Update on the latest research with regard to RAP

Recent Research on Use of RAP in HMA and RHMA
John Harvey
University of California Pavement Research Center
California Asphalt Pavement Association
Spring Asphalt Pavement Conference
8 March 2024
Ontario

Why Use RAP in HMA and RHMA?
• Cost Effectiveness: can reduce cost for material
producer and buyer
• Virgin binder costs a lot more than binder in RAP
• Environmental Benefits: can reduce global warming
potential and other environmental impacts
• Depending on transport, processing and use of recycling
agents
• Finite Resource Conservation: reduces use of finite
aggregate sources

As long as get same or better performance
• Rutting
• Not too soft in first 5 years
• Age-related (block) cracking
• Not too stiff and unable to relax thermal
contraction strains at intermediate
temperatures after aging
• Fatigue
• Desirable properties depend on
structural design and where used in
structure
• Low temperature cracking
• Same as age-related but at extreme low
temperatures
• Moisture damage
• Dependent on binder and aggregate
chemistry, water permeability
(compaction)
• All are critical in surface lift except
fatigue and moisture damage
• Fatigue involves whole structure
• Moisture damage happens anywhere
• All except fatigue are mix
performance only, fatigue involves
structure design
• Interaction of stiffness (controlling
bending strain) and fatigue (at a given
strain)
• Includes reflective cracking when asphalt
placed over cracked asphalt, concrete or
cemented base

Why performance determines whether RAP use
beneficial or not: simple example
Analysis period = 60 yrs
Material A Material B
0.85 GWP or $ 1.0 GWP or $
15 year life 20 year life
15 20
30 40
45
Total GWP or $ Total GWP or $
3.4 3.0

Overview of Caltrans/UCPRC High RAP Studies
• High RAP Laboratory Factorial Study, lab mixes
• One gradation and aggregate source
• Two RAP sources
• Two binders, PG64 and PG58, different crude sources
• 0, 25 and 50% RAP binder replacement
• Three rejuvenating agents
• High RAP and RAS pilot projects, plant mixes
• Four pilot projects built, three with testing completed, more coming
• 0, 25 to 40% RAP, 10 or 15% RAP+3% RAS combinations
• Mix designs to meet same binder and mix property as control 0% RAP mix
• JMF and QA sample testing

Overview of Caltrans/CalRecycle/UCPRC RAP in RHMA Studies
• RAP in RHMA and RHMA Thickness Heavy Vehicle
Simulator/Lab/CalME Simulation Study, plant mixes
• Two gradations
• 0 and 10% coarse RAP
• Two thicknesses for each gradation: 0.2 ft and 0.4 or 0.5 ft
• Additional lab mix testing of mixes with two other AR binders, open graded
lab mixes
• CalME simulations of all variables: gradation, RAP, binder source, RAP source,
thickness
• RAP in RHMA-G, plant mixes
• Five pilots built and tested
• 0 and 10% RAP
• Testing during QA

Performance related binder
tests used in studies
• PG characterization of virgin and extracted
RAP and RAS binders (AASHTO R28, T313)
• PG characterization of extracted blended
virgin/RAP/RAS/RA binders
• Frequency sweeps to determine stiffness
master curves and Black space diagrams
• Glover-Rowe aging related cracking testing
• Delta Tc analysis (AASHTO R29)
• Fourier transform infrared (FTIR)
spectroscopy tests to track changes in binder
chemistry with aging
1E-01
1E+00
1E+01
1E+02
1E+03
1E+04
1E-04 1E-02 1E+00 1E+02 1E+04
Complex
Shear
Modulus
(kPa)
Reduced Frequency (Hz)
Master Curve Low Temperature
Intermediate Temperature High Temperature
0
0.1
0.2
0.3
0.4
0.5
0.6
800
1,000
1,200
1,400
1,600
1,800
2,000
Normalized
Absorbance
Units
Wavenumber (cm-1)
Carbonyl

