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Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
WHRP Project 0092-10-06
Effect of Recovered Binders from Recycled Shingles and Increased
RAP Percentages on Resultant Binder PG
Ramon Bonaquist, Ph.D., P.E.
Advanced Asphalt Technologies, LLC
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Outline
• Objectives
• Approach
• Major Findings
• Conclusions and Recommendations
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Objectives
• Improve the AASHTO performance graded binder blending chart analysis.
• Use the improved blending chart analysis to evaluate current WisDOT criteria for binder replacement.
• Identify potential effects of using RAP and RAS on pavement service life, both positive and negative.
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Approach
• Review of current practice– WisDOT specs relative to other agencies– AASHTO M323 blending chart analysis
• Blending chart improvements– RAS– Multiple recycled binders
• Characterization of WI recycled materials– 6 RAP, 6 FRAP, and 6 RAS– Northern and Southern sources
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Approach Continued
• Reliability based blending chart analysis– Considered variation in temperature and
continuous grade temperature– Effect of WisDOT binder replacement criteria on
low temperature properties– Recommendations for adjustments
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Review of Current Practice
• WisDOT binder replacement relative to:– Alabama – Georgia– Minnesota– Missouri– South Carolina– Texas– Virginia
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Surface Mixtures
0 5 10 15 20 25 30 35 40 45 50
RAS
RAP/FRAP
RAS/RAP/FRAP
Binder Replacement, %
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Lower Layer Mixtures
0 5 10 15 20 25 30 35 40 45 50
RAS
RAP/FRAP
RAS/RAP/FRAP
Binder Replacement, %
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Blending Chart Improvements
• Issues– AASHTO M323 and AASHTO PP53 use linear
blending charts for RAP and RAS– Linear blending charts were developed for blends
of recovered RAP binders in virgin binder. Do they apply to RAS and blends with RAP and RAS?
– Can’t grade recovered RAS binders due to different rheology primarily at low temperatures.
• Fails stiffness at very low temperature• Fails m-value at very high temperature
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Blending Charts for RAS
-20
-10
0
10
20
30
40
50
0 10 20 30 40 50 60 70 80 90 100
% RAS Binder
Cri
tical T
em
pera
ture
fo
r m
-valu
e
Known Virgin Binder
50/50 Virgin/RAS Blend
Estimated RAS
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
High Temperature
58
64
70
76
82
88
94
100
0 10 20 30 40 50 60
Conti
nuou
s H
igh
Tem
pera
ture
Gra
de, Σ
C
% RAS Binder
Unaged RTFOT Aged
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Intermediate Temperature
16
19
22
25
28
0 10 20 30 40 50 60
Conti
nuou
s In
term
edia
te Te
mpe
ratu
re G
rade
, ΣC
% RAS Binder
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Low Temperature
-34
-28
-22
-16
-10
0 10 20 30 40 50 60
Conti
nuou
s Lo
wTe
mpe
ratu
re G
rade
, ΣC
% RAS Binder
m-valie Stiffness
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Linearity Limit
-34
-28
-22
-16
-10
0 10 20 30 40 50 60
Conti
nuou
s Lo
wTe
mpe
ratu
re G
rade
Bas
ed o
n m
-Val
ue, Σ
C
% RAS Binder
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Grading RAS Binders
• Extract and recover RAS binder
• Prepare a 30/70 blend of recovered RAS in virgin binder of known performance grade
• Grade blend per AASHTO R29
• Knowing virgin and 30/70 blend continuous grade extrapolate RAS continuous grade
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Notes on RAS Binder Recovery
• AASHTO T164 Method A, centrifuge extraction
• Rotovapor primary distillation
• Abson recovery
• Modifications– Heat flask in oven after primary distillation and
prior to start of Abson recovery– Use higher temperatures in Abson recovery
