1INTERNATIONAL SOCIETYfor ASPHALT PAVEMENTS

Editor: Prithvi (Ken) Kandhal

ISSUE NO. 29, October 2003

Board of Directors

E. Beuving

A. Collop

J. Harvey

A.Kasahara

M. Partl

H. Von-Quintus

Patron Members

S.M. Al-Blehed

N.M.Al-Salloum

T.M.A.Al-Shawaf

(continued on page 2)

Executive Committee

D.E. Newcomb Chairman

G.Huber 1st V.Chairman

N.M. Al-Salloum 2nd V.Chairman

J. Button Secretary

J. Mahoney Treasurer

At Large Members

S. F. BrownE. R. BrownJ. F. CorteJ. EppsG. KennepohlB. PidwerbeskyI. RickardsP. Ullidtz

E. L. Skok, Executive Administrator

ATTEND ISAP’S INTERNATIONALSYMPOSIUM ON LONG LASTINGASPHALT PAVEMENTS

The National Center for As-phalt Technology (NCAT) willhost the International Societyfor Asphalt Pavement’s (ISAP)international symposium onDesign and Construction ofLong Lasting Asphalt Pave-ments on June 7-9, 2004. Thesymposium is also sponsoredby the U.S. Department of Trans-portation (Federal HighwayAdministration), the AlabamaDepartment of Transportation,and the National Asphalt Pave-ment Association.

The venue of the interna-tional symposium is The Lodgeand Conference Center atGrand National Golf Course in

the Auburn/Opelika area, set inthe serene countryside of eastAlabama. Auburn is approxi-mately 100 miles southwest ofAtlanta, Georgia.

About 40 very good techni-cal papers from many countriesconcerning long lasting asphaltpavements will be presented inthree days at the symposium.Some of the topics are as fol-lows:•Experience with long lasting

pavements in United States,Canada, and Europe

•State-of-the-art review of approach to long lasting pavements

The Lodge and Conference Center at Grand National Golf Course, the venue ofInternational Symposium on Long Lasting Asphalt Pavements

2 THE ISAP REPORTER

(continued from page 1)—International Symposium

•Fatigue consideration andfoundation requirements fordesigning long lasting pavements

•Construction and quality control for long lasting pavements

•Stone matrix asphalt (SMA)•Asphalt pavement warranties

in Europe•Rehabilitation of heavy duty

pavements• Integrated approach to avoid

moisture-induced damage•Evaluation of segregation•Aggregate resistance to polish

ingThe tentative schedule of the

symposium is as follows:Sunday, June 6, 2004

Registration, 1-6 pmReception, 6-8 pm

Monday, June 7, 2004Technical sessions, 9 am - 5 pm

Tuesday, June 8, 2004Technical sessions, 8 am - 5 pmDinner, 7-9 pm

Wednesday, June 9, 2004Technical sessions, 8 am - 5 pmDinner

Thursday, June 10, 2004Optional tour of NCAT re-

search facility and Test Track,8 am - 12 noon

Exhibits will be open on Sun-day through Wednesday.

The following guest programhas been planned:• Tour and luncheon at the

Jules Collin Smith Art Museum featuring a 35 ft chandelier crafted by world-famous artist, Dale Chihuly.

• Day trip to Callaway Gardens,featuring the Sibley Horticultural Center followed by aluncheon, then your choiceof shopping in nearby WarmSprings, Georgia or a visit tothe Roosevelt Little WhiteHouse.To obtain a registration pack-

In the search for informationconcerning criteria to be usedin evaluating pavement founda-tions prior to paving, I cameacross a report on the practicesof different agencies for char-acterizing subgrade soils dur-ing construction. It was some-what disappointing to find verylittle information on what mini-mum stiffness or strength a soilshould have prior to buildingthe pavement layers. There wasconsiderable detail on testmethods and sampling, yet thecritical piece of the puzzle wasnot to be found. This is a goodexample of practical informa-tion not being useful.

At the other end of the spec-trum researchers are furiouslytrying to develop hypotheses ofhow top-down cracking occursin asphalt pavement. Many dif-ferent potential mechanismshave been identified and somevery sophisticated analysis tech-niques are being brought tobear on the problem. All thiseffort will be fruitful if guide-lines to mitigate top-downcracking result in meaningfulchanges to materials selection,mix design, testing, and pave-ment design processes. Thiswould be an example of relevanttheoretical work resulting in auseful outcome.

