Appendices A. List of Interviewees B. Committee and ETG Rosters C. Photographs D. History of Asphalt Mix Design E. Transcript of Reno Conference (electronic only)

Appendix A. List of Interviewees

Interviewee Affiliation (relative to this project) Mike Acott National Asphalt Pavement Association Dave Anderson Pennsylvania State University, A-002A Doug Bernard FHWA Ray Brown National Center for Asphalt Technology John Bukowski FHWA Dean Carlson FHWA Don Christensen Pennsylvania State University, A-002A Charlie Churilla FHWA Ron Cominsky University of Texas at Austin, A-001 John Conrad Washington State DOT, AASHTO Christine Curtis Auburn University, A-003B John D’Angelo FHWA Dale Decker National Asphalt Pavement Association Tom Deen FHWA Erv Dukatz Delphi Group Jon Epps University of Nevada – Reno, Superpave Center Frank Fee Binder industry, ETGs Fred Finn University of California –Berkeley, A-003A Frank Francois AASHTO Adam Hand University of Nevada – Reno, Superpave Center Doug Hanson National Center for Asphalt Technology Tom Harman FHWA Ed Harrigan SHRP Office Kathryn Harrington-Hughes SHRP Office, Communications Don Harriott SHRP Office Neil Hawks SHRP Office Gary Hicks Oregon State University Chuck Hughes University of Texas at Austin, A-006/ A-001 Wyn Jennings Montana State University, A-002C David Jones A-001 Tom Kennedy University of Texas at Austin, A-001 Gayle King Binder industry, ETGs Damian Kulash SHRP Office Don Lucas Indiana Department of Transportation, AASHTO Bob Lytton Texas A&M, A-005 Paul Mack New York State DOT, Superpave Lead State Team Chuck Marek Aggregate industry Dick McComb FHWA, Loaned Staff Bob McGennis Asphalt Institute, South Central Superpave Center Larry Michael Maryland State Highway Administration, AASHTO Carl Monismith University of California –Berkeley, A-003A Dave Newcomb National Asphalt Pavement Association Gale Page Florida DOT, AASHTO, Advisory Committee Charlie Potts HMA industry Roger Pyle Pine Instrument

Ron Reese CalTrans Ray Robertson Western Research Institute, A-002A Rey Roque Pennsylvania State University, A-005 Dave Rowlett Southwestern Laboratories, A-004 Margie Sheriff SHRP Office Scott Shuler Asphalt Institute, A-001 Ron Sines New York State DOT Haleem Tahir AASHTO Bob Templeton Texas DOT, AASHTO Jack Weigel Asphalt Industry, SPS-9A Sarah Wells C-SHRP Greg Williams C-SHRP Matt Witczak University of Maryland, Brown Book, A-001 Jack Youtcheff SHRP Office

Appendix B. Committee and ETG Rosters Executive Committee (SHRP-A-357 1993) John R. Tabb, Chairman Mississippi Department of Transportation William G. Agnew General Motors Research (retired) E. Dean Carlson, ex officio Federal Highway Administration A. Ray Chamberlain Colorado Department of Transportation Michael J. Cuddy New York Department of Transportation Raymond F. Decker University Science Partners, Inc. Thomas B. Deen, ex officio Transportation Research Board Thomas M. Downs New Jersey Department of Transportation Horace B. Edwards Kansas Department of Transportation Tom Espy, Jr. Alabama Highway Department Francis B. Francois, ex officio American Association of State Highway and Transportation

Officials Donald N. Geoffroy New York Department of Transportation William L. Giles Ruan Transportation Management Systems Harvey Haack Pennsylvania Department of Transportation Jack S. Hodge Virginia Department of Transportation Boris Hryhorczuk, ex officio Manitoba Department of Transportation Lester P. Lamm Highway Users Federation for Safety and Mobility Thomas D. Larson Federal Highway Administration Donald W. Lucas Indiana Department of Transportation John D. Mackenzie University of California at Los Angeles Harold L. Michael Purdue University Wayne Muri Missouri Highway and Transportation Dept M. Lee Powell, III Ballenger Paving Company, Inc. Rodney E. Slater, ex officio Federal Highway Administration Henry Thomason, Jr. Texas Department of Transportation Stanley Warshaw National Institute of Standards and Testing Roger L. Yarbrough Apcon Corp

1986 Asphalt Advisory Committee (as listed in SHRP Research Plans) William H. Goetz, Chairman Purdue University (retired) Don M. Harriott, Vice Chairman Montana Department of Highways David A. Anderson The Pennsylvania State University Ernest J. Barenberg University of Illinois Herbert W. Busching Clemson University Ronald J. Cominsky Pennsylvania Department of Transportation Clara D. Craver Chemir Laboratories Campbell Crawford National Asphalt Pavement Association Joseph E. Crowe Illinois Department of Transportation James V. Evans Amoco Oil Company William G. Gunderman Transportation Research Board Kenneth A. Gutschick National Lime Association Douglas I. Hanson New Mexico State Highway Department Richard E. Hay Federal Highway Administration Charles L. Huisman Iowa Department of Transportation P. W. Jennings Montana States University William J. Kari Consultant Glenn R. Kemp California Department of Transportation K. C. Kresge Mobil Research and Development Corporation Richard Langlois Universite Laval Phillip E. McIntyre New Hampshire Department of Transportation Robert B. McKeagney Vulcan Materials Company Roderick W. Monroe Iowa Department of Transportation Harold W. Muncy Bituminous Materials Co., Inc. Gale Page Florida Department of Transportation George E. Paul City of Albuquerque R. D. Pavlovich New Mexico Engineering Research Institute V. P. Puzinauskas The Asphalt Institute Tom Stapler Georgia Department of Transportation Garland W. Steele West Virginia Department of Transportation Donald O. Swing Nebraska Department of Roads J. D. Telford Oklahoma Department of Transportation Robert G. Warburton Wyoming State Highway Department James E. Wilson Oregon Department of Transportation

1993 Asphalt Advisory Committee (as listed in SHRP-A-357) Thomas D. Moreland, Chairman Moreland Altobelli Associates, Inc. Gale C. Page, vice chairman Florida Department of Transportation Peter A. Bellin Niedersachsisches Landesamt fűr strassenbau Dr. J. Don Brock ASTEC Industries, Inc. Mr. Campbell Crawford National Asphalt Pavement Association Dale Decker National Asphalt Pavement Association Joseph L. Goodrich Chevron Research Company Eric Harm Illinois Department of Transportation Mr. Roy S. Hodgson CONOCO Inc. Charles Hughes Virginia Highway & Transportation Research Council Robert G. Jenkins University of Cincinnati Dr. Rudolph A. Jimenez University of Arizona Anthony J. Kriech Heritage Group Company Richard Langlois Universite Laval Richard C. Meininger National Aggregates Association Nicholas Nahas EXXON Chemical Co. Charles F. Potts APAC, Inc. Ron Reese California Department of Transportation Dr. Asko Saarela Technical Research Centre of Finland Donald E. Shaw Georgia-Pacific Corporation Scott Shuler The Asphalt Institute Harold E. Smith City of Des Moines Thomas J. Snyder Marathon Oil Company Richard H. Sullivan Minnesota Department of Transportation A. Haleem Tahir AASHTO Jack Telford Oklahoma Department of Transportation George West Shell Oil Company Avery D. Adcock, Liaison United States Air Force Ted Ferragut, Liaison Federal Highway Administration Donald G. Fohs, Liaison Federal Highway Administration Edward T. Harrigan, Liaison SHRP Program Manager Frederick D. Hejl, Liaison Transportation Research Board Capt. Charles Manzione, Liaison Department of Defense Aston McLaughlin, Liaison Federal Aviation Administration Bill Weseman, Liaison Federal Highway Administration

A-001 Expert Task Group (SHRP-A-410, July 1994) Research Team: Thomas W. Kennedy, Gerald A. Huber, Edward T. Harrigan, Ronald J. Cominsky, Charles S. Hughes, Harold Von Quintus, James S. Moulthrop Dallas Little, chair Texas Transportation Institute Campbell Crawford National Asphalt Pavement Association Daniel W. Dearasaugh Transportation Research Board Francis Fee Westbank Oil, Inc. Eric Harm Illinois Department of Transportation Charles Hughes Virginia Highway and Transportation Research Council Kevin Stuart Federal Highway Administration Roger L. Yarbrough Apcon Corporation A-002A Expert Task Group (SHRP-A-367, 1994) Research Team: J. Claine Petersen, R. E. Robertson, J. F. Branthaver, P. M. Harnsberger, J. J, Duvall, S. S. Kim, WRI; D. A. Anderson, D. W. Christiansen, H. U. Bahia, Pennsylvania Transportation Institute Ernest Bastian, Jr. Federal Highway Administration Wayne Brule New York State Department of Transportation Joseph L. Goodrich Chevron Research Company Woody Halstead Consultant Gayle King Bituminous Materials Co., Inc. Robert F. LaForce Colorado Department of Transportation Mark Plummer Marathon Oil Company Raymond Pavlovich Exxon Chemical Company Ron Reese California Department of Transportation Scott Shuler Colorado Paving Association

A-002C Expert Task Group Research Teams: M.A. Desando, P.W. Jennings, J.A. Pribanic, M.F. Raub; Montana State University (SHRP-A-335 1993) B. Fanconi, W.F. Manders, D.L. VanderHart; National Institute of Standards and Technology (SHRP-A-335 1993) Ernest Bastian, Jr. Federal Highway Administration Wayne Brule New York State Department of Transportation David Esch Alaska Department of Transportation Joseph L. Goodrich Chevron Research Company Woody Halstead Consultant, Virginia Highway & Transportation Research Council Gayle King Bituminous Materials Company Robert F. LaForce Colorado Department of Transportation Mark Plummer Marathon Oil Company Ron Reese California Department of Transportation Scott Shuler Colorado Paving Association A-003A Expert Task Group Research Teams: Chris A. Bell, Alan J. Weider, Marco J. Fellin; Oregon State University (SHRP-A-390 1994) Wendy L. Allen and Ronald L. Terrell, Oregon State University (SHRP-A-396 1994) Carl Monismith, University of California Berkley (SHRP-A-404 1994) Jorge B. Sousa, Joseph Craus and Carl L. Monismith. SHRP-A/IR-91-104 Dallas Little, chairman Texas Transportation Institute Earnest G. Bastian FHWA Campbell Crawford NAPA Daniel W. Dearasaugh Transportation Research Board Francis Fee Westbank Oil, Incorporated/ELF Asphalt Douglas I. Hanson New Mexico State Highway Department Eric Harm Illinois DOT Chuck Hughes VTRC Kevin Stuart FHWA Roger L. Yarbrough Apcon Corporation

