(swooshing)
- [Announcer] The Texas Department of Transportation
has sponsored research with modified asphalt binders
in the laboratory and on Texas roads.
This work resulted in a catalog that is used
by district engineers during construction.
While previous research focused
on new road construction,
TxDOT realized a catalog was needed
specifically for overlays where new asphalt
is laid over existing pavement.
The Texas A&M Transportation Institute,
working with TxDOT,
has developed a catalog designed specifically
to address binder asphalt procedures on existing roadways.
- We do a lot of overlay construction,
which is on the top of existing pavement
that may be a flexible pavement
or a concrete pavement.
And we did not have a catalog that says,
okay, this is the most appropriate binder grade
that maybe you need to start with.
- Most of the work we're doing in Texas
or the whole nation is asphalt overlays.
So there are big differences between
asphalt overlay and the new construction.
One of the major differences is
existing crack for asphalt overlays.
The existing crack will shorten
the asphalt overlay pavement life.
- So in this research, obviously, this has been
a continuation of other projects
and the information collected
from over the years, right?
Because there is lot of overlay that is constructed,
and we did want to see what is the grade of the binder.
- We look at multiple aspects
of this binder selection catalog.
We look at from, asphalt binder, itself.
We also look at asphalt mixture, and then we also look
at pavement performance simulation based on models.
- So around 2,700 different simulation run from TxME
which is a TxDOT mechanical and empirical guide,
kind of in a software that was used to run the scenario.
A lot of laboratory test was also done
to validate some of these, you know, cases.
- Most importantly, we build multiple filter test sections
around the state to validate anything from, you know,
from the lab binder test,
from mixture test result,
also from the model simulation.
So that's given us the confidence to present the
the final binder selection catalog.
- The key finding obviously is the grade that we are
traditionally selecting for a new construction
may not work for overlay because of the thickness
of the overlay, which is, you know,
thinner than a new construction obviously.
And also the grade that is most likely
we need to go better grade
than in a new construction.
- Using right binder for asphalt overlays.
it will make the pavement last much, much longer.
And that means save millions dollars
of taxpayer money every year.
- We'll have a better selection of the material
which is basically on this particular is a binder grade
so less maintenance,
longer life,
and less disturbance in the general public use
of the, you know, pavement.
- For more information
and to find the publications for this project,
please visit the TxDOT Research Library
at the link shown below.