Presentation by Dr. John Harvey, University of California Pavement Research Center, Davis & Berkeley, on Pavement Research and Practical Applications. Presentation delivered during the CalAPA Fall Asphalt Pavement Conference Oct. 26-27, 2016 in Sacramento, Calif.

1. Pavement Research and Practical
Applications
presented by
John Harvey
University of California Pavement Research Center
Davis and Berkeley
CalAPA
26 October, 2016
Sacramento, CA

2. Outline
• Asphalt rubber binder projects
– Performance-based specification for AR binders
– PG+5 binder application and specification
• Reclaimed asphalt (RAP/RAS) projects
– Caltrans funded project
– CalRecycle funded project
– Federal Aviation Administration (FAA) project
– National Center for Sustainable Transportation (NCST)
• Bike route surface type selection
• LCA Framework and EPDs

3. Performance-Based Specification for AR
binders
Project 4.50
• Funded by Caltrans
• Started in October 2014
• Objective
– Recommend testing procedures and criteria for
performance based specification for asphalt
rubber binders

4. Draft PG-AR Specification
• Concentric-cylinder geometry for determining
high and intermediate grades of asphalt rubber
binder
• Modification of RTFO test for temperature and
rubber content to realistically simulate the
production of rubberized mixes and to provide
uniform aging conditions
• Development of a new mold for casting of
uniform asphalt rubber binder beams for testing
in BBR

5. PG-AR Specification
Concentric-Cylinder vs. Parallel Plate
6 mm
Critical factor Concentric cylinder
(CC)
Parallel plate (PP)
Sample trimming No Yes
Testing duration Long Short
Testing temperature High High and intermediate
Required material Large volume Little volume
Standard test method Not available AASHTO T315, ASTM
D7175
1 mm 2 mm

6. Linear Regression Analysis and Statistical
Comparisons: CC can be reasonably used in
place of PP for AR
• Almost identical for <250 µm
• Differ as mesh size gets bigger
6
Particle Size Range Correlation Between Geometries (R2)
µm #mesh G* (kPa) δ (°) G*/sin(δ) (kPa)
180-250
250-425
425-850
60-80
40-60
20-40
0.9973
0.9467
0.9504
0.9834
0.9621
0.9020
0.9963
0.9497
0.9490
Combined 0.9500 0.9294 0.9508

7. 35 g
45 g
Standard Aging Temp:
163°C
Proposed Aging
Temp: 190°C
35 g
45 g
PG-AR Specification
Modified RTFO for Asphalt Rubber Binder

8. PG-AR Specification
Modified BBR Mold for AR Binder
– Preheating of the mold is not necessary
– Oven conditioning is not necessary
– Sample size is acceptable
– Sample trimming is easy
– Demolding is easy

9. PG-AR Specification
Modified BBR Mold for AR Binder
From Conv.
mold
From
Modified
mold

10. PG+5 Application and Specification
Project 4.61
• Funded by CalRecycle
• Started in September 2016
• Objective:
– Evaluate different approaches for increasing
overall crumb rubber usage by using small
amounts of crumb rubber in hot mix asphalt.

11. PG+5 Application and Specification
• Approach-1: Terminal blend* 5-10 percent CRM (by
weight of binder), with particle size less than 250
micros in final binder, test with PG spec**
• Approach-2: Dependent on new PG-AR specifications
• Approach-3: 0.25-0.50 percent CRM per ton of HMA (~
5-10 lb/ton HMA); i.e., dry process
• Approach-4: Field blend* 5-10 percent CRM (by weight
of binder) and with particle size less than 250 microns
in final binder, test with PG spec**
*Terms describing these under review
**Solubility requirement may be modified
• Work plan under review, currently organizing sampling,
preliminary results in fall 2017

12. Reclaimed Asphalt Projects
• Caltrans 4.51a: Evaluate the effective binder
replacement rate in mixes with high RAP/RAS content
• NCST: Evaluate the compatibility of new and aged
binder (i.e., influence of virgin binder grade and
source)
• FAA: Evaluate the implication of high RAP mixes in
design and performance of airfield pavements
• CalRecycle: Evaluate the implications for design and
performance of HMA with rubberized RAP (R-RAP) and
rubberized gap-graded (RHMA-G) mixes with
conventional RAP

