Determining the Limitations of Warm Mix Asphalt by Water ... · 1 Determining the Limitations of...
Transcript of Determining the Limitations of Warm Mix Asphalt by Water ... · 1 Determining the Limitations of...
1
Determining the Limitations of
Warm Mix Asphalt by Water
Injection in Mix Design,
Quality Control and Placement
Ala R. Abbas, Ph.D.
Ayman Ali, Ph.D.
Ahmad Alhasan, M.S.
Munir Nazzal, Ph.D., P.E.
Shad Sargand, Ph.D.
Arjun Roy, M.S.
2
Acknowledgements
Mr. David Powers (Materials Management)
Mr. Craig Landefeld (Construction
Administration)
Mr. Eric Biehl (Materials Management)
Ms. Cynthia Gerst (Research Section)
Ms. Vicky Fout (Research Section)
Ms. Jill Martindale (Research Section)
Ms. Kelly Nye (Research Section)
3
Outline
Background
Study Objectives
Research Methodology
Material Information
Results and Discussion
Conclusions
Recommendations for Implementation
Questions
Background
4
5
Background
Traditional asphalt mixtures are produced at
temperatures ranging between 300oF to 325oF
(150oC to 165oC). These mixtures are
commonly referred to as hot mix asphalt (HMA).
In recent years, there has been an increased
interest in using a new type of asphalt mixtures
called warm mix asphalt (WMA).
6
Background (Cont.)
Several WMA technologies are available:
Chemical and organic additives
Foamed asphalt binders
Foamed WMA produced by water injection
has received increased interest and use in
Ohio since it requires a one-time plant
modification and does not require the use of
costly additives.
7
Background (Cont.)
Over the last five years, the amount of foamed
WMA used in Ohio has increased to more than
50% of the total amount of asphalt mixtures
used in the state.
Key benefits of foamed WMA include:
Reduced emissions during production
Improved field compaction
Improved working conditions
Ability to use higher RAP contents
8
Background (Cont.)
Despite the previous advantages, there are
several concerns regarding the long-term
performance of foamed WMA
Main concerns:
Increased rutting due to reduced binder aging
Increased moisture-damage due to insufficient
aggregate drying
Insufficient aggregate coating
Applicability of HMA mix design to foamed WMA
9
Background (Cont.)
Therefore, research is needed to evaluate the
performance of foamed WMA and determine
the factors that affect its long-term durability.
In addition, current mix design methods and
specifications used by ODOT for foamed WMA
mixtures shall be validated or revised to ensure
satisfactory long-term performance.
Study Objectives
10
11
Study Objectives
Evaluate the factors that affect the volumetric
properties, performance, and durability of
foamed WMA mixtures.
Determine the limitations of foamed WMA
mixtures.
Identify changes to current mix design and
evaluation procedures, if any, that will be
required for foamed WMA mixtures.
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Study Objectives (Cont.)
Evaluate current ODOT quality control and
placement procedures to determine applicability
to foamed WMA mixtures.
Identify changes to current ODOT specifications
for foamed WMA mixtures to ensure
satisfactory long-term performance.
Research Methodology
13
14
Research Methodology
Part 1: Performance Evaluation of Foamed WMA and HMA in the Laboratory
Part 2: Workability and Compactability of Foamed WMA and HMA
Part 3: Effect of Mix Preparation Procedure on Foamed WMA
Part 4: Performance Evaluation of Foamed WMA and HMA in the APLF
Part 5: Performance Evaluation of Foamed WMA and HMA using the MEPDG
Part 1:
Laboratory Performance
of Foamed WMA and HMA
15
Material Information
16
Material Information
Material Combinations
Limestone Crushed Gravel
Intermediate
PG 70-22
Surface Surface
PG 70-22 PG 64-28 PG 70-22
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Production of Foamed WMA
Foaming
Nozzle
Binder
Tank
Air
Tank
Water
Tank
Control
Panel
Laboratory Testing Plan
19
20
Laboratory Testing Plan
Laboratory
Testing Program
Fatigue CrackingDurabilityRutting
FN
APA
E*
Low Temp. Cracking
DCSE ITS
Wet APA
Mod. Lottman
Cond. E*
21
Asphalt Pavement Analyzer (APA)
Test method: AASHTO TP 63-07
and ODOT Supplement 1057
Specimen dimensions:
2.95” height x 6” diameter
Air voids: 7 ± 1%
Testing temperature: 120°F
Hose pressure: 100 psi
Wheel load: 115 lbf
Rut depth: 5, 500, 1000,
and 8000 passes
22
Dynamic Modulus |E*| (Cont.)
