavement designbegins with a strong foundation.

A Perpetual Pavement must have theproper combination of thickness and stiff-ness to resist deformation in the founda-

tion material. The hot mix asphalt(HMA) layers must be thickenough and must be able to resistfatigue cracking by minimizingthe strain at the bottom of the

pavement under loading.

Thickness DesignThere is a point where additional

thickness in a Perpetual Pavementdesign has no added benefit.Perpetual Pavements have a mini-

mum thickness of 8 inches and a

maximum of 12 to 15 inches.Newcomb cited the

example of a sec-

tion of I-710 inCalifornia.

KansasShowcasesPerpetualPavementsConstructionBy Dwight Walker, P.E.

Dr. Marshall Thompson(left foreground) viewsmeasurements for theproject instrumentation.

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Fall 2005

AsphaltNew

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STATE ASPHALT PAVEMENT ASSOCIATIONSSTAFF UPDATELongtime Plantmix Industry of Kentucky (PAIKY)Executive Director, Dean Blake, has accepted the

position of Deputy Executive Director. Brian Wood,who has been PAIKY’s Assistant Executive Directorand Engineer for the last five years, is the newExecutive Director.

Deanna Loveland is the new Executive Director ofthe Oklahoma Asphalt Pavement Association. Shereplaces Dr. Pat Jaynes.

UPCOMING EVENTSAlabama Rubblization Workshop will be heldDecember 5 – 6, 2005 in Montgomery, Ala. For moreinformation, contact Mel Monk of the AlabamaAsphalt Pavement Association at www.alasphalt.comor (334) 834-5314.

The National Pavement Expo 2006 will be held inCharlotte, NC, on February 15 – 18, 2006. For moreinformation, visit www.nationalpavementexpo.com.

The second Asian bitumen conference, AsianBitumen 2006, will be held in Singapore, February23 – 24, 2006. For more information, visit

www.cconection.org/asianbitumenflyer.pdf.

The World of Asphalt 2006 Show and Conferencewill be March 13 – 16, 2006, in Orlando, Fla. For

more information, visit www.worldofasphalt.com andsee the ad on page 40.

PAVEMENT PRESERVATION ACTIVITIESThe AASHTO Standing Committee on Highwaysand the AASHTO Board of Directors has approved a

three-year technical services program for pavement

preservation. The program will be operated by the

National Center for Pavement Preservation locatedat Michigan State University. An oversight group fromthe AASHTO Subcommittee on Maintenance willdevelop a specific work plan for the three-year effort.

Over the next two years, the FHWA’s Office of AssetManagement and their local Division Offices will offerstate highway agencies the opportunity to have theirpavement preservation program reviewed at no cost. TheNational Center for Pavement Preservation will conduct

a program review and interviews with key personnel foreach State Highway Agency that accepts FHWA’s invita-tion. FHWA will then identify opportunities and makerecommendations for improvements in the State’s pro-

gram. For more details on FHWA’s involvement withpavement preservation, see the related article on page 18.

FOUNDATION FOR PAVEMENTPRESERVATION NEWSThe Foundation for Pavement Preservation (FP2) heldtheir first annual meeting in Austin, Texas, on October4, 2005. The meeting preceded the Associated GeneralContractors Trade and Equipment Show. The seminarhad approximately 100 attendees who heard about thevarious methods used to extend pavement life.

One of the highlights of the meeting was the recognitionof the City of Los Angeles for Excellence in PavementPreservation. Nazario Sauceda, Assistant Director, and

Bill Robertson, Director of LA’s Department of PublicWorks, gave a presentation on their program.

The Foundation is committed to promoting pavementpreservation activities and bringing together industry

leaders and organizations to increase support and sharetechnology. FP2 invites TRB participants to their hos-pitality suite in January.

Quietpavement.com a WinnerThe Asphalt Pavement Alliance web siteQuietpavement.com continues to win major awards. InSeptember, the site was named “Outstanding Web Site”by the Web Marketing Association, and in October, the

Construction Writers Association gave the site an awardfor “Special Recognition for Website Interactivity.”Earlier this year, Quietpavement.com was distinguishedas “Webby Worthy” by the International Academy ofDigital Arts and Sciences in the 2005 Web Awards.

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AI Field Engineer Mark Blow (right) shares thelatest quality construction techniques withElmendorf AFB personnel in Alaska.

