1. Assoc. Prof., Envir. Engrg. Res. Ctr., School of Civ. and Struct. Engrg., Nanyang Technol. Univ., Nanyang Ave., Singapore 639798 (corresponding author).
2. Ceramic Technologies Pte Ltd, 61 Tuas Cresent, Singapore 638737.
3. Envir. Engrg. Res. Ctr., School of Civ. and Struct. Engrg., Nanyang Technol. Univ., Nanyang Ave., Singapore 639798.
4. Envir. Engrg. and Sci., Clemson Univ., 342 Computer Court, Anderson, SC 29625-6510.