(intense music)
- [Narrator] Asphalt seal Coat is an essential tool
in protecting existing roads
and making sure they maintain adequate skid resistance.
But there are times where the coated layer fails prematurely
because of poor durability
or when the seal coat is not compatible
with the previously laid road.
The Texas Department of Transportation
working with the Center for Transportation Research
investigated ways to gauge expected seal coat performance
and use that research as a tool for similar projects.
- Chip seals are a very important pavement
preservation technique that are used
across the state of Texas.
There's nearly $300 million of chip seal work that is done
on an annual basis to preserve our pavements
and also to ensure a safe riding surface.
Now, the way chip seals work is that there's a thin film
of asphalt binder or emulsion that is placed
on the pavement surface and aggregates one layer
of aggregates are placed on top of it typically,
and these aggregates need to glue
with the asphalt binder surface underneath it.
So the purpose of this project was to make sure
that we have a tool by which to assess
whether or not the aggregates are bonding well
with the asphalt binder surface underneath it.
- Seal Coat is something that we do across the entire state.
It's our mainstay, our bread and butter
for preserving the life of our infrastructure.
And we realized that we really didn't have
any performance based testing similar to hot mix
for seal coat.
So this research project was looking at developing
a test that measured some performance.
We didn't really have anything specifically in mind
when we did this.
We just knew that we wanted a performance measure
for seal coat.
- As a part of this project, we developed some
very simple tools that can be used by districts
or contractors to assess the quality of the bond
between the aggregate and the emulsion or the binder,
and as next steps,
we would like to see districts use these tools
or this equipment and run these tests
on a routine basis as a part of
their annual seal coat program to assess the quality
of the materials that are being used in the field.
- We did a lot of lab testing
and we developed some testing that we think shows promise
that needs to be further developed in the field.
So we had to do something that we could write, number one,
gain some kind of performance measure
and then two that was repeatable.
So we think we've identified a few tests
that could move forward.
Now we just need to move forward
with implementing those or furthering the research.
- The next steps in this project is to integrate
the findings into the specifications for chip seals.
There are specifications embedded in the chip seal spec
right now for asphalt and for aggregate.
and this would tie the two together to measure compatibility
of the two.
- If we have a performance based aspect of these seal coat,
we're gonna be able to check to make sure
that this provides a safer surface for the traveling public
and secondly, it's gonna be a cost saving.
- Typically, seal coats have a serviceable life
about seven years
and if you are able to extend the serviceable life
or avoid premature failures, that translates
into a lot of money saved.
- [Narrator] For more information and to find
the publications for this project,
please visit the Tex.Research Library
at the link shown below.