Study on Mix Proportion Design Procedure for Super-high Cementitious RCC with Stone Powder Replacement

Super-high cementitious roller-compacted concrete (SHCRCC) that have unit cementitious materials content of 220 kg/m3 or higher can be recognized as "construction friendly RCC". In this study, the proposition of how to reduce construction costs without sacrificing the workability was investigated. To solve the issue, mix proportions replacing the high volume of cementitious materials, cement, and fly ash with stone powder (SP) were surveyed. Based on exhaustive investigations, it was found that the mix proportion can be realized with sufficient tolerance of workability. In the proposed mix propor-tion, the cementitious materials replaced with SP up to about 100 kg/m3 provide a large paste volume of 240 to 260 L/m3. In addition, it was verified that the SP plays a sufficient role as an alternative to cementitious materials since the com-pressive and tensile strengths of the RCC, and the watertightness and bond strength at lift joints are the same as, if not better than high cementitious RCC (HCRCC). Reducing cementitious materials also helps to control the temperature rise of the RCC. In the case of a large-scale RCC dam of 150 m in height and 2 million m3 volume with 5 zones, it is found that a cost reduction is about 25 to 30% for cementitious materials and chemical admixture, and a placement speed is about 20% faster than that of medium cementitious RCC (MCRCC) thanks to a large workability margin.