[1] Costruction Material Div., SOC Co. Ltd., Ohjinbo-cho, Hunabahi, 274-0082, Japan
[2] Cement Concrete Res. Lab., SOC Co. Ltd, Toyotomi-cho, Hunabahi, 274-8601, Japan
[3] Dept of Civil and Earth Resources Eng., Kyoto Univ., Nishikyou-ku, Kyoto, 615-8530, Japan