A-003B (Fundamental Properties of Asphalt-Aggregate Interactions Including Adhesion and Absorption, SHRP-A-341 1993) Research Teams: Christine W Curtis; NCAT/Auburn University (SHRP-A-341 1993) Keith Ensley; Western Research Institute (SHRP-A-341 1993) Jon Epps; University of Nevada at Reno (SHRP-A-341 1993) Ernest Bastian, Jr. Federal Highway Administration Ervin Dukatz Vulcan Materials Jack Dybalski AKZO Chemical Incorporated Joseph L. Goodrich Chevron Research Company A-005 Expert Task Group Research Teams: Emmanuel G. Fernando, Robert L. Lytton, Jacob Uzan; Texas A&M University (SHRP-A-357 1993) Dennis Hiltunen, Reynaldo Roque, Shelley M. Stoffels; Pennsylvania State University (SHRP-A-357 1993) Dave Allen University of Kentucky Daniel W. Dearesaugh, Jr. Transportation Research Board Ervin Dukatz Vulcan Materials Charles Manzione United States Air Force Bill Maupin, Jr. Virginia Transportation Research Council Richard May The Asphalt Institute Roy McQueen Rajan-McQueen and Associates James A. Sherwood Federal Highway Administration George Way Arizona Department of Transportation

Participants in the SHRP Midcourse Meeting Denver, Colorado, August 1-3, 1990 Francis B. Francois American Association of State Highway Transportation Officials Charles F. Potts APAC Inc. Fred N Finn ARE Inc. Stanley R. Armstrong Alabama Highway Department William E. Page Alabama Highway Department David C. Esch Alaska Department of Transportation Tom Christison Alberta Research Council, Canada J. Z. Konarzewski Alberta Transportation and Utilities M. J. Knutson American Concrete Pavement Association Stan Lallue American Concrete Pavement Association Richard A. Lill American Trucking Association, Inc. John L. Reith American Trucking Association, Inc . Roger L. Yarbrough APCON Corporation Mark Anderson Applied Research Associates Frank R. McCullagh Arizona Department of Transportation Gary Robinson Arizona Department of Transportation George Way Arizona Department of Transportation Larry A. Scofield Arizona Transportation and Research Center Robert Walters Arkansas Highway and Transportation Departments Richard W. May The Asphalt Institute V. P. Puzinauskas The Asphalt Institute T. Scott Shuler The Asphalt Institute Eberhard Knoll Association for Research on Road Traffic, West Germany Feddy Roberts Auburn University John Oliver Australian Road Research Board Barbara T. Harder B.T. Harder, Inc. Gerald O. Davis Battelle Columbus Division Dirk Gorle Belgian Road Research Centre, Belgium Eugene L. Skok Braun Pavement Technologies Gary L. Fitts Brent Rauhut Engineering, Inc. Peter R. Jordahl Brent Rauhut Engineering, Inc. Brent Rauhut Brent Rauhut Engineering, Inc. Harold L. Von Quintus Brent Rauhut Engineering, Inc. Peter P. Canisius Bundesanstalt Fur Strassenesen, West Twiab Khan C-SHRP Roy S. Hodgson Conoco Inc. Abdulshafi Abdulshafi CTI, International, Inc. Osama Abdulshafi CTI, International, Inc. Leon Talbert CTI, International, Inc. John Apostolos California Department of Transportation Paul E. Benson California Department of Transportation E.B. Delano California Department of Transportation Richard B. Howell California Department of Transportation Ron Reese California Department of Transportation James E. Roberts California Department of Transportation James Woodstrom California Department of Transportation Michael J. Markow Cambridge Systematics, Inc. Art Greengard Chen-Northern, Inc. Joseph L. Goodrich Chevron Research Company Harold E. Smith City of Des Moines

David Gress Civil Engineering Department Richard L. Berg Cold Regions Research Engineering Laboratory-USA Vincent Janoo Cold Regions Research Engineering Laboratory-USA Gordon Bell Colorado Department of Highways A. Ray Chamberlain Colorado Department of Highways Robert I. Clevenger Colorado Department of Highways Steve Horton Colorado Department of Highways John R. Kiljan Colorado Department of Highways Audrey Meer Colorado Department of Highways Leo O’Connor Colorado Department of Highways Sharon B. Schuler Colorado Department of Highways Douglas I. Shaffer Colorado Department of Highways G. “Bill” Vidal Colorado Department of Highways Charles E. Dougan Connecticut Department of Transportation Paul Okamoto Construction Technology Laboratories, Inc. David Stark Construction Technology Laboratories, Inc. Paul Klieger Consultant – Concrete and Concrete Materials Stan Peters Cooley Gravel Co. Lynne H. Irwin Cornell University Thomas N. Gardner Corning, Inc. Hans Jorgen Ertman Larsen Danish Road Institute Dale M. Nesbitt Decision Focus, Inc. Kermit Justice Delaware Department of Transportation David Mills Delaware Department of Transportation Henry W. Kirchner Dow Chemical Richard N. Stubstad Dynatest Consulting, Inc. John (Jack) Bennett Eltech Research Corporation Patrick Boyd Ensco, Inc. Ramesh K. Kher Eres Consultants, Inc. Immanuel Owusu-Aniw Eres Consultants David Peshkin Eres Consultants Deiter Hanig Esso AG, West Germany Jim Heaton Edgington Oil Co. Francis Fee Elf Asphalt Gayle N. King Elf Asphalt Kenneth R. Wardlaw Exxon Chemical Co. Harald Augustin Federal Institute for Testing and Research, Austria Hubert Tiefenbacher Federal Ministry for Economic Affairs, Austria Aston L. McLaughlin Federal Aviation Administration Harry Siedentopf Federal Aviation Administration Ernest J. Bastian, Jr. Federal Highway Administration Robert J. Betsold Federal Highway Administration Doyt Y. Bolling Federal Highway Administration F. Dean Carlson Federal Highway Administration Charles J. Churilla Federal Highway Administration William C. Evans Federal Highway Administration Stephen W. Forster Federal Highway Administration Perry Kent Federal Highway Administration Roger M. Larson Federal Highway Administration Byron N. Lord Federal Highway Administration Richard A. McComb Federal Highway Administration Wesley S. Mendenhall, Jr. Federal Highway Administration Thomas J. Pasko, Jr. Federal Highway Administration

Jim Sorenson Federal Highway Administration Kevin D. Stuart Federal Highway Administration Paul Teng Federal Highway Administration Yash Paul Virmani Federal Highway Administration John F. Christenson, Jr. Florida Concrete Products Association Richard J. Kessler Florida Department of Transportation William N. Lofroos Florida Department of Transportation William G. Miley Florida Department of Transportation Gale C. Page Florida Department of Transportation A. F. Quilio, Jr. Florida Department of Transportation Lawrence I. Smith Florida Department of Transportation H. Eugene Cowger Florida Lime Rock and Aggregate Institute Ronald Collins Georgia Department of Transportation Richard Barksdale Georgia Tech Donald E. Shaw Georgia-Pacific Corporation Jerry L. Graham Graham-Migletz Enterprises, Inc. Walter A. Kuroiwa Hawaii Department of Transportation Martin Deinhard Hessian Highway Authority, West Germany Lester P. Lamm Highway Users Federation R. Bruce MacEwan Idaho Department of Transportation Clayton Sullivan Idaho Department of Transportation John Ebers Illinois Department of Transportation Eric Harm Illinois Department of Transportation Joseph S. Hill Illinois Department of Transportation John R. Olds Illinois Department of Transportation Donald W. Lucas Indiana Department of Transportation Kenneth R. Maser Infrasense, Inc. Jerry Bergen Iowa Department of Transportation Brian McWaters Iowa Department of Transportation Wallace Rippie Iowa Department of Transportation Leland Smithson Iowa Department of Transportation Michael S. Janoff JMJ Research Arien T. Swenson John Deere National Sales Division Jack Tinnea John S. Tinnea and Associates Lonnie S. Ingram Kansas Department of Transportation Dennis R. Slimmer Kansas Department of Transportation Dean M. Testa Kansas Department of Transportation Ronald I. Rizenbergs Kentucky Department of Highways William R. Monhollon Kentucky Transportation Cabinet Ed J. Breckwoldt Louisiana Department of Transportation and Development Steve I. Cumbaa Louisiana Transportation and Research Center Boris Hryhorezuk Manitoba Department of Transportation Canada Ray Van Cauwenberghe Manitoba Department of Transportation Canada Mark A. Plummer Marathon Oil Company A. Haleem Tahir Maryland State Highway Administration Phillip A. Hughes Massachusetts Department of Public Works Henry E. Haxo, Jr. Matrecon, Inc. S. Edward Boselly, III Matrix Management Group Douglas Jonas Matrix Management Group Charles J. Arnold Michigan Department of Transportation William J. MacCreery Michigan Department of Transportation Donald E. Orne Michigan Department of Transportation Robert A. Welke Michigan Department of Transportation

