TRB Expert Task Group for Superpave Mixtures and Aggregates - Update

TRB Expert Task Group for Superpave Mixtures and Aggregates - Update

Jim MusselmanFlorida Department of Transportation

Role of the ETGRole of the ETG! Provide technical advice to the TRB Superpave

Committee on mixture and aggregate issues;! Provide technical input on FHWA Superpave mixture

and aggregate projects;! Identify potential improvements to mixture and

aggregate specifications/test methods;! Identify needed standards; and! Provide a forum for government/industry discussion of

emerging issues

State MembersState Members! Jimmy Brumfield Mississippi DOT! Lon Ingram Kansas DOT! Eric Harm Illinois DOT! Rick Harvey Wyoming DOT! Judie Ryan Wisconsin DOT! Wade McClay Maine DOT! Karl Frick California DOT! Jim Musselman Florida DOT! Julie Nodes Arizona DOT (Rubber-R-Us)

Industry MembersIndustry Members! Erv Dukatz Mathy Construction Co.! Frank Fee Citgo Asphalt Co.! Jay Winford Louisiana Roads and Bridges! Gerry Huber Heritage Research Group! Todd Lynn APAC, Inc.! Adam Hand Granite Construction! Chuck Marek Vulcan Materials Co.! Ron Sines P. J. Keating Co.

Members (cont’d)Members (cont’d)! Kevin Hall University of Arkansas! Richard Kim North Carolina State University! Mike Anderson Asphalt Institute! John Bukowski FHWA

Tom Harman! Dave Newcomb NAPA

Current ActivitiesCurrent Activities!AASHTO Subcommittee on Materials Issues!Superpave Gyratory Compactor!QC/QA Proposed Standard Practice!Aggregate Issues!Simple Performance Test

Subcommittee on MaterialsSubcommittee on Materials! Changes to MP-2, PP28

Elimination of the Restricted ZoneNew 4.75 mm mixChanges well-received through Technical Section

– Forwarded on to Full Ballot ! Changes to T312

Addition of Dynamic Angle Validation option– Negative comments relating to “required” manufacturer maintenance– Change to “recommended” manufacturer maintenance

Forwarded on to Full Ballot & Approved! New Dynamic Angle Validation procedure

Balloted and Approved

Subcommittee on MaterialsSubcommittee on Materials! Provisional Standards

TP7 Superpave Shear TesterTP8 Beam FatigueTP9 Indirect Tensile Test

! Recently balloted and approved as full standards! Task Team will review and identify necessary changes

Led by Richard Kim (NC State)! Dynamic modulus test procedure balloted and approved as a

provisional standard! APA test procedure balloted and approved as a provisional

standard Needs work….

Superpave Gyratory CompactorSuperpave Gyratory Compactor! Dynamic Angle Validation Task Force

Studies indicate internal angle of 1.16°± 0.02° can reduce bias among compactors

– Not a “cure-all”Working on the development of a Guidance Statement on the use of the DAVRuggedness Evaluation

– Currently on-goingDevelopment of Precision/Bias statement

– Future….

DAV Ruggedness StudyDAV Ruggedness Study

TroxlerTroxler Electronics, Inc.Electronics, Inc.

Mixture stiffnessMixture stiffnessAsphalt InstituteAsphalt InstituteTroxlerTroxler 41414141NCATNCAT

Sample/provide mixesSample/provide mixesAPAC Material ServicesAPAC Material Services

Pine G1Pine G1Pine Instruments, Inc.Pine Instruments, Inc.TroxlerTroxler 4140 B4140 BFlorida DOTFlorida DOTBrovoldBrovoldFHWAFHWA

Pine AFGC125XPine AFGC125XTroxlerTroxler 4140 A4140 A

Univ. of ArkansasUniv. of Arkansas

SGC Model / SGC Model / ResponsibilityResponsibility

Participating LaboratoryParticipating Laboratory

Superpave Gyratory CompactorSuperpave Gyratory Compactor!Mold Wear

Identified by NCAT during Alabama DOT DAV study– Internal angle was properly calibrated– Noted variations in air voids

Source of problem found to be excessive mold wearMold diameter typically checked at top and bottom

– Not in area of wearPossible solutions identified

QC/QA Proposed Standard PracticeQC/QA Proposed Standard Practice!Based on NCHRP 9-7 work!Developed by:

Gerry Huber (Heritage) Lee Gallivan (FHWA Indiana Division)

!ETG reviewed and provided comments to QC/QA Task Team

Will be finalized at this meeting

Fine Aggregate AngularityFine Aggregate Angularity! Discussed original SHRP data on FAA

Is criteria set at appropriate level?Are 100% crushed materials unnecessarily excluded?Some states not using FAAShould 100% crushed materials be exempt?

! Compacted Aggregate Resistance (CAR) TestPossible solution?

! Task Team to look into issue furtherLed by Chuck Marek (Vulcan Materials)

Compacted Aggregate Resistance (CAR) Test

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34

Penetration (.01 in)

She

ar R

esis

tanc

e (lb

s)

Slag (47.0)

Indiana DOT Fine Aggregate Angularity Study

St. Sand(45.1)Cr.Gr.(49.0)

St. Sand(47.2)

St. Sand(44.2)

Dolomite(48.1)

Natural Sand(38.7)

Natural Sand(39.6)

Simple Performance TestSimple Performance Test! NCHRP 9-19

Recommended three test procedures– Dynamic Modulus– Creep Test (Flow Time)– Repeated Load Permanent Deformation Test (Flow Number)

! NCHRP 9-29Developing equipment specificationsFirst article procurement

– Simple Performance test ($25k - $45k)– Automated specimen fabrication system ($12k)

Equipment evaluation – early 2003

Thank You!Thank You!