1. University of Alaska, Anchorage, Alaska 99508
2. Department of Highway Engineering, Royal Institute of Technology, Brinellvägen 34, 100 44 Stockholm, Sweden
3. Department of Civil Engineering, Oregon State University, Apperson Hall 107, Corvallis, Oreg. 97331
4. U.S. Army Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, N.H. 03755.