Brazilian experience of roller compacted concrete (RCC)

The technology of RCC has been used for the construction of dams in Brazil for nearly 25 years since it was introduced at S (a) over tildeo Sim (a) over tildeo dam in 1977. During this period 43 new projects were concluded using RCC, and they included 8.26 million of m(3) of this special kind of concrete. The cementitious content of these projects ranged from 65 kg/m(3) to 200 kg/m(3) and new techniques of construction procedures are still being developed. Actually 13 new projects in Brazil are schedule or under construction considering the RCC technology. The RCC experience in Brazil includes the use of powdered aggregates (material finer than sieve #200 - 0.075mm) and also increasing the moisture of RCC - Cannon Time test range from 10 to 15 seconds have been used largely considering Furnas experience. New development of RCC as well as the sloped layer method and the use of slip form had already been used successfully in projects like Lajeado and Canabrava dams, and the structures are working satisfactorily with negligible seepage. Both dams are 40 m high and 3 00 m long and the cement content of RCC at Lajeado was 70 kg/m(3) resulting in 12.6 MPa average compressive strength at the age of 365 days. The results showing the Furnas experience are included in this paper.