Richard Steger, Platform Manger-Rehab, Ingevity, delivers a technical presentation on blanaced mix design and cracking test, addressing high-recycle content asphalt mixtures at the CalAPA Spring Asphalt Pavement Conference & Equipment Expo, April 12-13, 2017 in Ontario, Calif.

1. Managing Performance of High
Recycle Asphalt Mixtures
Richard K. Steger, P.E.
Ingevity Pavement Technologies

2. Outline
Managing Performance of High Recycle Asphalt Mixtures
• Background & History
• Changing Economic Environment
• Use of Recycle
• Address Performance Challenges
• The Balanced Mix Design (BMD)
• Using WMA, Rejuvenators & BMD
• A New Design Approach
• Summary

3. Background
All stakeholders involved in asphalt paving desire the
following:
• Predict optimal performance
• Produce the best performing asphalt mixtures
• Make sure what is produced will perform
HOW DO WE MEASURE PERFORMANCE?
Managing Performance of High Recycle Asphalt Mixtures

4. History of Mix Design
1890 –> 1993 –> Current
Balanced Mix Designs for Asphalt Mixtures, SHRP2SOLUTIONS, Buchanan, S., Sept 2016
asphaltmagazine.com/history-of-asphalt-mix-design-in-north-america-part-2/
1890
Barber Asphalt Paving Company
Asphalt 12-15%
Sand 70-83%
Pulverized carbonite of lime 5-15%
1905
Clifford Richardson, New York
Testing Company
Surface Sand Mix; 100% passing No. 10
15% passing No. 200, 9-14% asphalt
AC for lower layers; VMA terminology used
2.2% more VMA than current day mixes
or 0.9% higher binder content
1920s
Hubbard-Field Method
Sand Asphalt design
30 blow. 6’’ dia. with compression test
(performance) asphaltic mix design
Modified HF Method
Stability
1927
Francis Hveem (Caltrans)
Surface area factors used to determine
Binder content; Hveem Stabilometer
& Cohesiometer used
Air voids not used, mix design relatively
Drier, fatigue cracking issues
Stability + Durability
1943
Bruce Marshall, Mississippi DOT
Refinded Hubard Field Method
Standard compaction energy with drop hammer
Initially only used air voids and VFA
VMA added in 1962,
Stability and Flow used
Stability + Durability
1993
Superpave
Level 1 (Volumetric)
Level 2 & 3 (Performance
Based, but never implemented)
Managing Performance of High Recycle Asphalt Mixtures
B
I
N
D
E
R
C
O
N
T
E
N
T
L
O
W
E
R
E
D

5. Economic Environment has changed
Managing Performance of High Recycle Asphalt Mixtures
Liquid asphalt price volatility (as of April 4, 2017)
0
100
200
300
400
500
600
700
Oct-09
Jan-10
Apr-10
Jul-10
Oct-10
Jan-11
Apr-11
Jul-11
Oct-11
Jan-12
Apr-12
Jul-12
Oct-12
Jan-13
Apr-13
Jul-13
Oct-13
Jan-14
Apr-14
Jul-14
Oct-14
Jan-15
Apr-15
Jul-15
Oct-15
Jan-16
Apr-16
Jul-16
Oct-16
Jan-17
ProiceIndex
CALIFORNIA STATEWIDE CRUDE OIL PRICE INDEX
March 2017
= 284.7

6. Economic Environment has changed
Managing Performance of High Recycle Asphalt Mixtures
SHOPP & Maintenance Backlog & Transportation
Funding remains flat
http://www.lao.ca.gov/Publications/Report/3366#top

7. New gas tax passes!
• California Legislature votes to raise gas taxes, vehicle fees by
$5.2 billion a year for road repairs and transit, LA Times, April 6,
2017 http://www.latimes.com/politics/la-pol-sac-california-gas-tax-
vote-20170406-story.html
• Divided Senate approves gas tax and vehicle fee increases to
raise $5.2 billion annually for road repairs, LA Times, April 6, 2017
http://www.latimes.com/politics/essential/la-pol-ca-essentialpolitics-
updates-senate-on-gas-1491508666-htmlstory.html
• California Lawmakers Approve Taxes and Fees for Roads,
USNews.com, April 7, 2017 https://www.usnews.com/news/best-
states/california/articles/2017-04-06/vote-nears-for-california-gas-
tax-fee-hike
Managing Performance of High Recycle Asphalt Mixtures

8. One solution to address some of the
increased costs and funding uncertainty
Use of Recycled Asphalt Pavement (RAP) and
Recycled Asphalt Shingles (RAS) to reduce cost
• Agencies can stretch new budget dollars
• Covers more miles of roadway
• Industry use of recycle allows
• Reduced waste & eliminate growing RAP piles
• Divert asphalt-rich RAS from landfills
• It’s a Green alternative
Managing Performance of High Recycle Asphalt Mixtures

