[Music]
(Heather Dylla) For many highway agencies,
sustainability has emerged as an important
consideration in the way they manage
their assets. Sustainability encompasses
three key elements: economic, environment,
and social dimensions.
For pavement structures, sustainable pavements are
defined as those that:
1) achieve the engineering goals for which they
were constructed; 2) preserve and ideally
restore surrounding ecosystems;
3) use financial, human, and environmental
resources wisely; and 4) meet basic
human needs such as health, safety, equity,
employment, comfort, and happiness.
These remain aspirational goals as
sustainability practices continue to
evolve.
(narrator) Like many other highway agencies, the
Virginia Department of Transportation is
working to integrate sustainable solutions
in the management of its pavement network
in an era of limited resources
and increased construction
costs.
To meet this challenge, VDOT demonstrated
the use of full depth reclamation (FDR),
cold-in-place recycling (CIR), and
cold central-plant recycling (CCPR) methods
for rehabilitating two interstate highway projects:
one on I-81 and the other
on I-64.
During the 2011 construction season,
VDOT rehabilitated a 3.66-mile pavement section
of Southbound I-81 near Stanton.
(Brian Diefenderfer) The project on I-81 was the first time
in the United States that full depth reclamation,
cold-in-place recycling, and
cold central-plant recycling techniques
were used together on an interstate
project.
The project cost $7.64 million
and was completed within 8 months.
The recycling work was completed in
fewer than 20 working days.
(narrator) Work was done first on the right lane
and then on the left.
Structural designs were developed using
the AASHTO 1993 procedure, and a
mid-project design change was made in
the right lane.
The cold central-plant recycling and
cold-in-place recycling materials were
produced with a foam asphalt content of 2 percent
and a cement content of
1 percent.
The full depth reclamation was
stabilized using a 3 percent
combination of cement and a proprietary
lime kiln dust product.
Key to the project's success, VDOT worked
collaboratively with a contractor in
developing relevant materials and
testing specifications.
A unique traffic management plan
that allowed greater access for the contractor
while minimizing delays and disruptions
to the traveling public
was implemented.
To test the performance of the pavement
design used on I-81,
VDOT sponsored the construction and
testing of several recycled pavement
sections at the NCAT Test Track.
One of these sections mimicked the
design of the right lane of I-81 and
allowed VDOT and NCAT researchers to
quantify the performance of the design
using embedded instrumentation.
To date, that specific test section has
carried more than 30 million ESALs
with no signs of distress and appeared to function
as a perpetual section, based on
very low strain values recorded by the
instrumentation.
The good performance of the CCPR over
FDR concept on the I-81 project and on
the NCAT Test Track encouraged VDOT to
employ this design technique for the
widening and reconstruction of a portion
of I-64 near Williamsburg in 2017.
Recycling designs inspired by those used
on I-81 and at NCAT were developed to
add additional lanes and reconstruct the
existing lanes in the most
cost-effective way.
Both projects provided significant
benefits in terms of cost savings.
For example, when compared to several other
pavement rehabilitation alternatives,
the estimated cost savings for the I-81 project
range from a few percentages of
the $7.9 million contract to
more than $70 million.
On the I-64 project, VDOT identified
more than $10 million in cost savings
while using more than 500,000 tons
of recycled materials.
The projects also produced environmental
benefits as well.
Based on a simple life cycle assessment study,
using data from these projects,
the three recycled sections on the I-81 project
showed 50 to 70 percent potential energy reductions;
and the two recycled sections on I-64
showed 25 to 45 percent potential energy reductions
when compared to a
structurally similar conventional asphalt pavement
constructed without any
recycled materials.
(Brian Diefenderfer) These projects showed us that it is
possible to engineer the design of
high-volume asphalt pavements utilizing
recycling techniques to achieve both
lower costs
and environmental benefits.
VDOT continues to look for projects
where these innovative technologies can
be implemented.
(narrator) To learn more about how the
Sustainable Pavements Program can help you,
please visit our website.
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