NCHRP Project 9-54 Long-Term Aging of Asphalt
Mixtures for Performance Testing and Prediction
Asphalt Mixture & Construction Expert Task Group Ames, IA
May 1, 2017
Y. Richard Kim, Cassie Castorena, Farhad Yousefi Rad, Michael Elwardany
NC State University
Outline NCHRP 09-54 objectives Proposed Long-Term Aging Method Kinetics Modeling Aging Durations Based on Climatic Data
NCHRP 09-54 Objectives Develop a calibrated and validated procedure to
simulate long-term aging of asphalt mixtures for performance testing and prediction.
Develop an aging model that is more accurate than GAS model and less cumbersome than the Transport model (developed by Texas A&M).
Develop calibration functions by investigating the differences in mechanical properties as functions of traffic, climate, and moisture.
Aging Factors Investigated
Pressure vs. Oven Compacted specimen vs. Loose mix 95°C vs. 135°C
Oven aging of loose mix at 95°C was found to be the most promising method for long-term aging of asphalt mixture based on the following criteria:
• Specimen integrity (Compactability)
• Uniformity of oxidation
• Efficiency
• Practicality and versatility
• Simulation of physicochemical changes in field aging
Proposed Long-Term Aging Method
95°C
Kinetics Modeling
Verification of Existing Kinetics Models Using Rheological AIP (log G*) and Laboratory Aged Loose Mix Data
𝑃 = 𝑀 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑡
CA= 𝐶𝐶𝑡𝑡𝑡𝑡 + 𝑀 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑡
Herrington _ New Zealand
Charles Glover _ Texas A&M
Petersen and Glaser _ WRI
Kinetics Modeling
log 𝐺∗ = log𝐺0∗ + 𝑀(1 −𝑘𝑐𝑘𝑓
) 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑀𝑡
𝑘𝑓 = 𝐶𝑓 exp (−𝐸𝑡𝑓 𝑅𝑅� ) 𝑘𝑐 = 𝐶𝑐 exp (−𝐸𝑡𝑐 𝑅𝑅� ) 𝑤ℎ𝑒𝑒𝑒
NCHRP 09-54
𝐶 + 𝑆 = (𝐶 + 𝑆)0+𝑀(1 −𝑘𝑐𝑘𝑓
) 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑀𝑡
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40lo
g G
*, 6
4°C
, 10
rad
/s (
kPa)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40lo
g G
*, 6
4°C
, 10
rad
/s (
kPa)
Aging Duration (Days)
ALF-Control ALF-SBS
WesTrack-Coarse WesTrack-Fine SHRP-AAD-1
Kinetics Modeling
85°C Predicted 70°C Predicted STA
95°C Predicted
85°C Measured 70°C Measured
95°C Measured Single Binder
Dependent Variable
(M)
M = 1.104 M = 0.871
M = 0.743 M = 0.524
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
M = 0.725
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40lo
g G
*, 6
4°C
, 10
rad
/s (
kPa)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40lo
g G
*, 6
4°C
, 10
rad
/s (
kPa)
Aging Duration (Days)
LTPP-TX LTPP-SD Kinetics Model Verification
85°C Predicted 70°C Predicted STA
95°C Predicted
85°C Measured 70°C Measured
95°C Measured Single Binder
Dependent Variable
(M)
M = 0.88 M = 0.747
NCS9.5B
M = 0.937
LTPP-WI
M = 1.016
LTPP-NM
M = 0.546
Verification Using Non-Isothermal History
0
5
10
15
20
25
30
35
40
16D 33D 43D
G*,
64°C
, 10
rad/
s (k
Pa)
Aging Duration
PredictedMeasured
13% Error
13% Error14% Error
30
40
50
60
70
80
0 5 10 15 20 25 30 35 40 45
Tem
pe
ratu
re (
°C)
Aging Time (Days)
Loose Mix Sampling
2 D
6 D
6 D
13 D
5 D
10 D
1 D15% G* ≈ 10% E*
WesTrack Fine 1995
Kinetics Modeling to Find Required Duration to Match Field Aging
Field (EICM) Lab Oven Aging
95°C
Aging Duration?
