TXAPA-ANNUAL-REPORT-27Jan2020-Flip - Page 20

Aggregate, Soils, and Base
Harry Bush, Vulcan Materials, Co. – Chair
John Crowdy, Vulcan Materials, Co. – Board Member
Corey Schwarz, TXAPA Staff
Working with Richard Izzo of TxDOT’s Materials and Tests Division,
the Aggregate, Soils, and Base committee started the process of
rewriting Tex-400-A, Sampling Flexible Base, Stone, Gravel, Sand
and Mineral Aggregates. The TxDOT Materials and Test division
will deploy the new procedure, which was completed in early
January 2020, throughout the state. Again, working with Richard
Izzo, the committee began to develop guidance documents
for SAC A aggregates. Using skid value data collected by the
Materials and Tests Division – Aggregate Section, the goal is to
establish more defined guidelines as to whether the materials
used can meet required skid values. With data still being
collected and analyzed, the project remains ongoing in 2020.
Level 2 Mix Design Committee
Jimmy Whited, Austin Materials, LLC – Chair
Mark Miller, Big Creek Construction – Board Member
Corey Schwarz, TXAPA Staff
Thanks in large part to the efforts of the Level 2 Mix Design
Committee, Texas now has a first-generation Balanced Mix
Design Specification. Several TXAPA contractors volunteered
to build a total of 13 test projects, two of which have been
completed and have met the requirements for a Balanced
Mix Design in the design phase. The University of Texas at El
Paso, the University of Texas at Austin, and the Texas A&M
Transportation Institute are working with Ryan Barborak, TxDOT
Materials and Tests Division to evaluate their performance in the
field. The committee also worked with TxDOT to simplify ignition
oven correlation factors. The procedure, which calibrates the
oven to the material type, was overly complex, which was a
deterrent to its application.

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