Deep Windrow, Wide Paving - Hot-Mix Magazine

A SPECIAL TOOL
FOR DEEP WINDROWS
AND WIDE PAVING
They used their
Roadtec Shuttle Buggy ® MTV
to pave a major airport runway
at San Francisco on the weekends.
Then, during the week, they used it to pave
the base for another runway at the San Jose airport.
HOT-MIX MAGAZINE 22 VOLUME 7, NUMBER 2

MEETING A TIGHT DEADLINE
can be a challenge in itself.
But imagine tackling two
different airport paving jobs at the
same time. Both of them involve
extremely strict FAA specifications,
of course. And now picture using
the same piece of equipment on
both jobs—even though the jobs
are about 34 miles (55 km) apart.
Suddenly that challenge becomes
a little tougher, doesn’t it?
But working on tight schedules
under tough specifications can be
quite a bit easier if you utilize the
right tools. That was a key point
for management to consider when
the Pavex Construction Division of
Graniterock contracted to pave two
runways within the same time
period: one at Norman Y. Mineta
San Jose International Airport and
the other at the San Francisco
International Airport. The special
tool they picked so they could move
quickly on both jobs was a Roadtec
SB-2500B Shuttle Buggy ® material
transfer vehicle (MTV).
“The Shuttle Buggy MTV enabled
us to complete the jobs on time,”
said Ray Woolery, the northern
area superintendent for Pavex
Construction located in Redwood
City, California.
On past jobs, Woolery explained,
Pavex Construction had not used
a Shuttle Buggy MTV. Instead,
they used pickup machines to get
hot-mix asphalt (HMA) from the
windrows to the paver. But the
requirements for paving an airport
runway created special conditions
that made the Shuttle Buggy MTV
both desirable and necessary.
“When paving the San Francisco
and San Jose airports’ runways,
we were dealing with very wide
paving—in order to reduce the
number of joints—and varying
depths,” said Woolery. “That’s
where Roadtec’s Shuttle Buggy
MTV came in. You couldn’t do that
kind of work with a regular pickup
machine, because the windrows
would have to be too big in order
to supply the paver with enough
mix to meet the width requirements.
Really, the Shuttle Buggy
MTV is the only machine on earth
that I know of that could do
something like this.”
“You couldn’t do that kind of work
with a regular pickup machine
...The Shuttle Buggy MTV
is the only machine on earth
that I know of that could do
something like this.”
“We ran that thing almost nonstop for five weeks,” said Ray Woolery, northern
area superintendent for Pavex Construction. “There were no major problems.
Just routine maintenance—such as making sure the chains were tight and
cleaning the machine. The biggest thing was making sure it was clean.”
At the San Francisco airport,
Pavex Construction resurfaced the
10,800-ft. (3,292-m) main runway
with 3 to 9 in. (8 to 23 cm) of
HMA. For the San Jose project,
Pavex Construction laid a 2-in.
(5-cm) lift of HMA on Runway 30
Left that will serve as a base for a
16-in. (41-cm) layer of concrete.
The sheer volume of material on
the two projects—about 98,000
tons (88,902 tonnes) of HMA at
San Francisco and 55,000 tons
(49,894 tonnes) at San Jose—
called for the company to do a lot
of paving in a relatively short
amount of time. To expedite the
two jobs, Pavex Construction
came up with a demanding work
schedule for the crews.
“We did San Francisco 24-hours
a day on weekends, from 10 PM
on Friday until 7 AM on Monday.
We would only stop for fuel and
grease,” said Woolery. “Then, on
Monday mornings, we’d move the
Shuttle Buggy MTV the 34 miles
(55 km) to San Jose and pave the
runway there from Tuesday
through Friday.”
The virtually non-stop paving
schedule that Pavex Construction
tackled was another reason the
Roadtec Shuttle Buggy MTV
became a logical imperative for
these projects. Here’s how it
would usually work:
The Shuttle Buggy MTV would
move to an open space near the
paving site where the HMA had
been heavily windrowed from a
bottom-dump vehicle. Using the
SB-2500B MTV’s optional windrow
pickup head, the operator would
FOR MORE INFORMATION
call your Roadtec Regional Sales Manager or call Wendy Porto:
800-272-7100
Fax: 423-265-7521
E-mail: sales@roadtec.com
gather the mix and return to the
runway to supply the mix to the
paver—which never had to stop
working.
The use of the Shuttle Buggy
MTV not only allowed Pavex
Construction to pave unusually
wide areas non-stop. It also
allowed the company to meet its
own high quality standards.
“We strive for quality work, no
matter what equipment we’re
using,” said Woolery. “But with
the Roadtec Shuttle Buggy MTV,
we found improvements in the
quality of mat that would be hard
to achieve without it.”
Woolery went on to list some of
the ways the Shuttle Buggy MTV
improved the quality of paving:
❏ Better compaction: “We used
pickup machines on the shoulders
of the runway at the San Francisco
airport while the Shuttle Buggy
MTV did the mainline part of the
runway,” said Woolery. “And the
compaction density was about 2-
to 3-percent higher with the
paving that was done using the
Shuttle Buggy MTV.”
❏ Better quality mix: “There was
a big difference in the quality of
mix coming out of the paver that
was using the Shuttle Buggy MTV,”
said Woolery. “When the material
is dropped into the Shuttle Buggy
MTV’s hopper, it goes directly onto
the chain. None of it is dropped
into corners where the material
could segregate. And then, the
Shuttle Buggy MTV re-mixes the
material as it feeds it into the paver’s
hopper. Those are all advantages.
Plus, the heat in the mat is much
more even because the paver just
keeps moving.”
❏ Better longitudinal joints:
“Before, when we paved without
the Shuttle Buggy MTV, you could
easily find where the joints were,
even though we worked hard to
make them smooth,” Woolery said.
“But with the Shuttle Buggy MTV,
we can make the job so smooth
that it is very difficult to find the
joints. The inspectors like to take
core samples from the joints, but
on this particular job, they were
perplexed because they just
couldn’t find them!” ▼▲▼
HOT-MIX MAGAZINE 23 VOLUME 7, NUMBER 2