Edgard Hitti with Granite Construction delivers a presentation on modified asphalt binders, including the benefits and proper use of binders, types used, and how they are tested and graded. Presentation delivered on Nov. 7, 2019 at the California Asphalt Pavement Association Fall Asphalt Pavement Conference in Sacramento, Calif.

1. Polymer Modified Binder
CALAPA, 2019

2. Various Binder
Specifications
Penetration
Grading
ie
50-70
120-150
Viscosity
Grading
Superpave
PG Grading
Other
Systems /
hybrid
ie
AC-15P
Pba-6a
Original
Binder (AC)
ie
AC-20
AC-30
Aged
Residue (AR)
ie
AR4000
AR8000
M332 PG
Grading
ie
PG58S-28
PG58H-22
Grading
Systems
M320 PG
Grading
ie
PG58-28
PG64-22

3. Correlation between grading system
HarderBinderSofterBinder
Highviscosity&lowPen
LowViscosity&HighPen
Pen
60
70 Pen
85
100 Pen
120
150
Pen
200
300
Penetration Grades
AC 40
AC 20
AC 10
AC 5
AC 2.5
AR 16000
AR 8000
AR 4000
AR 2000
AR 1000
Pen
40
50
PG70-10
PG64-22
PG58-28
PG64H-10
PG58H-22

4. Viscosity
vs
temperature

5. Aging Criteria
Original- tank
sample prior to
mixing
Tested at high
temperature for
rutting potential
RTFO- age after
mixing and
compaction
Tested at high
temperature for
rutting potential
PAV- age about 5
to 10 years after
placement
Tested at intermediate
and cold temperatures
for fatigue and low
temperature cracking

10. Implementation of PG
grading system started
in 2006

11. Greenbook introduced
PG-PM in 2016

12. Grades
Consolidation
Grade Bump Down for Mixes Containing 16 - 25 Percent RAP
Specified PG Grade Bump Down Grade
PG64-10 PG58-22
PG64-16 PG58-22
PG70-10 PG64-16
PG64-28 PG58-34M
PG64-28M PG58-34M
PG76-22M PG64-28M

13. CA PMA
grades vs
surrounding
states
PG64-28NV
PG76-22NV
PG64-28P
PG76-22P
PG58-34M
PG64-28M
PG76-22M
PG70-22ER
PG70-28ER

14. Plus spec
variation
Orig. 4C Duct.
RTFO 4C Duct.
Orig. T&T
RTFO Jnr & %Rec.
Orig. d
Orig. ER @ 10C
Orig. soft. pt.
RTFO d
RTFO ER @ 25C
RTFO ER @ 25C

15. Testing
Certificate of Analysis
Property AASHTO
Test Method PG64-28M
Flash Point, Minimum °C T48 230
Solubility, Minimum % T44 97.5
Viscosity at 135°C,
Maximum, Pa·s
T316
3.0
Dynamic Shear,
Test Temp. at 10 rad/s, °C
Minimum G*/sin(delta), kPa
T315
64
1.00
RTFO Test ,
Mass Loss, Maximum, %
T240
1.00
Dynamic Shear,
Test Temp. at 10 rad/s, °C
Minimum G*/sin(delta), kPa
T315
64
2.20
Dynamic Shear,
Test Temp. at 10 rad/s, °C
Maximum (delta), %
T315
80
Elastic Recovery,
Test Temp.
Minimum recovery, %
T301
25
75
PAV Aging,
Temperature, °C
R28
100
Dynamic Shear,
Test Temp. at 10 rad/s, °C
Maximum G*sin(delta), kPa
T315
22
5000
Creep Stiffness,
Test Temperature, °C
Maximum S-value, MPa
Minimum M-value
T313
-18
300
0.300

16. Why plus spec
are needed ?

17. Useful
Temperature
Interval (UTI)
UTI > 92 typically needs modification
UTI < 92 typically straight refinery run
UTI, oC is the range between the high and the low
temperature.
UTI for PG64-10 is (64+10) = 74
UTI for PG70-10 is (70+10) = 80
UTI for PG58-22 is (58+22) = 80
UTI for PG76-22 is (76+22) = 96

18. CA PMA Testing Equipment

19. Phase angle,
d
Elastic PartElastic Part
d
G*Viscous
Part
G*
d
Viscous
Part
Asphalt A Asphalt B
sin d =
Viscous Part
G*

20. PMA vs Conventional elastic behavior

21. This study (published in
Feb 2005) uses national
field data to determine
enhanced service life of
pavements containing
polymer modified binders
versus conventional
binders.
The data is from a variety
of climates and traffic
volumes within North
America.

