Skid Evaluation of Asphalt Mixes Status and Plans John Zaniewski - - PowerPoint PPT Presentation

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Skid Evaluation of Asphalt Mixes Status and Plans John Zaniewski - - PowerPoint PPT Presentation

Oct 25, 2023 281 likes •562 views

Skid Evaluation of Asphalt Mixes Status and Plans John Zaniewski Asphalt Technology Professor West Virginia University Asphalt Paving Conference February 2019 1-1 Need for new method for laboratory skid evaluation WVDOH currently test

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SLIDE 1

Skid Evaluation of Asphalt Mixes Status and Plans

John Zaniewski Asphalt Technology Professor West Virginia University

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Asphalt Paving Conference February 2019

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SLIDE 2

Need for new method for laboratory skid evaluation

  • WVDOH currently test aggregate – not mixes
  • Method has been successful
  • Shortage of availability of aggregates that meet the skid requirements

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SLIDE 3

Requirements for skid testing in lab

  • a. Sample preparation
  • b. Polishing
  • c. Friction test

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SLIDE 4

Requirements for skid testing in lab

  • a. Sample preparation
  • Slabs
  • Cylinder
  • b. Polishing
  • c. Friction test

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Simple

  • Lab
  • Field cores
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SLIDE 5

Requirements for skid testing in lab

  • a. Sample preparation
  • b. Polishing
  • “rub on the

surface to simulate traffic”

  • c. Friction test

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  • a. Methods (US)
  • a. NCSU
  • b. NCAT
  • c. Ohio
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SLIDE 6

Requirements for skid testing in lab

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  • a. Polishing Methods

(US)

  • a. NCSU
  • b. NCAT
  • c. Ohio

North Carolina State University Developed in 1970’s Only method with an ASTM standard Not currently used by other agencies

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SLIDE 7

Requirements for skid testing in lab

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  • a. Polishing Methods

(US)

  • a. NCSU
  • b. NCAT
  • c. Ohio

National Center for Asphalt Tech.

  • Developed in 2000’s
  • Most commonly reported

method in current literature

  • Most agencies contract with

NCAT for testing

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SLIDE 8

Requirements for skid testing in lab

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  • a. Polishing Methods

(US)

  • a. NCSU
  • b. NCAT
  • c. Ohio

Akron University for ODOT

  • Developed in 2000’s
  • Commercially available
  • ODOT is implementing
  • Five contractors have devices
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SLIDE 9

Requirements for skid testing in lab

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  • a. Polishing Methods

(US)

  • a. NCSU
  • b. NCAT
  • c. Ohio

Selected by DOH

Cylindrical samples Polish 12 samples per run Not currently used by other agencies Custom fabrication

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SLIDE 10

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Four applications of tire per revolution

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SLIDE 11

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NCSU polisher in action

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SLIDE 12

Polishing Co. 1 SP 12.5 skid 8%

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Cycles 2000 8000

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SLIDE 13

Requirements for skid testing in lab

  • a. Sample preparation
  • b. Polishing
  • c. Friction test

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British Pendulum Dynamic Friction Meter Circular Track Meter

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SLIDE 14
  • NCSU
  • British Pendulum

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Friction Test Texture Test

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SLIDE 15

BP in action

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SLIDE 16

Typical results

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Shake down testing

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30 35 40 45 50 55 60 65 5000 10000 15000 20000 25000 30000 35000 40000 45000

BPN Number of Cycles Polished

Sample 2 Sample 3 Sample 5 Sample 6 Sample 8 Sample 9 Sample 11 Sample 12

British Pendulum Number

Number of cycles The polisher is operational. Hopefully more consistency can be achieved.

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SLIDE 18

Initial testing

1-18 40.0 45.0 50.0 55.0 60.0 65.0 70.0 75.0 80.0 85.0 90.0 2000 4000 6000 8000 10000 12000 14000 British Pendulum Number (BPN) Number of Polishing Cycles

Average BPN Trends per Mix Type and Air Void Content After 12000 Polishing Cycles

Co 1 12.5mm Skid-RAP 8% AC Co 1 12.5mm Skid-RAP 4% AC Co 2 W1-RAP 4% AC Co 2 W1-RAP 8% AC

Number of cycles

British Pendulum Number

Looks good 48,000 tire applications

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SLIDE 19

What does BPN mean?

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British >65 Good >55 Satisfactory 45 Minimum all sites Virginia 47 Minimum NY 52 Minimum

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SLIDE 20

Original Research 1967

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SLIDE 21

How did we do?

1-21 40.0 45.0 50.0 55.0 60.0 65.0 70.0 75.0 80.0 85.0 90.0 2000 4000 6000 8000 10000 12000 14000 British Pendulum Number (BPN) Number of Polishing Cycles

Average BPN Trends per Mix Type and Air Void Content After 12000 Polishing Cycles

Co 1 12.5mm Skid-RAP 8% AC Co 1 12.5mm Skid-RAP 4% AC Co 2 W1-RAP 4% AC Co 2 W1-RAP 8% AC

Number of cycles

British Pendulum Number

VA min

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SLIDE 22

How did the “typical results” do?

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VA min HMM

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SLIDE 23

Establish Protocol

Polishing

  • Tires
  • Pressure
  • Hardness
  • Tire toe in angle
  • Number of cycles
  • Air voids

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  • Friction

measurements

  • Water application BP
  • Texture measurement?
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SLIDE 24

Testing program

  • Evaluation of existing

wearing mixes

  • i. Skid mixes vs nonskid mixes
  • ii. 9.5 vs 12.5
  • iii. 4.75???
  • Compare laboratory to field
  • i. Plant mixes vs lab mixes
  • ii. Lab results vs field results

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Work with DOH and input from industry

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SLIDE 25

Next

  • More testing
  • Compare mix types
  • Compare aggregate

gradations

  • Compare aggregate types
  • What do the results

mean

  • Important to compare lab

and field results

  • Existing pavements
  • New construction

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SLIDE 26

You can ask questions but…

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Lets go Herd