Gilbert Baladi Michigan State University Mark B. Snyder Michigan State University Albert F. Wuori Michigan Technological University Robert R. Blackburn Midwest Research Institute Cecil C. Chappelow Midwest Research Institute Paul A. Brochu Ministere Des Transports de Quebec Richard Langlois Ministere Des Transports de Quebec Jeanne Pierre Leroux Ministere Des Transports de Quebec Rodney A Pletan Minnesota Department of Transportation Richard Sullivan Minnesota Department of Transportation Alfred B. Crawley Mississippi State Highway Department James W. Lyon, Jr. Mississippi State Highway Department James D. Quin Mississippi State Highway Department John R. Tabb Mississippi State Highway Department Thomas S Borgmeyer Missouri Highway and Transportation Kenneth E. Fryer Missouri Highway and Transportation Robert J. Girard Missouri Highway and Transportation Bruce Loesch Missouri Highway and Transportation Gerald M. Miner Missouri Highway and Transportation Kenneth H. Neumiller Montana Department of Highways P. W. Jennings Montana State University Thomas D. Moreland Moreland, Altobelli, and Associates, Inc. Joe Proctor Morton International Philip M. Smith National Academy of Science/National Research Council Christine W. Curtis National Center for Asphalt Technology at Auburn University Geoffrey J. Frohnsdorff National Institute of Standards and Technology

Richard D. Gaynor National Aggregates Association, National Ready Mixed Concrete Association

Richard C. Meininger National Aggregates Association, National Ready Mixed Concrete Association

Campbell Crawford National Asphalt Pavement Association Richard D. Morgan National Asphalt Pavement Association

David Small National Oceanic and Atmospheric Administration-Forecast Systems Laboratory

Charles A. Pryor National Stone Association Thomas A. Wais Nebraska Department of Roads George Woodstrum Nebraska Department of Roads Jim Dodson Nevada Department of Transportation Richard J. Nelson, P.E. Nevada Department of Transportation Keith E. Hicks New Brunswick Department of Transportation Canada Dorothy L. Andres New Jersey Department of Transportation Richard M. Balgowan New Jersey Department of Transportation Farhad Ansari New Jersey Institute of Technology David Albright New Mexico Department of Transportation George P. Baca New Mexico Department of Transportation David Belling New Mexico Department of Transportation James H. Stokes New Mexico Department of Transportation Duane E. Amsler New York State Department of Transportation Donald N. Geoffroy New York State Department of Transportation James J. Murphy New York State Department of Transportation Robert J. Perry New York State Department of Transportation Arun M. Shirole New York State Department of Transportation Raymond G. MacKay, Jr. New York State Thruway Authority James E. Nichols Nichols Consulting Engineers CHTD

Paul Zia North Carolina State University Ron Homer North Dakota Department of Transportation A. E. King Nova Scotia Department of Transportation, Canada William F. Edwards Ohio Department of Transportation C. Dwight Hixon Oklahoma Department of Transportation David A. Ooten Oklahoma Department of Transportation Ataur Bacchus Ontario Ministry of Transportation, Canada Graham J. F. Jones Ontario Ministry of Transportation, Canada Alex Kazakov Ontario Ministry of Transportation, Canada Magda M. Majesky Ontario Ministry of Transportation, Canada David G. Manning Ontario Ministry of Transportation, Canada Walter G. Bartel Oregon Department of Transportation Lyle Calvin Oregon State University Michael J. Bailey P.E.I. Transportation and Public Works, Canada Wade L. Gramling PACO, USA, Inc. Ken Grysbowski PRI Asphalt Technologies Matt Witezak Pavement Consulting Services William A. Phang Pavement Management Systems, LTD Gary Lee Hoffman Pennsylvania Department of Transportation Dean A. Maurer Pennsylvania Department of Transportation William R. Moyer Pennsylvania Department of Transportation Michael M. Ryan Pennsylvania Department of Transportation David A. Anderson Pennsylvania State University Philip D. Cady Pennsylvania State University Della M. Roy Pennsylvania State University Lawrence W. Cole Portland Cement Association Robert G. Packard Portland Cement Association Francisco Pantoja Puerto Rico Highway Authority Harold L. Michael Purdue University Charles F. Scholer Purdue University Thomas D. White Purdue University John Fenwick Queensland Department of Transportation, Australia Colin A. Franco Rhode Island Department of Transportation Greg J. Williams Roads and Transportation Association of Canada Dudley Carpenter Roy Jorgensen Associates, Inc John M. McCullough Roy Jorgensen Associates, Inc William I. Giles Ruan Transportation Management Systems Govert T. H. Sweere SHRP-Netherlands Lucio Aleman, Jr. SHRP Cindy M. Baker SHRP Cal Berge SHRP John Broomfield SHRP Brain E. Cox SHRP Stephen Day SHRP Guy Dore SHRP Denis E. Donnelly SHRP Fernando Fleitas SHRP Amir N. Hanna SHRP Ed Harrigan SHRP Don M. Harriott SHRP Neil F. Hawks SHRP John O. Hibbs SHRP Dick Ingberg SHRP

Ian Jamieson SHRP Inam Jawed SHRP Harry Jones SHRP Yasuhiko Kajiya SHRP Bob Kelley SHRP Damian J. Kulash SHRP Rita B. Leahy SHRP Dave Minsk SHRP Dick Parker SHRP Ivan J. Pecnik SHRP Cheryl Richter SHRP S. C. Shah SHRP Margie Sheriff SHRP James A. Sherwood SHRP Karen Haas Smith SHRP K. Thirumalai SHRP Torkild Thurmann-Moe SHRP Raymond J. Torrey SHRP Homer G. Wheeler SHRP Jack Youtcheff SHRP William G. Agnew SHRP Executive Committee Sam Hettiarachchi SRI International Digby D. Macdonald SRI International Richard L. Hanneman The Salt Institute Andrew T. Horosko Saskatchewan Highway and Transportation Canada Anthony C. Heitzman Science Applications International George A. West Shell Oil McRaney Fulmer South Carolina Department of Highways and Public Transportation David L. Huft South Dakota Department of Transportation D. Fred Martinez Southwestern Laboratories R. David Rowlett Southwestern Laboratories Harold H Weber The Sulphur Institute Wilson W. Overall Surface Systems, Inc Tord Lindahl Swedish Road and Traffic Research Bo II. Simonsson Swedish Road and Traffic Research Monica Sundstrom Swedish Road and Traffic Research Walter Knobel Swiss Federal Highways Office Mark E. Hallenbeck Transportation Research Center/University of Washington Ronald D. Tabler Tabler and Associates Asko Saarela Technical Research Centre of Finland Walter Durth Technical University-Darmstadt, West Germany Jacob Uzan Technion Israel Institute of Technology Dallas Little Texas A&M Research Foundation Robert L. Lytton Texas A&M University Byron C. Blaschke Texas Department of Highways and Public Transportation James N. Moss Texas Department of Highways and Public Transportation James M. Sassin Texas Department of Highways and Public Transportation Henry A. Thomason, Jr. Texas Department of Highways and Public Transportation Marcus L. Yancey Texas Department of Highways and Public Transportation James L. Brown Texas Department of Highways and Public Transportation Olga J. Pendleton Texas Transportation Institute Roger E. Smith Texas Transportation Institute D. M. Colwill Transportation and Road Research Laboratory England

David Thompson Transportation and Road Research Laboratory England Wiley Cunagin Transportation Research and Development Foundation Gary Elkins Transportation Research and Development Foundation John German Transportation Research and Development Foundation William Hadley Transportation Research and Development Foundation Paul Irick Transportation Research and Development Foundation Daniel W. Dearasaugh, Jr. Transportation Research Board Thomas B. Deen Transportation Research Board Frederick D. Hejl Transportation Research Board Crawford F. Jeneks Transportation Research Board Frank N. Lisle Transportation Research Board Jerome T. Maddock Transportation Research Board Richard F. Pain Transportation Research Board Fred Hanscom Transportation Research Corporation Gary Hicks Transportation Research Institute Paul H. Read Trow Inc., Canada Clyde E. Woodle Trucking Research Institute Bryant Mather U.S. Army Corps of Engineers Waterways Experiment Station Jim Pierce U.S. Bureau of Reclamation William E. Elmore University of Texas at Austin David R. Jones IV University of Texas at Austin Thomas W. Kennedy University of Texas at Austin James S. Moulthrop University of Texas at Austin Kenneth Stokoe, II University of Texas at Austin Ernest-Ulrich Hiersche University Karlsruhe West Germany Raymond F. Decker University Science Partners Inc. Henry R. Kerali University of Birmingham, England Johann Litzka University of Bodenkultur, Austria Carl Monismith University of California at Berkeley Robert G. Jenkins University of Cincinnati Marshall R. Thompson University of Illinois Wilfrid A. Nixon University of Iowa Carl E. Locke, Jr. University of Kansas Raymond K. Moore University of Kansas David E. Newcomb University of Minnesota Joseph V. Benak University of Nebraska Jon A. Epps University of Nevada at Reno Mary Stroup-Gardiner University of Nevada at Reno Wenji Victor Chang University of Southern California Richard Leahy University of Southern California Ronald J. Cominsky University of Texas Donald J. Jansen University of Washington Joe P. Mahoney University of Washington Ralph Haas University of Waterloo, Canada Kynric M. Pell University of Wyoming Michael Roshek Utah Department of Transportation Richard E Weyers Virginia Polytechnic Institute Aubrey D. Newman Virginia Department of Transportation James K. Skeens Virginia Department of Transportation Chuch Hughes Virginia Transportation Research Council David C. Malone Virginia Transportation Research Council Kenneth McGhee Virginia Transportation Research Council Howard Newton, Jr. Virginia Transportation Research Council

Charles R. Marck Vulcan Materials Company Lawrence R. Roberts W. R. Grace and Company J. P. Skalny W. R. Grace and Company Melvin W. Flanagan Walt Flanagan and Co. Gary Demich Washington State Department of Transportation Newton Jackson Washington State Department of Transportation Martin D. Pietz Washington State Department of Transportation James Spaid Washington State Department of Transportation John R. Strada Washington State Department of Transportation David R. Thompson Washington State Department of Transportation Elmar R. Reiter Wels Research Corporation Joseph K. Martin West Virginia Department of Transportation John R. Pearson Western Highway Institute J. Claine Peterson Western Research Institute Raymond E. Robertson Western Research Institute Michael O. Noggle Westinghouse Environmental and Geotechnical Division Craig A. Ballinger Wilbur Smith Associates Philip DeCabooter Wisconsin Department of Transportation Tom Atkinson Wyoming Highway Department G. Spencer Garrett Wyoming Highway Department Dave Pope Wyoming Highway Department James R. Vandel Wyoming Highway Department