Performance related mix
tests used in studies
• Dynamic modulus (AASHTO T 378; specimens
prepared in a gyratory compactor)
• Flexural modulus (AASHTO T 321; specimens
prepared using a rolling wheel compactor)
• Repeated load triaxial (RLT, flow number, AASHTO
T 378; specimens prepared in a gyratory
compactor)
• Beam fatigue (AASHTO T 321; specimens
prepared using a rolling wheel compactor)
• IDEAL-CT indirect tensile strength test (IDEAL-CT,
ASTM D 8225, specimens prepared in a gyratory
compactor)
• Used on early projects: I-FIT (AASHTO T393,
specimens prepared in a gyratory compactor)
• Used on recent projects: Caltrans draft protocol
for medium term oven aging (MTOA) 0
2
4
6
8
10
12
14
16
18
20
0 5 10 15
Load
(kN)
Displacement (mm)
P100
P85 =85%P100
P75 =75%P100
P65 =65%P100
L85
L75
L65

High RAP Laboratory Study
• Background at conception of study in 2019
• Little known about RAP/RAS impact on mechanical properties of HMA
• Little known about recycling agent impact on mechanical properties of HMA
• What is the best approach to dose recycling agent?
• Goal
• Study how the mechanical properties of the HMA change upon the addition
of high contents of RAP and RAS (between 25 and 50% binder replacement)
and how the RAP effects (e.g. decrease in cracking resistance) can be offset by
using recycling agents
Original slides prepared by Angel Mateos

Recycling Agent Dose Determination
• Match high PG of the Control mix virgin
binder (Target PGH = 67.5°C)
Mix with 25% RAP A
PG 64-16
virgin
RAP A
Example...
25%
75%
PGH = 74.8°C
PGH = 66.8°C
PG 64-16
virgin
RAP A
19.0%
75%
Aromatic
6.0%
PG 64-16
virgin
RAP A
21.8%
75%
Tall oil
3.2%
PG 58-28
virgin
RAP A
21.0%
75%
Aromatic
4.0%
PG 58-28
virgin
RAP A
22.5%
75%
Tall oil
2.5%
PGH = 67.5°C
PGH = 68.3°C
PGH = 67.7°C

What are the effects of the addition of high RAP content on the mechanical properties of the
HMA? Property What we were expecting What we measured
Stiffness
Increase in stiffness, particularity at
high temperatures
As expected
1 000
10 000
100 000
1 000 000
10 000 000
1.E-05 1.E-03 1.E-01 1.E+01 1.E+03 1.E+05
Axial
dynamic
modulus
(psi)
Reduced frequency (Hz)
100% PG64, 0% RAP, 0% Rej
75% PG64, 25% RPG102, 0% Rej
75% PG64, 25% RPG109, 0% Rej

Stiffness
high temperatures
As expected
Fatigue resistance Decrease Opposite!!!
1 000
10 000
100 000
1 000 000
10 000 000
100 1000
Fatigue
life
Peak-to-peak strain (με)
100% PG64, 0% RAP, 0% Rej
75% PG64, 25% RPG102, 0% Rej

Stiffness
high temperatures
As expected
1 000
10 000
100 000
1 000 000
10 000 000
100 1000
Fatigue
life
Peak-to-peak strain (με)
100% PG64, 0% RAP, 0% Rej
PG64-16 w/RAP10% (ELD-49)
PG64-16 w/RAP0% (ELD-49)
PG64-16 w/RAP18% (SAC-49)
PG64-16 w/RAP25% (SAC-49)
PG64-16 w/RAP15% (GLEN-5)
PG64-16 w/RAP15% (NAPA-29)
Statewide Median
- The Control mix 4PB fatigue
performance is very low
compared to other Caltrans
mixes with PG64 from other
sources
- Increasing RAP binder %
without RA increases fatigue
performance