22
𝐸∗ = 𝜎𝑜
𝜀𝑜 ϕ =
𝑇𝑖
𝑇𝑝 × 360𝑜
Dynamic Modulus Phase Angle
23
Dynamic Modulus |E*| (Cont.)
24
Dynamic Modulus |E*|
Test method: AASHTO TP 62-03 and NCHRP 513
Specimen dimensions: 6” height x 4” diameter
Air voids: 7 ± 0.5%
Conditioning:
Age loose mixture for 4 hours at 275oF
(short-term AASHTO R30)
Loading magnitude: 75 to 125 micro-strain
Loading frequencies: 25, 10, 5, 1, 0.5, and 0.1 Hz
Testing temperature: 40, 70, 100, and 130oF
NCHRP 513 {Annex B}
Temperature: 54.4°C
Haversine compressive
stress
Stress level: 30 psi
Loading: 0.1 sec
Rest period: 0.9 sec
FN
Tertiary failure
10,000 cycles Flow
Number
25
Flow Number (FN)
26
Modified Lottman (AASHTO T 283)
Test method: AASHTO T 283 and ODOT Supplement 1051
Specimen dimensions: 3.75” height x 6” diameter
Air voids: 7 ± 0.5%
Conditioning:
Age loose mixture for 4 hours at 275oF
Soak compacted samples in water for about 4 hours
Partially saturate to 80 to 90%
Apply one freeze and thaw cycle
Loading rate: 2 inch/min
Testing temperature: 77°F
Protocol: Roque et al. (2002)
Temperature: 10°C
Specimen: 150 mm x 50 mm
Two tests:
Resilient Modulus (MR)
[NCHRP-285]
ITS [AASHTO T 322-03]
)(2
10
ftSFEDCSE
EEFEDCSE
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Dissipated Creep Strain Energy (DCSE)
Test method: AASHTO
T 322
Temperature: -10°C
MTS 810
Specimen: 150 mm x 50 mm
Loading: 12.5 mm/min
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Indirect Tensile Strength (ITS)
Test Results
29
Permanent Deformation
(Rutting)
30
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Asphalt Pavement Analyzer
0.00
0.05
0.10
0.15
0.20
0.25
0.30
1 2 3 4
Per
man
ent
Def
orm
atio
n, R
utt
ing
(in
.)
HMA Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
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Asphalt Pavement Analyzer
Analysis Data Statistical Factors F-value Prob.
19.0 mm, Limestone, PG 64-28
&
19.0 mm, Limestone, PG 70-22
Mix Type 0.088 0.775
Binder Type 67.108 0.000
Binder Type × Mix Type 0.427 0.532
12.5 mm, Gravel, PG 70-22
&
12.5 mm, Limestone, PG 70-22
Mix Type 0.219 0.653
Agg. Type 0.017 0.900
Agg. Type × Mix Type 2.700 0.139
12.5 mm, Limestone, PG 70-22
&
19.0 mm, Limestone, PG 70-22
Mix Type 0.136 0.722
Agg. Size 0.096 0.764
Agg. Size × Mix Type 0.868 0.379
ANOVA Results Obtained for APA Test Results
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Dynamic Modulus, |E*|
10000
100000
1000000
10000000
1E-05 0.001 0.1 10 1000 100000
Dy
nam
ic M
odulu
s, |E
*| (
PS
I)
Reduced Frequency, f (Hz)
19.0 mm NMAS Limestone & PG 70-22 (HMA)
19.0 mm NMAS Limestone & PG 64-28 (HMA)
19.0 mm NMAS Limestone & PG 70-22 (WMA)
19.0 mm NMAS Limestone & PG 64-28 (WMA)
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Flow Number
0
1000
2000
3000
4000
5000
6000
7000
1 2 3 4
Flo
w N
um
ber
, F
N
HMA Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
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Flow Number
Analysis Data Statistical Factors F-value Prob.