TRB Superpave Committee (according to LST Transition Plan 2000) Members Organization Joseph A. Mickes Missouri DOT (retired) Martin F. Baker Albuquerque NM Public Works Department Wade B. Betenson Utah DOT Frank L. Danchetz Georgia DOT Fred M. Fehsenfeld, Sr. The Heritage Group Eric E. Harm Illinois DOT Dallas N. Little Texas Transportation Institute Donald W. Lucas Indiana DOT Paul J. Mack New York State DOT Joe P. Mahoney University of Washington Charles R. Marek Vulcan Materials Company John B. Metcalf Louisiana State University Gale C. Page Florida DOT Charles E. Potts APAC, Inc. Douglas R. Rose Maryland DOT Byron E. Ruth University of Florida Support Team Neil F. Hawks TRB Representative David E. Newcomb National Asphalt Pavement Association Ken F. Kobetsky AASHTO Bernard M. McCarthy The Asphalt Institute Vincent F. Schimmoller FHWA, Office of Infrastructure Sarah Wells Transportation Association of Canada Greg Smith ARTBA Ted Ferragut Consultant to Committee

Appendix C Photographs of Superpave Research Part of the record of the Strategic Highway Research Program lies within photographs. This section contains a selection of photographs showing people involved in various parts of the program as well as key events.

Strategic Highway Research Program Executive and Asphalt Advisory Committee

The Strategic Highway Research Program (SHRP) was guided by an Executive Committee chaired by John Tabb of the Mississippi Department of Transportation. The committee oversaw activities of all the research programs including the Asphalt Program. Damien Kulash as Executive Director for SHRP was a member of the Executive Committee.

Figure C1 SHRP

Executive Committee, circa 1988 (see below for

listing of members)

Number Name Organization

1 Bill Agnew General Motors Research

2 Ray Chamberlain Colorado Department of Transportation

3 Boris Hryhorczuk Manitoba Department of Transportation

4 William Giles Ruan Transportation Management Systems

5 Henry Thomason, Jr. Texas Department of Transportation

6 Wayne Muri Missouri Department of Transportation

7 Tom Deen TRB Executive Director

8 Harold Michael Purdue University

9 Frank Francois American Association of State Highway and

Transportation Officials

10 Harvey Haack (?) Pennsylvania Department of Transportation

11 Roger Yarbrough Apcon Corp

12 Dean Carlson Federal Highway Administration

13 Ray Decker University Science Partners, Inc.

14 Tom Downs New Jersey Department of Transportation

15 Tom Larson Pennsylvania Department of Transportation

16 Don Lucas Indiana Department of Transportation

17 John Tabb Mississippi Department of Transportation

18 Tom Espy Alabama Highway Department

19 Damian Kulash SHRP Executive Director

1 2

5 8

6

11

9

12 16

7

10

15 13

17

14

18 19

3 4

Figure C2 Tom Deen of TRB

speaking at Pacific Rim Conference, Seattle Washington, July 25, 1993. The Pacific Rim Conference was selected as the

venue to present the final results of all the SHRP Programs. Here

Tom Deen, as head of the Transportation Research Board provides an introduction to the Strategic Highway Research

Program. (photo by G.A. Huber)

Figure C3 SHRP Asphalt Advisory Committee meeting, July 26, 1993. The final meeting of the Advisory Committee was held during the Pacific Rim Conference in Seattle, Washington where the products of the each SHRP program were presented. It was at this meeting where one of the final technical details was finalized. Information was reviewed regarding the angle of gyration

for the Superpave gyratory compactor. The angle was finalized at 1.25 degrees. Back row L-R Gerry Huber (SHRP A-001 Contract), unidentified, unidentified, Tony Kriech

(Asphalt Materials), unidentified, Haleem Tahir (Maryland Department of Transportation), Dale Decker (National Asphalt Pavement Association), and John D’Angelo (FHWA). Front row L-R Chuck Hughes (retired Virginia Transportation Research Council), Damien Kulash (Executive Director SHRP), Gale Page (Florida Department of Transportation, Chairman of the Asphalt Advisory Committee), Ed Harrigan (SHRP Asphalt Program Manager), Eric Harm (Illinois Department of Transportation) and Peter Bellin (visiting SHRP loaned staff from Germany)

Figure C4 Gale Page, Florida Department of Transportation, Vice-Chairman of the SHRP Asphalt Advisory Committee speaking at the Pacific Rim

Conference in Seattle, Washington. July 25, 1993 (photo

by G.A. Huber)

Figure C5 Damian Kulash, SHRP Executive Director,

presenting to the conference. Pacific Rim Conference,

Seattle Washington, July 25, 1993. Tom Deen (TRB) visible at side of lectern. (photo by G.A. Huber)

Figure C6 Ed Harrigan, Program Manager for SHRP

Asphalt Program, Pacific Rim Conference, Seattle

Washington, July 25, 1993. (photo by G.A. Huber)

Figure C7 Tom Kennedy presenting results of the

asphalt research program. Pacific Rim Conference,

Seattle Washington, July 25, 1993. (photo by G.A. Huber)

SHRP Contractor Activity Photos

As part of making presentations during the SHRP program, one of the early aspects was to introduce the researchers from the different contracts to the audience. As a result, Tom Kennedy had “official” team portraits taken of the key people in each research team. Often, the photo was taken at a landmark characteristic of the research organization.

Figure C8 Contract A-001 team. L to R is Dave Jones, Tom Kennedy, Bill Elmore and Jim Moulthrop. Taken in front of office building

in Austin, Texas about 1990. (photo by Tom

Kennedy)

This photo was taken outside the building that had been leased as an off-site office for the A-001 contract. The office was located about 10 miles from the main campus near

the intersection of US183 and Mopac in northwest Austin. Tom Kennedy felt strongly that for the asphalt research program to succeed, that it was necessary to devote full attention to the program. Unlike usual research done by a professor, where the research becomes one of the many activities, Tom received permission to shift teaching and other university duties to other faculty and devoted full time to the SHRP research. Dave Jones, Bill Elmore and Jim Moulthrop were hired as part of the program and were employees of the University of Texas at Austin. Dave Jones was a chemist hired from the asphalt industry. Bill Elmore had been with the Texas Department of Transportation. Jim Moulthrop, most recently

with the asphalt industry, had been a long time employee of the Pennsylvania Department of Transportation.

Figure C9 L-R Tom Kennedy, Dave Jones

(sitting), Bill Elmore, Ron Cominsky (sitting) and Jim

Moulthrop. Taken at Atrium Office Building in Austin, TX

circa 1989. (photo by Tom Kennedy)

This les formal photo was taken outside the Atrium office building where the A001 offices were housed. Ron Cominsky, a key part of the team usually resided in Washington, DC and interacted with the SHRP Asphalt Program staff at SHRP headquarters. Ron had worked with Jim Moulthrop at the Pennsylvania Department of Transportation.

Figure C10 A-001 team with SHRP Asphalt Program

team. L-R Tom Kennedy (A-001 team leader), Jim

Moulthrop (A-001), Rita Leahy (A-001), Ian Jameson (SHRP), Ed Harrigan (SHRP Asphalt Program Manager), Jack Youtcheff (SHRP), Bill

Elmore (A-001), Ron Cominsky (A-001) and Dave Jones (A-001). (photo source

unknown)

This photograph was taken at TRB Green Building on

Wisconsin Avenue NW about 1989. Many of the SHRP meetings held in Washington occurred in the Green Building. Ed Harrigan and Rita Leahy joined the SHRP asphalt program from the Asphalt Institute. Ian Jameson was a loaned staff person from Ireland and Jack Youtcheff joined SHRP from industry.

Figure C11 Meeting at TRB Green Building. Back row L to

R Kieran Sharp (Australia Road Research Board), Ian Shelling (Shell Petroleum

Australia), Steve Day (Victoria Roads Department), Ken Porter

(Allen’s Asphalt) and, Ian Richards (Australian Asphalt Pavement Association). Front

row, L to R Lindsay Edser (Main Roads Queensland), Ted Booth (Highway Department

South Australia) Geoff Youdale (Road and Traffic

Authority New South Wales) and Ken Wonson (Boral Asphalt). Taken January 1990

Figure C12 Collecting asphalt for SHRP Material

Reference library. Jim Moulthrop, A-001 member, at Husky Refining, Lloydminster,

Alberta, circa 1988. (photo by Jim Moulthrop)

One of the early tasks for the A001 team was to identify asphalt and aggregates that would be used by all researchers in the different contracts that would follow. In order to create synergy, the researchers were required to use the same materials. This would allow cross fertilization of ideas among the different contracts. The asphalt and aggregate sources were intended to cover the range of materials used in North America. Large bulk samples were collected and stored in a climate controlled warehouse in Austin, Texas.

Figure C13 This

photo shows collection of an asphalt binder at the Husky Oil

asphalt refinery in Lloydminster,

Alberta, circa 1988. (photo by Jim Moulthrop).

Note the pallet of empty pails to be used for the sample. Since experimental plans had not yet been made for the contracts it was important to have sufficient material available for the future research.

Figure C14 Ron Cominsky standing in front of SHRP

Materials Reference Library asphalt

samples, Austin, Texas, circa 1988.

