ABSTRACT
A 100-m high arch dam built in a high sismicity area usually will require a maximum compressive strength of 30 Mpa at 180 days, and a straight gravity type one may require ca. 15 Mpa, or the associated tensile strength capacity. This values will approach to 40 MPa and 20 MPa, respectively for arch dams or straight gravity dams, if the height is increased to 200 m. From this perspective, why are high strengths required, and therefore high cementitious content, in straight gravity RCC dams? Is the answer in the impermeability demand? Or, is it a requirement imposed by the construction joints and construction methods? Or, is it just a heritage of the general knowledge (or lack of) in the Roller Compacted Concrete? In this paper, the Authors make a discussion on this topics mainly orientated to show evidences that the RCC is just CONCRETE, placed on site by a somehow different methodology and that there are particular tools already designed and developed that may be used during construction to guarantee the impermeability and monolithism at the construction joints. It seems like the application of so many different criteria in different site conditions and regions and by different people makes RCC something different than a concrete. However, the cares that need to be taken in the selection of materials, in the design of the site installations and in the quality control do not differ much from conventional vibrated mass concrete (CVC) practice. Those countries with a large experience in concrete dam construction that are considering the use of RCC for their future dams, should not take RCC as a new material but just as a different method of construction, that if successfully implemented, might bring a reasonable economy for the Project.