9. U.S. RAP Materials Use - 2015
Managing Performance of High Recycle Asphalt Mixtures
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
340.0
345.0
350.0
355.0
360.0
365.0
370.0
2009 2010 2011 2012 2013 2014 2015
RAPTons(MM)inHMA/WMA,est
TotalMixTons(MM),est
Asphalt Mix Tons Vs RAP Tons
Total Mix Tons (MM), est RAP Tons (MM) in HMA/WMA, est
Hansen, K.R., & A. Copeland (2017). Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2015,
6th Annual Survey (IS 138). National Asphalt Pavement Association, Lanham, Maryland

10. California RAP Materials Use - 2015
Managing Performance of High Recycle Asphalt Mixtures
Hansen, K.R., & A. Copeland (2017). Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2015,
6th Annual Survey (IS 138). National Asphalt Pavement Association, Lanham, Maryland
2009 2010 2011 2012 2013 2014 2015
Mix Tons 20.0 13.8 23.0 22.5 24.3 23.1 25.5
DOT Tons 5.7 4.6 7.2 5.3 6.3 9.4 7.4
RAP Tons, HMA/WMA 2.0 2.6 2.2 3.6 2.7 2.9 4.0
-
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
-
5.0
10.0
15.0
20.0
25.0
30.0
Tons,MM
Tons,MM
California Mix & RAP Tons Used through 2015, (est)

11. U.S. RAS Materials Use - 2015
Managing Performance of High Recycle Asphalt Mixtures
0
0.5
1
1.5
2
2.5
340.0
345.0
350.0
355.0
360.0
365.0
370.0
2009 2010 2011 2012 2013 2014 2015
RASTons(MM)inHMA/WMA,est
TotalMixTons(MM),est
Asphalt Mix Tons Vs RAS Tons
Total Mix Tons (MM), est RAS Tons (MM) in HMA/WMA, est
Hansen, K.R., & A. Copeland (2017). Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2015,
6th Annual Survey (IS 138). National Asphalt Pavement Association, Lanham, Maryland

12. California RAS Materials Use - 2015
Managing Performance of High Recycle Asphalt Mixtures
Hansen, K.R., & A. Copeland (2017). Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2015,
6th Annual Survey (IS 138). National Asphalt Pavement Association, Lanham, Maryland
2009 2010 2011 2012 2013 2014 2015
Mix Tons 20.0 13.8 23.0 22.5 24.3 23.1 25.5
Avg % RAS in DOT Mix 0% 0% 0% 0% 0% 0% 0%
RAS Tons, HMA/WMA - 1.8 7.2 11.1 19.5 14.9 3.8
-
5.0
10.0
15.0
20.0
25.0
-
5.0
10.0
15.0
20.0
25.0
30.0
Tons,thousands
Tons,MM
California Mix & RAS Tons Used through 2015, (est)

13. U.S. WMA Use - 2015
Managing Performance of High Recycle Asphalt Mixtures
Hansen, K.R., & A. Copeland (2017). Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2015,
6th Annual Survey (IS 138). National Asphalt Pavement Association, Lanham, Maryland

14. Early Use of RAP/RAS in Asphalt
Mixtures
Managing Performance of High Recycle Asphalt Mixtures
The addition of recycled binder created challenges
Does it create
POOR PERFORMANCE ???
• Early onset raveling
• Oxidation
• Low binder content
• How much recycle binder is mobilizing?
• Low temperature & fatigue cracking
= SHORTENED LIFE CYCLE

15. Reaction to early pavement problems using
Recycle
Many agencies began REDUCING the allowable
amount of recycle
Specifying binder “dumping” when increasing
recycle content to counter stiff recycle
Blending charts that predict IN-PLACE PG
But, do PG binder tests give us enough
understanding or prediction of mix performance?
USE WARM MIX? USE REJUVENATORS?
Managing Performance of High Recycle Asphalt Mixtures

16. Address Performance Challenges
• Use Best Management Practices for the RAP & RAS stockpiles
– Done by the Contractor
• Sampling and Testing
• Stockpile Management
• Manage the recycled binder
– Characterization of recycled binder through PG
– Use of WMA and/or Rejuvenators
– Balanced Mix Design (BMD) approach
– Mix Performance Testing
Managing Performance of High Recycle Asphalt Mixtures

17. Contractor Stockpile Sampling
Managing Performance of High Recycle
Asphalt Mixtures
Use loader to sample RAP
Representative sample collected around padLoader smooths sample pad
Loader builds sample pad
Courtesy Shane Buchanan, Ph.D., P.E., Old Castle Materials Group