Often times theoretical workis derided as not useful, butpractical solutions that have nofundamental basis are appli-cable only to the conditions

ISAP CHAIRMAN’S REPORTRELEVANCE AND USEFULNESS

under which they were devel-oped. An example of this is thee x i s t i n gA A S H T Oflexible pave-ment perfor-mance pre-diction equa-tion. Origi-nally devel-oped 40years agofrom the re-sults of theAASHO Road Test where 1.1million load repetitions wereapplied to flexible pavementswith asphalt surfaces up to 150mm in thickness, this same per-formance equation is extrapo-lated to 50 million ESALs forpavements with asphalt layersof 400 mm or more. Clearly, wehave gone beyond the condi-tions of the AASHO Road Testand it is time for a new ap-proach. In the design of the re-cent I-710 rehabilitation in Cali-fornia, the design traffic for a40-year period was estimated tobe 200 million ESALs. CarlMonismith and his team em-ployed mechanistic design witha fundamental understanding offatigue and rutting behavior ofasphalt mixtures to provide auseful design process that al-lowed the construction of a long-life pavement structure. This isan example of theory with apurpose.

In defining our research prob-lem statements, do we really un-

age or questions about thesymposium, please call NCATat 334-844-6228, or email<taplecp@eng.auburn.edu>.Online registration available atwww.ncat.us; follow the link to“Upcoming Meetings” on the left.

Mark your calendar for June7-9, 2004! You don’t want to missISAP’s first international sym-posium on Design and Con-struction of Long Lasting As-phalt Pavements.

David Newcomb,ISAP Chairman

3INTERNATIONAL SOCIETYfor ASPHALT PAVEMENTS

(continued on page 4)

derstand the questions to beanswered? We frequently limitinnovation by the way we poseproblems. For instance, shouldwe define the limit of recycledasphalt allowed in a mix orshould we try to find a way tomaximize its use? Should wedefine the minimum tempera-ture and conditions underwhich we pave or should wedevelop materials and construc-tion methods to ensure the qual-ity of pavement placed in ad-verse conditions? Are we fo-cused on developing a newcrack growth model or ways toinhibit cracking?

A new model in and of itselfdoes not solve a problem, a newfundamental test does not im-prove performance, and newtechnology does not guaranteesuccess in improving a product.It is the end application of thesethat will define their relevanceand usefulness. It is certain thatone needs to understand an ill-ness before coming up with acure, but we must not lose sightthat the cure is the importantissue, not the definition of thedisease.

NEWS FROMNORTH AMERICA

Research on tire/pavementnoise is underway at the Insti-tute for Safe, Quiet, and DurableHighways (SQDH) at PurdueUniversity. The institute is theonly center in the United Statesdedicated to research aimed atreducing highway noise whilestill maintaining and improvingthe safety, durability, and eco-nomics of highways.

The SQDH center has devel-oped a huge Tire/Pavement TestApparatus (TPTA), which is theonly one of its kind in the worldfor measuring tire/pavementnoise. The TPTA is basically a

12-foot-diameter vertical drumon which different types of pave-ment samples are formed. Twoarms with mounted tires onwheels then are “driven” aroundthe drum.

Pavement specimens can bechanged while the tire remainsconstant or the pavement sur-face type remains constantwhile the tire design is changed.Measurements can be made onthe tire, in the pavement, andwith microphones that travelbeside the tire.

Details of the research stud-ies undertaken by the SQDHCenter are available on theirweb site at <http://widget.ecn.purdue.edu/~sqdh>.

* * *

Maryland State Highway Ad-ministration has discovered aninnovative method for trackingpavement management andmonitoring performance on along-term basis. This method isbased on a Web site and pro-gram created by Professor JoeMahoney and his staff at theUniversity of Washington. Thesite, HMAView, has been in ser-vice since 1998. It was originallypopulated with 30 WashingtonState Department of Transpor-tation contracts and now

The Tire/Pavement Test Apparatus at Purdue University’s SQDH Center is one of itskind in the world

contains Maryland informationas well. This site could archiveall project design information,store aggregate and mix designdata, assemble constructiondetails, and prepare controlcharts.

You can view HMAView liveby visiting the web site at <http://hotmix.ce.washington.edu/md>.

