(whoosh)
- [Narrator] Geosynthetics are products such as fabrics
or grids used to stabilize and strengthen
the terrain supporting roadway pavements.
Over a decade of research
and implementation conducted in partnership
between the Texas Department of Transportation
and the Center for Transportation Research has produced
new testing devices, procedures, and refined specifications
in the use of geosynthetics to stabilize roadways.
In the most recent implementation phase of this effort,
researchers supported the design, construction,
monitoring, and data interpretation
of pavement sections constructed on Interstate Highway 10
near San Antonio using multiple geogrid products.
- The geogrids were installed on flexible pavement sections
on the frontage road of IH-10, just east of San Antonio.
And the pavement structure itself was a new construction,
so the experiments included the testing
of three different types of geogrids.
And then the test sections, I guess what's what's unique
about this research study is that they were instrumented
with a variety of different instruments and gauges.
- This was a major monitoring program, so in the ground,
we installed many, many, I'm guessing on the order of 300,
400 sensors for multiple cross-sections,
and these are flexible pavements.
Some of them have geogrids,
some of them do not have geogrids,
and essentially a monitoring program
and a field testing program has been conducted
over the last several years
in order to evaluate the performance of the sections
and how the sections compare to each other.
- So following construction and every six months thereafter,
the researchers ran a variety
of controlled load experiments
on top of the instrumented and controlled collection.
And they use falling weight deflectometer testing
and static load tests to gauge the response of the pavement.
- The sensors allow us to understand
how these different pavements are working
without having to wait the 10, 15, 20 years to understand
just because time has passed by, which one performed better.
The sensors allow us to do that way ahead of time.
- We are one step closer to including geogrid
in flexible pavement design methods in Texas.
I don't think we're quite there yet.
And I think importantly, geogrids could potentially be used
to reduce the thickness requirements
of base and surface layers.
- We do know that geosynthetics improved the performance
of roadways, and we did know that for a while,
but now we know why
the geosynthetics improve the performance of roadways.
By knowing why, we're now able to optimize the design,
we're now able to write appropriate specifications,
we're able to improve this technology for good.
- [Narrator] For more information,
and to find the publications for this project,
please visit the TxDOT Research Library
at the link shown below.