18. Contractor Testing
Predict and confirm performance through
• Sampling & Testing
• Fractionating
• Gradation
• RAP properties
• Binder content & Performance Grade (PG)
• Details in NCHRP Report 752
Managing Performance of High Recycle Asphalt Mixtures
NCHRP Report 752, Improved Mix Design, Evaluation and Materials Management Practices for HMA with High Reclaimed Asphalt
Pavement Content, Transportation Research Board, 2013

19. Contractor Stockpile Management
Managing Performance of High Recycle
Asphalt Mixtures
Fractionating & Separating Sources
Courtesy Shane Buchanan, Ph.D., P.E., Old Castle Materials Group

20. Consequences to adding recycle binder???
SHRP Performance Grading (PG) was designed to
predict the virgin binder grade without RECYCLE
• When PG64-22 is specified, the extracted
binder is expected to grade as a PG64-22
• Addition of RECYCLE stiffens IN-PLACE binder
grade
• PG predicts rutting and low temperature
cracking on the binder side, but falls short in
predicting non-load associated cracking in the
mix when using RECYCLE
Managing Performance of High Recycle Asphalt Mixtures

21. Balanced Mix Design
• FHWA Mix ETG established Balanced Mix Design TF in September
2015
– TF leader is Shane Buchanan, PhD, P.E. with Old Castle Materials
Group
– Includes agency and industry members (26 members)
• Balanced Mix Design – “Asphalt mix design using performance
tests on appropriately conditioned specimens that address
multiple modes of distress taking into consideration mix aging,
traffic, climate and location within the pavement structure”
– Basically, it consists of designing the mix for an intended
application and service requirement
Managing Performance of High Recycle Asphalt Mixtures
Balanced Mix Design (BMD) for Asphalt Mixtures, Buchanan, September 2016

22. BMD – Three Approaches
1. Volumetric Design with Performance Test Verification (Illinois,
Louisiana, New Jersey Wisconsin, Texas)
2. Performance Modified Volumetric Design
3. Performance Design with Volumetric Analysis (New Jersey has a draft
approach)
Managing Performance of High Recycle Asphalt Mixtures
Balanced Mix Design (BMD) for Asphalt Mixtures, Buchanan, September 2016

23. Managing Performance of High Recycle
Asphalt Mixtures
Balanced Mix Design (BMD) for Asphalt Mixtures, Buchanan, September 2016

24. Hamburg Wheel Tracker - Rutting
Managing Performance of High Recycle Asphalt Mixtures
http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w219.pdf
NCHRP W219 Hamburg Wheel-Track Test (HWTT) Equipment Requirements & Improvements to
AASHTO T 324, Mohammad, et.al, September 2015

25. Cracking Tests
Managing Performance of High Recycle
Asphalt Mixtures
Disk Shaped Compact Tension (DCT) ASTM D7313
Semi-Circular Bend (ASTM D8044)Semi-Circular Bend (AASHTO TP105 or I-Fit)
Overlay Test (Tex 248-F)

26. Example of Balance Mix Design Approaches
Managing Performance of High Recycle Asphalt Mixtures
Buttlar, et.al, Performance-Space Diagrams for Asphalt Concrete Mixtures, AAPT, 2016

27. Example of Balance Mix Design Approaches
Managing Performance of High Recycle Asphalt Mixtures
Zhou, et. al, Rejuvenator Characterization, Blend Characteristics, and Proposed Mix Design Method, AAPT 2015

28. Example of Balance Mix Design Approaches
Managing Performance of High Recycle Asphalt Mixtures
Al Qadi, et.al, Impact of High Recycled Mixes on HMA Overlay Crack Development Rate, AAPT, 2017

29. Example of Balance Mix Design Approaches
Managing Performance of High Recycle Asphalt Mixtures
Cooper, et.al Testing and Analysis of LWT and SCB Properties of Asphalt Concrete Mixtures, FR 536, LTRC, April 2016

30. Using WMA can help with BMD
Managing Performance of High Recycle Asphalt Mixtures
• Using WMA (such as EVOTHERM) & lower
production temps, improves the low temp
properties of the virgin binder
• This, in turn, allows 10% additional RAP to the
mix when using a blending chart analysis
• Allowing more RAP without changing virgin PG
is a significant cost savings without impacting
performance
NCHRP Report 714 - Special Mixture Design Considerations and Methods for Warm-Mix Asphalt: A Supplement to NCHRP
Report 673: A Manual for Design of Hot-Mix Asphalt with Commentary, TRB, 2012

31. Using Rejuvenators can help with BMD
• Additives allow responsible use of more recycled
materials
• How?
–Restore aged asphalt characteristics to a consistency
level appropriate for construction purposes and for
the end use of mixture (workability)
–Restore aged asphalt to its optimal chemical
characteristics for durability
–Provide sufficient additional binder to coat new
aggregate and satisfy mix design requirements
Zhou, F. et.al. Rejuvenator Characteristics, Blend Characteristics, and Proposed Mix Design Method, AAPT Symposium, March 2015
Managing Performance of High Recycle Asphalt Mixtures