Stiffness
high temperatures
As expected
Rutting resistance Improve As expected
Ideal Results Strength increase & IdealCT decrease As expected
0
5
10
15
20
25
30
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Load
(kN)
Displacement (mm)
100% PG64, 0% RAP, 0% Rej
75% PG64, 25% RPG102, 0% Rej
75% PG64, 25% RPG109, 0% Rej
IdealCT = 79
IdealCT = 68
IdealCT = 20

Can the RAP addition effects be predicted based on testing of the blended binder?
✓ Overall, the effect on rutting resistance and mix stiffness can be predicted... and
indirectly Ideal ITS (ITS strongly corelated to mix stiffness)
✓ Nonetheless, the effect on fatigue resistance and IdealCT cannot be predicted
0
2 000 000
4 000 000
-40 -35 -30 -25 -20 -15 -10 -5 0
Axial
dynamic
modulus
@
68°F
(20°C)
&
10+4
Hz
(psi)
PG low of binder blend (°C)
100% PG64, 0% RAP, 0% Rej 75% PG64, 25% RPG102, 0% Rej 75% PG64, 25% RPG109, 0% Rej
0
50
100
150
200
250
300
0 10 20 30 40
Ideal
strength
(psi)
PG intermediate (°C)
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40
IdealCT
0
50
100
150
200
250
0 10 20 30 40
4PB
ε6

What are the effects of the recycling agent addition on the mechanical properties of HMA with high RAP
content?
Property What we were expecting What we measured
Stiffness
Decrease in stiffness, particularity at
high temperatures
As expected
1 000
10 000
100 000
1 000 000
10 000 000
1.E-05 1.E-03 1.E-01 1.E+01 1.E+03 1.E+05
Axial
dynamic
modulus
(psi)
Reduced frequency (Hz)
100% PG64, 0% RAP, 0% Rej
75% PG64, 25% RPG102, 0% Rej
75% PG64, 19% RPG102, 6% Aromatic
75% PG64, 21.8% RPG102, 3.2% TallOil

By using recycling agent, can the mechanical properties of the HMA with high RAP
content be restored back to the properties of the HMA with low RAP content?
Property Can be restored?
Stiffness Yes
Fatigue resistance
???
• No improvement for PG64-16
• Yes for PG58-28
Rutting resistance
No need to restore; need to check RA does
not produce rutting problems
Ideal Results
Overall yes, with exceptions (IdealCT for
PG58-28)
• Overall Yes, with some caveats

What is the recommended approach to determine recycling agent dose?
Initial considerations: What is the goal of adding the recycling agent?
✓Restore the mechanical properties of the mix
with high RAP/RAS content back to the
properties of the control mix with either no
RAP/RAS or low/standard RAP/RAS content
✓Optimizing mix properties for different
applications (thin surface, thick overlay, etc)
within the balanced mix design framework
Approach 1
Approach 2

What is the recommended approach to determine recycling agent dose?
Initial considerations: Recycling agent dose Overshooting
• A common approach to determine recycling agent dose: restore PGH of the base binder
What do we mean by “Overshooting”?
-15
-10
-5
0
5
10
15
20
PGH PGI PGL
PG
verus
PG
of
base
binder
(PG
64-16)
100% PG64, 0% RAP, 0% Rej
50% PG64, 50% RPG102, 0% Rej
50% PG64, 41.9% RPG102, 8.1% TallOil
PG "compliant" zone
This should be
our target
The target should be
meeting PG
specifications:
• PGH ≥ Required PGH
• PGI ≤ Required PGI
• PGL ≤ Required PGL
• Not matching PGH of
base binder

Conclusions
• Most of the negative effects of RAP/RAS addition can be offset by using recycling
agents and/or step-down binder
• By using recycling agents and/or step-down binder, introducing high RAP/RAS content
(up to 50% binder replacement) in HMA while maintaining performance is doable
• Restoring the PGH of the binder blend may result in unnecessarily high recycling
agent dose that may hurt performance HMA with high RAP/RAS
• Out of the different parameters evaluated in this study, the PGI of the binder blend
and the ITS measured in the Ideal cracking test were found to relate to HMA stiffness
at intermediate temperature, which is related to 4PB fatigue life and structural
bending
• Two approaches for dosing the recycling agent have been proposed:
o Approach 1 focuses on restoring the stiffness of the HMA at intermediate
temperature
o Approach 2 focuses on meeting the BMD PRS by using the minimum amount of
recycling agent