Advanced Asphalt Technologies, LLC
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Blending Chart for Multiple Recycled Binders
Tblend=Tvirgin+ቀ%RB1100 ቁ×൫TRB1-Tvirgin൯+ቀ
%RB2100 ቁ×൫TRB2-Tvirgin൯+…ቀ%RBn100 ቁ×൫TRBn-Tvirgin൯
Where:
Tblend = continuous grade for the blended binder °C,
Tvirgin = continuous grade for the virgin binder, °C TRB1= continuous grade for recycled binder 1, °C
%RB1 = percentage of total binder made up of recycled binder 1, % TRB2= continuous grade for recycled binder 2, °C
RB2 = percentage of total binder made up of recycled binder 1, % TRBn= continuous grade for recycled binder n, °C
RBn = percentage of total binder made up of recycled binder 1, %
n = number of recycled binders
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Blending Chart vs R29 High
64.0
66.0
68.0
70.0
72.0
74.0
76.0
78.0
80.0
82.0
84.0
86.0
88.0
64.0 66.0 68.0 70.0 72.0 74.0 76.0 78.0 80.0 82.0 84.0 86.0 88.0
Blen
ding
Cha
rt C
onti
nuou
s G
rade
, �C
AASHTO R29 Continuous Grade, � C
Tank RTFOT Equality
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Blending Chart vs R29 Intermediate
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0
Blen
ding
Cha
rt C
onti
nuou
s G
rade
, �C
AASHTO R29 Continuous Grade, � C
Equality
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Blending Chart vs R29 Low
-34.0
-32.0
-30.0
-28.0
-26.0
-24.0
-22.0
-34.0 -32.0 -30.0 -28.0 -26.0 -24.0 -22.0
Blen
ding
Cha
rt C
onti
nuou
s G
rade
, �C
AASHTO R29 Continuous Grade, � C
S M Equality
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Recycled Material Characterization
Recycled Material
North Wisconsin Sources South Wisconsin Sources 1 2 3 1 2 3
RAP Cisler Wimmie Glenmore Christian Tri-
County I94 Badger Interchange
FRAP Menasha Eau Claire Rhinelander Rock Road Madison Vienna
Waukesha
RAS Northeast Asphalt
Bruce Co. A Amon Allied Black
Top Co. Tri-
County LaCrosse
City
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RAP/FRAP High
70.0
76.0
82.0
88.0
RAP South FRAP South RAP North FRAP North Grand Average
Hig
h Te
mpe
ratu
re G
rade
, o C
Source
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
RAP/FRAP Intermediate
22.0
25.0
28.0
31.0
RAP South FRAP South RAP North FRAP North Grand Average
Inte
rmed
iate
Tem
pera
ture
Gra
de, o C
Source
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
RAP/FRAP Low
-28.0
-22.0
-16.0RAP South FRAP South RAP North FRAP North Grand AverageLo
w T
empe
ratu
re G
rade
, o CSource
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Average Grade of WI RAP
• PG 82.8 (26.9) -21.8
• Standard Deviation
Property WI RAP Virgin PG 64-22
High 2.2 0.5
Intermediate 1.4 1.1
Low 1.4 0.8
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“Engineering Services for the Asphalt Industry”
Extrapolated RAS High
106.0
112.0
118.0
124.0
130.0
136.0
North South Grand Average
Hig
h Te
mpe
ratu
re G
rade
, o C
Source
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Extrapolated RAS Intermediate
28.0
31.0
34.0
37.0
40.0
North South Grand Average
Inte
rmed
iate
Tem
pera
ture
Gra
de, o C
Source
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Extrapolated RAS Low
-16.0
-10.0
-4.0
North South Grand AverageLo
w T
empe
ratu
re G
rade
, o CSource
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Average Grade of WI RAS
• North– PG 122.1 (34.4) -4.7
• South– PG 111.3 (31.0) -8.4
Property WI RAS Virgin PG 64-22
High 5.4 0.5
Intermediate 1.8 1.1
Low 1.8 0.8
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“Engineering Services for the Asphalt Industry”
WI RAP vs WI RAS
Property WI RAP North RAS South RAS
High 82.2 122.1 111.3
Intermediate 26.9 34.4 31.0
Low -21.8 -4.7 -8.4
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“Engineering Services for the Asphalt Industry”
Reliability Analysis
• Two sources of variability– Pavement temperature at the project location– Continuous grade of blended binder
• Overall reliability
GradeeTemperatur rxrR
Average and Standard Deviation of Pavement Temperature at Project Location
