WHRP Project 0092-10-06 Effect of Recovered Binders from Recycled Shingles and Increased RAP Percentages on Resultant Binder PG

1
WHRP Project 0092-10-06 Effect of Recovered
Binders from Recycled Shingles and Increased RAP
Percentages on Resultant Binder PG

• Ramon Bonaquist, Ph.D., P.E.
• Advanced Asphalt Technologies, LLC

2
Outline

• Objectives
• Approach
• Major Findings
• Conclusions and Recommendations

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Objectives

• Improve the AASHTO performance graded binder
  blending chart analysis.
• Use the improved blending chart analysis to
  evaluate current WisDOT criteria for binder
  replacement.
• Identify potential effects of using RAP and RAS
  on pavement service life, both positive and
  negative.

4
Approach

• Review of current practice
• WisDOT specs relative to other agencies
• AASHTO M323 blending chart analysis
• Blending chart improvements
• RAS
• Multiple recycled binders
• Characterization of WI recycled materials
• 6 RAP, 6 FRAP, and 6 RAS
• Northern and Southern sources

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Approach Continued

• Reliability based blending chart analysis
• Considered variation in temperature and
  continuous grade temperature
• Effect of WisDOT binder replacement criteria on
  low temperature properties
• Recommendations for adjustments

6
Review of Current Practice

• WisDOT binder replacement relative to
• Alabama
• Georgia
• Minnesota
• Missouri
• South Carolina
• Texas
• Virginia

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Surface Mixtures
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Lower Layer Mixtures
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Blending Chart Improvements

• Issues
• AASHTO M323 and AASHTO PP53 use linear blending
  charts for RAP and RAS
• Linear blending charts were developed for blends
  of recovered RAP binders in virgin binder. Do
  they apply to RAS and blends with RAP and RAS?
• Cant grade recovered RAS binders due to
  different rheology primarily at low
  temperatures.
• Fails stiffness at very low temperature
• Fails m-value at very high temperature

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Blending Charts for RAS
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High Temperature
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Intermediate Temperature
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Low Temperature
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Linearity Limit
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Grading RAS Binders

• Extract and recover RAS binder
• Prepare a 30/70 blend of recovered RAS in virgin
  binder of known performance grade
• Grade blend per AASHTO R29
• Knowing virgin and 30/70 blend continuous grade
  extrapolate RAS continuous grade

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Notes on RAS Binder Recovery

• AASHTO T164 Method A, centrifuge extraction
• Rotovapor primary distillation
• Abson recovery
• Modifications
• Heat flask in oven after primary distillation and
  prior to start of Abson recovery
• Use higher temperatures in Abson recovery

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Blending Chart for Multiple Recycled Binders
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Blending Chart vs R29 High
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Blending Chart vs R29 Intermediate
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Blending Chart vs R29 Low
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Recycled Material Characterization
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RAP/FRAP High
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RAP/FRAP Intermediate
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RAP/FRAP Low
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Average Grade of WI RAP

• PG 82.8 (26.9) -21.8
• Standard Deviation

Property WI RAP Virgin PG 64-22
High 2.2 0.5
Intermediate 1.4 1.1
Low 1.4 0.8
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Extrapolated RAS High
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Extrapolated RAS Intermediate
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Extrapolated RAS Low
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Average Grade of WI RAS

• North
• PG 122.1 (34.4) -4.7
• South
• PG 111.3 (31.0) -8.4

Property WI RAS Virgin PG 64-22
High 5.4 0.5
Intermediate 1.8 1.1
Low 1.8 0.8
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WI RAP vs WI RAS
Property WI RAP North RAS South RAS
High 82.2 122.1 111.3
Intermediate 26.9 34.4 31.0
Low -21.8 -4.7 -8.4
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Reliability Analysis

• Two sources of variability
• Pavement temperature at the project location
• Continuous grade of blended binder
• Overall reliability

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Standard Deviation of Blend
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Standard Deviation of Blend
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Standard Deviation of Blend
Property Virgin RAP RAS
High 0.5 2.2 5.4
Intermediate 1.1 1.4 1.8
Low 0.8 1.4 1.8
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Reliability Analysis
PG 58-34 61 Weather Stations
Mid Grade Binder Exceptional Binder
PG 58-28 79 Weather Stations
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Mid Grade Surface Current Limits
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Exceptional Surface Current Limits
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Mid Grade Surface Revised Limits
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Mid Grade Lower Revised Limits
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Revised Limits
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Conclusions

• Linear blending is applicable to blends of RAS up
  to about 30 percent
• Linear blending provides a reasonable estimate of
  the continuous grade of blends of multiple
  recycled binders
• WI RAP/FRAP is very consistent having a recovered
  grade of PG 82.8 (26.9) -21.8

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Conclusions

• Appears to be a geographic difference in WI RAS
• North 122.1 (34.4) -4.7
• South 111.3 (31.0) -8.4
• RAS changes binder grade much more than RAP
• Current WisDOT binder replacement does not treat
  RAP and RAS mixtures equally

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Recommendations

• Consider modifying binder replacement criteria to
  provide similar reliability for RAP and RAS
  mixtures
• Use reliability analysis to approve mixtures with
  recycled contents greater than the binder
  replacement limits
• Monitor continuous grade of recycled sources
  using the procedures developed in this project

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Recommendations

• Monitor continuous grade of virgin binder sources
• Monitor cracking performance of pavements with
  recycled binders

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Questions/Discussion
Ramon Bonaquist Advanced Asphalt Technologies,
LLC 108 Powers Court, Suite 100 Sterling, VA
20166 703-444-4200 aatt_at_erols.com