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AMRL Mixing Demos. June 9-18, 2014. The Plan. Explain Two AMRL Programs Perform Mixing Demos One Residency in each of 8 Division’s Potential OHD L-14 Changes. Explain Two AMRL Programs. OMRL Program Replaced by Two AMRL Programs OMRL Program Started 1987

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amrl mixing demos

AMRL Mixing Demos

June 9-18, 2014

the plan
The Plan
  • Explain Two AMRL Programs
  • Perform Mixing Demos
    • One Residency in each of 8 Division’s
  • Potential OHD L-14 Changes
explain two amrl programs
Explain Two AMRL Programs
  • OMRL Program Replaced by Two AMRL Programs
    • OMRL Program Started 1987
      • Aid in Calibration of Hveem Compactor
      • 26 ODOT Labs Participated originally
      • 2013 – 88 Labs Participated in Program
    • “A” and “AD” Labs Required to Participate in Proficiency Programs
      • Link for Policy and Qualification Status Follows
explain two amrl programs1
Explain Two AMRL Programs

explain two amrl programs2
Explain Two AMRL Programs
  • Two AMRL Programs to replace OMRL Program
    • Hot Mix Asphalt Gyratory
    • Hot Mix Asphalt Ignition Oven
    • AMRL Links Follows
explain two amrl programs3
Explain Two AMRL Programs
  • > Proficiency Samples > Fees
explain two amrl programs4
Explain Two AMRL Programs

explain two amrl programs5
Explain Two AMRL Programs
  • Ratings After Final Report and Login
explain two amrl programs6
Explain Two AMRL Programs
  • Ratings of -1, 0, and 1 Require a Corrective Action Report
  • Consult with ODOT Bituminous Engineer
    • Kenneth Ray Hobson, PE
  • Send Report to ODOT Liaison Supervisor
    • Michael Groom
  • Link Follows
explain two amrl programs7
Explain Two AMRL Programs > Proficiency Samples

explain two amrl programs8
Explain Two AMRL Programs
  • Schedule for Samples
    • SGC ~ June, Ignition Oven ~ January
explain two amrl programs9
Explain Two AMRL Programs

Schedule for Samples

explain two amrl programs10
Explain Two AMRL Programs

Datasheet & Instructions

explain two amrl programs11
Explain Two AMRL Programs
  • Download and Save All Instruction Sets
perform mixing demos1
Perform Mixing Demos
  • Recorded Videos at:
    • McAlester -

    • Muskogee -

Links to videos to be removed in 2015.

perform mixing demos2
Perform Mixing Demos
  • Key Items in Mixing:
    • See PDF File for 2014 SGC Sample Instructions
    • Tips for Items of Note to Follow
      • Most were Discussed during Demos
perform mixing demos3
Perform Mixing Demos
  • SGC 2014 Samples 37&38 Deadline Dates
  • Split minus #8 (-#8, Fines) for A and B samples into 2 parts each (4 total) using Methods C or D in AASHTO T 248
  • Dry Coarse and Fines Aggregates to 230ºF
    • Crack Lid of Mineral Filler (MF) Can
  • Cool Aggregates to Room Temperature ~77ºF
perform mixing demos4
Perform Mixing Demos
  • Combine Aggregates According to Table of Instructions
    • Use Square Scoop for Flat Pans
    • Use Semi-Circular Scoop for Semi-Circular Pans
    • MF
      • Secure Can’s Lid
      • Dry Mix in Can by Inverting until Fully Mixed
      • Add to Batch by Spatula from Can or Scoop from a Pan
perform mixing demos5
Perform Mixing Demos
  • Use Cumulative Weights in Table
    • Add Each Aggregate Size Portion in Pile Sections
    • Cover MF and -#8 Fines with Coarse Aggregates
      • This Minimizes Fine Loss in Oven
    • Place Batch into Pans used for AASHTO T312
perform mixing demos6
Perform Mixing Demos

Crack Open Binder Can’s Lid

Place Aggregate Batches, Binder(s), Mixing Bowl(s), and Whip(s) in Oven at 310.5ºF (avg. may vary each year)

