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- [Narrator] Some new pavements,

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which have cement treated materials,

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fail prematurely, experiencing
rutting, or cracking.

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This project tries to determine
why the problem exists

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and how to make these specific
pavements more reliable.

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Researchers with the
University of Texas at El Paso

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have developed new mixed
design specifications

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after an extensive laboratory evaluation.

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- In Texas, we have several thousand miles

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of cement treated pavements
with cement treated layers.

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And a lot of our districts
now are grappling

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with issues related to
the premature failure,

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cracking of the pavements,

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and anything that jeopardizes
the longevity of our pavement.

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- There have been cases
where pavements using

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cement treated layers had not reached

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their predicted pavement life.

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And so it was thought that
there could be two problems.

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One could be either with
the cement treated layers

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or the prediction using the models.

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- [Reza Ashtiani] So the main motivation

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that we had for this project was

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to look into the current
practices that we have

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for the design of cement treated layers.

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And then we basically we'll look into

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how we can improve the
current mixture designs

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that we have.

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- [Wade Blackmon] We
actually have quite a bit

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of cement treated materials projects

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because it's one of the
more cost-effective means

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of recycling materials or adding strength.

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The issue was strength versus cracking.

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- There are several
issues that contributes

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to the cracking failure
and issues related to

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the longevity of the pavements.

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Obviously the first one

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is the laboratory mixture design.

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If we get the mixture designed wrong

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all the dominoes will fall afterwards.

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We also looked into other
aspects such as fatigue cracking

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that we have in cement treated layers

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and the way that we looked at it was

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we basically looked into development

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of a new fatigue performance model.

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And we calibrated that
over 62 pavement sections

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all across Texas, making sure
that we consider the diversity

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of the climate that we have in Texas

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as well as the diversity of
the materials that we have.

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One of the major outcome of this project

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was a refined specification
for cement treated material.

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In this newest specification

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we considered compressive
strength, tensile strength,

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shrinkage cracking potential,

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as well as looking at
the durability protocols.

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- Some of the main benefits would be

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smoother pavements,
longer lasting pavements,

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which would be a significant
cost savings to the public.

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So better testing, which
is what is suggested

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by this new specification,
better testing will lead to

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longer-lasting pavements,
better riding pavements

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- [Narrator] For more information,

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and to find the publications
for this project,

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please visit the TexDOT research library

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at the link shown below.