High RAP and RAS pilot projects
• San Joaquin 26
(built Oct 2022):
• PG64-28M control
binder
• 0% RAP and RAS
• 15% RAP (mainline)
• 25% RAP+RA
• 30% RAP+RA
• 35% RAP+RA
• 40% RAP+RA
• 25% RAP+3%RAS+RA
• El Dorado 49
(built Nov 2021):
• PG64-16 control
binder
• 0% RAP and RAS
• 3% RAS+RA
• 3% RAS+10% RAP+RA
• San Bernardino 215
(built Aug 2022):
• PG64-28M control
binder
• 0% RAP
• 25% RAP+RA
• 30% RAP+RA
• 35% RAP+RA
• 40% RAP+RA
In process: Ventura 150 (built Sep 2023), Contra Costa 4 (to be built in 2024)
Plots prepared by Jeff Buscheck, Justin Chu, Angel Mateos, Heather Tom, Anai Ramirez-Cazares

JMF PG binder grade checks: SBD 215

JMF PG binder grade checks: SJ 26

26
Medium
Term Oven
Aging
(MTOA)
compared to
reheating
effects on
Indirect
Tensile
Strength
(psi)
y = 0.791x + 13.024
R² = 0.5259
0
20
40
60
80
100
120
140
160
180
200
0 50 100 150 200
Box:
IdealCT
Index
(#)
Bucket: IdealCT Index (#)
y = -35.56ln(x) + 261.34
R² = 0.5237
0.0
50.0
100.0
150.0
200.0
250.0
300.0
0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0
Indirect
Tensile
Strength
(psi)
IdealCT Index (#)
SJ 26 Buckets
SJ 26 Boxes
SJ 26 MTOA
SBd 215 Buckets
SBd 215 Boxes
SBd 215 MTOA
JMF Trials
y = 0.4379x + 11.758
R² = 0.5325
0
20
40
60
80
100
120
140
160
180
200
0 50 100 150 200
MTOA:
IdealCT
Index
(#)
Reheated: IdealCT Index (#)
y = 1.0002x + 20.692
R² = 0.7106
0
50
100
150
200
250
300
0 50 100 150 200 250 300
MTOA:
Indirect
Tensile
Strnegth
(psi)
Reheated: Indirect Tensile Strength (psi)
Mix Aging

27
y = 0.791x + 13.024
R² = 0.5259
0
20
40
60
80
100
120
140
160
180
200
0 50 100 150 200
Box:
IdealCT
Index
(#)
Bucket: IdealCT Index (#)
y = -35.56ln(x) + 261.34
R² = 0.5237
0.0
50.0
100.0
150.0
200.0
250.0
300.0
0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0
Indirect
Tensile
Strength
(psi)
IdealCT Index (#)
SJ 26 Buckets
SJ 26 Boxes
SJ 26 MTOA
SBd 215 Buckets
SBd 215 Boxes
SBd 215 MTOA
JMF Trials
y = 0.4379x + 11.758
R² = 0.5325
0
20
40
60
80
100
120
140
160
180
200
0 20 40 60 80 100 120 140 160 180 200
MTOA:
IdealCT
Index
(#)
Reheated: IdealCT Index (#)
Mix Aging
Medium
Term Oven
Aging
(MTOA)
compared to
reheating
effects on
IDEAL-CT
index value
(CT #)

Preliminary Observations
• Different base binders and rejuvenating agents and different
base binders can be used to engineer mixes that have same or
better performance than control mixes with no RAP or RAS
• Mixes with up to 40% RAP
• Mixes with 3% RAS
• In many cases, the performance is better than the mainline
mixes meeting current specifications:
• <15% RAP
• <25% RAP and a stepped down PG binder
• Data from additional pilot projects and further analysis will be
used to arrive at preliminary recommendations
• Testing IDEAL-CT specimens after MTOA draft method for all
pilot projects

