Abstract
For the first time, mass underwater concrete with S. C. A. (Segregation Control Admixture) was used for a substructure of a bridge on laying-down Caisson method. The underwater concrete with S. C. A. has the following advantages. First, it keeps strength deterioration under water at minimum. Second, it is uniform in quality; that is good for execution of work. Third, it hardly makes water turbid, for it is controlled to prevent segregation under water. The present paper refer mainly to the result of examination on such as the flow gradient, temperature rise of the concrete caused by heat of hydration, execution efficiency of the concrete plant, and so on.