32. Rejuvenators
Category Examples Description
• Paraffinic Oil
• Refined & de-
waxed
Paraffinic base
oil
• Waste Engine Oil
• Waste Engine oil bottoms
• Valero VP165
• Storbit
• Refined used lubrication
oils
• Industrial and Marine
Lubricants
• Aromatic
Extract
• Hydrolene
• Reclamite
• Cyclogen L
• Valero 130A
• Refined Crude Oil with
Polar Aromatic Oil
Components
• Naphthenic
Oils
• SonneWarmix RJ
• Ergon Hyprene
• Engineered Hydrocarbons
for asphalt modification
• Triglycerides
• Fatty Acids
• Waste vegetable oil
• Waste vegetable grease
• Brown grease
• Oleic Acid
• Derived from vegetable
oils
• Tall Oil • Sylva Road RP1000
• Hydrogreen
• EVOFLEX CA/CA4
• Green
• Paper industry by-
products
• Same family as liquid
anti-strip & emulsifiers
http://www.eng.auburn.edu/research/centers/ncat/info-pubs/newsletters/spring 2014/rejuvenators.html
Managing Performance of High Recycle Asphalt Mixtures

33. Rejuvenators Benefits
Improve Workability
A. Improved compaction & workability
B. Increased production – Batch Plant
Binder Modification – SOFTEN
A. Virgin binder dumping
B. In-Place binder grade
Improved Mixture Performance
A. Balanced Mix Design
B. Improved Crack Resistance
Managing Performance of High Recycle Asphalt Mixtures

34. National Research - NCHRP Project 09-58
The Effects of Recycling Agents on Asphalt Mixtures
with High RAP and RAS Binder Ratios
• Main Objective of Study
–evaluate the effectiveness of recycling agents in HMA
and WMA mixtures with high RAP, RAS, or combined
RAP/RAS binder ratios through a coordinated
program of laboratory and field experiments
• Research Agency: Texas Transportation Institute
• Status: Work on Phase II underway
• Completion Date: October 2017
http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=3645
Managing Performance of High Recycle Asphalt Mixtures

35. Improved binder & mixture
measurement
BINDER: Glover-Rowe Damage Parameter
• Evaluation using Dynamic Shear Rheometer (DSR)
• DSR: common tool; equipment is in majority of all
DOT central labs
• G/R parameter developed from IN-PLACE mixes
• Indication of non-load associated cracking
• DSR – G/R parameter @ 45C, 10 rad/s is simpler
version of Glover-Rowe; correlates well with DC(T)
Managing Performance of High Recycle Asphalt Mixtures
Industry BMD Solution

36. Managing Performance of High Recycle Asphalt Mixtures
Mix 1
Mix 2
Mix 3
Mix 4
Mix 5 Mix 6
Mix 7
Mix 8
y = -0.0483x + 8.5737
R² = 0.944
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
40 50 60 70 80
LogG*(Pa)
Phase Angle
G/R Damage Parameter
LTOA E&R Binder, 45C, 10 rad/sec
G-R = 450 kPa
G-R = 180 kPa
SHRP Fatigue
Parameter
45C, 10 rad/sec
Linear (45C, 10
rad/sec)
Block Cracking
No Block Cracking
Binder Evaluation
Industry BMD Solution

37. Industry BMD Solution
Improved binder & mixture measurement
MIXTURE: Disc-shaped Compact Tension Test – DC(T)
• Also developed from IN-PLACE mixes
• Measures low temperature mixture cracking
• Thermal
• Reflective
• Block
• Used to obtain the fracture
energy of asphalt mixture lab
or field specimens
Managing Performance of High Recycle Asphalt Mixtures

38. Industry BMD Solution
Managing Performance of High Recycle Asphalt Mixtures
Mix 1
Mix 2
Mix 3
Mix 4
Mix 5
Mix 6Mix 7
Mix 8
R² = 0.9079
200
250
300
350
400
450
500
0.00 0.50 1.00 1.50 2.00 2.50
DCT,-12C,Gf,J/m2
G/R Parameter, log(G*)(cosδ)^2/( sinδ)
G/R Parameter Relationship to Fracture Energy
LTOA Binders, Glover-Rowe damage parameter
45C, 10 rad/sec
Lower Performance
Improved
Performance

39. SUMMARY
• Increased recycle content replaces virgin
asphalt binder
• Reduced mix costs help off-set budget
constraints
• Contractors can manage RAP variability
• Mix and binder performance can be more
easily predicted with new tools and
technology
• Increasing recycle material can be
successful if using a balanced mix design,
performance tests, WMA, & rejuvenators
Managing Performance of High Recycle Asphalt Mixtures

40. QUESTIONS?
Managing Performance of High Recycle Asphalt Mixtures