1. Research Assistant Professor, Dept. of Civil Engineering, Clemson Univ., Clemson, SC 29634-0911 (corresponding author).
2. Research Assistant Professor, Dept. of Civil Engineering, Clemson Univ., SC 29634-0911.
3. Guest Professor, State Key Laboratory of Silicate Materials for Architectures, Wuhan Univ. of Technology, Wuhan 430070, China.