19.0 mm, Limestone, PG 64-28
&
19.0 mm, Limestone, PG 70-22
Mix Type 8.220 0.046
Binder Type 97.327 0.001
Binder Type × Mix Type 12.538 0.024
12.5 mm, Gravel, PG 70-22
&
12.5 mm, Limestone, PG 70-22
Mix Type 6.170 0.056
Agg. Type 77.336 0.000
Agg. Type × Mix Type 5.939 0.059
12.5 mm, Limestone, PG 70-22
&
19.0 mm, Limestone, PG 70-22
Mix Type 10.979 0.030
Agg. Size 43.086 0.003
Agg. Size × Mix Type 0.503 0.517
ANOVA Results Obtained for FN Test Results
Moisture-Induced Damage
36
37
AASHTO T 283
0
50
100
150
200
250
300
1 2 3 4
Indir
ect T
ensi
le S
tren
gth
, IT
S (
PS
I)
HMA Conditioned HMA
Foamed WMA Conditioned Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
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AASHTO T 283
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4
Ten
sile
Str
ength
Rat
io, T
SR
HMA Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
TSR = 80%
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AASHTO T 283
Analysis Data Statistical Factors F-value Prob.
19.0 mm, Limestone, PG 64-28
&
19.0 mm, Limestone, PG 70-22
Mix Type 3.150 0.094
Test Cond. 72.618 0.000
Binder Type 224.969 0.000
Mix Type × Test Cond. 0.104 0.751
Mix Type × Binder Type 3.337 0.085
Test Cond. × Binder Type 16.770 0.001
12.5 mm, Gravel, PG 70-22
&
12.5 mm, Limestone, PG 70-22
Mix Type 0.338 0.569
Test Cond. 15.759 0.001
Agg. Type 0.121 0.732
Mix Type × Test Cond. 0.163 0.692
Mix Type × Agg. Type 3.094 0.097
Test Cond. × Agg. Type 0.229 0.639
12.5 mm, Limestone, PG 70-22
&
19.0 mm, Limestone, PG 70-22
Mix Type 1.175 0.294
Test Cond. 32.344 0.000
Agg. Size 0.078 0.783
Mix Type × Test Cond. 0.335 0.570
Mix Type × Agg. Size 1.240 0.281
Test Cond. × Agg. Size 2.284 0.149
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Conditioned Dynamic Modulus
10000
100000
1000000
10000000
1E-05 0.001 0.1 10 1000 100000
Dy
nam
ic M
odulu
s, |E
*| (
PS
I)
Reduced Frequency, f (Hz)
12.5 mm NMAS Limestone & PG 70-22 (HMA)
12.5 mm NMAS Limestone & PG 70-22 (HMA/Conditioned)
12.5 mm NMAS Limestone & PG 70-22 (WMA)
12.5 mm NMAS Limestone & PG 70-22 (WMA/Conditioned)
12.5 mm Limestone and PG 70-22
41
Wet Asphalt Pavement Analyzer
0
0.05
0.1
0.15
0.2
0.25
0.3
1 2 3 4
Ru
t D
epth
(in
ch)
HMA (Dry APA) HMA (Wet APA)
Foamed WMA (Dry APA) Foamed WMA (Wet APA)
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Crushed Gravel
PG 70-22
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Wet Asphalt Pavement Analyzer
Analysis Data Statistical Factors F-value Prob.
19.0 mm, Limestone, PG 64-28
&
19.0 mm, Limestone, PG 70-22
Mix Type 0.889 0.359
Test Cond. 4.164 0.057
Binder Type 226.157 0.000
Mix Type × Test Cond. 0.183 0.675
Mix Type × Binder Type 0.830 0.375
Test Cond. × Binder Type 0.590 0.453
12.5 mm, Gravel, PG 70-22
&
12.5 mm, Limestone, PG 70-22
Mix Type 0.011 0.919
Test Cond. 3.633 0.074
Agg. Type 0.158 0.696
Mix Type × Test Cond. 0.838 0.373
Mix Type × Agg. Type 1.977 0.178
Test Cond. × Agg. Type 0.386 0.543
12.5 mm, Limestone, PG 70-22
&
19.0 mm, Limestone, PG 70-22
Mix Type 0.558 0.465
Test Cond. 2.210 0.155
Agg. Size 0.047 0.831
Mix Type × Test Cond. 0.036 0.851
Mix Type × Agg. Size 0.495 0.491
Test Cond. × Agg. Size 0.063 0.804
Fatigue Cracking
43
44
Dissipated Creep Strain Energy
0.00
1.00
2.00
3.00
4.00
5.00
6.00
1 2 3 4
Dis
sipat
ed C
reep
Str
ain E
ner
gy,
DC
SE
(kJ/
m3) HMA Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
DCSE = 0.75 kJ/m3
45
Dissipated Creep Strain Energy
ANOVA Results Obtained for DCSE Test Results
Analysis Data Statistical Factors F-value Prob.