Average and Standard Deviation of Continuous Grade Temperature
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Standard Deviation of Blend
2Virgin
2RAS
22RAP
2c 1
where:
c = standard deviation of the blended binder
RAP = standard deviation of the RAP binder
RAS = standard deviation of the RAS binder
Virgin = standard deviation of the virgin binder
= proportion of the total binder made up by the RAP binder
= proportion of the total binder made up by the RAS binder
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Standard Deviation of Blend
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 10 20 30 40 50 60 70 80 90 100
Stan
dard
Dev
iatio
n of
Ble
nd o
f Tw
o Bi
nder
s
% Binder 2
s2 =s1
s2 = 1.5 s1
s2 = 2.0 s1
Advanced Asphalt Technologies, LLC
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Standard Deviation of Blend
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 10 20 30 40 50 60 70 80 90 100
Stan
dard
Dev
iatio
n of
Ble
nd o
f Tw
o Bi
nder
s
% Binder 2
s2 =s1
s2 = 1.5 s1
s2 = 2.0 s1
Property Virgin RAP RAS
High 0.5 2.2 5.4
Intermediate 1.1 1.4 1.8
Low 0.8 1.4 1.8
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Reliability AnalysisPG 58-3461 Weather Stations
PG 58-2879 Weather Stations
Mid Grade BinderExceptional Binder
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Mid Grade Surface Current Limits
0
10
20
30
40
50
60
70
80
90
100O
vera
ll Lo
w T
empe
ratu
re G
rade
Rel
iabi
lity,
%
Mixture
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Exceptional Surface Current Limits
0
10
20
30
40
50
60
70
80
90
100O
vera
ll Lo
w T
empe
ratu
re G
rade
Rel
iabi
lity,
%
Mixture
Advanced Asphalt Technologies, LLC
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Mid Grade Surface Revised Limits
0
10
20
30
40
50
60
70
80
90
100
Ove
rall
Low
Tem
pera
ture
Gra
de R
elia
bilit
y, %
Mixture
Advanced Asphalt Technologies, LLC
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Mid Grade Lower Revised Limits
0
10
20
30
40
50
60
70
80
90
100O
vera
ll Lo
w T
empe
ratu
re G
rade
Rel
iabi
lity,
%
Mixture
Advanced Asphalt Technologies, LLC
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Revised Limits
Recycled Binder Type Maximum Binder Replacement1, % Surface Layers Lower Layers2
RAP3 20 45 RAS 5 20
Combination of RAP and RAS Reduce RAP binder replacement 4 % for each 1 % RAS binder replacement.
Reduce RAP binder replacement 2.25 % for each 1 % RAS binder replacement.
Notes: 1 Defined as ratio of recycled binder content to total binder content 2 Layers 50 mm (2 in) or more below surface of the pavement 3 Includes RAP, FRAP, and combinations of RAP and FRAP
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Conclusions
• Linear blending is applicable to blends of RAS up to about 30 percent
• Linear blending provides a reasonable estimate of the continuous grade of blends of multiple recycled binders
• WI RAP/FRAP is very consistent having a recovered grade of PG 82.8 (26.9) -21.8
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Conclusions
• Appears to be a geographic difference in WI RAS– North 122.1 (34.4) -4.7– South 111.3 (31.0) -8.4
• RAS changes binder grade much more than RAP
• Current WisDOT binder replacement does not treat RAP and RAS mixtures equally
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Recommendations
• Consider modifying binder replacement criteria to provide similar reliability for RAP and RAS mixtures
• Use reliability analysis to approve mixtures with recycled contents greater than the binder replacement limits
• Monitor continuous grade of recycled sources using the procedures developed in this project
Advanced Asphalt Technologies, LLC
“Engineering Services for the Asphalt Industry”
Recommendations
• Monitor continuous grade of virgin binder sources
• Monitor cracking performance of pavements with recycled binders
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Questions/Discussion
Ramon BonaquistAdvanced Asphalt Technologies, LLC108 Powers Court, Suite 100Sterling, VA [email protected]