Reporting on innovative products
and strategies for building better, safer roads
June/July 1999
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Pavement Smoothness Tips from the King
of the Asphalt Oval
As the most successful race car driver in NASCAR (National Association
for Stock Car Auto Racing) history, Richard Petty is known as the king of
the asphalt oval. Now, as star of a new Federal Highway Administration (FHWA)
videotape, Smoother Pavements: Highways Fit for a King, he’s headlining
a campaign to achieve smoother asphalt pavements nationwide.
Developed by FHWA’s Western Resource Center, in cooperation with the
Arizona Department of Transportation (DOT), the video describes Arizona DOT’s
pavement smoothness program. Under the program, the State inserts a smoothness
clause into highway contracts, which provides incentive payments for pavements
that meet a specified standard of smoothness.
"After several contracts with the smoothness clause had been
completed," says Jim Delton of Arizona DOT, "we were able to show
contractors that they could obtain significant incentive payments by using the
new technologies and equipment available today." Some contractors have
earned as much as $280,000 in incentive payments. "We consider that money
well spent because we’re getting much better final smoothness levels than we
ever achieved in the past," says Delton. And in an unexpected bonus, some
contractors are reducing their up-front bid price, with the expectation of
earning an incentive later.
Arizona DOT and its contractors have found that the simplest, least expensive
way to improve pavement smoothness is to maintain a more continuous,
uninterrupted paving process instead of stopping and starting, which can result
in bumps in the mat. For example, crews should make sure that the paving machine
always has hot mix in front of it, so that there’s no need to stop and wait for
another load. Smoothness can also be improved by making sure that the steel
wheeled rollers are clean, track straight, and stay on the mat. If the roller
is not 100 percent on the mat, it could pick up material on the edge of the
roadway and transfer it to the new surface. And while improving paving operations
is key to achieving smoother pavements, the asphalt plant also has an important
role, keeping the temperature of the hot mix as consistent as possible and
preventing mix segregation.
By introducing the smoothness specification, "we have changed the state
of the art, " says Delton. "The smoothness specification encourages
innovation and quality work from contractors."
The video was originally slated for distribution only in western States, but
FHWA’s new national focus on improving pavement smoothness means that distribution
has broadened to include transportation departments and contractors across the
country, as well as such organizations as the National Asphalt Pavement Association.
To obtain a copy of the video, contact John Cagle at FHWA, 415-744-2613 (fax:
415-744-2620; email: john.cagle@fhwa.dot.gov).
For information on pavement smoothness specifications, contact George Jones at FHWA,
202-366-1554 (fax: 202-366-9981; email:
george.jones@fhwa.dot.gov).
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