抄録
In part 3, authors analyze theoretically about the condition of prevention of concrete from cracking due to drying shrinkage and tensile creep in reinforced concrete structure. The conclusion of this study is as follow; (1) The average of drying shrinkage of medium concrete is 25〜30% smaller than that of wet concrete. (2) The average of tensile creep coefficient of medium concrete is 10〜15% larger than that of stiff concrete. (3) The limitation of water cement ratio in the mix-proportion of medium concrete in site is 50% for the case of using normal portland cement and 55% for the case of using high-early portland cement so as to prevent the crack. And the suitable range of unite cement is 300〜475kg/m^3 from some economical factors and effects of fire explosion.
