ACPA Quarter 3 2016

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Quarter 3, 2016 9
n e w s t a n t o n i n t e r c h a n g e
Stringless paving technology was selected for the
roundabout because it required less labor, less
time and produced a smoother paving surface.
Jointing represented the greatest challenge, ad-
mits Sciullo. “The approach and exit legs to the
roundabout are odd angles, which don’t work
well with concrete,” he says. “Pre-planning of
the joints was critical to make sure all the joints
were carefully laid out to the proper alignment
and distance,” he says. CAD [computer-aided
drafting] software was used to develop a joint
plan that worked. “We also isolated the circular
roundabout with an expansion collar so it did
not affect the joints of the approach and exit
legs,” he adds.
According to John M. Becker, P.E., President
of the Pennsylvania Chapter of the American
Concrete Pavement Association, construction
of concrete roundabouts in future projects will
be a bit simpler. “PennDOT central office will
be issuing new standard drawings on jointing
details for concrete roundabouts later this year,”
he says. “This will make concrete pavement
a viable alternative for engineers to consider
when designing roundabouts all across the
Commonwealth.”
Sciullo points out that even though they’ve gone
through the process for the first roundabout, each
of the remaining roundabouts in the project is
different. “One is circular but larger than the first
roundabout, and the other is a teardrop shape
so each requires its own joint plan.”
Tining the roundabout was also a change from
PennDOT’s standard, says Sciullo. “Transverse
tining is our standard but that doesn’t work in
a circle, so we used a stiff broom finish, which
is also better aesthetically.”
One of the lessons learned in the project is that
paving a roundabout in concrete is not too
much different than paving in asphalt, says
Sciullo. “In fact, asphalt takes more time be-
cause concrete is placed in one lift,” he says. The
main difference is the pre-planning for joints,
setting up the machine and training the crew
on the minor differences in technique. He adds,
“Actually, once we finished the pre-planning
and testing, the paving was the easiest part of
the job!” 
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