* * *

The Arizona Department ofTransportation (ADOT) is under-taking a pilot program to evalu-ate the use of asphalt rubberfriction courses (ARFCs) as anoise mitigation measure. Un-der Arizona’s Quiet PavementPilot Program, ADOT will use a4 dBA (decibel) reduction intheir noise evaluation whenARFCs are used. This shouldreduce the height and lengthof noise barriers (primarilywalls and berms) needed tomeet the noise criteria; and insome cases, will eliminate theneed for noise barriers entirely.There are other benefits as well.Increasingly, citizens are con-cerned about the negative ef-fects of higher noise walls andberms—due to the loss of viewsand shading effects among oth-ers.

4 THE ISAP REPORTER

(continued from page 3)—News from N. America

* * *

Recent research has indi-cated that different brands ofgyratory compactors may yielddifferent compaction results inspite of having the required1.25° external gyratory angle.These compaction differencesmay result in a design air voidcontent difference of up to 1percent, and a change in as-phalt content of up to 0.4 per-cent. The problem is that dif-ferent brands or models of com-pactors have different levels ofcompliance (give) in theirframes. This lack of consistencyin compliance is responsible fora difference in the internalangle (inside the mold) wherethe specimen is being com-pacted.

In order to address this, aDynamic Angle Validator (DAV)was developed by Test Quip, Inc.for the Federal Highway Admin-istration. The DAV allows theinternal angle of different ma-chines to be checked and sub-sequently adjusted. AASHTOstandards now allow a stateagency to choose either exter-nal or internal angle calibration.It is recommended that the cali-bration be done for the inter-nal angle if different brands ormodels of gyratory compactorsare being used. The cost of theDAV is around $9,000.

* * *

The Asphalt Pavement Alli-ance (APA) has announced thatit is accepting nominations forthe prestigious Perpetual Pave-ment Awards for 2003. Winnerswill be honored at the APAAsphalt Pavement Conference:21st Century Construction at theWorld of Asphalt 2004 Show andConference in Nashville next

March.The Perpetual Pavement

Award was created to encour-age public agencies, contrac-tors, engineers, and pavementowners to build long-life, high-quality pavements which bringmore value for the benefit oftaxpayers and the public.

To be eligible, a pavementmust be at least thirty-five yearsold and must never have had astructural failure. The pavementmust demonstrate the smooth-ness, quality, and user friendli-ness of hot mix asphalt pave-ment. Engineers at the NationalCenter for Asphalt Technologyat Auburn University, Alabama,review all nominations. Win-ners are validated by a panel ofindustry experts.

Six highway pavement sec-tions in five states and threeairport runways received the2002 Perpetual PavementAward: Iowa (two sections of I-80); Minnesota (I-35); Missouri(I-44); Oklahoma (I-40); Tennes-see (I-65); two runways at Balti-more-Washington InternationalAirport; and one runway atEareckson Air Station inAlaska.

* * *

The Transportation ResearchBoard (TRB) has a complimen-tary electronic newsletter, TRBE-Newsletter, which containssections on TRB publications,TRB news, and other researchreports. The E-Newsletter alsooffers a search engine to searchfor a news item by keyword orphrase. To find the E-Newslet-ter online, go to <http://gulliver.trb.org/news>.

* * *

The National CooperativeHighway Research Program(NCHRP) is undertaking animportant research project, “En-

durance Limit of Hot Mix As-phalt Mixtures to Prevent Fa-tigue Cracking in Flexible Pave-ments.” Fatigue cracking origi-nating at the bottom of a hotmix asphalt (HMA) structurehas long been acknowledged asthe most costly form of distressto correct through rehabilita-tion.

Performance data from well-constructed flexible pavementswith a thick HMA structure,some of which have been inservice for more than 40 years,show that bottom-up fatiguecracking does not occur inthese pavements. This field ex-perience suggests that an en-durance limit, that is, a level ofstrain below which fatigue dam-age does not occur for any num-ber of load repetitions, is a validconcept for HMA mixtures; itsquantification could aid in theefficient design of long-life flex-ible pavements with a signifi-cantly reduced life cycle cost.

The objectives of this studyare to (1) test the hypothesisthat there is an endurance limitin the fatigue behavior of HMAmixtures and measure its value

2002 Perpetual Pavement Award winnerInterstate 80 in Cedar County, Iowa.The pavement has withstood 40 years offreeze-thaw cycles with flying colors.

5INTERNATIONAL SOCIETYfor ASPHALT PAVEMENTS

for a representative range ofHMA mixtures and (2) recom-mend a procedure to incorpo-rate the effects of the endurancelimit into mechanistic pavementdesign methods.

