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The Latest Rap on RAP
RECYCLED ASPHALT PAVEMENT
Gerry HuberHeritage Research GroupChairman RAP and Shingle ETG
CANADIAN USER
PRODUCER GROUP
FOR ASPHALT 2010
RAP Expert Task Group
Formed 2007
Members
DoTs
Industry
Academia
Purpose of ETG
National Guidance
Coordinate
Develop
Improve
Recommendations
Correct use of technology
State of practice
Main Issues Identified
Performance Test
Best Practices Manual
Binder Grade Changes
Field Performance
Variability
5
Performance Studies of Asphalt Pavements with Greater than 25% RAP
Randy C. West, NCAT
October 7, 2009
Barriers to Increasing RAP
6
7
A Performance Comparison of RAP vs. Virgin Mixes
LTPP SPS-5 pavement sections
18 U.S. states and Canadian provinces
At least 30% RAP used in recycled mixes
Projects range in age from 6 to 17 yrs
General Performance
8
Distress Parameter
Threshold RAP Sections Virgin Sections
IRI 2.0 m/km 86% 89%
Rutting 10 mm 71% 78%
Fatigue Cracking 25% of WP area 60% 72%
Longitudinal Cracking
25% of section length
79% 86%
Transverse Cracking
20 cracks per section
47% 64%
Block Cracking 10% of section area
89% 94%
Raveling 10% of section area
75% 69%
Percentage of Sections Below General Pavement Performance Thresholds
9
10
11
12
13
14
High RAP Performance in Florida
Jim Musselman
Florida Department of Transportation
Statewide Pavement
Performance
Deficient Pavements (%)
Criteria 2004 2005 2006 2007 2008 2009
Ride 6.3 5.6 3.8 3.5 3.2 2.6
Crack 16.5 17.0 15.8 14.6 14.9 13.0
Rut 1.2 1.2 0.9 0.9 1.0 0.6
Section 334.046 of Florida Statutes: “Ensuring that 80% of the
pavement on the SHS meets Department Standards”
D.R.I.P
Data Rich….
Information Poor
Pavement Management Data
0
2
4
6
8
10
12
14
16
18
Age
(yr
s)
Percent RAP (%)
0 % 30 %
35 %
40 %
45 %
50 %
Only Projects >5,000 tons(No consideration for traffic)
20
RAP Management Best Practices
RAP Needs Analysis
Milling for Success
Multiple-source RAP piles
Crushing Considerations
Screening Options
Best Practices for Stockpiling
Sampling and Testing of RAP Stockpiles
Production of Recycled Asphalt Mixes
Barriers to Increasing RAP
21
Keep millings from different projects in separate stockpiles.
Milled RAP can typically be used “as is” in HMA without further crushing.
Milled RAP
Multiple Source RAP Stockpiles
• It is vital to prevent dumping of any deleterious materials in the pile from the beginning.
• Clearly instruct all truck drivers hauling materials to the yard where to dump different types of materials
RAP Crushing Process
Small dozer to break up
RAP and push it to a loader
Mix up the material while
feeding it into the
Processing Unit
25
Fractionating RAP
The practice should not be mandated; it should be the contractor’s business decision if and when to fractionate RAP.
26
Variability: RAP vs. Aggregate
27
Based on 74 RAP stockpiles in 14 states, and 60 Aggregate stockpiles in 6 states
Fractionated vs. Unfractionated
28
Becky McDanielRAP ETG
December 17, 2009
Investigation of Low and
High Temperature Properties
of Plant-Produced RAP
Mixtures
Experimental Design
Reclaimed Asphalt Pavement
Asphalt Binder Grade
0% 15% 25% 40%
PG 64-22X
Mix AX
Mix BX
Mix CX
Mix D
PG 58-28X
Mix EX
Mix F
Example Binder Data
ID GradeHT
Grade(DSR)
LT Grade(BBR)
True Grade
Tcrit
(TSAR)
Virgin Binders
PG64-22 67.4 -24.2 67-24PG58-28 60.7 -28.3 60-28
4A
PG64-22
73.7 -20.5 73-20 -22.64B 72.8 -20.8 72-20 -22.54C 74.4 -20.5 74-20 -20.14D 75.0 -19.6 75-19 -20.24E
PG58-2867.8 -24.2 67-24 -26.2
4F 70.0 -23.3 70-23 -23.4
One Example - Mix |E*|
100
1000
10000
100000
1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
Lo
g |E
*|, M
Pa
Log Reduced Frequency, Hz
PG64-22
MixA (0%0 RAP)
MixB (15% RAP)
MixC (25% RAP)
MixD (40% RAP)
One Example - Mix |E*|
100
1000
10000
100000
1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
Lo
g |E
*|, M
Pa
Log Reduced Frequency, Hz
Control versus PG58-28
MixA (0% RAP)
MixE (25% RAP)
MixF (40% RAP)
One Example - Mix |E*|
100
1000
10000
100000
1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
Lo
g |E
*|, M
Pa
Log Reduced Frequency, Hz
PG64-22 versus PG58-28
MixC (25% RAP)
MixE (25% RAP)
MixD (40% RAP)
MixF (40% RAP)
Second Example - Mix |E*|
100
1000
10000
100000
1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06
|E*|
, M
Pa
Reduced Frequency, Hz
Control versus PG58-28
Mix 5A (0% RAP)
Mix 5E (25% RAP)
Mix 5F (40% RAP)
IDT Strength Example 1
-28
-22
-16
-10
2500
3000
3500
4000
PB-A PB-B PB-C PB-D PB-E PB-F
Pv
mt. C
rack
ing T
em
per
atu
re,
C
Str
eng
th,
kP
a
Mixes
Strength
Temperature
IDT Stiffness Example 1
-28
-22
-16
-10
10
15
20
25
PB-A PB-B PB-C PB-D PB-E PB-F
Pv
mt. C
rack
ing
Tem
per
atu
re,
C
Sti
ffn
ess,
GP
a
Mixes
Stiffness
Temperature
IDT Strength Example 2
-28
-22
-16
-10
2000
2500
3000
3500
JH-A JH-B JH-C JH-D JH-E JH-F
Pv
mt. C
rack
ing
Tem
per
atu
re,
C
Str
eng
th,
kP
a
Mixes
Strength
Temperature
IDT Strength Example 3
-22
-16
-10
3000
3500
4000
EB-A EB-B EB-C EB-D EB-E EB-F
Pv
mt. C
rack
ing
Tem
peratu
re, C
Str
eng
th,
kP
a
Mixes
Strength
Temperature
IDT Stiffness Example 3
-22
-16
-10
20
30
40
EB-A EB-B EB-C EB-D EB-E EB-F
Pv
mt. C
rack
ing T
em
per
atu
re,
CS
tiff
nes
s, G
Pa
Mixes
Stiffness
Temperature
General Conclusions
Low Temperature Cracking (IDT)
Slight effects on critical cracking temp at up to 25% RAP with PG64-22
Critical cracking temp of 40% RAP with PG64-22 was slightly warmer but still around -22°C
Current ETG Activities
Best Practices document by TRB 2011
Research Needs statements
Performance Prediction tests
Shingles
Recommend changes to R35
Superpave Volumetric Design
Change to % Binder Replacement
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