Samples of aggregate and asphalt were

collected and stored in a central

repository. (photo by Jim Moulthrop)

Figure C15 Bill Elmore and Dave Jones (L-R) of the A-

001 team at meetings following the Peterson Conference in Laramie,

Wyoming, July 1989 or 1990. Dave toasts the photographer with a glass of soda. (photo

from Jim Moulthrop)

Figure C16 Tom Kennedy and Rita Leahy (L-R) of the A-001 team at meeting of SHRP asphalt researchers

following Peterson Conference in Laramie, Wyoming, July 1989 or 1990. (photo from Jim

Moulthrop)

Figure C17 Tom Kennedy, Dave Jones and Rita Leahy at meeting following Peterson Conference

in Laramie, Wyoming in July 1989 or 1990. This photo appears to be taken at a break and shows typical team interaction. Often team

members would debate and interact regarding information that had been presented... (photo

from Jim Moulthrop)

Figure C18 Initial meeting with Rick Deighton to set up

Superpave software development. L to R,

Rick Deighton, of Deighton Associates and Tom Kennedy. Meeting at Kennedy Airport in New York, June 15,

1991.

Rick Deighton fulfilled a need to encode results of the asphalt research into

software that was envisioned for the design system. The final implementation of Superpave did not included

performance tests or performance prediction models and so software is not necessary to perform Superpave mix designs. In the end the performance tests were not implementable and the

software was never used. (photo by G.A. Huber)

Figure C19 Internal meeting of A-001 staff in a meeting

room at the Green Building in Washington, DC. L to R Jim

Moulthrop and Harold von Quintus, July 15, 1992 (photo

by G.A. Huber)

Figure C20 SHRP prototype

gyratory at the Asphalt Institute, Spring 1991. This gyratory was a 6-inch Texas gyratory on loan from the Texas Department of

Transportation. It was modified to change the angle of gyration

and the speed of rotation. Specimen height readings were taken manually from the dial gage. Operator is Dave Ross,

an Asphalt Institute technician. (photo by G.A. Huber)

Figure C21 Visit to the

Ministry of Transport of Quebec (MTQ) to inspect a

French (LCPC) gyratory compactor. At the time this

was the only LCPC compactor in North America. L to R

Pierre Langlois and Richard Langlois (not related). Photo

taken in MTQ central laboratory in Quebec City, Quebec, August 28, 1991.

(photo by G.A. Huber)

Figure C22 L-R Francis Moutier, Francois Travers and Chantal de la Roche all of LCPC.. Taken at LCPC Nantes in mobile LCPC

van, August 28, 1992.

This was the second of two trips to Nantes to visit with Francis, the developer of the gyratory compactor in the French method of mix design. (photo by G.A. Huber)

Figure C23 Visit to Engineering Development Company, March 9,

1992. L to R John McRae of EDCO and Gerry Huber of The Asphalt Institute (A-001 team). Purpose of visit was to discuss

operation and potential for use of Corps of Engineers gyratory in the

SHRP program. (photo by G.A. Huber)

Figure C24 Contract A-002A team. L to R is Dave Anderson professor at Penn State University and Claine Peterson of University of Wyoming. Taken at Western Research Institute, Laramie, Wyoming about 1989 Claine headed work on the chemistry of asphalt binder and Dave focused on physical properties providing much of the input into the current PG specification.

Figure C25 L-R Costas Synolakis, professor at the

University of Southern California (A-002B), Bill

Elmore, University of Texas (A-001) and Ron Cominsky, University of Texas (A-001) in background at meeting of SHRP asphalt researchers

following Peterson Conference in Laramie,

Wyoming, July 1989 or 1990.

Costas led one of the A-IIR projects that were designed to investigate new ideas. Costas

developed the technology of X-ray core tomography this is today used by researchers Figure C26 L-R Wenji (Victor)

Chang professor at the University of Southern

California (A-002B), Peter Bellin (loaned staff to SHRP

from Germany) and Gary Hicks, professor at Oregon State University (A-003A team) at meeting of SHRP

asphalt researchers following Peterson Conference in

Laramie, Wyoming, July 1989 or 1990.

Victor led an A-IIR project to investigate acoustic emissions from asphalt binder sandwiched between two small plates. The test became known as the poker chip test because of similarity in size to a poker chip. The concept was to discover a method to characterize low temperature properties of asphalt binder by cooling wafer sandwiches and listening for cracking to occur.

Figure C27 L-R Bob Lytton, professor at Texas A&M

University (A-005 team) and Dave Anderson, professor at

Penn State University (A-002A team) at meeting of SHRP

asphalt researchers following Peterson Conference in

Laramie, Wyoming, July 1989 or 1990. The A-005 team was tasked with developing asphalt mixture performance models to predict pavement performance.

Figure C28 Jan Branthaver, researcher at Western

Research Institute (A-002A) at meeting of SHRP asphalt

researchers following Peterson Conference in Laramie,

Wyoming, July 1989 or 1990.

Figure C29 Contract A-003A team. L to R is Fred Finn,

ARE Consulting, Carl Monismith; professor at the University of California at Berkeley and Gary Hicks professor of Oregon State

University. Taken at University of California

Berkeley about 1989.

The A-003A team was tasked with confirming performance-based properties of the asphalt binder developed by A-002A and developing performance-

based mixture tests. UC Berkeley focused on rutting and fatigue cracking. Oregon State focused on low temperature cracking and moisture damage. Figure C30 A-003B team from

Auburn University. L to R Christine Curtis, Principal

Investigator, Freddy Roberts of the National Center for Asphalt Technology, and Ray Tarer of

Auburn University

The A-003B team was tasked with investigating the bonding of asphalt and aggregate and measuring bonding in the presence of water. The Auburn group investigated the chemistry of bonding and sought to develop a test to quantify the potential for asphalt binder to remain bound to aggregate. This was supporting work to the research at Oregon State that sought to develop a performance based test for moisture damage.

Figure C32 Ron Cominsky of the A-001 team at meeting of SHRP asphalt

researchers following Peterson Conference in Laramie, Wyoming, July

1989 or 1990.

Figure C31 Dave Rowlett of Southwestern Lab (A-004 team leader) at meeting of SHRP

asphalt researchers following Peterson Conference in Laramie, Wyoming, July 1989

or 1990. The A-004 team was tasked with confirming performance-based tests applied

to modified asphalt binders and modified asphalt mixtures.

Figure C33 Christine Curtis,

professor at Auburn University (A-003B) and Jim Moulthrop (A-001) at meeting of SHRP asphalt researchers

following Peterson Conference in Laramie,

Wyoming, July 1989 or 1990

Figure C34 SHRP Asphalt Contractors team meeting. Front row L-R is Bill Elmore, Victor Chang, Rita Leahy, Wyn Jennings (Montana State University), Christine Curtis, Mo (last name

unknown), Ron Cominsky. Second row L-R is Mansour Solaimanian, Tom Kennedy, Dave Anderson, unidentified, Dave Jones, Dave Rowlett, Gary Hicks. Third row L-R is Rick

Holmgreen, Fred Finn, Bob Lytton, Jan Branthaver and unidentified. Fourth row L-R is Costas Synolakis, Jack Youtcheff, Ray Robertson, Jim Moulthrop, and unidentified. Photo was taken

at Holiday Inn Northwest in Austin, Texas about 1990.

In the first few years of the program multiple day meetings were held with the contractors. Data was presented and interpreted. New experiments were vetted. Experiment results were presented and discussed. The purpose was to generate cross fertilization of ideas and to allow alternate views of data interpretation. An example of this process occurred when Christine Curtis was presenting the results of an experiment dealing with moisture damage. She had hypothesized that the difference between stripping and non-stripping aggregates was the number of active sites on the aggregate surface available for bonding. But when asphalt dissolved in a solvent was circulated over a bed of aggregate both the granite and limestone adsorbed the same number of asphalt molecules. However, when water was added to the system the granite aggregate released a greater number of molecules. Bob Lytton who had been listening patiently got up and explained the data using Gibbs Free-energy.

Figure C35 Visit to Richmond Field Station at the University of California Berkley. L to R Jorge Souza, graduate student of Carl Monismith, unknown technician in background and Ed Harrigan. March 16, 1992.

Photo taken in A003A laboratory. (photo by G.A.

Huber)

Figure C36 Visit to Richmond Field Station at the University of California Berkley, March

16, 1992. Demonstrating specimen preparation for

shear testing. L to R Jorge Souza (graduate student), Ed Harrigan, Barney Vallerga

(consultant) and Akhtar Tayebali (graduate student)

(photo by G.A. Huber)

Figure C37 Visit to Richmond Field Station at the University

of California, March 16, 1992. Jorge Souza

demonstrating shear action on specimen to Tom Kennedy in

front shear tester control panel. They are standing in

front of the control panel of a prototype Superpave Shear

Tester. (photo by G.A. Huber)

Figure C38 John Harvey, graduate

student of Professor Carl Monismith working on A003A

project. Photo taken at Richmond Field Station, March 16, 1992

(photo by G.A. Huber)

Figure C39 Visit to Oregon State University, March 17,

1992. Tom Kennedy (L) listens to presentation by Ted Vinson, professor at Oregon State University (R) (photo

by G.A. Huber)

Figure C40 Visit to Oregon State University, March 17,

1992. Todd Shultz, graduate student of Gary

Hicks, discusses equipment used for making rolling wheel compacted slabs (photo by G.A. Huber)

Figure C41 Program meeting

about development of Superpave. Harold von

Quintus Taken at National Academy of Sciences Green Building, October 6, 1992

(photo by G.A. Huber)

Figure C42 Program meeting

about development of Superpave. Fred Finn. Taken

at National Academy of Sciences Green Building, October 6, 1992 (photo by

G.A. Huber)

Figure C43 Program meeting. L-R Chuck Hughes,

consultant, Ron Cominsky and Tom Kennedy, all of A001. Taken at National

Academy of Sciences Green Building, October 6, 1992

(photo by G.A. Huber)

Figure C44 Program meeting,

Matt Witczak, professor at University of Maryland,

working with A001, October 6, 1992 (photo by G.A.

