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- [Narrator] Full depth reclamation, or FDR,
reuses asphalt bound and unbound granular materials,
offering the Texas Department of Transportation
a cost-effective way to recycle previously used pavement.
Studies over the past few years
have shown a need for revision
of currently used mixture specifications.
The Texas Department of Transportation
and the Texas A&M Transportation Institute
conducted lab tests
to propose a revised criteria
and validate those proposals with current field sections.
- Roads with time deteriorate.
It's just a nature of them being exposed
to environment and traffic.
So, whenever you reach that point
you will need to do something to it
to make it functional again.
So, the need for this research was to come up
with mix design strategies
so that we can manufacture these materials
in a more consistent way
and provide that sustained level of service
for the public.
- The original process takes a long time.
It takes 28 days to do all the testing per spec.
So the process that was developed in this
actually allowed us to reduce the amount of time used
to get the samples.
So instead of a 28-day turnaround,
it turned into a seven-day turnaround.
- [Edith] Whenever we started this project,
there was a concern that the mix design methods
could lead to some variability.
And so we as researchers
tried to come up with several ways of exploring variables
that could affect the outcome of the mix design process.
So we look at things in the lab,
like the specimen size, the compaction level,
the curing time and temperature, the testing temperature.
And then with those results we came up with something
that could lead to more consistent results in the lab
and also between laboratory.
So say, TTI is doing the mix design
versus TxDOT versus a contractor.
Everybody's kinda getting the same or similar answer
as close as possible.
- Obviously, any time that we can save in the lab
is time saved on the duration of the contract.
The contractor is basically,
they're time dependent on us
and anytime that they're waiting on us is something that,
you know, we may be responsible for financially.
So anytime that we can eliminate that or minimize that,
it's in TxDOT's benefit
as well as it's for the state's benefit.
- The beauty of these methods is that
it allows for the materials to be stronger,
therefore, they last longer.
The road is also smoother,
so it provides a very nice ride.
And it's also environmentally friendly.
Why? Because you're doing these processes on site.
You're not holding in new materials, new raw materials.
There's also saving on emissions.
So it's a very friendly in terms of the environment,
and also cost savings for the contractor
and even the taxpayer.
You know, you're not having to devote those dollars
and it can be spread out in other maintenance efforts.
- [Narrator] For more information
and to find the publication for this project,
please visit the TxDOT research library
at the link shown below.