13. Reclaimed Asphalt Projects
Caltrans 4.51a Project
• Objective: Evaluate effective asphalt binder
replacement in mixes with high RAP and RAS
contents
- Evaluate the diffusion and aging mechanisms
during blending of aged and new binders during
mix production
- Evaluate effective binder replacement rates
- Evaluate the influence of virgin binder type, RAP
type and content, and rejuvenating agents on
blended binder and mix properties

14. Caltrans 4.51a:
Two-Layer Asphalt
Binder Testing
Objective:
Evaluate degree of
blending/diffusion between
reclaimed and fresh binder at
various stages of production
Approach:
• Testing of properties of
composite asphalt binders
using DSR
• Modeling diffusion/aging
mechanism

15. Caltrans 4.51a:
Two-Layer Asphalt
Binder Testing
• With RAP, achieve full
diffusion (binder
replacement) eventually
• Time for full blending
dependent on temperature
0 2000 4000 6000 8000 10000 12000 14000 16000 18000
10
0
10
1
10
2
G* over Time following HMA Path
Time (second)
ComplexShearModulusG*(kPa)
Fitted
Fitted (exclude aging)
DSR Measured
Fully Blended
D=4.876E-11 m2
/sec
0 2000 4000 6000 8000 10000 12000 14000 16000 18000
10
0
10
1
10
2
G* over Time following WMA Path
Time (second)
ComplexShearModulusG*(kPa)
Fitted
Fitted (exclude aging)
DSR Measured
Fully Blended
D=2.521E-11 m2
/sec
HMA production
WMA production temperature (20 C less)
Full blending
after 2 hours
Partial blending
after 2 hours

16. Caltrans 4.51a Project:
FAM Mix Testing as a Solvent-Free Approach
FAM consists of fine
aggregate, fine RAP/RAS, and
virgin binder. The gradation
and binder content of FAM
represents those of the fine
portion (passing #4 or #8) of a
full-graded mix

17. NCST/Caltrans 4.51a Project:
Combined Effect of RAP, RAS, and Different Virgin
Binder Sources and Grades on Performance of the
Blended Binder and Asphalt Mixtures
• Questions asked, answered using binder, FAM and
limited mix testing:
– Does RAS blend well with virgin materials?
• No, the RAS did not appear to blend (no binder
replacement) based on binder and FAM and mix testing
– Is virgin binder source a significant factor affecting new and
aged binder blending?
• Yes, there were differences in blending for binders with
same PG grade but from different sources
– Did rejuvenating agent reduce stiffnesses in high RAP mixes?
• Yes

18. NCST/Caltrans 4.51a Project:
Combined Effect of RAP, RAS, and Different Virgin
Binder Sources and Grades on Performance of the
Blended Binder and Asphalt Mixtures
– Will use of virgin binder that is one grade softer for mixes
containing high RAP/RAS have a significant effect on the
performance of the mix?
• Yes, in general acceptable high temperature properties
were obtained when using 25% binder replacement
when reduce one PG grade to meet intermediate/low
temperature properties
– Can the less expensive and more efficient FAM mix testing
be used as a substitute for more expensive mix tests?
• Early results are promising for using FAM for initial mix
design and QC/QA testing

19. CalRecycle Project
Effect of R-RAP on HMA and RAP on RHMA-G
Rubberized RAP (R-RAP) in HMA
• Mixes with 15% and 25% R-RAP binder replacement
were designed and met required volumetric
properties
• Adding R-RAP to new HMA mixes will generally result
in better rutting performance, but diminished
cracking performance, at both intermediate and low
temperatures
• There appears to be no reason or justification for
separating R-RAP and RAP or maintaining separate
R-RAP and RAP stockpiles at asphalt plants

20. CalRecycle Project
Effect of R-RAP on HMA and RAP on RHMA-G
RAP in RHMA-G
• Initial RHMA-G experimentation shows that hard to
have more than 10% RAP binder replacement
without violating gap-graded aggregate gradation
requirements
• Adding RAP to RHMA-G mixes will potentially
improve rutting performance, but potentially have a
negative effect on fatigue cracking performance in
medium and thin overlays
– Bottom line: adding RAP starts negating performance
reasons for specifying RHMA for thin overlays