The $750,000 research projectis expected to begin in Marchnext year and is scheduled forcompletion in two years.

* * *

The Texas Transportation In-stitute has developed a StirredAir-Flow Test (SAFT) to replacethe rolling thin-film oven test(RTFOT) and the thin-film oventest (TFOT), which are used tosimulate the asphalt binderaging process during HMA pro-duction and construction. SAFTuses air blowing to oxidize theasphalt binder. SAFT is faster(testing time of 35 minutes), andits cost is half of the currenttest equipment. It also elimi-nates the glass bottles used inRTFOT. SAFT is also suited fortesting polymer-modified bind-ers.

* * *

Research conducted atPurdue University for the SouthDakota Department of Transpor-tation has concluded that theuse of different types of burnerfuels in well-maintained andwell-tuned HMA plants had nosignificant effect on HMA mixproperties. A small amountof burner fuel residue (less than35 parts per billion by weightof aggregate) was found in ag-gregate heated with No. 6 fuelwhen there was insufficientoxygen available for combus-tion. The report concludes thatmixture contamination is notlikely to be a problem whenfuels are properly preheatedand the plant is in good work-ing order. The report is avail-able from South Dakota DOT,

Office of Research, 700 EastBroadway Avenue, Pierre, SD57501-2586.

* * *

The International Slurry Sur-facing Association (ISSA) hasrecently released their publica-tions A-105 (RecommendedPerformance Guidelines forEmulsified Asphalt SlurrySeal) , and A-143 (Recom-mended Performance Guide-lines for Micro-Surfacing). Thenew versions are available forfree download, on the ISSAwebsite: <http://www.slurry.org>.

* * *

The Federal Highway Admin-istration has released the fourthedition of its Distress Identifi-cation Manual for the Long-Term Pavement Performance(LTPP) program. The manualprovides a common languagefor describing cracks, potholes,rutting, spalling, and otherpavement distresses beingmonitored by the LTPP program.Pavement types addressed bythe manual include asphalt con-crete-surfaced, jointed portlandcement concrete, and continu-ously reinforced portland ce-ment concrete.

* * *

Thousands of’ highway con-struction specifications from all50 states, the District of Colum-bia, and Puerto Rico are nowinstantly available online atthe new National HighwaySpec i f i ca t ions Web s i t e(www.specs.fhwa.dot.gov). The siteis a collaborative effort of theFederal Highway Administra-tion (FHWA) and the AmericanAssociation of State Highwayand Transportation Officials(AASHTO).

* * *

The American Association ofState Highway and Transporta-tion Officials (AASHTO) Guidefor the Design of PavementStructures has served as theprimary document for the de-sign of new and rehabilitatedhighway pavements. The guideincorporates empirical designapproaches developed fromfindings of the historic AASHORoad Test of the early 1960s. TheRoad Test, however, covered alimited range of traffic loading,climatic conditions, subgradesoil, paving materials, and struc-tural features and did not in-clude rehabilitated pavements.

The next generation of designapproaches will need to incor-

(continued on page 11)

ISAP AND AAPT CDs AVAILABLEThe following ISAP CDs are available (each CD is $25 for

ISAP members and $100 for non-members):7th Conference (1992)8th Conference (1997)9th Conference (2002)The following AAPT CDs are available (each CD is $25 for

AAPT members and $100 for non-members):CD 1 Volumes 48-52 (1979-1983)CD 2 Volumes 53-57 (1984-1988)CD 3 Volumes 58-62 (1989-1993)CD 4 Volumes 63-67 (1994-1998)CD 5 Volumes 43A-47 (1975-1978) (NEW)CD 6 Volumes 39-43 (1970-1974) (NEW)

6 THE ISAP REPORTER

NEWS FROMEUROPE

Preparations are underwayfor the 3rd Eurasphalt &Eurobitume Congress to beheld on May 12-14, 2004 inVienna, Austria. The theme ofthe Congress will be on “practi-cal solutions.” The Congressseeks to increase the involve-ment of road authorities and ofresearch and development spe-cialists.

The Eurasphalt & Euro-bitume Congress has been es-tablished as the preeminentasphalt and bitumen event forindustry in Europe. Four tech-nical sessions will be held inthe 3rd Congress as follows:

Technical Session 1: Implemen-tation, Innovative Solutionsand Transfer of TechnologyPapers have been invited onexamples of recent innovativeapplications and proven practi-cal solutions for the followingend uses: roads, airfields,bridges, railways, industrialflooring, hydraulic, leisure,landfill, agricultural, and urbanareas. The other subjects aretechnology transfer, trainingand education, economics ofasphalt pavements, whole lifecosting and finance.

