1. School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology; Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha, Hunan 410004, CN (Corresponding author), e-mail: yao26402@126.com
2. School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Changsha, Hunan 410004, CN, e-mail: 280077543@qq.com
3. Chengnan College, Changsha Univ. of Science and Technology, Changsha, Hunan 410015, CN, e-mail: yuanjb01@163.com
4. School of Traffic and Transportation Engineering, Changsha Univ. of Science and Technology, Changsha, Hunan 410004, CN, e-mail: 1004331988@qq.com