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(gentle music)

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- [Narrator] High
performance concrete, or HPC,

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has many applications in Texas,

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including its use in bridge decks.

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The durability of HPCs offers
extra protection to bridges,

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especially in areas where corrosion

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from deicing salts can be an issue.

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The Texas Department of Transportation

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and researchers with the Texas
A&M Transportation Institute

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are working to develop new
performance-based specifications

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for high performance concrete

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that will help ensure
its long-term durability.

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- TEX DOT use the mix
design option one to five

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and eight in item 421,

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as in high performance
concrete in bridge deck.

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However, these mixes
are originally developed

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for alkali silica reaction mitigation,

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and primarily focused on
maintaining high strength

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and with low water-cement ratio.

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So high strength is the main criteria,

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but that doesn't really define
high performance concrete.

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- So currently, TEX DOT requires
prescriptive specifications

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when we talk about high
performance concrete requirements,

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so there has been a move
through industry nationwide

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to go more of a performance-based
type of specification,

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and so this research was
the attempt to develop

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what those performance limits would be,

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what tests we need to have
the contractor focus on

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to determine whether that mix design

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is going to be considered
a high performance concrete

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with these new criteria limits.

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- In the major durability issues,

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like alkali silicon reaction in concrete,

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shrinkage in concrete, transport property,

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the chloride durability,
and freeze-thaw durability

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are not addressed in the current options,

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so we actually address these
four major durability aspects

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in this project.

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The transport property,
so what we did is a rapid

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and reliable way to measure the
concrete transport property.

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We introduce resistivity,
we improve that test,

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we improve a better procedure
to do formation factor

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from resistivity, better
transport property,

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which leads to better way to
do the chloride prediction

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and increase the durability prediction.

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And we also develop a
Excel-based TEX DOT tool.

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That tool allow you

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to do the very rapid way
of performance evaluation

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during mixed design
and trial batch stages.

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- We're trying to help the
contractor out as well,

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so we're trying to help him to say

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if you know some basic
information about your materials,

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you could input 'em into the
tool and then it would tell you

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we think these are going to meet,

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so you could kind of selectively
pick your mix designs

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that you're gonna go send for testing.

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- So basically, TEX DOT
tool that we developed

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as a performance specification,

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it's going to help to test
the common mix design practice

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and see whether it is
qualified as an HPC or not.

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And if it is not, then the fine tuning

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and improving recommendation
will be provided.

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- Those deicing salts do tend to corrode

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or distress our bridges, so the idea

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of making sure we have
high performance concrete

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in those regions is going to save us

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in terms of a maintenance budget

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and then delays for the
traveling public as well,

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and the life of the structure
should extend as well, right?

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So we're not gonna be replacing decks

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because they're corroding
or doing deck overlays.

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We can now push maybe that
activity out 10, 20 years further

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because we have a better concrete

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that was used to construct those.

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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 TEX DOT Research library

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at the link shown below.