Technical Session 2: Safety andEnvironmentPapers have been invited whichpresent safety in the workplace,emissions, classification andlabelling, life cycle assessment,sustainability, noise reduction,recycling, risk assessment,contribution to safe driving,leaching, road run-off, and wasteclassification.

Technical Session 3: Researchand Development - Search forNew ApplicationsPapers have been invited on the

following subjects: new re-search, new developments andnew applications on the follow-ing subjects: binders, aggre-gates, additives, use of second-ary materials, hot mixes, coldtechnique, surface treatments,construction, maintenance, andproduction.

Technical Session 4: Perfor-mance Requirements and As-sessmentsPapers have been invited whichpresent performance-relatedspecification, performance as-sessment, functional contracts,regulatory frameworks, develop-ments in CEN standardization,pre-normative research, bitu-men quality, quality control,testing, the philosophy of binderand mix specifications, and pri-orities for research and stan-dardization.

Detailed information on theprogram, organization, and reg-istration can be seen at <http://www.eecongress.org>.

* * *

The European Committee forNormalisation, or ComitéEuropéen de Normalisation(CEN) is actively preparing apackage of harmonized asphalt

standards, which will include acomprehensive set of tests forasphalt mixtures. The standardsinclude both functional (empiri-cal) and rational (fundamental)tests. The procedures are in-tended to be practical, simple,not too expensive, and not tooslow. Many options have beenretained in the procedures,which will facilitate rationaliza-tion in the future. Specificationstogether with the associated testmethods are due to be pub-lished in 2005.

* * *

The Danish Road Directorateand Greenwood Engineeringhave developed a laser-basedequipment to measure the bear-ing capacity of roads at normaltraffic speeds. The new HighSpeed Deflectograph gives in-creased traffic safety when mea-suring bearing capacity andprovides a considerably largerbasis for planning of pavementmaintenance.

The High Speed Deflectograph developed by the Danish Road Directorate

7INTERNATIONAL SOCIETYfor ASPHALT PAVEMENTS

NEWS FROMAUSTRALIA

The 12th International Flex-ible Pavements Conference washeld successfully in Melbourneon October 5-8. The followingtopics were covered in the con-ference: warm asphalt mix ad-vances, performance based stan-dards for local governments,asset management, perfor-mance testing and evaluationof bituminous materials, bitu-minous seals, international de-velopments (Europe), safety andenvironment (including trafficnoise), and asphalt technologyadvances (stone matrix asphalt,porous asphalt, pavement de-sign, etc.).

The conference related infor-mation can be seen at <http://www.aapa.asn.au>.

* * *

An ultra high pressure (UHP)watercutting machine has beendeveloped by New Zealand com-pany Fulton Hogan. The UHPwatercutter removes excess bi-tumen from road surfaces (re-storing macrotexture) and in-creases the microtexture of ag-gregate particles in the asphaltsurface. Both serve to increasethe skid resistance of the as-phalt surfaces, thereby improv-ing road safety.

NEWS FROMSOUTH AFRICA

Synopses of papers havebeen received for the 8th Con-ference on Asphalt Pavementsfor Southern Africa (CAPSA)to be held on September 12-16,2004 in Sun City, North WestProvince, South Africa.

The CAPSA five-yearly con-ferences are premier events insouthern Africa, having interna-

tional status for quality and rel-evance in the highway indus-try.

Following on from the proudtradition of previous CAPSAssince 1969, the 2004 Conferencewill focus on four separatethemes, each encompassingseveral sub-topics:1. Economic Growth and De-

velopment•Strategic road initiatives for

rural development, urbanrenewal and poverty alleviation

•Asset management throughoptimal life cycle costs

•Sustainable employmentcreation for the provisionand maintenance of blacktop roads

2. Efficient Road Provision andMaintenance•Institutional arrangements

and procedures for efficientand effective delivery (roadsagencies, public-privatepartnerships, concessions)

•Equitable sharing of riskthrough performancecontracts

3. Human Capital Development•Current and envisaged edu

cation and trainingschemes and research anddevelopment programs

•Broadening the base of participation in the roads industry

4. Best Practice in FlexiblePavement Design, Construction and Maintenance•Studies on the performance

of pavements componentsor systems

•Innovations through theapplication and implementation of research

•Pavement surveillance andevaluation

•Worker health and safetyand environmental conservation

* * *

South Africa’s bitumen andbituminous products industryhas taken pre-emptive steps toentrench self-regulating policiesand guidelines which ensurecompliance with internationalstandards of worker health andsafety, and environmental con-servation.