Huber)

Figure C45 Meeting at Texas A&M University to discuss

“automation” of the performance models,

September 29, 1992. Rick Deighton with flow chart of

software on the board. (photo by G.A. Huber)

Figure C46 Meeting at Texas A&M University to discuss

“automation” of the performance models,

September 29, 1992. L to R Bob Lytton (A-005 contract), Ming Lou (graduate student of Bob Lytton) and Gerry Huber (A-001 contract). (photo by G.A. Huber)

Figure C47 Mock up of Superpave Software. April 1,

1993. This was done as a joke among researchers. April 1st was the delivery

date for the Superpave software but delays pushed the completion back to mid-May 1993. (photo by G.A.

Huber)

Figure C48 Visit to Penn State

University to discuss the experiment to determine the

design number of gyrations in the Superpave mix design

system. L to R Charles Antle, professor Penn State

University (A001) and Gerry Huber (A-001). Photo taken

in living room of Antle home, December 10, 1992 (photo by

G.A. Huber)

Figure C49 L-R Peter Pell leaning on truck in

background (Professor University of Nottingham),

Eshan Sharegh (Technician), and Geoffrey Rowe (PhD

candidate) Circa 1991, photo source unknown.

This task was making wheel tracking slabs for fatigue wheel tracking experiment in support of A-003A and A-004 studies – as a small scale validation of the beam fatigue results.

Figure C50 Mike Anderson, Asphalt Institute Research

Engineer, about 1991 Taken in Asphalt Institute laboratories

in Lexington, Kentucky. (photo by G.A. Huber)

Figure C51 Ed Harrigan in his office at SHRP headquarters,

Washington DC, February 1993 (photo by G.A. Huber)

Figure C52 Ron Cominsky in

his office at SHRP headquarters, Washington

DC, February 1993 (photo by G.A. Huber)

Figure C53 Harold von

Quintus in his office at SHRP headquarters, Washington,

DC, February 1993 (photo by G.A. Huber)

Figure C54 Tom Kennedy in

his office at the Atrium Building, Austin TX, March

28, 1993 (photo by G.A. Huber) Note the asphalt

emulsion plant visible through the window. Tom would

remark that having an asphalt plant next door gave him

inspiration.

Figure C55 Rita Leahy, taken during initial meeting about

Superpave software in meeting room at LaGuardia

Airport, June 15, 1991 (photo by G.A. Huber)

Figure C56 AASHTO meeting in Milwaukee,

Wisconsin, October 13, 1991. L to R Jim Moulthrop (A-001), Chantal de la Roche

(LCPC), Gerry Huber (A-001) and Ron Cominsky (A-001)

(photo by G.A. Huber)

Figure C57 AASHTO meeting in Milwaukee,

Wisconsin, October 13, 1991. L to R Tom Kennedy and

Don Lucas, Chief Engineer of Indiana Department of

Transportation clowning for the camera. Don was a

member of the Executive Committee and the first Chairman of the North

Central User Producer Group (photo by G.A. Huber)

Figure C58 Greg Williams of

Canadian SHRP program taken at CTAA meeting in Victoria, British Columbia, November 1995 (photo by

G.A. Huber)

Greg, an employee of the Transportation Association of Canada, headed up the C-SHRP program. He coordinated with the SHRP Asphalt Program team in Washington, DC.

Figure C59 C-SHRP Low Temperature test road near Lamont, Alberta April 1996

(photo by G.A. Huber)

This experiment provided field performance for asphalt binders that were part of the SHRP Materials Reference Library.

Figure C60 Modified Texas gyratory compactor at Payne

and Dolan plant site, I-43 trial Superpave project, July 28, 1992 (photo by G.A. Huber)

Figure C61 Trial project paving on I-43 near

Waukesha, Wisconsin. Jack Weigel, Quality Control Supervisor for Payne and

Dolan Contracting, July 28, 1992 (photo by G.A. Huber)

Figure C62 Quality Control

laboratory of Payne and Dolan, contractor on second Superpave trial construction

project, Waukesha, Wisconsin. L-R Jack Weigel, (QC Manager), Lupe Arandia, temporary service tech (name

unknown), Kerry Williams and Gail Hoard, all of Payne and Dolan. Taken July 28,

1992. (photo by G.A. Huber)

Figure C63 Leonard Makowski, Construction

Engineer, Wisconsin Department of Transportation. Taken at Payne and Dolan hot

mix plant site, Waukesha, Wisconsin during

construction of second Superpave trial project, July

28, 1992. (photo by G.A. Huber)

Figure C64 I-65 SPS trial section, L-R, unknown,

unknown, unknown, Kurt Sommer (District Materials

Engineer INDOT), Ron Walker (State Materials

Engineer INDOT), taken at hot mix plant, West Lafayette,

IN, September 24, 1992 (photo by G.A. Huber)

Figure C65 Pilot Superpave Training Course, Asphalt

Institute circa 1994. (photo by G.A. Huber)

Figure C66 L to R, Tom Harman (FHWA Mobile Trailer Program), John

Bukowski (FHWA) and Bob McGennis (Asphalt Institute).

Taken at Asphalt Institute during pilot Superpave

training course, circa 1994 (photo by G.A. Huber)

Figure C67 L to R, Chuck Paugh (FHWA Mobile Trailer Program), Dan Quire (Asphalt

Institute), Kevin Stuart (FHWA Turner Fairbank Lab,

partly hidden) and Bob McGennis (Asphalt Institute).

Taken at Asphalt Institute pilot Superpave training

course, circa 1994 (photo by G.A. Huber)

Figure C68 Kevin Stuart of

FHWA Turner-Fairbank Lab and Dan Quire of Asphalt Institute. Taken at Asphalt Institute pilot Superpave training course, circa

1994 (photo by G.A. Huber)

Figure C69 Tom Kennedy and Ed Harrigan preparing presentations for SHRP Asphalt Technology Conference, October 25, 1994,

Reno, NV. This five-day conference was regarded as the

roll-out of SHRP asphalt products to the asphalt industry. (photo by

G.A. Huber)

Figure C70 Tom Kennedy and

Gerry Huber preparing presentations for SHRP Asphalt

Technology Conference, October 25, 1994, Reno, NV (photo by

G.A. Huber) The A-001 team had an all day time slot to present how

the results of the SHRP contractors were included into the Superpave system Together Tom Kennedy, Ed Harrigan and Gerry Huber presented over 700 slides

describing the background of Superpave mix design

components.

Figure C71 AASHTO Superpave Committee

meeting held at Woods Hole, MA May 28, 1997. L-R Dale Decker of NAPA speaking,

unidentified, Frank Fee, Charles Pryor (photo by G.A.

Huber)

Figure C72 Dale Decker of NAPA (back to camera)

explaining to Don Lucas of Indiana DOT, chairman of the Superpave Technical Working

Group why Superpave was not ready for nationwide

implementation, Woods Hole, MA, May 28, 1997 (photo by

G.A. Huber)

Figure C73 Meeting of NAPA and FHWA to discuss plan for implementation of Superpave.

L-R Dale Decker of NAPA and John D’Angelo of FHWA, Palm Desert California during NAPA Annual meeting 1994.

(photo by G.A. Huber)

Figure C74 L-R Brian Killingsworth (Fugro

Consulting, Austin, TX), Mansour Solaimanian (Texas

Superpave Center, Austin), Pat Cain (Interlaken

Technologies), Gerry Huber (Heritage Research Group) and

Tom Brovold (Interlaken Technologies, Eden Prairie,

MN). Interlaken was selected to develop a Shear Test

machine. Taken at Interlaken Technologies office in Eden Prairie, MN, about January

1994 (photo by G.A. Huber)

Figure C75 L to R, Paul Burch

of Arizona DOT and John Bukowski of FHWA at

Superpave trial section on US 93 north of Kingman, AZ, January 22, 1998 (photo by

G.A. Huber)

Figure C76 L to R, John

D’Angelo of FHWA and Julie Kliewer of Arizona DOT at

Superpave trial section on US 93 north of Kingman, AZ, January 22, 1998 (photo by

G.A. Huber)

Figure C77 FHWA Mobile

Trailer on location near Livermore, California. L to R

John D’Angelo (FHWA Washington DC), Joe

Massucco (FHWA California) and Chuck Paugh (FHWA

Trailer Program), circa 1992 (photo by G.A. Huber)

Figure C78 FHWA Mobile Trailer on location near

Livermore, California. L to R Roger Smith (Asphalt

Institute), Joe Massucco (FHWA California) and John

D’Angelo (FHWA Washington), circa 1992 (photo by G.A. Huber)

Figure C79 Sirous Alavi (Nichols Consulting) and Jon Epps (University of Nevada

Reno) during investigation of WesTrack failed pavement

sections, November 22, 1996 WesTrack was paved with Superpave mix designs and

became a proving ground for Superpave. Early rutting of the coarse-graded mixtures

led to this forensic investigation. (photo by G.A.

Huber)

Appendix D History of Mix Design The Strategic Highway Research Program developed a new mix design method for hot

mix that became known as Superpave. To understand the context within which Superpave was developed it is useful to review the history of mix design. Most people in the industry today are aware of the Marshall method of mix design and the changes involved in switching from Marshall to Superpave. Less known are some of the older methods of design and how the ideas in the legacy design methods have been carried over into Superpave.

EARLY MIX DESIGN METHODS In 1890 E.G. Love of New York published a series of articles from volumes of the

Engineering and Building Record on the topic of roads and paving. These articles were not predominantly technical but were similar to articles in current trade magazines such as Better Roads. The articles contained competing ideas for designing a pavement but one article of interest was published by F.V. Greene of the Barber Asphalt Paving Company. It was a specification for the construction of an asphalt pavement. Although design technology was not discussed, a recipe was given for the asphalt surface. A Barber wearing surface was specified as follows: Asphalt cement 12 to 15% Sand 83 to 70% Pulverized carbonate of lime 5 to 15%

Mix was laid in two lifts. The first lift, called the cushion coat, contained 2 to 4% more asphalt and was compacted to a depth of one half inch. The second coat is called the surface coat and was made according to the specifications above. The pulverized lime was added cold to the hot (300ºF) sand before the asphalt was mixed in. The quantity of lime was adjusted according to the properties of the sand. It would appear that proportions were adjusted based on visual observation of experienced pavers.