19.0 mm, Limestone, PG 64-28
&
19.0 mm, Limestone, PG 70-22
Mix Type 0.787 0.404
Binder Type 45.524 0.000
Binder Type × Mix Type 2.127 0.188
12.5 mm, Gravel, PG 70-22
&
12.5 mm, Limestone, PG 70-22
Mix Type 6.992 0.057
Agg. Type 2.381 0.198
Agg. Type × Mix Type 9.467 0.037
12.5 mm, Limestone, PG 70-22
&
19.0 mm, Limestone, PG 70-22
Mix Type 0.006 0.941
Agg. Size 13.521 0.014
Agg. Size × Mix Type 0.135 0.728
Low-Temperature Cracking
46
47
Low-Temp. Indirect Tensile Strength
0
100
200
300
400
500
600
700
800
1 2 3 4
Indir
ect T
ensi
le S
tren
gth
@ 1
4oF,
ITS
(P
SI)
HMA Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
48
Low-Temp. Indirect Tensile Strength
ANOVA Results Obtained for Low-Temp ITS Test Results
Analysis Data Statistical Factors F-value Prob.
19.0 mm, Limestone, PG 64-28
&
19.0 mm, Limestone, PG 70-22
Mix Type 27.887 0.001
Binder Type 119.957 0.000
Binder Type × Mix Type 0.028 0.872
12.5 mm, Gravel, PG 70-22
&
12.5 mm, Limestone, PG 70-22
Mix Type 0.776 0.404
Agg. Type 131.681 0.000
Agg. Type × Mix Type 1.277 0.291
12.5 mm, Limestone, PG 70-22
&
19.0 mm, Limestone, PG 70-22
Mix Type 13.093 0.007
Agg. Size 25.440 0.001
Agg. Size × Mix Type 3.642 0.093
Conclusions
49
50
Permanent Deformation
Foamed WMA mixtures exhibited slightly higher rut
depth values in the unconditioned and conditioned
APA tests, slightly lower dynamic moduli, and slightly
lower flow number values than the traditional HMA
mixtures.
However, the difference was found to be statistically
insignificant. Therefore, the rutting potential of foamed
WMA mixtures is expected to be comparable to that of
the HMA mixtures.
51
Moisture-Induced Damage
Foamed WMA mixtures exhibited slightly lower
unconditioned and conditioned ITS values and
comparable TSR ratios to the HMA mixtures in the
AASHTO T 283 test. In addition, foamed WMA
mixtures exhibited slightly higher unconditioned and
conditioned rut depth values in the APA test.
However, the effect of the mix type was found to be
statistically insignificant on the unconditioned and
conditioned ITS values as well as the unconditioned and
conditioned APA rut depths.
52
Moisture-Induced Damage
By comparing the unconditioned and conditioned APA
rut depths, it was observed that the effect of sample
conditioning was more pronounced on the HMA
mixtures than the foamed WMA mixtures. This trend
was also observed in the unconditioned and
conditioned dynamic modulus tests for some of the
mixtures.
53
Fatigue Cracking
The foamed WMA mixtures exhibited slightly lower DCSE
values than the HMA mixtures. However, the difference was
found to be statistically insignificant.
In addition, the DCSE values for all foamed WMA and HMA
mixtures were greater than 0.75 kJ/m3, which has been
suggested by Roque et al. (2007) as a minimum DCSE
threshold value to ensure satisfactory resistance to fatigue
cracking.
This indicates that both foamed WMA and HMA mixtures are
expected to have adequate resistance to fatigue cracking.
54
Low-Temperature Cracking
Foamed WMA mixtures exhibited slightly lower ITS
values at 14oF (-10oC) and comparable or slightly higher
failure strain values than the corresponding HMA mixtures.
The effect of the mix type was found to be statistically
significant on the low temperature ITS values, but not on the
failure strains.
Since the HMA mixtures had higher ITS values and similar
failure strain values to the foamed WMA mixtures, the HMA
mixtures are expected to have better resistance to thermal
cracking.
Part 2:
Workability and Compactability
of Foamed WMA & HMA
55
Testing Program
56
57
Testing Program
Workability and Compactability
Testing Plan
Workability
UA Workability Device
Compactability
SGC Data
58
Workability Device
Safety Cage
Mixing Paddle
Rotating Bucket
Motor and
Gear-Reduction
Unit
Sensors Cage
Emergency
Stop Button
Electric Box
59
Workability Device (Cont.)
