1. Associate Professor, Key Laboratory for Expressway Maintenance Technology of Ministry of Communications, No. 38, Wuyingshan Middle Rd., Jinan, China 250031 (corresponding author).
2. Professor and Head, Key Laboratory for Expressway Maintenance Technology of Ministry of Communications, No. 38, Wuyingshan Middle Rd., Jinan, China 250031.
3. Associate Professor, Key Laboratory for Expressway Maintenance Technology of Ministry of Communications, No. 38, Wuyingshan Middle Rd., Jinan, China 250031.