INTRODUCTION GeneralRoller-compacted concrete (RCC) is probably the most important development in concrete dam technology in the past quarter century. The use of RCC has allowed many new dams to become economically feasible due to the reduced cost realized from the rapid construction method. It also has provided design engineers with an opportunity to economically rehabilitate existing concrete dams that have problems with stability and need buttressing@ and has improved embankment dams with inadequate spillway capacity by providing a means by which they can be safely overtopped. This document summarizes the current state-of-the-art for design and construction of RCC in mass concrete applications. It is intended to guide the reader through developments in RCC technology@ including materials@ mixture proportioning@ properties design considerations@ construction@ and quality control and testing. Although this report deals primarily with mass placements@ RCC is also used for pavements@ which are covered in ACI 325.1R.