RAP in RHMA and RHMA Thickness Heavy Vehicle
Simulator/Lab/CalME Simulation Study
HVS Test Track, Four RHMA-G
Plant Mixes, 0.2’ and thicker
• ½” no RAP
• 0.2 and 0.4 ft thicknesses
• ½” with 10% RAP
• 0.2 ft thick
• 3/4” no RAP
• 0.2 ft thick
• 3/4” with 10% RAP
• 0.5 ft thick
• Additional Laboratory Mixes
with Plant Sampled Binders
• Same aggregates and ½ “
gradation
• Two plant sampled AR
binders:
• PG64 base from But-162
• PG70 base from Imp-186
• Two RAP sources
• Coarse RAP, less aged
• Fine RAP, more aged

HVS Track Experiment Design
Section RHMA-G Mix Thickness Purpose in the Experiment
(ft.) (mm)
704 1/2 in. NMAS, no RAP 0.2 60 Control for all 1/2 in. RHMA-G mixes
703 1/2 in. NMAS, no RAP 0.4 120 Compare two layers with single layer
701
1/2 in. NMAS with 10%
RAP, no binder
replacement
0.2 60
Compare mix with RAP to control mix for
same layer thickness
698 3/4 in. NMAS, no RAP 0.2 60
Control for all 3/4 in. RHMA-G mixes.
Compare 3/4 in. mix with 1/2 in. mix
700
3/4 in. NMAS with 10%
RAP, no binder
replacement
0.5 150
Compare two layers, both with RAP, to
two layers with no RAP

HVS and HWT Rut Testing Summary
HVS
• Four of the five sections had
similar trends
• Control section (1/2” no RAP)
had a faster rate of permanent
deformation
• Due to underlying base rutting
• RAP and NMAS did not appear
to have a significant effect,
with silo aging/stiffness
appearing to have a larger
influence
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1/2in.; No RAP 1/2in.; With RAP 3/4in.; No RAP 3/4in.; With RAP
Rut
Depth
after
35k
Reps
(mm)
Mix
HWT

Silo Time and RAP Effects on Flexural Stiffness
• MixA (1/2", 0% RAP, 64-
16 AR), estimated silo
storage: 8 to 10 hours
• Other mixes, estimated
silo storage: 0 to 2 hours
• Axial modulus only
showed silo effect
High temp Low Temp

RAP Effects on Flexural Stiffness for Additional Binders
• Expected effects on
stiffness from including
RAP, and including more
aged fine RAP
• Mostly at intermediate
temperatures
• Generally mixed small
effects on fatigue for all
mixes
High temp Low Temp

Combined effects of 10% RAP in RHMA-G on stiffness
and fatigue life using CalME simulations
• Many questions addressed:
• Pavement fatigue and reflective cracking performance?
• Considering: inclusion of RAP, RHMA-G aggregate NMAS, softer coarse RAP
and stiffer fine RAP, different AR binders, RHMA-G thicknesses, full-depth
RHMA-G
• Analyzed for three types of structures with different thicknesses for
each:
• New Asphalt on asphalt overlays
• Asphalt on asphalt overlays
• Asphalt on concrete overlays

Selected CalME simulation conclusions
• For “thin” overlays (<= 0.25 ft thick) RHMA overlays on cracked asphalt pavement, the
results for 10% RAP vs no RAP depended on the base binder and RAP properties
• Silo aging can have a larger effect on RHMA simulated performance than 10% RAP
• For RHMA-G on HMA in “thick” total asphalt layers
• Adding 10% RAP and RAP from different sources had different effects on simulated
performance, depending on the asphalt rubber binder and its base binder, as well as
pavement structure type and RHMA thickness
• For full depth RHMA versus RHMA/HMA in an application of 0.5 ft of total new asphalt
• Full depth RHMA can be beneficial when the RHMA has good performance, and worse when
it doesn’t
• Adding RAP generally had a beneficial effect on using full depth RHMA compared with
RHMA with no RAP

