1. Ph.D. Student and Research Assistant, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., Houghton, MI 49931-1295.
2. Associate Professor, Dept. of Civil and Environmental Engineering, Michigan Technological Univ., 1400 Townsend Dr., Houghton, MI 49931-1295 (corresponding author).
3. Associate Professor, Dept. of Civil, Construction, and Environmental Engineering, Iowa State Univ., 490 Town Engineering Building, Ames, IA 50011.
4. Asphalt Mixture Scientist/Laboratory Manager, ESCINC Turner-Fairbank Highway Research Center, Federal Highway Administration, 6300 Georgetown Pike, Rm. F114, HRD1-11 McLean, VA 22101.