These initiatives include theestablishment of a Centre forOccupational Safety and Healthand Environmental Conserva-tion, and an industry-sponsoredresearch project to analyze andclassify selected bitumen prod-ucts for disposal in terms of theMinimum Requirements of theDepartment of Water Affairs andForestry.

A significant preliminaryfinding of the research projectis that penetration grade bitu-mens can safely be de-listedfrom their current “hazardousmaterials” category, since theyare neither carcinogenic to hu-mans or animals, nor do theythreaten negative impact on theenvironment if disposed of atless stringently controlled land-fill sites.

NCAT TEST TRACKREADY FORSECOND CYCLEOF LOADING

The first cycle of loading ofthe National Center for AsphaltTechnology (NCAT) Test Tracksections was completed lastDecember. The performance ofthe test sections after 2-year, 10million ESALs loading was re-ported in the May/June issueof the ISAP Reporter.

Construction of the new testsections for second cycle ofloading began in May this year.

(continued on page 10)

8 THE ISAP REPORTER

UPCOMING EVENTSPlease inform Dr. Eugene Skok, Jr., Executive Administrator of the ISAP office, at

<secretary@asphalt.org> of any upcoming events so that we can include them in the calendar.

DATE EVENT LOCATION CONTACT

Dec. 2-4, 2003 Asphalt Rubber 2003Conference

Brasilia, Brazil <www.consulpav.com>

Jan. 11-15, 2004 83rd Annual Meetingof TransportationResearch Board

Washington, DC,USA

<www.trb.org>

Jan. 16-22, 2004 49th Annual Conven-tion of NationalAsphalt PavementAssociation

Phoenix, Arizona,USA

<www.hotmix.org>

Jan. 21-24, 2004 National PavementExpo

Nashville,Tennessee, USA

<www.pavementonline.com>

Feb. 8-10, 2004 5th Annual Meeting ofthe Association of Modi-fied Asphalt Producers

Nashville, Tennessee,USA

email: <amap@sbcglobal.net>

Feb. 25-28, 2004 Annual Meeting ofthe InternationalSlurry Surfacing Asso-ciation

San Diego,California, USA

<www.slurry.org>

Mar. 8-10, 2004 Annual Meeting of theAssociation of AsphaltPaving Technologists

Baton Rouge,Louisiana, USA

<www.asphalttechnology.org>

Mar. 14-18, 2004 8th International Sym-posium on Heavy Ve-hicle Weights and Di-mensions

Gauteng,South Africa

<www.8ishvwd.co.za>

Mar. 14-18, 2004 Second Gulf Confer-ence on Roads

Abu Dhabi, UnitedArab Empirates

<www.gulfroad2004.ae>

Mar. 15-18, 2004 World of Asphalt 2004Show and Conference

Nashville,Tennessee, USA

<www.worldofasphalt.com>

May 5-8, 2004 5th Rilem Interna-tional Conference(Cracking in Pave-ments)

Limoges, France

May 12-14, 2004 3rd Eurasphalt &Eurobitume Con-gress—“Forum forPractical Solutions”

Vienna, Austria

June 6-10, 2004 5th International Sym-posium on PavementSurface Characteris-tics (PIARC)

Toronto, Canada email: <surf2004@jegel.com>

http://www.cp2004.unilim.fr

cp2004@unilim.fr

http://www.eecongress.org�

9INTERNATIONAL SOCIETYfor ASPHALT PAVEMENTS

June 7-9, 2004 International Confer-ence: Design andConstruction of LongLasting AsphaltPavements