NEW AI STAFF APPOINTMENTSAlexander (Sandy) Brown is the new AI CanadianField Engineer. A life-long resident of the Toronto area,Sandy’s 30 years of asphalt experience includes exten-

sive knowledge of pavement materials, asphalt mixes,road design, construction and evaluation. Sandy’s officeis located in Ontario. His position is shared with theOntario Hot-Mix Producers Association.

The Institute welcomes Jacqueline Goins as AI’s newLibrary Services and Resources Specialist. Withextensive experience, as well as a degree in Library and

Information Science, Jacqueline leads a variety of ini-

tiatives in the management and retrieval of AIresources.

Jonathon Oepping is AI’s Division of Research andLaboratory Services’ new Asphalt MaterialsTechnician. He works in all aspects of the AILaboratory with a focus on mix testing and analysis.

Becky Boston-Sharron is the new CommunicationsSpecialist in AI’s Marketing Department. Becky works

with AI’s publications, seminars, promotional mail-ings and trade shows.

Barbara Day joins the AI staff as the new AsphaltPavement Alliance Coordinator and AdministrativeAssistant in the Finance Department.

AI RESEARCH AI and the University of Kentucky TransportationCenter were recently awarded a federal research grantto study the relationship between good construction

practices and the long-term durability of asphalt pave-ments. “This will be an applied research study thatwill produce results that can be practically and directlyused at all levels of the road transportation system,”

said AI President Pete Grass.

The Airfield Asphalt Pavement TechnologyProgram, which is administered by Auburn Universityin partnership with the Federal AviationAdministration, recently awarded the Asphalt Institutea research project to develop state-of-the-art guidelinesfor rubblization. The research team is composed ofAI’s Mark Buncher and Gary Fitts, along with consult-ants Roy McQueen and Tom Scullion.

WELCOME NEW AI MEMBERS

Asphalt OperatingServices, LLC

Flint Hills Resources, LP

Lunday-Thagard Refining

Peoria RiverTerminal, Inc.

AI Field Engineer Bob Humer, AI Director ofResearch and Lab Services Mike Anderson, and AILab Technicians Mike Beavin and Shay Emmonsrecently conducted a training session for theCalifornia Department of Transportation(Caltrans) in Sacramento on asphalt bindertechnology. Caltrans is implementing PG binderspecifications and asked AI for training.

Fall 2005

AM-Fall05 11/1/05 10:22 PM Page 4

Asphalt 3Fall 2005

For the latest information from theAsphalt Institute, visit the Institute’swebsite at www.asphaltinstitute.org

Asphalt Institute2696 Research Park Dr.Lexington, KY 40511-8480(859) 288-4960

Agreement #40112592Canadian Return Address:Station AP.O. Box 54Windsor ON N9A 6J5cpcreturns@wdsmail.com

Asphalt Magazine is printed in the USA andpublished by the Asphalt Institute, an internationalnonprofit organization sponsored by members of thepetroleum asphalt industry to serve both users andproducers of asphalt materials, through programs ofengineering service, research, and education.

Peter T. Grass, P.E., PresidentBrian Clark, PublisherDwight Walker, P.E., EditorJohn Davis, Contributing EditorLaura Doolittle, Designer

Copyright © 2005, Asphalt InstituteAll rights reserved.

Cover photo courtesy of expresswaysonline.com.

