1. Professor, Changsha Univ. of Science and Technology, Chiling Road #45, Changsha, Hunan, P.R. China, 410076; and Texas Dept. of Transportation, 4203 Bull Creek #39, Austin, TX 78731 (corresponding author).
2. Associate Professor, Civil and Environmental Engineering, Texas Tech Univ., M.S. 41023, Lubbock, TX 79409-1023.
3. Pavement Engineer, Texas Dept. of Transportation, Texas Tech Univ., 4203 Bull Creek #39, Austin, TX 78731.