log 𝐺𝐹𝐹𝑒𝐹𝐹∗ = log 𝐺𝑜∗ + 𝑀[(1 − 𝑡𝑐𝑡𝑓� ) 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑡]𝐹𝐹𝐹𝐹𝐹
log 𝐺𝐿𝐿𝐿∗ = log 𝐺𝑜∗ + 𝑀[(1 − 𝑡𝑐𝑡𝑓� ) 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑡]𝐿𝑡𝐿
[(1 − 𝑘𝑐𝑘𝑓� ) 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑡]𝐹𝐹𝐹𝐹𝐹 = [(1 − 𝑘𝑐
𝑘𝑓� ) 1 − exp −𝑘𝑓𝑡 + 𝑘𝑐𝑡]𝐿𝑡𝐿
Required Aging Duration to Match Field Aging is Independent of
Binder Source/Type (i.e., STA G* and M value)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C, 1
0 ra
d/s
(kP
a)
Aging Duration (Days)
Non-Isothermal Laboratory Aging Trial • FHWA ALF Control • WesTrack Fine 1995
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64 °
C,
10 r
ad/s
(kP
a)
Aging Duration (Days)
Non-Isothermal Aging Verification
M = 0.871
M = 0.743
ALF-Control
WesTrack-Fine
30
40
50
60
70
80
0 5 10 15 20 25 30 35 40 45
Tem
pe
ratu
re (
°C)
Aging Time (Days)
Loose Mix Sampling
2 D
6 D
6 D
13 D
5 D
10 D
1 D
Non-Isothermal Aging Verification
30
40
50
60
70
80
0 5 10 15 20 25 30 35 40 45
Tem
pe
ratu
re (
°C)
Aging Time (Days)
Loose Mix Sampling
2 D
6 D
6 D
13 D
5 D
10 D
1 D
Non-Isothermal Laboratory Aging Trial • FHWA ALF Control • WesTrack Fine 1995
0
0.5
1
1.5
2
2.5
3
0 10 20 30 40 50
Mea
sure
d D
urat
ion
Non-Isothermal Oven Aging Duration
ALF - ControlWesTrack - Fine 1995
y = 0.8665x + 0.2657R² = 0.96
0
0.5
1
1.5
2
2.5
3
0 0.5 1 1.5 2 2.5 3
ALF
-C
ontr
ol
Mea
sure
d D
urat
ion
WesTrack - Fine Measured Duration
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40lo
g G
*, 6
4°C
, 10
rad
/s (
kPa)
Aging Duration (Days)
Field Cores from: • FHWA ALF Control • FHWA ALF SBS-LG Modified
0
0.5
1
1.5
2
2.5
3
3.5
4
0 5 10 15 20 25 30 35 40
log
G*,
64°
C,
10 r
ad/s
(kP
a)
Aging Duration (Days)
Verification from Field Cores
M = 0.743
ALF-Control
ALF-SBS
M = 0.524
Field (19 mm depth) Required Durations
ALF-Control 7.7 days
ALF-SBS 8 days
Verification from WMA vs. HMA Manitoba Sections – 4 Years Old
Matching field aging levels in the laboratory
85°C
Field Section Depth Required Durations at 85°C
MIT-Control HMA 19 mm 16.5 days
MIT-WMA Evotherm 19 mm 16.1 days
y = 0.0249x + 0.1151R² = 0.9825
y = 0.0181x + 0.1442R² = 0.9995
y = 0.0217x + 0.0935R² = 0.9935
0
0.2
0.4
0.6
0.8
0 5 10 15 20 25 30
log
G*,
64°C
, 10
rad/
s (k
Pa)
Duration (Days)
MIT-HMA
MIT-Evotherm
MIT-Foam
Verification from WMA vs. HMA NACT Sections – 4 Years Old
Matching field aging levels in the laboratory
85°C
Field Section Depth Required Durations at 85°C
NCAT-Control HMA 19 mm 35.6 days
NCAT-WMA Foam 19 mm 31.3 days
y = 0.021x + 0.88R² = 0.9451
y = 0.0188x + 0.8397R² = 0.9525
0.5
0.7
0.9
1.1
1.3
1.5
0 5 10 15 20 25 30
log
G*,
64°C
, 10
rad/
s (k
Pa)
Duration (Days)
NCAT-HMA
NCAT-Foam
Aging Durations Based on Climatic Data
Matching 4, 8, and 16 Years of
Field Aging
Climatic Aging Index
Climatic Aging Index (CAI)
CAI= ∑ (A × exp −𝐸𝑎𝑅𝑅� /24)
where 𝐶, 𝐸𝑡 = Fitting Parameters R= Universal Gas Constant T= Air Temperature in Kelvin
Aging Durations Based on Climatic Data
y = 1xR² = 0.56
0
5
10
15
20
25
0 5 10 15 20 25
Agin
g Du
ratio
n at
95°
C (D
ays)
Climatic Aging Index, CAI
ALF-CTRL ALF-SBSWesTrack-Fine WesTrack-CoarseLTPP-TX LTPP-NMLTPP-SD LTPP-WI
t3
t2
t1
CAI4Y CAI8Y CAI16Y
Questions?