Test Results
60
61
Workability
Torque = 4,160 e -0.025 Temperature
R² = 0.94
Torque = 4,385 e -0.032 Temperature
R² = 0.91
0
100
200
300
400
500
600
80 90 100 110 120 130 140 150 160
Torq
ue
(in
-lb)
Temperature (oC)
HMA (12.5 mm Limestone + PG 70-22)
WMA (12.5 mm Limestone + PG 70-22)
62
Workability
Mix
Type
Aggregate
Type
Aggregate
NMAS
(mm)
Binder
Grade
Workability
Model R2
HMA
Limestone 12.5 PG 70-22 Torque = 4,160 e-0.025 Temp 0.94
Limestone 19.0 PG 70-22 Torque = 2,179 e-0.017 Temp 0.87
Limestone 19.0 PG 64-28 Torque = 742 e-0.012 Temp 0.79
Gravel 12.5 PG 70-22 Torque = 1,611 e-0.019 Temp 0.95
WMA
Limestone 12.5 PG 70-22 Torque = 4,385 e-0.032 Temp 0.91
Limestone 19.0 PG 70-22 Torque = 2,183 e-0.022 Temp 0.86
Limestone 19.0 PG 64-28 Torque = 964 e-0.018 Temp 0.75
Gravel 12.5 PG 70-22 Torque = 3,426 e-0.028 Temp 0.94
Workability Exponential Models
63
Workability
98
170
123
93
36
81
65
51
0
20
40
60
80
100
120
140
160
180
200
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Torq
ue
(in
-lb)
HMA
WMA
(a)
Workability at 150oC
64
Workability
342
398
223241
179
242
159
208
0
50
100
150
200
250
300
350
400
450
500
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Torq
ue
(in
-lb)
HMA
WMA
(b)
Workability at 100oC
65
Compactability
Average No. of Gyrations
Mix Agg.
Type
Agg.
Size
Binder
Type APA T283 E* ITS/DCSE
HMA Limestone 12.5 mm PG 70-22 38 36 29 41
HMA Limestone 19.0 mm PG 70-22 23 23 18 27
HMA Limestone 19.0 mm PG 64-22 29 22 18 24
HMA Gravel 12.5 mm PG 70-22 15 15 12 14
WMA Limestone 12.5 mm PG 70-22 43 28 29 38
WMA Limestone 19.0 mm PG 70-22 27 22 18 24
WMA Limestone 19.0 mm PG 64-22 27 17 17 18
WMA Gravel 12.5 mm PG 70-22 16 12 9 14
Conclusions
66
67
Workability
The foamed WMA mixtures exhibited better workability
than the traditional HMA mixtures. This was attributed
to the lower asphalt binder absorption observed for the
foamed WMA mixtures.
Another factor that might have contributed to the
improvement in workability for foamed WMA mixtures
is the presence of vapor pockets entrapped within the
foamed asphalt binder that serve to keep the binder
slightly expanded and reduce its viscosity.
68
Compactability
By comparing the compaction data obtained using the
Superpave gyratory compactor during the preparation of
the laboratory specimens, it was observed that the
number of gyrations needed to achieve the target air
void levels for the foamed WMA specimens was
relatively close to that of the HMA specimens.
This indicates that the compactability of the foamed
WMA mixtures is comparable to that of the
corresponding HMA mixtures.
Part 3:
Limitations of Foamed WMA
69
70
Test Factorial
Material Combination
WMA
Effect of Temperature Reduction
0% Agg. w(%), 1.8% Foaming w(%), 30oF Temp. Red.
0% Agg. w(%), 1.8% Foaming w(%), 50oF Temp. Red.
0% Agg. w(%), 1.8% Foaming w(%), 70oF Temp. Red.
Effect of Foaming Water Content:
0% Agg. w(%), 1.8% Foaming w(%), 30oF Temp. Red.
0% Agg. w(%), 2.2% Foaming w(%), 30oF Temp. Red.
0% Agg. w(%), 2.6% Foaming w(%), 30oF Temp. Red.
Effect of Aggregate Moisture Content:
0% Agg. w(%), 1.8% Foaming w(%), 30oF Temp. Red.
1.5% Agg. w(%), 1.8% Foaming w(%), 30oF Temp. Red.
3.0% Agg. w(%), 1.8% Foaming w(%), 30oF Temp. Red.
HMA
0% Agg. w(%)
APA ITS AASHTO T 283
APA ITS AASHTO T 283
Test Results
71
72
Effect of Temp. Red.
0
0.05
0.1
0.15
0.2
0.25
0.3
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Crushed Gravel
PG 70-22
Ru
t D
epth
(in
ch)
HMA
WMA 30F Temp. Red.
WMA 50F Temp. Red.
WMA 70F Temp. Red.