In 1905 Clifford Richardson, owner of the New York Testing Company published a book entitled The Modern Asphalt Pavement. The second edition was published in 1912. In that book he refers to many pavements built across the United States in the 1890s and 1900s. Richardson describes two types of asphalt mixes: surfacing mixtures and asphaltic concrete.

Surfacing mixture is a sand mix. Typical gradations are 100% passing the #10 sieve and 15% passing the #200 sieve. Asphalt contents are 9 to 14%. He talks about the ability of sand to carry asphalt and the calculation of the area of spherical particles. The method of determining asphalt content for these mixtures was the “pat-paper test” which is an asphalt stain on paper. A typical result is shown in Figure D1.

In doing the pat-paper test Richardson warns that the mixture must be sufficiently hot for the asphalt to be fluid. Cold mixtures are of no use and excessively hot ones may cause too much staining. Although he does not describe the test method in detail, the streaks on the paper as shown in Figure D1 suggest that the mixture is spilled onto the paper.

Asphaltic concrete is used for lower courses. Richardson warns that asphaltic concrete is

not suitable as a surface layer on main streets but may be suitable for lesser streets. Horse’s shoes and hoofs ravel particles from the surface. In his opinion the high asphalt content sand mix must be used to resist the impact of horseshoes.

Asphaltic concrete is more typical of what current-day HMA looks like. A cross section of asphaltic concrete is shown in Figure D2. Interestingly, the design of this mixture did not use the pat-paper test. Instead, Richardson calculates the voids in mineral aggregate. In fact, he refers to it as VMA.

Figure D1 Pat-Paper Test for Sand Asphalt Showing Strong Stain (after Richardson, 1912, p, 355)

Figure D2 Asphaltic Concrete Surface on Broadway Street in Patterson, N.J. 1906 (after

Richardson, 1912, p. 384)

Richardson describes how the VMA must be adjusted to include the correct amount of

asphalt. The gradation of the cross section in this picture is similar to a pavement Richardson used in Michigan that was as follows:

- 1.5 inch 100% - 1 inch 83.6% - ½ inch 50.1% - ¼ inch 40.3% - #8 36.8% - #200 5.2% - VMA 13.2% - Bitumen 7.4%

Under today’s specifications this mixture would be a 1.5 inch nominal maximum size

mixture. It would be considered fine-graded because the percent passing the primary control sieve (3/8-inch sieve not shown in the table) is above 40%. The VMA requirement under modern specifications would be 11.0%which is 2.2% less than the VMA in Richardson’s mixture. This would mean the asphalt content would be about 0.9% lower than the 7.4% that Richardson used.

Figure D3 Typical Asphalt Pavement consisting of Sand Asphalt Surface on Asphaltic Concrete

on Aggregate Base (after Richardson, 1912, p. 387)

The Richardson mix design method for asphaltic concrete did not use the pat-paper test.

Trial mixtures were mixed in the lab at different asphalt contents and placed on the road. The surface was tamped down with a heated hand tool and the surface was inspected. The different mixtures were inspected visually to see how much the macro-texture was filled with mastic. There should be enough asphalt to fill the voids but not so much as to have excess asphalt at the surface. From this the design asphalt content was chosen.

Air voids are not calculated as part of Richardson’s mix design but Richardson analyzed several pavements and talks about the correct level of density as compared to the theoretical density. By calculation, the air voids can be seen to be about 2 percent. Note that this is the in-place air voids. If air voids were higher, say 5 to 8 percent Richardson noted that the pavements were unable to withstand thermal shock and would crack.

The key idea evolving from pavement design at the beginning of the 20th century was the concept of using an asphaltic concrete as the base layers with a sand asphalt mix as the surface.

HUBBARD FIELD MIX DESIGN In the mid-1920s Charles Hubbard and Frederick Field, both employees of the newly

created Asphalt Association (later to become the Asphalt Institute), developed a new method of mix design called the Hubbard Field Method of Design. The Hubbard Field method was commonly used among state highway departments in the 1920s and 1930s although use continued on into the 1960s in some states.

Initially the Hubbard Field method was focused on the surfacing mixture, the sand asphalt used for wearing course of asphalt pavements. Specimens were 2 inches in diameter and were compacted with a hand rammer.

A modified version of Hubbarddiameter specimens that were compacted with two diffewere applied with the 2-inch rammer followed by 30 blows with a 5.75The specimen was turned over and pushed to the opposite end of the mould. Again 30 blows of the 2-icnh rammer were applied followed by 30 blows of a 5.75specimen was then placed in a compression machines and was loaded with a 10,000 pound load and was allowed to cool in a cold water bath while under compression.

Figure D4 Hubbard Field Stabilometer

The Hubbard Field mix method of

Richardson. Specimens were made in the laboratory but instead of using a stain test on a piece of paper, they developed a method of evaluation to determine design asphalt contentspecific gravity of the compacted specimens was measured. Maximum theoretical specific gravity was computed using aggregate bulk specific gravity (Note that therefore not accounted for.) . Air voids were calculated as was (VMA by today’s terminology). So, the volumetric analysis was similar to the properties used today.

In addition to the volumetric analysis, the Hubbard Field method used a stability test shown in Figure D4 where the compacted mix is squeezed through a ring slightly smaller than the specimen diameter. The peak load sustained before the mix started flowing through the orifice was called the Hubbard Field stability.

The Hubbard Field method selected asphalt content based oVoids in the aggregate were evaluated to help adjust the mixture stability.

Initially the Hubbard Field method was focused on the surfacing mixture, the sand r wearing course of asphalt pavements. Specimens were 2 inches in diameter and

A modified version of Hubbard-Field was developed for asphalt concrete. It used 6 inch

diameter specimens that were compacted with two different rammers. First 30 “heavy blows” inch rammer followed by 30 blows with a 5.75-inch diameter rammer.

The specimen was turned over and pushed to the opposite end of the mould. Again 30 blows of llowed by 30 blows of a 5.75-inch diameter rammer. The

specimen was then placed in a compression machines and was loaded with a 10,000 pound load and was allowed to cool in a cold water bath while under compression.

Figure D4 Hubbard Field Stabilometer

method of design built upon the process described by Richardson. Specimens were made in the laboratory but instead of using a stain test on a piece of paper, they developed a method of evaluation to determine design asphalt content. Bulk specific gravity of the compacted specimens was measured. Maximum theoretical specific

ggregate bulk specific gravity (Note that asphalt absorption was . Air voids were calculated as was voids in the aggregate skeleton

(VMA by today’s terminology). So, the volumetric analysis was similar to the properties used

In addition to the volumetric analysis, the Hubbard Field method used a stability test cted mix is squeezed through a ring slightly smaller than

the specimen diameter. The peak load sustained before the mix started flowing through the orifice was called the Hubbard Field stability.

The Hubbard Field method selected asphalt content based on air voids and stability. Voids in the aggregate were evaluated to help adjust the mixture stability.

Initially the Hubbard Field method was focused on the surfacing mixture, the sand r wearing course of asphalt pavements. Specimens were 2 inches in diameter and

Field was developed for asphalt concrete. It used 6 inch rent rammers. First 30 “heavy blows”

inch diameter rammer. The specimen was turned over and pushed to the opposite end of the mould. Again 30 blows of

inch diameter rammer. The specimen was then placed in a compression machines and was loaded with a 10,000 pound load

Richardson. Specimens were made in the laboratory but instead of using a stain test on a piece . Bulk

specific gravity of the compacted specimens was measured. Maximum theoretical specific asphalt absorption was

voids in the aggregate skeleton (VMA by today’s terminology). So, the volumetric analysis was similar to the properties used

In addition to the volumetric analysis, the Hubbard Field method used a stability test cted mix is squeezed through a ring slightly smaller than

the specimen diameter. The peak load sustained before the mix started flowing through the

n air voids and stability.

HVEEM MIX DESIGN Early pavements in California were made using natural bitumen from the La Brea Tar

pits located in the Los Angeles and Santa Barbara area, see Figure D5. Although referred to as tar, these were actually natural asphalt seeps.

This asphalt was quite soft and was used in the role of penetrating macadam, in which it was sprayed on top of compacted open-graded aggregate, or it was used by mixing with gravel and making an oil mix.

In the 1920s oil mix made with cutback asphalt was a common method of paving. Much of the mix was made in windrows where the asphalt was sprayed on top of a knocked-down windrow and was mixed back and forth with a motor grader. Proper oil content was determined by eye, so an experienced person was needed to ensure that the mix had the proper brown color.

Figure D5 The Lagoon at Rancho La Brea. The surface of the pond is streaked with oil and gas

bubbles are seen escaping through the water. The banks around the lagoon consist to a large extent of asphalt. (after John C Merrriam, 1911, p. 205)

Two engineers, McKesson and Frickstad developed a formula based on oil mixes

constructed from 1923 to 1926. The percent of oil was based on gradation as follows: P = 0.015a + 0.13b + 0.17c Where P = percent of oil required a = percent retained on #10 sieve b = percent passing #10 sieve and retained on #200 sieve c = percent passing #200 sieve In addition, they recommended use of a paper stain test, along the lines that was used in sand asphalt, because allowance was needed in their formula for absorption.

In 1927 Francis Hveem became a resident engineer in California and having no experience with oil mixes used the information about gradation with the paper stain test to evaluate asphalt content. He recognized that this process was controlled by surface area of the aggregate and so he found a method to calculate surface area. He found surface area factors

published in 1918 by a Canadian engineer, Captain L.N. Edwards that were proposed for use in Portland cement design.

Francis Hveem applied the mix design process used for oil mixes to hot mix asphalt. By 1932 he had developed an analysis method to determine asphalt content based on surface area. He continued to make changes to the surface area factors and developed a test using motor oil to estimate asphalt absorption. The surface area factors contained in today’s Asphalt Institute manual MS-2 for Hveem mix design are the ones developed by Hveem for the California Department of Highways in the 1940s.

