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(whoosh)

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- [Narrator] Geosynthetics
are products such as fabrics

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or grids used to stabilize and strengthen

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the terrain supporting roadway pavements.

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Over a decade of research

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and implementation
conducted in partnership

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between the Texas
Department of Transportation

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and the Center for Transportation
Research has produced

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new testing devices, procedures,
and refined specifications

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in the use of geosynthetics
to stabilize roadways.

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In the most recent implementation
phase of this effort,

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researchers supported
the design, construction,

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monitoring, and data interpretation

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of pavement sections constructed
on Interstate Highway 10

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near San Antonio using
multiple geogrid products.

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- The geogrids were installed
on flexible pavement sections

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on the frontage road of IH-10,
just east of San Antonio.

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And the pavement structure
itself was a new construction,

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so the experiments included the testing

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of three different types of geogrids.

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And then the test sections,
I guess what's what's unique

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about this research study is
that they were instrumented

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with a variety of different
instruments and gauges.

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- This was a major monitoring
program, so in the ground,

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we installed many, many, I'm
guessing on the order of 300,

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400 sensors for multiple cross-sections,

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and these are flexible pavements.

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Some of them have geogrids,

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some of them do not have geogrids,

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and essentially a monitoring program

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and a field testing
program has been conducted

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over the last several years

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in order to evaluate the
performance of the sections

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and how the sections
compare to each other.

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- So following construction and
every six months thereafter,

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the researchers ran a variety

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of controlled load experiments

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on top of the instrumented
and controlled collection.

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And they use falling weight
deflectometer testing

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and static load tests to gauge
the response of the pavement.

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- The sensors allow us to understand

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how these different pavements are working

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without having to wait the
10, 15, 20 years to understand

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just because time has passed
by, which one performed better.

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The sensors allow us to
do that way ahead of time.

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- We are one step closer
to including geogrid

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in flexible pavement
design methods in Texas.

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I don't think we're quite there yet.

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And I think importantly, geogrids
could potentially be used

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to reduce the thickness requirements

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of base and surface layers.

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- We do know that geosynthetics
improved the performance

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of roadways, and we did
know that for a while,

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but now we know why

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the geosynthetics improve
the performance of roadways.

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By knowing why, we're now
able to optimize the design,

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we're now able to write
appropriate specifications,

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we're able to improve
this technology for good.

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- [Narrator] For more information,

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and to find the publications
for this project,

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please visit the TxDOT Research Library

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at the link shown below.