ABSTRACT
This report describes the characteristics of dam concrete used for the construction of four dams that have been completed with the RCD construction method, from the viewpoint of mix design and quality control. As regard to mix design, (1) in the Nunome Dam, replacement percentage of flyash contained in flyash cement was increased from 30% to 35%; (2) in the Urayama Dam, dry-type production of coarse aggregate was undertaken; (3) in the Hiyoshi Dam, low-grade aggregate and fine grain were used as efficient utilization of materials; (4) in the Tomisato Dam, site mixing method for cement and flyash was adopted. In addition, the relation between flyash replacement percentage and elongation of long-term age is also described. As regard to quality control of concrete, optimum chemical admixture and additive were decided after tests to secure workability of RCD concrete placing in summer.