Auburn, Alabama,USAISAP

<http://www.asphalt.org>

Sep. 12-16,2004

CAPSA: 8th Confer-ence of AsphaltPavements for South-ern Africa

Sun City, SouthAfrica

<http://www.sabita.co.za>

Sep. 25-29, 2004 Second InternationalConference on Accel-erated PavementTesting

Minneapolis,Minnesota, USA

<www.cce.umn.edu/engineering/accelerated_pavement>

Oct. 19-24, 2004 6th InternationalConference on Man-aging Pavements

Brisbane, Australia <http://www.icmp6.com>

Jan. 9-13, 2005 84th Annual Meetingof TransportationResearch Board

Washington, D.C.,USA

<http://www.trb.org>

June 16-20,2005

International RoadFederation, 15thWorld Meeting

Bangkok, Thailand email: <irf2005@bkkrai.com>

June 27-29,2005

7th InternationalConference on Bear-ing Capacity ofRoads, Railway, andAirfields

Trondheim, Norway <http://www.ntnu.no/forskning/konfover>

Jan. 22-26,2006

85th Annual Meetingof TransportationResearch Board

Washington, D.C.,USA

<http://www.trb.org>

March 2006 Annual Meeting ofthe Association ofAsphalt Paving Tech-nologists

Savannah,Georgia, USA

<www.asphalttechnology.org>

July 6-7, 2004 European AsphaltTechnology Associa-tion (Inaugural Meet-ing)

Nottingham, U.K. email:<marzena.newton@nottingham.ac.uk>

Oct. 28-31, 2004 3rd International Sym-posium on AsphaltEmulsion Technology

Washington, DC,USA email: <krissoff@aema.org>

March 7-9,2005

Annual Meeting ofthe Association ofAsphalt PavingTechnologists

Long Beach,California, USA

<www.asphalttechnology.org>

Aug. 12-17,2006

10th InternationalConference on As-phalt Pavements(ISAP)

Quebec, Canada <http://www.ICAP2006.fsq.ulaval.ca>

10 THE ISAP REPORTER

—NCAT Track(continued from page 7)

Hot mix asphalt (HMA) wasproduced and placed in Julyand August. All constructionactivities were completed bymid-September.

As shown in the layout plan,the second-cycle test sectionscan be categorized as follows:• New eight structural sections

N1 through N8 (shown inblue)

• Milling and inlaying of 14 testsections with different HMAmixes for rutting evaluation(shown in red)

• Leaving 24 first-cycle test sections in place to apply additional 10 million ESALs overthe next two years (shown inblack)

Structural Test SectionsEight first-cycle test sections

(N1 through N8) were milledvery deep and reconstructed tofacilitate a small, instrumentedAASHO-like structural experi-ment. As illustrated in the cross-section of the new structuraltest sections, the two primaryvariables are as follows:• Varying HMA thickness.

Three total HMA thicknessesof 5, 7, and 9 inches (127, 178,and 229 mm) have beenplaced over 6 inches (152mm) of dense crushed aggregate base.

• Asphalt binder type (unmodified versus polymer-modified). Most highway agenciesassign the same structural coefficient to all dense-gradedHMA regardless of asphaltbinder type. Many laboratorystudies have shown polymer-modified HMA is strongerand has longer fatigue lifecompared to conventionalHMA. However, this is probably the first time such comparison will be evaluated in

a full-scale field experiment.

The structural test sectionsalso involve two other variables.Stone matrix asphalt is thewearing course in two test sec-tions (N7 and N8), whereasSuperpave mix (gradation abovethe restricted zone or ARZ) hasbeen used as the wearingcourse in the other six test sec-tions. One test section (N8) hasa rich HMA base course with abinder content of optimum plus0.5 percent. The rich basecourse has a potential of mini-mizing the propagation of fa-tigue cracks from the bottomupwards.

All structural test sectionsare fully instrumented to mea-sure stress, strain, moisture, andtemperature.

Milled and Inlaid Test SectionsFourteen first-cycle test sec-

tions were milled and inlaidwith new binder and/or wear-ing course mixtures to evalu-ate their resistance to ruttingand/or overall performance. Thefollowing mix attributes will beevaluated:• Superpave and stone matrix

asphalt (SMA) mixescontaining aggregate with

NCAT Test Track layout showing second-cycle test sections

high Los Angeles abrasionloss.

• SMA mixes with varying aggregate quality: does notmeet specifications; borderline; and exceeds the specification requirements.

• Fine Superpave mix (4.75 mmnominal maximum aggregatesize) for low-volume roads.

• Superpave mix with Ndesign

=75 gyrations (the same mixwith Ndesign = 125 gyrationshad negligible rutting in thefirst cycle).

• Thin Superpave mix overlayversus Novachip overlay(both are 25 mm thick andcontain the same aggregate).

• Superpave mix containingPG 67 and PG 76 asphaltbinders.