In the same time era, Francis Hveem started developing a stability test. He recognized that mechanical strength of the mix was also important and he developed the Hveem stabilormeter, which is a pseudo-triaxial test. A vertical load is applied to a confined specimen and the resulting horizontal pressure is measured. When asphalt content exceeds a threshold, the horizontal pressure increases and Hveem related this property to discern stable and unstable pavements. Based on oil mixes he developed some threshold values for stability and carried them over to HMA.

The philosophy of Hveem mix design is that sufficient asphalt binder is needed to satisfy absorption into the aggregate and to have a minimum film thickness on the surface of the aggregates. In order to carry load, the aggregates had to have a sliding resistance (measured by the Hveem stabilormeter) and a minimum tensile strength to resist turning movement (measured by the cohesiometer). Stability and cohesion were influenced by the aggregate properties and the amount of asphalt binder. For durability Hveem developed the swell test and moisture vapor sensitivity test to measure the reaction of the mix to water. The swell test used liquid water and the vapor sensitivity test used moisture vapor. The effect on Hveem stability after conditioning was measured. Hveem found that the thicker the asphalt films were, the more resistance they had to moisture effects.

Note that air voids is not part of Hveem’s mix design system. He believed that the film thickness and mechanical properties as described by Hveem stability was the most important. It was not until years later (1980s?) that air voids was added as a consideration. Interestingly, if one takes a step back and looked at performance of HMA in the 1980s or early 1990s when rutting was a huge national problem, California and other states using Hveem mix design did not have as great a rutting problem. A general statement could be made that California pavements had lower asphalt contents and that fatigue cracking was the major concern. It is not surprising that historically fatigue cracking research was centered in California. In states using Marshall design pavements rarely failed by fatigue. Rutting was the issue.

MARSHALL MIX DESIGN Marshall mix design was developed by Bruce Marshall of the Mississippi Department of

Highways in the late 1930s- early 1940s. In 1943 Marshall was frustrated at attempts to have the Mississippi Department of Highways adopt the method and left the Highway Department to join the Corps of Engineers in Vicksburg, MS. The Corps of Engineers adopted the Marshall system in World War II for use on airfields. Post WW II, it was “civilianized” for use by state highway departments.

Marshall Mix Design is essentially an outgrowth of the Hubbard-Field mix design method. The approach is similar although the practice was different. Hubbard-Field used two

load

test specimen

breaking head

rammers of different sizes to compact samples. Marshall matched the compactor diameter to the diameter of the mold. Hubbard-Field used a rammer, basically a hand tamp. Marshall tried to standardize the amount of compaction energy applied by using a drop hammer.

Marshall used the calculation of air voids from Hubbard-Field but not the VMA. Instead, he used a voids filled with asphalt criteria. In the 1950s Norman McLeod advocated use of VMA in the mix design method. Presumably, he was aware of the use of VMA in the Hubbard-Field method and believed it should apply to the Marshall method as well. Many in the industry credit McLeod as the originator of VMA, but indeed he was just bringing it forward from the Hubbard-Field method and was advocating use of it in the Marshall method.

Bruce Marshall adopted the concept of Hubbard Field stability but changed the geometry. Instead of a cylinder being squeezed through a ring, Marshall turned the cylinder on it’s side and squeezed the specimen between two horseshoe shaped platens. As the specimen was being squeezed the load increased until the specimen started to fail. The maximum load was known as the Marshall Stability and the amount of deformation was known as the Marshall Flow.

In the 1950s and 1960s the Asphalt Institute was the de facto keeper of the Marshall

standard and published it in MS-2, a manual of mix design methods for asphalt concrete. It is interesting that even though ASTM was the main home of the Marshall method (D-1889) the ASTM standard was a reflection of MS-2. Even AASHTO, which adopted its own standard, mirrored the ASTM standard. Marshall mix design was an ASTM (and AASHTO) test method but the setting of the properties had been done by the Asphalt Institute looking at research and participating in technical debates regarding various aspects of the design method

Figure D6 Concept of Marshall Stability Breaking Head

Files at the Asphalt Institute contain letters and data from both Bruce Marshall, who went on to be a consultant after leaving the Corps of Engineers and Norman McLeod who worked for Imperial Oil in Canada. McLeod’s most notable research papers on VMA are a 1956 Highway Research Board paper, a 1957 AAPT paper and a 1959 ASTM symposium paper. In 1962, after much debate, the Asphalt Institute changed MS-2 to include VMA as a mix design criteria. AASHTO and ASTM changed their standards to reflect the Asphalt Institute change.

SUPERPAVE MIX DESIGN Superpave mix design was the product of the Strategic Highway Research Program. The

objective of the Asphalt Research Program was to develop a performance based asphalt binder specification, a performance-based asphalt mixture specification and a mix design system. The Performance-Graded asphalt binder specification is the result of the research.

The performance based mix specification was less successful. Although performance tests for asphalt mixture were developed and models were designed to predict mixture response (stress, strain, etc.) and to predict mixture performance (rutting, fatigue cracking, thermal cracking) the system ended up being too difficult to implement and was never used by state DOTs.

Superpave mix design as originally conceived had three levels, each of increasing complexity. They were referred to as Level 1, Level 2 and Level 3 mix design. The performance based mixture tests were to be used in the Level 2 and Level 3 designs. As the SHRP research progressed it became apparent that testing and analysis for the performance predictions would be sufficiently complex to justify using a simple, empirical design method as the base or entry level mix design. When the performance-based tests and models were not implemented, the mix design method that remained was the base level (also known as Level 1). Superpave, as specified in AASHTO M323, is the Level 1 mix design that was developed during SHRP.

So, Level 1 mix design was decided to be based on the old mixture properties. Such was the necessity of developing a workable system. The problem facing SHRP was how to answer questions such as:

- “What is the proper level of air voids?” - “How should minimum asphalt content be specified?” - “How should gradation be specified?”

The Federal Highway Administration convened a Technical Working Group (TWG) to

determine which empirical volumetric properties should be included in Superpave. The purpose of the TWG was to determine key volumetric properties of asphalt mixes that affect performance. It was agreed that the following properties would be used:

- Air voids. Air voids were to be calculated using the measured maximum theoretical gravity (Gmm) of the mixture and the measured bulk specific gravity of the compacted hot mix asphalt.

- Voids in mineral aggregate. The definition proposed by the Asphalt Institute in the Manual of Asphalt Mix Design (MS-2). A recommendation to calculate VMA using effective specific gravity of the aggregate back calculated from the Gmm was

- Voids filled with asphalt would be calculated using VMA and air voids.

SHRP studied state DOT specifications and found that there was no consensus in current

specifications as to what should be specified and at what VMA criteria should be specified. The FHWA TWG made recommendations on what properties should be used but not on what levels or how those levels should change with mix type. Superpave needed the old volumetric properties but there were no clear answers to the questions of “Which properties should be used?” and “What criteria should be used for them?” So SHRP convened a group commonly called the Delphi group

The Delphi group contained 14 experts that represented state DOTs, and industry. The group determined which properties should be used, under what circumstances they should be adjusted and what the specification limits should be. The Delphi group decisions are as follows:

- Compaction was to be done with a gyratory compactor.

- Air voids. The Delphi group agreed with the FHWA Volumetric TWG that air voids should be calculated using Gmm and Gmb.

- VMA. The FHWA Volumetric TWG recommended VMA as the method of setting minimum asphalt content. There was some discussion about specifying film thickness especially since NCAT was at the time proposing use of film thickness. The debate never carried the group.

- Voids Filled with Asphalt (VFA). There was lots of discussion about the need for this property. In the end, the Delphi group concurred with the FHWA Volumetric TWG to recommend VFA.

- Aggregate gradation. This was debated by both the TWG and the Delphi group. The TWG debated the existence of a maximum density line. Research from the Asphalt Institute was convincing enough for the TWG to recommend the Superpave gradation specifications. The restricted zone was maintained in the specification at the time because European mixtures were “discovered” to have coarse aggregate skeletons, and the restricted zone was a method of ensuring coarse aggregate skeletons and preventing excess sand (especially natural sand) from being used. Later research indicated that Fine Aggregate Angularity was adequate for controlling quality of the sand and so the restricted zone was changed to a Primary Control Sieve in the ASHTO specifications. The purpose of the PCS is to allow definition of coarse-graded and fine-graded mixtures.

- Crushed faces. The method of designating crushed faces was accepted by the Delphi group and the criteria were based on traffic level and depth from surface.

- Natural Sand. There was much concern about excessive use of natural sand. The epidemic of rutting that had occurred nation-wide in the 1980s was partly related to excessive natural sand in hot mix. The National Sand and Gravel Association had

recently begun promoting use of the Fine Aggregate Angularity test and the Delphi group adopted it.

SUMMARY OF MIX DESIGN HISTORY The purpose of this section was to provide a history of mix design technology. As with

many other technologies, today’s technology represents an evolution of ideas that been evaluated through the years. One of the limitations of current mix design systems (Marshall, Hveem or Superpave) is the inability to measure expected performance. Specifically, the ability to measure rut resistance, fatigue cracking, low temperature cracking, asphalt binder aging or mixture resistance to moisture damage. Prediction or evaluation of these properties for a given application was the goal of SHRP. But the SHRP tests could not be implemented. Surrogate properties are used to control the performance properties of Superpave asphalt mixtures as follows:.

- Rutting is controlled by o Aggregate properties

§ Crushed faces on coarse aggregate § Fine aggregate angularity on fine aggregate

o Volumetric properties § Air voids § Voids filled with asphalt

- Fatigue cracking is controlled by o Asphalt content

§ VMA and air voids together define the volume of effective asphalt binder content.

- Low temperature cracking o Low temperature grade of the asphalt binder o Asphalt binder content

- Mixture aging o Asphalt content

- Moisture damage o Bond strength of asphalt-aggregate interface

§ Enhanced by antistrip agents o Asphalt binder content