1. Transportation Engineer, Office of Flexible Pavement Materials, Transportation Laboratory, 5900 Folsom Blvd., Sacramento, CA 95833 (corresponding author). E-mail: huiming_yin@dot.ca.gov
2. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 1212 Newmark Civil Engineering Laboratory, 205 N. Mathews Ave., Urbana, IL 61801.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 2209 Newmark Civil Engineering Laboratory, 205 N. Mathews Ave., Urbana, IL 61801.