The popularity of Roller Compacted Concrete, commonly referred to as RCC is soaring as more contractors and construction companies begin to better understand the benefits associated with the paving material. The highly durable material has evolved since its creation in 1976 into an affordable and fast construction material used in dams, storage and parking areas, as a base for conventional pavement, and surface for low speed roads, streets, intersections and many other projects.
Roller Compacted Concrete is a very high density, low slump mix usually consisting of mostly aggregates, low cement, and just enough water for hydration. This creates a very dry stiff mix (low slump) that can be placed with conventional concrete equipment or high-density asphalt paving machines, then compacted with rollers. This creates a finished material that has the strength and qualities of conventional concrete with the price and ease of application as asphalt.
Unlike asphalt, the strength of RCC resists many of the problems commonly associated with asphalt like rutting, softening under high temperature, deteriation from fuel and fluid spills, and deforming under heavy loads. Roller Compacted Concrete is placed with the same equipment commonly used for asphalt pavement construction and requires no forms, finishing, surface texturing, joint sawing or sealing; although some projects may elect to seal, saw joints or other work based on aesthetics or special project requirements.
RCC concrete is usually mixed in large high intensity mixers at or near the job site, then dispensed into a dump truck for transport to the job site where it is fed into an asphalt paver and finally compacted. Traditional concrete batch plants do not typically produce roller compacted concrete unless outfitted with a mixing device that can handle very low slump mix. Traditional central mix concrete plants commonly do not have mixers with enough power to properly blend roller compacted concrete at a rate fast enough to be economical.
Innovative products such as portable mixers equipped to handle roller compacted concrete mixing are entering the market that allow a traditional concrete plant to pour RCC up to the rate of the batch plant, but large construction projects commonly require higher production than one typical ready mix plant outfitted with an RCC mixer can produce.
Roller Compacted Concrete becomes most economical when produced in high speed, high volume continuous mixing plants. These style plants can commonly produce 450+ yards of RCC an hour and still be completely portable and self contained. Continuous mixing plants designed for blending roller compacted concrete usually have of high production continuous mixer often called a pugmill. High efficiency pugmills are able to evenly mix the aggregates and cement with the small amount of water used for the RCC at high rates or production allowing one continuous mixing plant to accomplish the job of two or more retrofitted traditional concrete plants.