- [Announcer] Prime coats, curing materials, seal coats,
all are essential to pavement structures statewide.
The Texas Department of Transportation
and the Texas A and M Transportation Institute
investigated when, where, and why
a prime or cure is needed for a pavement layer.
Guidelines were developed from tests in the field and lab
to help determine what would be best for each project.
- It is common to have questions
about the materials required in a pavement structure
that are non-structural layers.
This include prime coats, curing materials,
seal coats, and tack coats.
- The designers and the inspectors,
the people who monitor construction/set up design,
needed to have an understanding
of what these materials were, how they should be paid for,
and when we should use them.
And that's really why we started this
is to have a little bit more education
of what the purpose of this material is.
- [Gisel] The common questions are,
what materials should we use for bonding?
What are the difference
between priming, curing, and sealing?
Although these materials can be sometimes be the same,
their performance may be depending
on the application rates and timing.
- We did surveys with TxDOT districts
to see how they were using these materials,
when they were using it,
and to get their impression of how well it worked.
We visited some projects
and looked at it in place from the construction standpoint,
and we even looked at some products
that weren't traditionally used as prime
to see how they performed.
And then we did an extensive lab study,
where we molded different types of base
that will be used on the roadway
and applied different primes to that
to determine curing time, what the benefits were,
whether it was bonding or moisture control.
- [Gisel] The developed guidance
can assist designers and inspectors to understand
the where, when, and why these materials are used
in new construction and rehabilitation projects.
- [Darlene] It's a benefit because
without the understanding of why we use it,
it could lead to some people
makin' a decision to not use it.
And we found that the benefits of using this product
outweigh the benefits of leaving it out.
So, it's a benefit
in the long-term durability of our pavement structure,
and so we need to continue using it.
- [Announcer] For more information
and to find the publication for this project,
please visit the TxDOT Research Library
at the link shown below.