Sharon Kershbaum, deputy director of DDOT, said VRAM is safe to drive over shortly after it is applied to the road — if cars are driving perpendicular to the sealant. In this case, Kershbaum said, cars were driving parallel to the freshly applied asphalt, and workers who applied the VRAM apparently didn’t know the material couldn’t be driven on so soon.
“That was the problem,” she said. “Really, it’s easy to modify. We’ve learned with some sand, some dust, some stone, there’s ways you can coat it and then cars can continue to drive on it. We’ve really figured out the problem, which means we can continue to use [VRAM].”
The work on D.C. 295, which is ongoing, is the first District project to use VRAM, Kershbaum said, although the city has used similar sealants in the past.
“We know it’s tested,” she said. “We know other jurisdictions use it all the time.”
Kershbaum said the VRAM was applied by Fort Myer Construction Corporation, but the company said in a statement it was applied by the certified contractor of the sealant’s manufacturer.
Fort Myer handles many D.C. government construction projects. Kershbaum said the city would need to “unpack” what consequences, if any, the District might impose on the company.
“Fort Myer Construction Corporation is working closely with the District Department of Transportation to investigate the cause of the incident," the Fort Myer statement said. “We have proudly served the District of Columbia, Maryland, and Virginia for 50 years completing infrastructure construction projects that keep our neighbors on the go and make our communities beautiful.”
The city told drivers whose tires were gummed up with asphalt to file a claim with the D.C. Office of Risk Management to cover the cost of repairs. DDOT reported about 5 a.m. Thursday the road was reopened.
R. Christopher Williams, director of the Asphalt Materials and Pavement Program at Iowa State University, said VRAM is meant to help make roads last longer by sealing the junctions between 12-foot lanes of pavement that make up a road.
Crews generally apply a 12-inch to 18-inch layer of VRAM, that is 1/8 of an inch thick before large paving machines roll through to lay down the pavement, Williams said. The heat of the pavement essentially draws in the VRAM, sealing the long joint between each of the new lanes of pavement. That better prevents water from getting in and damaging the new road, he said.
“They chose to use a premium product that was going to extend the pavement life and reduce the amount of maintenance,” Williams said, adding that using VRAM could help make the road last longer than the typical 20 years.
Williams speculated that “either the VRAM was put down too far in advance of the paving operations, or … they didn’t have the intermediate traffic control necessary to keep the traffic off.”
Both VRAM and pavement contain liquid asphalt, which is derived from crude petroleum. But VRAM has a lot more of the liquid asphalt, Williams said. Still, it should only take an hour or two from the end of construction for the hot pavement to become cool enough for motorists to safely driver over it, he said.
Emily Davies contributed to this report.
This story was updated Friday to include a statement from Fort Myer Construction Corporation.