Roller Compacted Concrete (RCC) is, as it name implies, concrete compacted by roller. It is therefore differs from conventional concrete in its consistence as it must support rollers in its unhardened state.
The RCC concrete mix must be dry enough to prevent the sinking of the roller but wet enough to permit adequate distribution of the binder during mixing and compaction operations. The development of RCC has caused a major shift in the practice of constructing mass concrete dams which can now be finished as much as 1 to 2 years earlier than conventional mass concrete dams. Up tp 18 000 cubic meter of RCC can be placed in one day.
RCC is constructed similarly to layer-works in road construction and using similar equipment. RCC is placed using dump trucks or conveyors, spread by bulldozers or special modified asphalt pavers. Extenders are extensively used in RCC to reduce costs and to control temperature rises during hydration of cement. RCC is proportioned by using both soil compaction principle and basic concrete technology.
The first Roller Compacted Concrete RCC dam built in the USA was the Willow Creek Dam on Willow Creek, a tributary in Oregon of the Columbia River. RCC is also extensively used for concrete pavements, particular in Canada and Spain. Some low-volume roads have been build in South Africa.
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