Benefits, Limitations and Uses of Roller Compacted Concrete – RCC
Paving contractors, highway builders, and even government agencies are turning to roller-compacted concrete as the pavement of choice in greater numbers as acceptance of roller-compacted concrete, also known as RCC, grows in the United States. RCC offers unique qualities unlike traditional concrete or asphalt that make the pavement an economical, fast-build candidate for many applications previously reserved for conventional asphalt or concrete.
RCC has traditionally been used for surfaces carrying heavy loads at low speeds due to its relatively coarse texture, but in recent years RCC has been selected as the preferred flooring for a greater number of commercial and industrial applications. Cities such as Columbus, Ohio, have begun using roller-compacted concrete for residential streets, and Atlanta, Georgia, has used RCC for interstate shoulder construction. RCC is primarily used in the construction of industrial and commercial parking areas and low-traffic road surfaces.
Typical RCC applications include:
- Industrial access roads and parking areas
- Shipyards and seaports
- Truck and freight terminals and distribution centers
- Bulk commodity storage and composting areas
- Aircraft parking areas
- Urban, rural roads and parks
- large commercial parking lots
- Temporary travel lanes
The RCC is also being used in paving systems for higher traffic speeds, serving as the base for traditional concrete or the bottom level in a two-level paving operation.
The use of roller-compacted concrete has many benefits, but the main factor is that RCC can be built faster and cheaper than traditional concrete and multi-layer asphalt pavements. RCC can be built quickly because it is typically placed with an asphalt paver equipped with a standard or high-density screed, and then compacted with rollers. Unlike conventional concrete, forms, dowels, reinforcing steel and vibration are not used. Also, no transverse joints are required; however, when the project specifies that they must be present, the joints are further apart than conventional concrete.
The cost savings associated with RCC are attributed not only to the ease of construction, but the material also uses less Portland cement, the most expensive ingredient in conventional concrete. The specific savings associated with the use of roller-compacted concrete depend on the complexity of the construction, the size of the project, and the specified mix design.
Additional benefits of RCC – Roller Compacted Concrete
- Durability and resistance to chemical attack
- High freeze-thaw durability even without the use of entrained air
- High strength capable of withstanding repetitive heavy loads without failing
- Reduced cracking and shrinkage
- Rigid surface eliminates rutting except in areas where heavy tire chains or studded tires are used
- Resists abrasion even under heavy traffic volume and loads
- Light colored surface reduces lighting needed for parking and storage areas
- Light vehicles and cars can travel on RCC soon after completion
While the benefits of RCC are numerous, it is important to understand that there are also some limitations to the use of roller compacted concrete. For example, the production of large quantities of RCC requires specialized equipment. While a transit mix truck can mix RCC, the mixing time is significantly longer than conventional concrete and the amount of RCC that can be mixed in the truck is reduced due to the dryness of the RCC mix. Also, the RCC surface may not be suitable for high speed traffic without diamond grinding.
Other RCC limitations
- Adjacent slabs and multiple horizontal layers should be placed within one hour to ensure good bond, unless a cold joint is planned.
- Pavement edges are more difficult to compact, causing most specifications to call for a modified proctor density of 96% in cold joints
- The use of admixtures in RCC can be higher than traditional concrete due to the dryness of the material
- RCC paving in hot weather requires extra attention to reduce the potential for water loss and evaporation
When considering the versatility of RCC, its ease of application compared to conventional concrete, and its durability compared to asphalt, it becomes clear that roller-compacted concrete is a suitable paving substitute. When considering the rising cost of oil and petroleum products such as asphalt, it becomes clear that RCC is likely the paving material of the future.