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Cement strengthens US 79
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Cement-recycled US 79
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State inspector Ken Smith, TxDOT Jacksonville office, digs
down to check the depth of pulverization during a cement recycling
project on US 79
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 When
severe alligator cracking reared its ugly head along a heavily trafficked
US 79 near Jacksonville, state engineers faced a challenge. Drop
offs along the narrow, hilly two-lane highway meant building detours
would be impractical. "We had to keep traffic on it while we
strengthened it," says Mark Sturrock, assistant area engineer,
Jacksonville area office, Texas Dept. of Transportation. Engineers
decided to recycle the roadway in-place. They tested lime and cement
to determine which material worked best, says Sturrock. Full-depth
recycling (FDR) with cement proved "the most efficient way
to keep the road open and not double-handle the material,"
he says. In March 2002, crews from Madden Contracting Inc., Minden,
La., began the $7.4-million contract to rebuild an 11-mile stretch
of US 79 west of Jacksonville. Madden mixed the existing asphalt
and base with more than 8,000 tons of cement, 4% cement by dry weight
of the materials, into 333,864 sq. yd. of roadway to create a strong,
long-lasting base. A five-inch asphalt surface topped the new road.
"There really were no negatives but the tempo was fast. It
kept us on our toes," says Ken Smith, the project's TxDOT inspector.
Madden crews mixed in 260 tons of cement per day. "It's simpler
than fooling with lime because you have to cut lime twice,"
adds Kirkland. Finished four months ahead of schedule, the project
was deemed "a tremendous success," says Ken Smith, the
state inspector overseeing the project. "With cement, you get
a tremendous strength." The success of the FDR project encouraged
engineers to design a second project for US 79, now underway east
of Jacksonville. The 10-mile, $6.1-million project is slated for
completion next summer.
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