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- [Narrator] A key to creating longer lasting roadways
is preventing issues due to asphalt rutting and cracking.
And having simulations that closely mimic
real world conditions
is key to understanding how asphalt will ultimately perform.
The Texas Department of Transportation,
working with the University of Texas at El Paso
and the Center for Transportation Research,
investigated current laboratory practices
to determine methods that best imitate
different aging states
to help design an asphalt mixture
that is more resistant to rutting and cracking.
- The project that we are focusing on
has to deal with the aging of the hot mix asphalt pavement
after it's been laid down.
- We can design material on day one,
but we don't know how environmental effects
negatively impact it over time.
- [Soheil] As we lay down the asphalt
and as the sun hits it day in and day out,
the material becomes more brittle.
One of the goals of this project
is to simulate that state of brittleness
in the material in the laboratory
before we lay down the asphalt
to make sure that it would last.
- [Travis] If we can impose those environmental effects
in the laboratory today,
we can design a material that will last much longer.
- One of the problem is that it would take
around five days to a week
to simulate the system in the laboratory.
Or on the other hand, if they accelerated,
they would not achieve the state
that the pavement has, the asphalt has in the field.
- [Travis] And then you start throwing in multiple projects
and multiple mixtures,
you're really gonna tie up a lot of ovens and a lot of time.
And so while this seems to give us good data,
it doesn't necessarily lend itself
to being a usable test all the time, right,
because it's not very practical.
- [Soheil] So our mission was to come up with a way
of ranking the different mixes in a short period of time
so that it can be practical for the DOTs to use.
So we looked at two different processes,
one oxidizing and generating the brittleness
through oxidation by using ozone,
and the second one by using pressure
with the goal of reducing the time
from a week, five to days to a week,
to maybe less than 48 hours.
- If we can utilize these different methods and say,
"Can we design a mixture on day one that's good?"
and then see, you know,
we predicted in two years it would still be good,
and let's see if it's still good.
And so this is going to be a lengthy process,
but I do think this is the next step
in ensuring that we're making cracking-resistant material.
- [Soheil] The main benefit
is that you can achieve the oxidation
that is representative of the field condition.
These are the two important things.
You can achieve it in a very short period of time.
So for every mix, we can go through this process
and not delay the construction.
- [Narrator] For more information,
and to find the publication for this project,
please visit the TxDOT Research Library
at the link shown below.