Test Sections for AdditionalTrafficking

As mentioned in the last is-sue of the ISAP Reporter, mostfirst-cycle test sections had neg-ligible rutting after 2 year, 10million ESALs loading. Somestate DOTs have decided to keeptheir test sections in place foradditional trafficking of 10 mil-lion ESALs. The test sections,which perform well after 20

11INTERNATIONAL SOCIETYfor ASPHALT PAVEMENTS

(continued on page 12)

(continued from page 5)—News from North America

million ESALs loading, will bedeemed suitable for very hightraffic, interstate highway pave-ments. The additional traffick-ing may also better discern per-formance differences amongdifferent mix types (such asSuperpave versus SMA) com-pared to the first cycle.

Test sections for the secondcycle of loading have been spon-sored by the Federal HighwayAdministration and ten states:Alabama, Florida, Georgia, In-diana, Mississippi, Missouri,

porate mechanistic principles,because mechanistic-empiricalapproaches realistically charac-terize the behavior of in-servicepavements and improve the re-liability of designs.

In 1998, the National Coop-erative Highway Research Pro-gram (NCHRP) initiated Project1-37A to provide the highwaycommunity with a guide for thedesign of new and rehabilitatedpavement structures that as-sembles the best knowledge onpavement design into a single,cohesive package of writtenguidance and software. Nearingcompletion, the guide incorpo-rates proven technologies toaccount for the changes in cli-mate, traffic loading, and mate-rial properties during pavementlife.

The Guide for Design of Newand Rehabilitated PavementStructures and the accompany-ing computational software arescheduled for delivery toAASHTO for consideration andadoption this fall.

Cross-section of eight structural test sections

Reconstruction in progress for installing eight structural test sections

North Carolina, Oklahoma,South Carolina, and Tennessee.

Trafficking of the second-cycle test sections will begin inOctober and will continue un-til 10 million ESALs are appliedin about two years (by October2005). Detailed design and con-struction details can be seen atthe test track web site, <http://www.pavetrack.com/>. Perfor-mance data will continually beposted on this web site as it isgathered from time to time.

RESEARCH ONLOW-TEMPERATUREASPHALTPERFORMANCEIN CANADA

The Ontario Ministry ofTransportation (MTO) has un-dertaken an important researchproject on asphalt performancein cold weather. Superpavespecification system does a rea-sonable job of predicting thelow-temperature performance ofconventional asphalt cement.However, it is not true for poly-mer-modified, chemically-modi-fied, gelled or “engineered” as-phalt binders.

12 THE ISAP REPORTER

Inte

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4711

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WORLD OFASPHALT� SHOWAND CONFERENCE

The 2004 World of Asphalt�Show and Conference will beheld in Nashville, Tennessee,USA on Monday through Thurs-day, March 15-18, 2004. The As-phalt Pavement Alliance spon-sored asphalt pavement confer-ence: 21st Centruy Constructionwill kick off the week’s eventswith two full days of practitio-ner-oriented technical sessionson March 15-16. The World ofAsphalt exhibits will be openTuesday through Thursday,March 16-18. Concluding the ac-tivities will be an open houseat a quarry and asphalt planton the afternoon of Thursday,March 18.

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Researchers evaluating Highway 118 for low-temperature asphalt performance

Preliminary results from re-search performed by Queen’sUniversity in 2001, on Highway118 experimental sections (con-structed in 1994) nearBracebridge, Ontario, have con-firmed that the Superpave grad-ing system is inadequate forpredicting low-temperature as-phalt performance since someof the test sections have threetimes the cracking of other sec-tions that are supposedly of thesame grade of asphalt.

Queen’s University has devel-oped a new test method which

measures the energy that cracksthe pavement. This method isable to correctly predict the dif-ferences in performance of thevarious experimental test sec-tions placed on Highway 118.

A field experiment is beingorganized to test and validatethe newly developed methodand the preliminary findings ofthis research project. The firstfield monitoring test results areexpected to be available by thesummer of 2004. (Road Talk,February 2003).

The People, Plants, and Pav-ing Training Program will againbe a key educational componentof the event in 2004, similar tothe 2003 World of Asphalt�Show and Conference, whichwas an outstanding success.

The World of Asphalt� Showand Conference is a unique edu-cational event for the asphaltindustry and for their public-sector customers in the DOTs,cities, counties, etc. It is anumbrella event that includes theAsphalt Pavement Conference;the People, Plants, and PavingTraining Program; a Live Pav-ing Demonstration/Open House,and the World of Asphalt TradeShow.