Two Hours is Often Sufficient in Force Draft Ovens

perform mixing demos7
Perform Mixing Demos
  • Quickly:
    • Place Aggregate Batch in Mixing Bowl
    • Make a Crater in Center of Aggregate Pile
    • Place Bowl on Scale and Tare to Zero
    • Place Scrap Papers (~4”x4” or more) Next to Scale
      • Used for Wiping Binder Can’s Lip and Adjusting a Small Excessive Amount of Binder Quantity
    • Place Trash Can Next to Scale
perform mixing demos8
Perform Mixing Demos
  • Quickly but Carefully:
    • Remove Binder from Oven and Place Near Scale
    • Pour Binder from Can into Crater in Bowl to Proper Amount (204.8 g Sample 37(A) in 2014)
      • Always use proper safety equipment and procedures in the lab to avoid burns and know how to react to accidents.
      • E.g.. Tongs or Pliers can help with pouring binder from a can.
perform mixing demos9
Perform Mixing Demos
  • Remove Whip from Oven
  • Shove Whip Towards Bottom of Bowl
    • Twisting Action Can Help
  • Shove Top of Whip to Side of Bowl
  • Place Bowl’s Back Post Nub into Mixer First
  • Align Two Side Posts and Snugly Fit Bowl onto Mixer at the Two Posts
    • Slide Safety Latch Over Post(s)
perform mixing demos10
Perform Mixing Demos
  • Securely Insert Whip into Mixer
  • Set Mixer Speed to Lowest Level
  • Set Mixer On/Timer for Two (2) Minutes (3 at Most)
  • Crank Mixer Lever to Mixing Position
  • Periodically, Remove Safety Latch to Side
    • Shove a Corner of the Bowl, Near a Side Post, Up for ~3 Passes
      • Take care to not get fingers near mixing action.
perform mixing demos11
Perform Mixing Demos
  • Stay Near the Timer or Kill Switch for the Mixer
    • If a Whip Breaks:
      • Cut Mixer’s Power Off (Timer Switch or Toggle Switch, or Drop Lever for Bowl Height)
      • Cut Whip Strand near Top and Bend Towards Center of Whip
        • Try to Avoid Loss of Mixture (Shake Whip Against Side)
      • Reheat Mixer, Whip, and Mixture to Mixture Temperature and Mix Until Aggregates are Coated
perform mixing demos12
Perform Mixing Demos
  • After Two Minutes of Mixing
    • All Aggregates Should be Coated with Binder
      • If not, check temperature or do another minute of mixing.
    • Remove Whip from Mixer Post and Shove Down into Mixture
    • Remove Bowl from Mixer
    • With Heated Spatula, Edge Corners Rounded:
      • Quickly (~10 s) Scrap Down along Edges of Bowl
        • Depth is usually 2” to 3”
perform mixing demos13
Perform Mixing Demos
  • Pour Mixture into Batch Pans
  • Fines from the Batch Pan or Few Fines not Fully Coated During Mixing:
    • Hand mix with heated spatula or bent spoon in T 312 Batch Pan (Spread 1” to 2” thick).
  • Label this Pan as “A-Rice”
  • Place Pan in Oven at Compaction Temperature – Avg. of 288.5ºF (this year’s sample requirement)
perform mixing demos14
Perform Mixing Demos
  • Place Whip in Oven at Mixing Temperature
  • Pour 2nd Batch for Sample “A” into Bowl
  • Repeat Previous Mixing Steps
  • Label this Pan as “A-SGC”
    • Pan Labeling is optional. Noting a pan number is sufficient if sample number and test type is identified . Key here is to know what each pan contains.
perform mixing demos15
Perform Mixing Demos
  • Age Each Sample “A” (two mixtures) the Same Amount of Time
    • Samples May be Staggered to Allow Stirring
    • Stir Each Sample at Hour’s One and Two
      • ± 5 Minutes for each Hour
    • After 2nd Stirring for “A-Rice”
      • Split to Rice Test Size (1,500 g minimum) AASHTO T 209 (Rice)
perform mixing demos16
Perform Mixing Demos
  • After 2nd Stirring of “A-SGC”
    • Load into Transfer Shute and Compact in SGC by AASHTO T 312
    • Note: Use Ndes and Nini as Required by AMRL (e.g. SGC 37(A), Ndes = 100, Nini =8)
  • Note: A Clean Bowl and Whip is Required for the Rice Sample for Sample’s “A” and “B”.
    • e.g. Sample “B” may be delayed a day or more if extra bowls and whips are not used.
perform mixing demos17
Perform Mixing Demos
  • Once AMRL Samples are Mixed and Compacted:
    • Perform Tests as Instructed (Similar to previous OMRL tests.)
    • Test SGC compacted sample at room temperature according to AASHTO T 331 (similar to OHD L-45) first.
    • Record Height at Nini During Compaction
      • Gmb(Nini) = Gmb(Ndes) X Ndes(height mm) / Nini (height mm)
perform mixing demos18
Perform Mixing Demos
  • If Bag Punctures, note that on the datasheet and use AASHTO T 166 method(s) to re-dry the specimen and perform T 331 again.
perform mixing demos19
Perform Mixing Demos
  • Non-Destructive Drying Methods Allowed in AASHTO T 166:
    • Dry at 125 ± 5ºF in Oven for 24 Hours
      • Weigh Back Every 2 Hours Until No Mass Loss
    • Dry Using ASTM D7227 (Vacuum Dried Method)
potential ohd l 14 changes
Potential OHD L-14 Changes
  • Density for Roadway Cores Computation Changed
    • Governed by Special Provision 411-17 Table

e.g. PGmm = Gmb / Gmm X 100

  • Report %Air Voids to 0.1 rather than 0.01.
  • Non-Nuclear Gauge (NNG) to be Removed
potential ohd l 14 changes1
Potential OHD L-14 Changes
  • Common Nuclear Gauge (NG) Excel File Developed
    • R2 minimum of 0.50 required for NG fit to Core Gmb
    • ASTM E178 Outlier Method Detailed
  • NG Orientation and Readings Changed
  • Allows Vacuum Drying Methods for Roadway Cores (see AASHTO T 166)
potential ohd l 14 changes2
Potential OHD L-14 Changes

Added Note, if needed, do not take Longitudinal Joint Density Cores within 15’


It was a pleasure performing the demonstrations and meeting field personnel. Thanks to lab personnel for accommodating the demonstrations.

Bituminous Engineer

Kenneth Ray Hobson, P.E.

[email protected]

(405) 522-4986