After Hurricane Harvey broke the US record for rainfall from a single storm dumping more than 51 inches of rain (CNN News) in and around the Houston, Texas area in August, 2017, the floodwaters slowly receded to reveal one positive sign: the Texas DOT freeway system within the city was intact. Survival of that infrastructure points to the high resiliency of continuously reinforced concrete paving (CRCP) after flooding and other disasters, says Elizabeth Lukefahr, Executive Director-Texas Concrete Pavement Association (TCPA) and former Concrete and Concrete Pavement Engineer-Texas Department of Transportation (TxDOT). “When the waters receded, other than cleaning up debris, there was no repair of any (CRCP) section of Texas DOT’s pavements in the city that were flooded,” says Lukefahr.
Lukefahr added that for many of those pavements, it was the third time they had flooded in 15 years. Texas is a state already committed to CRCP as its primary concrete pavement, so the freeways’ ability to weather the flood brought a fresh look at why spending more upfront to install CRCP makes sense.
From highways to airports, owners are weighing the higher initial cost of CRCP against long-term advantages, including fewer repairs and maintenance and more rehabilitation options. Lukefahr says the resiliency of CRCP can be critical, not just in flooded areas, but also for roads with heavy truck traffic. And in areas with wildfires, it will fare much better than asphalt, she says. “Those TxDOT CRCP sections in downtown Houston have performed better under those extreme weather events than most people would have otherwise predicted,” says Lukefahr.
Texas DOT officials confirm that repairs were NOT needed for CRCP. Danny Perez, Public Information Officer-TxDOT said, “We are not aware of any issues with the CRC pavement occurring after waters receded following Hurricane Harvey. It is the joint area where many distresses occur in concrete pavement. This could certainly be one of the reasons why CRCP outperforms jointed concrete pavement.”
There are no comparative data between flooded CRCP sections of Texas DOT pavements and other jointed and flexible paving, according to the agency, the main reason being that all of metro Houston’s main lanes are CRCP. The TCPA is working with the Texas A&M Transportation Institute to document CRCP performance and cost data. One goal of the research is to encourage engineers to factor pavement resiliency into their decisions. “This resiliency topic can be tailored to whatever the most immediate threat is in your geographic area,” Lukfahr says. Owners may start recognizing resiliency to extreme weather as a decision factor, perhaps leading to more CRCP in evacuation routes, she adds.
SEVERAL STATES INCORPORATING CRCP:
As Texas, Illinois and California lead CRCP use, other states are beginning to incorporate it, such as Virginia, Oklahoma and New Mexico. Indiana recently used CRCP to rebuild the interstate pavement under a bridge that needed higher clearance because it kept getting hit by trucks. CRCP requires less concrete thickness compared to jointed plain.
Even though CRCP tests in 1949 and 1971 were successful, California stuck with jointed plain concrete pavement (JPCP). But CRCP’s minimal repair and rehabilitation advantages have led California to return to it in the past decade, and other states are following suit. The Federal Highway Administration (FHWA) is working with several states to advance CRCP use, said Sam Tyson, Concrete Pavement Engineer-FHWA and ISCP Member. “A significant new CRCP project slated for Spring 2018 on New Mexico’s NM-136 will carry high volumes of heavily loaded truck traffic from an international border-crossing from Mexico to a rail facility north of the border in New Mexico,” he said. Nearly $22.7M/of $47.6M total project cost is for CRCP, according to Benito Trevino, New Mexico DOT (NMDOT).
Lukefahr said states interested in incorporating CRCP have sought advice from TxDOT officials for specifications, design standards, and programs because “the ability to continue the life of the CRCP (vs. the much-used jointed pavement) is more attractive than continual repair and maintenance of jointed sections on busy roadways.”
HIGHER INITIAL COST, YET MORE DURABILITY, STRENGTH, AND LONGEVITY:
CRCP will be a better long-term performer of roads with a lot of 18-wheel truck traffic, according to Lukefahr. Texas A&M Transportation Institute has been studying impacts of truck drafting, or platooning, to reduce wind resistance. The trucking industry is also working with TxDOT on having the lead vehicle operated by a conventional driver with vehicles trailing electronically. These platoons impact pavement in an entirely different way—no opportunity to rebound between sets of axles. CRCP would fare best of all the pavement types under that pressure, Lukefahr says.
“Continuously reinforced really is the workhorse, heavy-duty, long-lasting pavement,” she says.
ILLINOIS TOLLWAY PLANS AIM FOR 50-YEAR DESIGN WITH CRCP:
In a $4B-expansion of the Illinois Tollway’s most congested stretch, CRCP will be used on more than 25 miles of I-294 stretching from O’Hare International south to 95th Street. Mike Plei, Consultant-Illinois said the privately funded tollway chose CRCP because of its zero-maintenance and longer life. “The life-cycle analysis done by the agency showed that the CRCP would be the best option with the lowest overall cost.”
Plea, who served on a research committee that built test sections for the massive project, added that Illinois has used CRCP for years, and the cracks don’t get wider or deteriorate. With jointed pavement, Midwestern states have experienced deterioration in joints—partly from using de-icing chemical solutions, and temperature effects moving the concrete, Plei explained. “There is a lot of research on reducing the use of joints because that’s where the problems come in, and with CRCP, you can pretty much eliminate the joints.”
CONTRACTOR CONSIDERATIONS:
Bill Davenport, American Concrete Pavement Association (ACPA) and ISCP Silver Organizational Member explained that because of CRCP’s price and relatively new use, a lot of transportation agencies and contractors stay with what they know – jointed plain pavement. “We are using dowel bars and tie bars, so we are using steel, obviously, in a lot of our concrete pavements, but the jointed plain is probably the most prevalent. That has to do with cost but also the experience of the contractors with that type of pavement,” he said.
Gerald Voigt, President and CEO-ACPA and ISCP Silver Organizational Member, doesn’t see much difference between jointed concrete pavement and CRCP. “In fact, CRCP can be a more uniform placement since the steel is continuous, and with jointed concrete pavement, there are dowel baskets every 15 feet. The learning curve is probably more about steel placement, splicing and fastening. Vibration is one consideration, so the contractor has to have this set up properly to ensure quality, since the vibration has to get consolidation below the steel.”
Eric Ferrebee, Technical Service Engineer-ACPA and ISCP Silver Organizational Member, said a consistent mix must be properly consolidated. “The consolidation is key for CRCP, as the concrete needs to adequately bond to the steel for proper performance.”
Plei has viewed most CRCP projects in the United States and said that he has met Texas contractors who love CRCP and won’t build jointed pavement, noting that Texas hit a record in August with 1 million square yards of CRCP bid.
He said that because of their vast experience and other factors, Texas contractors also tend to build at much lower prices than in the rest of the country. “Texans are so used to building CRCP, they do it efficiently compared to contractors outside of Texas who build maybe one CRCP project every 10 years, so those crews need to pay a little more attention.”
For the entire Equipment World Better Roads online article titled “CRCP roadways proved resilient after Hurricane Harvey—and states are taking note”, please go to: https://www.equipmentworld.com/crcp-roadways-proved-resilient-after-hurricane-harvey-and-states-are-taking-note/