FOR ADVERTISING INFORMATION CONTACT:John Davis . . . . . . . . . . . . 859-223-0993

jdavis@asphaltinstitute.org

Ed Misajet . . . . . . . . . . . . 502-292-2125emisajet@att.net

AsphaltFall 2005 • Vol. 20, No. 3

1 President’s Message

3 Features

4 Asphalt News

6 Kansas Showcases Perpetual Pavements Construction

10 Precision of Tests for Roofing Asphalt Binders

14 Ohio Smoothseal: HMA PavenentPreservation Option

18 Tools for the Pavement Preservation Industry

22 Pavement Preservation:Techniques for Making Roads Last

28 Fred Waller: Asphalt Engineer Par Excellence

32 Product Showcase

35 Evolution of Asphalt Plant Automation

38 Polyphosphoric Acid Modification of Asphalt

42 AI Lab Corner

AsphaltFeaturesFeatures

AM-Fall05 11/1/05 10:22 PM Page 3

Fall 2005 Asphalt 1

** AAkkzzoo NNoobbeell SSuurrffaaccee CChheemmiissttrryy LLLLCC, Willowbrook, ILAAllll SSttaatteess AAsspphhaalltt,, IInncc.., Sunderland, MAAAlloonn UUSSAA, Dallas, TX** AAnnddrriiee IInncc.., Muskegon, MI** AARRRR--MMAAZZ CCuussttoomm CChheemmiiccaallss,, IInncc.., Winter Haven, FLAAsspphhaalltt MMaatteerriiaallss,, IInncc.., Indianapolis, IN* AAsspphhaalltt OOppeerraattiinngg SSeerrvviicceess,, LLLLCC,, Bartlett, ILAAsspphhaalltt PPrroocceessssoorrss IInnccoorrppoorraatteedd, BARBADOSAAsspphhaalltt RReeffiinniinngg && TTeecchhnnoollooggyy CCoommppaannyy, Douglasville, GAAAssssoocciiaatteedd AAsspphhaalltt,, IInncc.., Roanoke, VA* AAssttaarriiss LLLLCC, Saint Louis, MOBBiittuummaarr IInncc.., Montreal, QC, CANADA* BBoouucchhaarrdd CCooaassttwwiissee MMaannaaggeemmeenntt CCoorrpp.., Melville, NYBBPP BBiittuummeenn, Whiting, INCCaalluummeett LLuubbrriiccaannttss, Indianapolis, INCCaannaaddiiaann AAsspphhaalltt IInndduussttrriieess IInncc.., Markham, ON, CANADA** CCaannaaddiiaann NNaattiioonnaall RRaaiillwwaayy, Montreal, QC, CANADACChheevvrroonn CCoorrppoorraattiioonn, San Ramon, CACChheevvrroonn –– AAssiiaa PPaacciiffiicc AAffrriiccaa aanndd PPaakkiissttaann RReeggiioonn ((CCaalltteexx)), Sydney,

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AI Membersas of 11/1/2005 (* — Affiliate Member )

PRESIDENT’S MESSAGE

B ill Haverland, Manager, AsphaltSales and Marketing, ofConocoPhillips is Chairman of

the Asphalt Institute this year —noteworthy in that this is his secondtime in that position. Bill first servedas our Chairman in 1996. He is theonly individual that has come backfor a second term. That invites somecomparisons.

In 1997, the Asphalt Institute had 60members; today we enjoy 85 as we goto press and I’ve no doubt we’ll actuallyfinish this year higher. In fact, duringthe last 12 months, we’ve added 12percent to our membership rolls. Why?We deliver value to our members fortheir investment, and perhaps unlike1997, we are more focused on solvingindustry problems than ever before.

Based on 2004 reported numbers,U.S. markets alone reflected totalsales on the order of 36.1 milliontons of liquid asphalt. Compare thatto 32.9 million tons in 1997. That isa 1.4 percent annual increase, aboutwhat we’d expect over this eight yeartime period — given the turbulenteconomic conditions.

Looking back to 1997, the FHWAexpected to have all states using thethen new Superpave specifications. In2006, California is now the final stateto adopt Superpave — in fact, AI staffrecently conducted two Asphalt BinderTechnology (ABT) courses inCalifornia in late September. Thesecourses were requested to helpCalifornia with their transition to PGasphalt binders beginning next year.

Bill’s first round as Chairman was whilehe served with Shell Oil; then it wasbought by Tosco Refining and then byPhillips 66 who merged to becomeConocoPhillips. We’re glad he is stillwith the industry. He is the uncontest-ed champion of the “most membershipplaques hanging on one wall” contestand while the extreme case, Bill demon-strates that the business isn’t static.Mergers and acquisitions are part of thereality of the oil business.

Our industry owes a debt of gratitudeto Bill and people like him. They def-initely have a day job, but somehowfind time to give back to the industryin a significant and appreciated way.Whether it is serving on a committee,taking a leadership role or supportingthe collective efforts of the industry

by joining theassociation—con-tributing todayensures a brightfuture for ourmarkets tomorrow.

FROM THE CHAIRMAN

A long with changes within ourindustry, the leadership and staffof the Asphalt Institute has also

changed. There is a different feelwithin the staff and in the way theyconduct their work. The dedicationand resourcefulness of the staff hasallowed us to make the great stridesnoted above. We are financially stableonce again, have a dominant voice inindustry activities, and take proactiveapproaches to challenges as theydevelop. It has been through theirhard work and creativity that theAsphalt Institute is recognized as therefining industry’svoice in the busi-ness. We, asmembers, owethem well deservedthanks for bring-ing us where weare today.

Peter T. Grass, President

Bill Haverland, Chairman

AsphaltPresident’s M

essagePresident’s M

essage

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