0
50
100
150
200
250
300
350
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Dry
IT
S (
psi
)
HMA
WMA 30F Temp. Red.
WMA 50F Temp. Red.
WMA 70F Temp. Red.
0
50
100
150
200
250
300
350
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Wet
IT
S (
psi
)
HMA
WMA 30F Temp. Red.
WMA 50F Temp. Red.
WMA 70F Temp. Red.
0%
20%
40%
60%
80%
100%
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
TS
R (
%)
HMA WMA 30F Temp. Red.
WMA 50F Temp. Red. WMA 70F Temp. Red.
(a) (b)
(c) (d)
73
Effect of Temp. Red.
Performance Test
APA Rut Depth Dry ITS Wet ITS
Analysis Data Statistical Factors F-value Prob. F-value Prob. F-value Prob.
WMA, 19.0 mm, Limestone, PG 64-28
&
WMA, 19.0 mm, Limestone, PG 70-22
Binder Type 136.4 0.00 97.5 0.00 31.4 0.00
Prod. Temp. 5.5 0.02 22.8 0.00 10.0 0.00
Binder Type × Prod. Temp. 1.4 0.29 7.3 0.01 1.6 0.25
WMA, 12.5 mm, Gravel, PG 70-22
&
WMA, 12.5 mm, Limestone, PG 70-22
Agg. Type 55.3 0.00 18.8 0.00 0.0 0.91
Prod. Temp. 53.3 0.00 40.7 0.00 30.6 0.00
Agg. Type × Prod. Temp. 4.7 0.03 0.5 0.64 1.5 0.26
WMA, 12.5 mm, Limestone, PG 70-22
&
WMA, 19.0 mm, Limestone, PG 70-22
Agg. Size 4.4 0.06 3.3 0.10 4.5 0.06
Prod. Temp. 20.7 0.00 24.4 0.00 10.5 0.00
Agg. Size × Prod. Temp. 0.6 0.54 2.8 0.10 0.4 0.71
74
Effect of Foaming Wtr. Cont.
0
0.05
0.1
0.15
0.2
0.25
0.3
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Crushed Gravel
PG 70-22
Ru
t D
epth
(in
ch)
HMA
WMA 1.8% Foaming w(%)
WMA 2.2% Foaming w(%)
WMA 2.6% Foaming w(%)
0
50
100
150
200
250
300
350
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Dry
IT
S (
psi
)
HMA
WMA 1.8% Foaming w(%)
WMA 2.2% Foaming w(%)
WMA 2.6% Foaming w(%)
0
50
100
150
200
250
300
350
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Wet
IT
S (
psi
)
HMA
WMA 1.8% Foaming w(%)
WMA 2.2% Foaming w(%)
WMA 2.6% Foaming w(%)
0%
20%
40%
60%
80%
100%
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
TS
R (
%)
HMA WMA 1.8% Foaming w(%)
WMA 2.2% Foaming w(%) WMA 2.6% Foaming w(%)
(a) (b)
(c) (d)
75
Effect of Foaming Wtr. Cont.
Performance Test
APA Rut Depth Dry ITS Wet ITS
Analysis Data Statistical Factors F-value Prob. F-value Prob. F-value Prob.
WMA, 19.0 mm, Limestone, PG 64-28
&
WMA, 19.0 mm, Limestone, PG 70-22
Binder Type 138.5 0.00 43.0 0.00 42.9 0.00
Foaming Wtr. Cont. 5.4 0.02 1.2 0.29 4.3 0.06
Binder Type × Prod. Temp. 0.4 0.67 1.8 0.20 0.0 0.97
WMA, 12.5 mm, Gravel, PG 70-22
&
WMA, 12.5 mm, Limestone, PG 70-22
Agg. Type 16.6 0.00 7.4 0.03 1.9 0.19
Foaming Wtr. Cont. 4.7 0.03 0.5 0.50 0.6 0.47
Agg. Type × Prod. Temp. 0.2 0.26 0.6 0.47 1.6 0.23
WMA, 12.5 mm, Limestone, PG 70-22
&
WMA, 19.0 mm, Limestone, PG 70-22
Agg. Size 1.8 0.20 3.7 0.08 6.0 0.03
Foaming Wtr. Cont. 14.2 0.00 3.0 0.11 0.5 0.48
Agg. Size × Prod. Temp. 1.2 0.35 0.3 0.57 1.2 0.29
76
Effect of Agg. Moist. Cont.