21. 0
1
2
3
4
5
0 500 1,000 1,500 2,000 2,500 3,000 3,500
PermanentAxialStrain(%)
Number of Cycles
RHMAG_Cont.
RHMAG_10RAP
Rutting Performance
Cracking Performance
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
1.E+11
FatigueLife(NumberofCycles)
µstrain
RHMAG_Cont.
RHMAG_10RAP
100 200 300 400 600 1,000

22. FAA Project
RAP in Airfield Pavement Mixes
• Meeting the FAA Superpave volumetric requirements
for mixes containing more than 25% binder
replacement (40% was evaluated) was challenging
• Adding RAP generally increased the stiffness of the
mix resulting in improved resistance to permanent
deformation, but diminished resistance to fatigue
cracking in thinner asphalt layers
• The results also indicated that RAP cannot be
considered as a generic material and that some
performance-related testing is required to assess the
compatibility of the reclaimed and virgin binders

23. FAA Project
RAP in Airfield Pavement Mixes
• Use of softer virgin binders justified to compensate
for the stiffening effect of the reclaimed binder in
high RAP mixes (i.e., more than 25% binder
replacement)
• The known benefits of using a polymer modified
binder were compromised by adding RAP into the
mix
• The influence of RAP on thermal cracking
performance and on the rate of mix aging in the
longer-term need to be investigated in more detail

24. Preservation and Bicycle Riders
• Objective: Develop guidelines for design of
preservation treatments suitable for bicycle
routes on state highways and local streets in
California
• Measurements
– Pavement textures for
chip seals, slurries, HMA
– Bicycle vibration
• Surveys of bicycle ride quality
– 6 bicycle clubs
– General public in Davis, Richmond, Chico, Sacramento,
Reno
• Correlations between pavement texture,
bicycle vibration and ride quality

25. Conclusions from Bicycle Studies
• 80% of riders rate pavements with Mean Profile
Depth values 1.8 mm or less as acceptable
– Limit chip seal stone size
• Most HMA and slurries on city streets produce high
acceptability
• Distresses, particularly
transverse cracking,
reduces ride quality
• Chip seal specification
recommendations
in Caltrans report
• Can be considered in PMS
• Consider “Complete Pavement”, restripe to add
wider bike lanes and safer turning lanes when paving

26. Environmental Facts
Functional unit: 1 metric ton of asphalt concrete
Primary Energy Demand [MJ] 4.0x103
Non-renewable [MJ] 3.9x103
Renewable [MJ] 3.5x102
Global Warming Potential [kg CO2-eq] 79
Acidification Potential [kg SO2-eq] 0.23
Eutrophication Potential [kg N-eq] 0.012
Ozone Depletion Potential [kg CFC-11-eq] 7.3x10-9
Smog Potential [kg O3-eq] 4.4
Boundaries: Cradle-to-Gate
Company: XYZ Asphalt
RAP: 10%
Image source: adapted from N. Santero
Pavement Interactive
Example LCA results
Environmental Product Declaration (EPD):
Concise, quantitative information
PCA and NRMCA already producing EPDs

27. FHWA Pavement LCA Framework
Document
• Published January 2016
• Guidance on uses, overall
approach, methodology,
system boundaries, and
current knowledge gaps
• Specific to pavements
• Includes guidelines for
EPDs
https://www.fhwa.dot.gov/pavement/pub_details.cfm?id=998

28. NAPA has a webinar on the FHWA LCA
Framework
Contact
Heather
Dylla at
NAPA for
more
information

29. EPDs: What’s Happening?
• Asphalt industry is working to produce EPDs
– Asphalt Institute is working on Product Category Rules to
produce EPDs for different types of asphalt binder
– National Asphalt Pavement Association is doing same for
national average EPDs for different mix types
– Both should be out within next one to two years
• Customers are starting to ask for EPDs
– High Speed Rail is requiring EPDs for reporting
– LEED4 is giving points for EPDs
• How will they be used?
– Caltrans/UCPRC participated in September 2016
TRB/FHWA Workshop to discuss obstacles and possible
paths forward for EPDs
– Stay tuned!

30. Questions?