1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Chalmers Univ. of Technology, Gothenburg 412 96, Sweden (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Chalmers Univ. of Technology, Gothenburg 412 96, Sweden.
3. Professor, CBI Swedish Cement and Concrete Research Institute, Borås 504 62, Sweden.