0
0.05
0.1
0.15
0.2
0.25
0.3
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Crushed Gravel
PG 70-22
Ru
t D
epth
(in
ch)
HMA
WMA 0% Aggregate w(%)
WMA 1.5% Aggregate w(%)
WMA 3.0% Aggregate w(%)
0
50
100
150
200
250
300
350
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Dry
IT
S (
psi
)
HMA
WMA 0% Aggregate w(%)
WMA 1.5% Aggregate w(%)
WMA 3.0% Aggregate w(%)
0
50
100
150
200
250
300
350
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
Wet
IT
S (
psi
)
HMA
WMA 0% Aggregate w(%)
WMA 1.5% Aggregate w(%)
WMA 3.0% Aggregate w(%)
0%
20%
40%
60%
80%
100%
12.5 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 70-22
19.0 mm NMAS
Limestone
PG 64-28
12.5 mm NMAS
Gravel
PG 70-22
TS
R (
%)
HMA WMA 0% Aggregate w(%)
WMA 1.5% Aggregate w(%) WMA 3.0% Aggregate w(%)
(a) (b)
(c) (d)
77
Effect of Agg. Moist. Cont.
Performance Test
APA Rut Depth Dry ITS Wet ITS
Analysis Data Statistical Factors F-value Prob. F-value Prob. F-value Prob.
WMA, 19.0 mm, Limestone, PG 64-28
&
WMA, 19.0 mm, Limestone, PG 70-22
Binder Type 67.5 0.00 331.8 0.00 58.5 0.00
Agg. Moist. Cont. 0.1 0.94 25.0 0.00 5.4 0.02
Binder Type × Prod. Temp. 2.3 0.14 3.2 0.08 0.3 0.73
WMA, 12.5 mm, Gravel, PG 70-22
&
WMA, 12.5 mm, Limestone, PG 70-22
Agg. Type 0.0 0.96 0.1 0.74 8.6 0.01
Agg. Moist. Cont. 2.7 0.11 6.8 0.01 6.9 0.01
Agg. Type × Prod. Temp. 0.5 0.61 1.7 0.22 4.2 0.04
WMA, 12.5 mm, Limestone, PG 70-22
&
WMA, 19.0 mm, Limestone, PG 70-22
Agg. Size 3.3 0.09 4.2 0.06 9.3 0.01
Agg. Moist. Cont. 15.0 0.00 1.6 0.24 2.6 0.12
Agg. Size × Prod. Temp. 1.9 0.20 0.1 0.93 1.8 0.20
Conclusions
78
79
Effect of Temp. Red.
Reducing the production temperature of foamed WMA
resulted in increased susceptibility to permanent
deformation (or rutting) and moisture-induced damage.
Therefore, it is recommended that a maximum reduction
temperature of 30oF (16.7oC) be specified for the
production of foamed WMA.
80
Effect of Foaming Wtr. Cont.
Increasing the foaming water content (up to 2.6% of the
weight of the asphalt binder) during production of
foamed WMA did not seem to have a negative effect on
the rutting performance or moisture sensitivity of foamed
WMA.
Therefore, a higher foaming water content can be
specified for the production of foamed WMA in Ohio.
81
Effect of Agg. Moist. Cont.
Producing foamed WMA using moist aggregates
resulted in inadequate aggregate coating leading to
concerns with regard to moisture-induced damage and
long-term durability.
Therefore, it is critical to use fully dried aggregates in the
production of foamed WMA to ensure satisfactory mix
performance. Given that foamed WMA is typically
produced using lower production temperatures than
conventional HMA, the aggregates may need to be
dried for a longer period of time.
