1. Pavement Technology, Swedish National Road and Transport Research Institute, SE-581 95 Linköping, Sweden, and Division of Highway and Railway Engineering, Royal Institute of Technology, KTH, SE-100 44 Stockholm, Sweden.
2. Faculty of Civil and Environmental Engineering, University of Iceland, Hjardarhagi 2-6, IS-107 Reykjavik, Iceland, and Pavement Technology, Swedish National Road and Transport Research Institute, SE-581 95 Linköping, Sweden.