Concrete: What's New, What's Changed and What's Coming - Mark Finnell Concrete Engineer-Consultant

Concrete: What’s New, What’s
Changed and What’s Coming
          Mark Finnell
    Concrete Engineer-Consultant
            Materials Training
               Spring, 2021

Topics for Today

• The SAM: Common Mistakes and the Future
• Optimized Aggregate Gradations (OAG)
• The Rise of Portland Limestone Cements (PLCs)
• Miscellaneous Items
   MIT Dowel Scanner
   Surface Resistivity

The SAM: Common Mistakes and
          the Future

Common Mistakes
• Poor filling procedure           • Not recording equilibrium
    Poor use of squeeze bottles     pressures
    Not tipping meter
                                   • Not letting SAM acclimate to
• Accidental lever press             surrounding air temperature
• Using an internal vibrator to
  consolidate sample

Future of the SAM

• This construction season:
    Business as usual
    QC will be testing at a frequency of once per lot (715.3.1.1 Para. 2)
    QV will continue testing at a frequency of every 5th lot (715.3.1.3 Para. 1)
      • It is strongly encouraged to practice the SAM prior to operating it

Future of the SAM

• The future:
    WisDOT’s goal is to implement SAM by 2023 Specifications
      • Finalize limits for SAM Number
      • Frequency of testing for QC and QV
      • Develop dispute resolution process
    Assess future technologies for the SAM
      • The MinT
      • CAPE 2.0

Optimized Aggregate Gradations:
 What to Know and What to Look For

Optimized Aggregate Gradations (OAG): What is
                     It?
• The idea of maximizing the volume of aggregates in a mixture
• The goal of OAG is to reduce cementitious content
    Increases strength, durability and sustainability
    Reduces cost

OAG: The Tarantula Curve

• Developed by Dr. Tyler Ley at                              25
                                                                                             Tarantula

  Oklahoma State University                                  20

                                   Percent Retained, % Vol
• Based on blended aggregate                                 15

  gradations                                                 10

    Volumetric Percent Retained                              5

                                                              0

                                                                                                           #4

                                                                                                                  #8
                                                                                     3/4"

                                                                                            1/2"

                                                                                                   3/8"

                                                                                                                       # 16

                                                                                                                              # 30

                                                                                                                                     # 50

                                                                                                                                            # 100

                                                                                                                                                    # 200
                                                                  2"

                                                                                1"
                                                                       1 1/2"
                                                                                                          Sieve

OAG and WisDOT

• OAG is covered under STP-715-005
   Covers pavement only
   Allows cementitious contents of 520 lbs./cy
   Typically used on High Performance Concrete (HPC) corridors
   Contractor’s may volunteer to use it
• The STP includes incentive

OAG and WisDOT: Common Questions

• How do I apply a failing QV Gradation Test to OAG?
    Add the QV data point to the QC running average
    Think of it as an extra QC test
      • Moves the running average 1 extra step
• When do I apply the incentive?
    The incentive is applied to lots that are within the Tarantula Curve Limits
      • The Job Mix Formula (JMF) is independent of the incentive

OAG and WisDOT: Common Questions

• What role does the Job Mix Formula (JMF) play?
   The JMF is a tool used to control the contractor’s operations. It determines if
    operations can continue.
   The JMF does not dictate incentive.

OAG and The Future

• OAG is coming to the 2022 Specification
    Key Differences:
      • No more incentive
      • New minimum cementitious content: 500 lbs./cy
      • No more JMF
    More on this will be discussed in the future

The Rise of Portland Limestone
        Cement (PLC)

What is Portland Limestone Cement (PLC)?

• A blended cement containing finely ground limestone
    ASTM Designation: Type IL (C595)
• Limestone is a mineral filler
• Typical nominal replacements:
    As low as 5%
    No more than 15%

What Benefit Does PLC Have?

• The limestone acts as a catalyst
    Aids in cement hydration
• Reduces carbon footprint of
  concrete
• Does not affect other properties
    Only true at replacement levels
     lower than 15%
                                       Courtesy of: Berodier, E. S. K. S. G., & Scrivener, K. (2014). Understanding the
                                       Filler Effect on the Nucleation and Growth of C‐S‐H. Journal of the American
                                       Ceramic Society, 97(12), 3764-3773.

PLCs and WisDOT

• WisDOT recognizes PLCs under 501.2.1
   Uses ASTM C595 as guidance
   Key difference:
     • Only allow up to 10% replacement
     • No individual test should exceed 12% replacement
• PLC will become more common
   Cement and Concrete industry becoming more carbon neutral

How to Handle PLCs

• No different than handling ordinary cement
    Cement acceptance based on C595
• Limestone in cement is not a supplementary cementitious material
  (SCM)
    It is not a fly-ash, slag or silica fume
    Does not contribute to replacement of SCMs

How to Handle PLCs

• PLCs containing greater than 10% replacement in 2021
   ASTM C595 allows 15% replacement
   The 2022 Specification will mirror C595
   Reach out to BTS for assistance
     • Mark Finnell
     • Jim Parry

Miscellaneous Items

The MIT Dowel Scanner

• Uses the same technology as the
  T2
• The device can scan dowel bar
  alignment and depth
   DBIs
   Dowel Bar Baskets

The MIT Dowel Scanner

• Currently gathering data with the scanner
• Used in forensic investigation
• Need to assess the accuracy of scanner for Dowel Bar Baskets
    A new software upgrade removes interference
• The goal: use as a preventative tool
    Scan joints to identify potential issues
• It would be helpful for the regions to identify projects
    Contact Mark Finnell or Jim Parry

Surface Resistivity

• WisDOT is moving forward with
  surface resistivity (AASHTO
  T358)
• This measures the permeability of
  concrete
    Will replace RCPT test
• Fast and easy test

Surface Resistivity

• When to expect surface resistivity:
    Shadow spec in the 2022 Specification
• What will be expected:
    QC will be testing once per lot
    QV will be testing every 5th lot
    Concrete Strength Testers will be responsible for measurements
    CMM guidance and updates to HTCP will be provided

Questions?

• Contact Information:
    Mark Finnell
    Email: mark.finnell@dot.wi.gov
    Work phone: (608) 449-1337