1. Dept. of Civil Engineering, Univ. of Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia (corresponding author).
2. Research Fellow, Housing Research Centre, Dept. of Civil Engineering, Univ. of Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
3. Lecturer, School of Civil and Environmental Engineering, Nanyang Technological Univ., 50 Nanyang Ave., Singapore 639798, Singapore.
4. Professor, Dept. of Civil Engineering, Univ. of Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
5. Reader, BRE Centre for Innovative Construction Materials, Dept. of Architecture and Civil Engineering, Univ. of Bath, Bath BA2 7AY, U.K.
6. Dept. of Civil Engineering, Univ. of Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.