1. Environment-Friendly Concrete Research Institute, Kongju National University, 1223-24 Cheonan-daero, Cheonan City 330-717, Chungcheongnam-do, Republic of Korea
2. Department of Architectural Engineering, Kongju National University, 1223-24 Cheonan-daero, Cheonan City 330-717, Chungcheongnam-do, Republic of Korea