1. Associate Professor, Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha Univ. of Science & Technology), Chiling Rd. 45#, Changsha, Hunan, P.R. China, 410076 (corresponding author).
2. Ph.D. Candidate, School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Chiling Rd. 45#, Changsha, Hunan, P.R. China, 410076.
3. Graduate Student, School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Chiling Rd. 45#, Changsha, Hunan, P.R. China, 410076.