1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Sejong Univ., 98 Gunja-dong, Gwangjin-gu, Seoul 143-747, Republic of Korea.
2. Professor, Dept. of Civil and Environmental Engineering, Sejong Univ., 98 Gunja-dong, Gwangjin-gu, Seoul 143-747, Republic of Korea (corresponding author).
3. Director, Pavement Research Center, Quality Inspection Office Division, Seoul Metropolitan Government, 131 Taebong-ro, Seocho-gu, Seoul 137-900, Republic of Korea.