Better Roads Digital Magazine
Issue link: http://read.dmtmag.com/i/221550
RoadScience by Tom Kuennen, Contributing Editor Photo courtesy of Tom Kuennen Photos courtesy of Tom Kuennen A parking lot demonstration of roller-compacted concrete (RCC), including test trip pavement, curing, saw cutting and testing, was conducted at World of Concrete 2013. The ABCs of RCC Roller-compacted concrete advances its invasion of pavements A s roller-compacted concrete inexorably penetrates existing asphalt pavement markets, research into their composition and performance is ramping up as specifications are being fine-tuned by ASTM. Up to the past decade, roller-compacted concrete (RCC) mixes principally were used in a variety of heavy-duty applications such as logging yards, loading docks, intermodal port facilities, large parking areas and dams. But as highway agencies and contractors followed in the wake of early adopters, in the past 10 years, it has started to move into pavements. "Roller-compacted concrete is gaining popularity as a paving alternative for a number of roadway applications," says Stacy G. Williams, Ph.D., P.E., research associate professor in Department of Civil Engineering at the University of Arkansas-Fayetteville. "RCC is a zero-slump concrete mixture that does not require forms, reinforcing, jointing or finishing," Williams says. "This type of material combines [some] advantages of conventional concrete pavements with the ease of construction of an asphalt pavement and can be opened to traffic more quickly than conventional concrete pavements." Simplicity is the essence of RCC, compared to conventional portland cement concrete and even hot- or cold-mix asphalt. "Roller-compacted concrete is concrete pavement placed a different way," says David R. Luhr, Ph.D., P.E., former program manager, Portland Cement Association, and now with the Washington State Department of Transportation. "RCC has zero slump, uses no forms, dowels or reinforcing steel and requires no finishing," he says. Benefits of RCC, Luhr says, include low construction cost and rapid construction sequence, resulting in a tough, strong, durable product with low maintenance demands and a longtime low life-cycle cost. What it doesn't do, he says, is provide a high-level pavement suitable for arterials or interstate-type highways. "RCC does not provide all of the features of conventional concrete pavement," Luhr says. The final product will lack acceptable pavement surface texture and uniformity, smoothness and, for that matter, aesthetics. Better Roads December 2013 5