10% RAP in RHMA-O: Cantabro loss
• RHMA-O lab mixes made with
But-162 and Imp-186 plant
sampled RA binders with 0 and
10% RAP
• Cantabro durability test results
showed no detrimental effect of
using 10% coarse RAP
IMP 86 PG70 RHMA-O
with no RAP mix before
and after Cantabro

RAP in RHMA-G Pilot Projects Comparing 0 and 10% RAP

Some Preliminary Conclusions and Recommendations
• High RAP HMA mixes up to 40 or 50% RAP
• Can be engineered to meet performance related specifications producing similar or
better performance for rutting, fatigue, stiffness, low temperature cracking
• Virgin binder source and grade, RAP mix binder and aggregates, and rejuvenating
agents are tools to engineer desired properties for different design scenarios (thin
overlay [PM], thick overlay, surface vs underlying lifts)
• Range of fatigue performance for a given stiffness controlled by virgin binder
source; IDEAL-CT and other fracture tests only correlate with stiffness not fatigue
• Need performance related specifications for mix design, including a fatigue test
• 10% RAP in RHMA-G and RHMA-O
• 10% RAP in RHMA-G will generally result in similar fatigue performance in surface
overlays, better or worse than no RAP depending on individual mix properties
• 10% coarse RAP in RHMA-O appears to not hurt Cantrabro (raveling) performance
• Use of RHMA-G in surfaces thicker than 0.2 ft
• Allow designers to consider RHMA-G layers up to 0.5 ft when using CalME

Reports
• High RAP laboratory study: report under Caltrans review
• RAP in RHMA and RHMA thickness HVS testing:
https://escholarship.org/uc/item/7wq3s753
• RAP in RHMA and RHMA thickness laboratory study and CalME
simulation study: report under Caltrans review
• High RAP and RAS pilot studies:
• El Dorado 49: https://escholarship.org/uc/item/8h67s9z0
• San Bernardino 215 and San Joaquin 26: reports being prepared
• Ventura 150: testing not yet completed
• RAP in RHMA five pilot studies: report under Caltrans review
• Environmental life cycle assessment (LCA) and life cycle cost analysis
in progress for all of above

Thanks to:
• UCPRC Asphalt Team
• UCPRC HVS Testing Team
• Caltrans Office of Asphalt
Pavement Technical Leads
• CalRecycle Technical Leads
• Caltrans Research
• Contractors on pilot projects
and test sections
www.ucprc.ucdavis.edu
Questions

What are the effects of the addition of high RAP content on the mechanical properties of the HMA?
Stiffness
high temperatures
As expected
Rutting resistance Improve As expected
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 10 000 20 000 30 000 40 000
Rut
(in.)
Wheel passes
100% PG64, 0% RAP, 0% Rej
75% PG64, 25% RPG102, 0% Rej
75% PG64, 25% RPG109, 0% Rej
Hamburg Wheel Tracking Test

0
5 000
10 000
15 000
20 000
25 000
30 000
35 000
40 000
50 60 70 80
HWT
test:
Number
of
passes
to
0.5
in.
(12.5
mm)
PG high (°C)
✓ Overall, the effect on rutting resistance and mix stiffness can be precited... and
indirectly Ideal ITS (ITS strongly correlated to mix stiffness)
✓ Nonetheless, the effect on fatigue resistance and IdealCT could not be predicted
0
2 000 000
4 000 000
-40 -35 -30 -25 -20 -15 -10 -5 0
Axial
dynamic
modulus
@
68°F
(20°C)
&
10+4
Hz
(psi)