Part 4:
Performance of Foamed WMA
and HMA in the APLF
82
83
Field Performance of WMA vs. HMA
Testing Location: Accelerated Pavement
Loading Facility (APLF) at Ohio University (OU)
in Lancaster, OH
Material Combinations:
HMA Superpave 19.0 mm (Intermediate)
WMA Superpave 19.0 mm (Intermediate)
HMA Superpave 12.5 mm (Surface)
WMA Superpave 12.5 mm (Surface)
Asphalt Contractor: The Shelly Company
HMA
3” 19 mm 64-28
WMA
3” 19 mm 64-28
HMA
1.5” 12.5 mm 70-22
1.5” 12.5 mm 70-22
WMA
1.5” 12.5 mm 70-22
1.5” 12.5 mm 70-22
1
4 3 2
45 ft
22.5 ft
22.5 ft
8 ft 8 ft 8 ft
Loading
Direction
84
APLF Testing
85
APLF Testing
1 ¼ inch Surface Course
3 inch Intermediate Course
7 ¾ inch AC Base Course
4 inch Fatigue Resistant AC Layer
6 inch Dense Graded Aggregate Base
Silty Clay Subgrade
Mill and Pave
Top 3 inches
86
APLF Testing
87
APLF Testing
88
APLF Testing
89
APLF Testing
90
APLF Testing
91
APLF Testing
92
APLF Testing
93
APLF Testing
94
APLF Testing
95
APLF Testing
96
APLF Testing
97
APLF Testing
98
APLF Testing
99
APLF Testing
100
APLF Testing
101
APLF Testing
Test conditions and procedure:
Testing Temperature: 104oF
Load Level: 9000 lbs
Wheel Speed: 5 mph
No. of Passes: 10,000
Rutting measurement: lane profiler (two locations per
section)
102
APLF Testing
103
APLF Testing
104
Rutting (19 mm – Intermediate HMA)
4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5
0 20 40 60 80 100 120
Su
rfa
ce E
leva
tion
(in
ch)
Transverse Distance (inch)
0
300
1,000
3,000
10,000
105
Field Testing Plan
Rutting Performance
Laboratory
APA Test
Laboratory-Produced
Laboratory-Compacted
Plant-Produced
Laboratory-Compacted
Plant-Produced
Field-Compacted (Cores)
APLF
Rolling Wheel Test
Plant-Produced
Field-Compacted (Sections)
106
Field and Laboratory Results
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
HMA 12.5 mm LS &
PG 70-22M
Foamed WMA 12.5
mm LS & PG 70-22M
HMA 19.0 mm LS &
PG 64-28
Foamed WMA 19.0
mm LS & PG 64-28
Rut
Dep
th (
inch
)
Laboratory-Produced Laboratory-Compacted
Plant-Produced Laboratory-Compacted
Plant-Produced Field-Compacted (Field Cores)
Plant-Produced Field-Compacted (APLF Sections)
HMA
12.5 mm NMAS
Limestone
PG 70-22
Foamed WMA
12.5 mm NMAS
Limestone
PG 70-22
HMA
19.0 mm NMAS
Limestone
PG 64-28
Foamed WMA
19.0 mm NMAS
Limestone
PG 64-28
107
Field and Laboratory Results
Effect F-value Prob.
Preparation Method 45.92 <.0001
Mix Type 0.77 0.3874
Preparation Method × Mix Type 1.31 0.2853
Method Estimate Standard Error Ranking
Laboratory-Produced Laboratory-Compacted 0.1275 0.008440 A
Plant-Produced Laboratory-Compacted 0.1324 0.008440 A
Plant-Produced Field-Compacted (Field Cores) 0.2512 0.008440 B
Multi-Factor ANOVA Results for APA Rut Depths.
Results of Post ANOVA analyses on APA Rutting Values.
Conclusions
108
109
Conclusions
The APLF and APA rut depth values obtained
for the foamed WMA and HMA mixtures were
comparable for both surface and intermediate
mixtures.
This suggests that the foamed WMA mixtures
have similar rutting resistance to the HMA
mixtures.
110
Conclusions
The plant-produced laboratory-compacted and
laboratory-produced laboratory-compacted
specimens had comparable APA rut depth
values for both foamed WMA and HMA
mixtures.
This indicates that the laboratory mix
preparation procedure used in this study
resulted in comparable foamed WMA and HMA
mixtures to those produced in the field.
Recommendations for
Implementation
111
112
Recommendations for Implementation
Reducing the production temperature of foamed
WMA led to increased susceptibility to
permanent deformation (rutting) and moisture-
induced damage. Therefore, it is recommended
to continue to use a reduction temperature of
30oF (16.7oC) for the production of foamed
WMA.
113
Recommendations for Implementation
Increasing the foaming water content (up to
2.6% of the weight of the asphalt binder) during
production of foamed WMA did not seem to
have a negative effect on the rutting
performance or moisture sensitivity of foamed
WMA. Therefore, a higher foaming water
content can be specified for the production of
foamed WMA in Ohio.
114
Recommendations for Implementation
Producing foamed WMA using moist
aggregates resulted in inadequate aggregate
coating leading to concerns with regard to
moisture-induced damage and long-term
durability. Therefore, it is critical to use fully
dried aggregates in the production of foamed
WMA to ensure satisfactory mix performance.
115
Recommendations for Implementation
There is no need to compact the foamed WMA
mixtures to a higher density level that
commonly used for HMA mixtures.
Since the performance of the foamed WMA
was comparable to that of the HMA, no
modifications are needed to the current mix
design process used by ODOT for foamed
WMA mixtures.
116
Questions?