1. Assistant Research Scientist, Materials and Pavement Div., Texas Transportation Institute, The Texas A&M Univ. System, 3135 TAMU, College Station, TX 77843-3135.
2. Associate Research Engineer, Materials and Pavement Div., Texas Transportation Institute, The Texas A&M Univ. System, 3135 TAMU, College Station, TX 77843-3135 (corresponding author).
3. Senior Research Engineer, Materials and Pavement Div., Texas Transportation Institute, The Texas A&M Univ. System, 3135 TAMU, College Station, TX 77843-3135.