22. PMA Expected
Increase in
Service Life, yrs
vs
Conventional
Site Factor Condition Description Added Life
Foundation
Non-Expansive 5-10
Expansive 2-5
Frost Susceptible – Cold Climate 2-5
Water Table &
Drainage
Deep 5-10
Shallow;Adequate 5-8
Shallow; Inadequate 0-2
Existing Pavement
Condition
HMA
Good 5-10
Poor-Extensive Cracking 1-3
PCC
Good 3-6
Poor-Faulting & Cracking 0-2
Climate;
Temp.
Fluctuations
Hot Hot Extremes 5-10
Mild 2-5
Cold Cold Extremes 3-6
Traffic,Truck
Volumes
Low
Intersections 5-10
Thoroughfares 3-6
Heavy Loads 5-10
Moderate 5-10
High 5-10

23. Summary
Many studies have
shown PMA enhances
fracture and
distortion resistant
properties
Reduced Maintenance Activities
Crew Safety Eliminate Traffic Delays
Enhanced Performance
25 to 100 % increase in
service life
3 to 10 years increase in
service life
Field & laboratory investigations of PMA
mixes suggest:

24. Conclusions:
• The overall performance of the
PG64-28NV (PG64-28M) is superior to
the PG64-22 (PG64-16) mixtures (both
regular and rich)
• RTC should consider using the
PG64-28NV (PG64-28M) mix in both
the top and bottom lifts
• The rutting resistance of PG64-
28NV (PG64-28M) mix is significantly
better than the PG64-22 (PG64-16)
mix

25. RUTTING
11/10/2019 25
PG64-22
(PG64-16)
PG64-22 RICH
(PG64-16)
PG64-28NV
(PG64-28M)
Rut Depth, mm 6.5 7.1 2.5
Std Dev 0.59 0.43 0.04
COV 9% 6% 1%

26. FATIGUE PERFORMANCE
11/10/2019 26
Pavement Structure
Traffic
speed
Tensile strain at the bottom of HMA
layer, 4"depth, (microns)
Number of repetitions to
fatigue failure, Nf
Structure 1
2.0” PG64-28NV
2.0” PG64-22
Fast 204 540,000
Slow 285 220,000
Structure 2
2.0” PG64-28NV
2.0” PG64-22 rich
Fast 200 2,200,000
Slow 285 560,000
Structure 3
2.0” PG64-28NV
2.0” PG64-28NV
Fast 264 will not fail in fatigue
Slow 407 33,000,000

27. Follow up study:
• Utilize PG76-22NV (PG76-22M) and
PG70-16 (PG70-10)
• The mechanistic Empirical analysis
shows that the use of polymer
modified mix throughout the HMA
layers offers significant advantages
in the fatigue and rutting
performance of HMA pavements

29. Wave of
change:
Various DOT
Binder
specification
M320, M332,
DTc, etc…

30. PG, AASHTO M320 MSCR PG, AASHTO M332 % Recovery
PG58-22 PG58S-22 N/A
PG64-22 PG58H-22 N/A
PG70-22ER PG58V-22 30% Min
PG64-28ER PG64S-28 20% Min
PG70-28ER PG64H-28 25% Min
PG76-28ER PG64V-28 30% Min
WA Example, Equivalency table between PG grades and MSCR PG grades
MSCR (Multiple Stress Creep Recovery)
Grade ESALs, millions Jnr
Standard “S” 10 and standard traffic loading 2.0 – 4.0
Heavy “H” 10 – 30 or slow moving traffic loading 1.0 – 2.0
Very Heavy “V” > 30 or standing moving traffic loading 0.5 – 1.0
Extreme “E” > 30 and standing moving traffic loading 0.25 – 0.5

31. What is DTc
 ΔTc is the difference between the critical temperature of the stiffness (Ts) obtained from BBR testing and the
critical temperature of m-value (Tm) obtained from BBR testing:
 DTc = Ts –Tm
 DTc a good indicator of binder relaxation properties
 Positive DTc means the binder is S-control
 Negative DTc means the binder is m-control
 With age, binder will be m-controlled
 DTc moves to more negative values
 Pavement are more susceptible to cracking distress
 Most research are looking for a DTc of -5oC max
 Debate between 20 hrs vs 40 hrs PAV aging criteria
 UT max of -1oC (20hrs) on modified grades only
 TX within 6oC (20hrs) on all grades per SSP
 KS max of -5oC (40hrs) on all grades
 OK max of -5oC or -6oC (20hrs) by Jan 2020 on all grades

32. LCA & EPD

33. Take Away
Use of PMA reduce
distresses in pavements &
overlays:
- Less Fatigue Cracking
- Fewer Transverse Cracks
- Smaller Ruts
Quality of Construction:
STILL IMPORTANT, IF NOT
THE MOST IMPORTANT
FACTOR.
Many Mix Designs Functions
are stiffness based for
binder & mix:
OTHER MATERIAL
PROPERTIES ARE MORE
IMPORTANT.

34. Questions &
Answers,
Maybe