By Joe Pomerenke
Principal-ARCO/Murray National Construction Company
Roller compacted concrete, or as it is known in the industry as “RCC,” gets its name from the method in which it is constructed. RCC has the same ingredients as conventional concrete mixes, but uses a different portioning of the components to allow it to be placed using asphalt paving equipment. With RCC, the concrete batch supplier reduces the water to cement ratio to provide the required consistency. The resulting mix is wet enough to allow it to pass through the paver equipment while dry enough to prevent sinking of the vibratory roller equipment that compacts the concrete after it is placed. Instead of pouring the concrete mix out of the chute of a concrete truck, RCC is dumped from the back of a dump truck into the paving machine. Once placed, vibratory rollers pass over the paving a set number of times to achieve the proper density. The finished RCC paving can be opened to traffic within hours of final placement. Typical section thickness ranges from 6 inches to 16 inches with a limited stone sub-base depending on the location of the project.
To help understand RCC further, we offer answers to some of the common questions regarding its use and advantages.
Q: What are the most common applications of RCC in Chicago?
A: The most common applications have been in large intermodal yards with crane runways and public roadways. The applications have widened greatly in the past decade to include additional roads and streets, drop lots, container yards and parking lots.
Q: What advantages does it have over concrete paving and asphalt?
A: “RCC has the strength and performance of conventional concrete with the economy and simplicity of asphalt. Coupled with long service life and minimal maintenance, RCC’s low initial cost adds up to economy and value,” according to the Portland Cement Association. RCC is less expensive than conventional concrete paving due to lower cement consumption, minimum formwork, joints and finishing, as well as lower cost of transportation, placement and compaction as RCC is hauled in by dump trucks, spread by paving equipment and compacted by rollers. RCC is priced competitively with asphalt, yet eliminates common and costly problems traditionally associated with asphalt pavement. RCC’s higher strength and durability to resist freeze-thaw damage results in lower maintenance and increased longevity.
Q: What are the disadvantages of RCC?
A: Consistency and appearance are the largest drawbacks to RCC. Exposed RCC is less uniform than traditional concrete or asphalt and has a rougher texture. Also, due to the specific water to cement ratio required for placement, quality control measures and experience in installation are keys to successful RCC installations. For a smoother riding surface, RCC can be topped with a traditional asphalt surface coat.
Q: Why are we not seeing RCC used more for exterior paving in Chicago?
A: Chicago has a very strong asphalt market and RCC has slowly gained traction in the past three years with more asphalt contractors starting to see the benefits of its uses. Due to the limited number of qualified installers and relative newness of the product, growth of RCC is slow, but we expect to see more adoption for the product in the years ahead.
Locally, roller compacted concrete has been used by rail companies to pave heavy crane runways at the intermodal transfer rail yards. More recently, CenterPoint Properties worked with ARCO/Murray National Construction Company to complete a container and wheeled storage yard project for Central States Trucking in Joliet that utilized 12 acres of roller compacted concrete. Since the project, ARCO/Murray has been solicited by owners to evaluate the advantage of incorporating more RCC in future paving projects.
Joe Pomerenke is a principal and director of business development at ARCO/Murray National Construction Company. Pomerenke has led ARCO/Murray’s sales and business development team since 2007 and is responsible for overseeing the overall growth of the company. As a trained engineer, Pomerenke provides ARCO/Murray’s clients with design guidance, project planning and turnkey design and construction proposals.