1. Research Assistant, National Center for Asphalt Technology (NCAT), 277 Technology Pkwy, Auburn, AL 36830; formerly, Dept. of Civil and Environmental Engineering, Univ. of Iowa, Iowa City, IA 52240.
2. Ph.D. Student, Dept. of Civil and Environmental Engineering, Univ. of Iowa, Iowa City, IA 52240.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Iowa, Iowa City, IA 52240 (corresponding author).
4. Professor, Civil, Construction, and Environmental Engineering, Iowa State Univ., 490 Town Engineering Bldg., Ames, IA 50011.
5. Bituminous Engineer, Materials Office, Iowa Dept. of Transportation, 800 Lincoln Way, Ames, IA 50010-6915.