0
500 000
1 000 000
1 500 000
2 000 000
2 500 000
3 000 000
3 500 000
-40 -30 -20 -10 0
Axial
dynamic
modulus
@
68°F
(20°C)
&
10+4
Hz
(psi)
PG low (°C)
0
200 000
400 000
600 000
800 000
1 000 000
1 200 000
1 400 000
0 10 20 30 40
Axial
dynamic
modulus
@
68°F
(20°C)
&
1
Hz
(psi)
0
5 000
10 000
15 000
20 000
25 000
30 000
50 60 70 80
Axial
dynamic
modulus
@
68°F
(20°C)
&
10-4
Hz
(psi)
PG high (°C)
✓ Overall, the effect on rutting resistance and mix stiffness can be precited... and
indirectly Ideal ITS (ITS strongly corelated to mix stiffness)
✓ Nonetheless, the effect on fatigue resistance and IdealCT cannot be predicted
0
2 000 000
4 000 000
-40 -35 -30 -25 -20 -15 -10 -5 0
Axial
dynamic
modulus
@
68°F
(20°C)
&
10+4
Hz
(psi)
High Temp
(rutting)
Intermediate Temp
(fatigue)
Low Temp
(fatigue and
thermal cracking)

What are the effects of the recycling agent addition on the mechanical properties of HMA with high RAP content?
Stiffness
high temperatures
As expected
Fatigue resistance Increase
No effect for PG64-16!!!
As expected for PG 58-28
0
50
100
150
200
250
300
350
400
100% PG64 75% PG64 75% PG64 75% PG64 100% PG58 75% PG58 75% PG58 75% PG58
0% RAP 25% RPG102 19% RPG102 21.8% RPG102 0% RAP 25% RPG102 21% RPG102 22.5% RPG102
0% Rej 0% Rej 6% Aromatic 3.2% TallOil 0% Rej 0% Rej 4% Aromatic 2.5% TallOil
0% BR 25% BR 25% BR w/Rej 0% BR 25% BR 25% BR w/Rej
PG64 PG58
4PB
ε
6
Not
Tested
in 4PB

Stiffness
high temperatures
As expected
Rutting resistance Decrease Not consistent
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 10 000 20 000 30 000 40 000
Rut
(in.)
Wheel passes
100% PG64, 0% RAP, 0% Rej
75% PG64, 25% RPG102, 0% Rej
75% PG64, 19% RPG102, 6% Aromatic
75% PG64, 21.8% RPG102, 3.2% TallOil
In this case, the Aromatic improved rutting
resistance while Tall Oil did the opposite...

0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 10 000 20 000 30 000 40 000
Rut
(in.)
Wheel passes
100% PG58, 0% RAP, 0% Rej
75% PG58, 25% RPG102, 0% Rej
75% PG58, 21% RPG102, 4% Aromatic
75% PG58, 22.5% RPG102, 2.5% TallOil
Stiffness
high temperatures
As expected
In this case, the Tall Oil improved rutting
resistance while Aromatics did the opposite...

Stiffness
high temperatures
As expected
Ideal Results Strength decrease & IdealCT increase
As expected for strength
Not consistent for IdealCT
0
50
100
150
200
250
0
20
40
60
80
100
120
140
160
100% PG64 75% PG64 75% PG64 75% PG64 100% PG58 75% PG58 75% PG58 75% PG58
0% RAP 25% RPG102 19% RPG102 21.8%
RPG102
0% RAP 25% RPG102 21% RPG102 22.5%
RPG102
0% Rej 0% Rej 6% Aromatic 3.2% TallOil 0% Rej 0% Rej 4% Aromatic 2.5% TallOil
0% BR 25% BR 25% BR w/Rej 0% BR 25% BR 25% BR w/Rej
PG64 PG58
Strength
(psi)
IdealCT
RA did not improve
IdealCT of PG58
mixes

JMF PG binder grade checks: ElD 49

Update on the latest research with regard to RAP

Recommandé

Recommandé

Contenu connexe

Similaire à Update on the latest research with regard to RAP

Similaire à Update on the latest research with regard to RAP (20)

Plus de California Asphalt Pavement Association

Plus de California Asphalt Pavement Association (20)

Dernier

Dernier (20)

Update on the latest research with regard to RAP