High Modulus Asphalt (HiMA)
Technology Transfer (T2)
November 2010 Progress report
Prepared for presentation at the 20th meeting of
the Roads Pavements Forum (RPF),
CSIR ICC, 10 November 2010
Erik Denneman
Presentation structure
• Background on HiMA,
• The sabita HiMA T2 project,
• Progress since RPF May
• Design guide,
• Way forward.
Slide 2
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High Modulus Asphalt (HiMA)
•
•
Slide 3
Origin: France early 90s “Enrobés à Module Elevé”
(EME)
Typical characteristics:
• High binder content ≈ 6% by mass of aggregate,
• Hard binder: Pen 10-25,
• Low air voids content,
• High Modulus > 14 GPa at 15°C, 10 Hz,
• High resistance against permanent deformation,
• Good fatigue resistance,
• Impermeable,
• High mixing temperature.
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sabita HiMA T2 project
Phase I
Feasibility study
Phase II
Preliminary mix and structural design guidelines
Phase III
Validation through APT,LTPP and lab study
Phase IV
Drafting of guidelines and specs
Slide 4
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HiMA T2 progress (since previous RPF)
• Preliminary design guidelines complete,
• Validation mix design for APT pending,
• Waiting for suitable binder
Slide 5
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Comparison of mix moduli
100000
Dynamic Modulus (MPa)
10000
1000
BTB Mix
100
Coarse/SBS
Medium/SBS
10
HiMA
1
0.00001
Slide 6
0.001
0.1
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10
1000
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Reduced frequency
(Hz)
100000
Permanent deformation (RSST-CH)
5.0%
Permanent strain [%]
4.5%
4.0%
3.5%
3.0%
2.5%
2.0%
1.5%
1.0%
0.5%
0.0%
0
5 000
10 000
15 000
20 000
25 000
Load repetitions
Slide 7
BTB 1 55°C
HiMA 55°C
Coarse AE2 www.csir.co.za
55°C
Medium 60/70 55°C
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Medium AE2 55°C
BRASO 55°C
30 000
Fatigue results (10 °C 25 Hz)
Strain-fatigue relationship at test temperatures at 70% initial stiffness reduction
All at 10 Degrees C
10000
Mix 1 (BTB)
Mix 3
Mix 4 (HiMA)
STRAIN (Microstrain)
1000
100
10
1000
Slide 8
10000
100000
1000000
Number of load cycles
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10000000
100000000
French mix design effort
Parameter
Requirement
Result
SA equivalent
test
Workability
(Gyratory
compactor)
Durability
(Duriez test)
Rutting
(Wheel tracker)
Max 6% voids
after 100
gyrations
Retained
strength: >0.7
Rut depth after
30 000 cycles
<7.5 mm
15 °C-10 Hz:
>14 GPa
5.7 %
Gyratory
0.9
Modified Lottmann
με for 106
fatigue life:
>130
90 με
Beam dynamic
modulus
Fatigue
(Prism)
Slide 9
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5.2 mm RSST-CH, Wheel
tracking
17 GPa Beam or cylinder
dynamic modulus
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Beam fatigue
Gyratory study
Specification Superpave
French
Gyratory angle
1.25
0.82
Pressure
600kPa
600kPa
Rate
30 gyrations/min
30 gyrations/min
Slide 10
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Air voids [%]
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
F Sample1
F Sample2
F Sample3
F sample4
F sample5
S Sample1
S sample2
S sample3
S Sample4
S Sample5
French
SUPERPAVE
0
50
100
150
200
Number of gyrations
Slide 11
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250
300
Interim guideline
•
Slide 12
Warning! Do not try this at home.
• Validation through APT pending
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Select components
Guideline
Formulate design grading
Select binder content
Compact gyratory specimens
Workability criteria met?
No
Yes
No
Durability criteria met?
Yes
No
Rut resistance criteria met?
Yes
No
Dynamic modulus criteria met?
Yes
Compact slab
No
Fatigue criteria met?
Yes
Slide 13
Implement!
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Aggregate selection
Property
Test
Hardness
Fines aggregate crushing test: 10 %FACT TMH1, B1
≥ 160 kN
Aggregate crushing value ACV
TMH1, B1
≤ 25%
Flakiness Index test
SANS 3001
≤ 25
Particle index test
ASTM D3398
>15
Polished stone value
SANS 3848
>50a
Particle shape & texture
Water absorption
Water
Method
absorption
coarse
aggregate TMH1, B14
Criteria
≤ 1.0 %
(>4.75mm)
Cleanliness
Slide 14
Water absorption fine aggregate
TMH1, B14
≤ 1.5 %
Sand equivalency test
TMH1, B19
≥ 50
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SA sieve size envelope
Target
European sieve size envelope
100
Grading
D=14
Percentage passing
90
80
70
60
50
40
30
20
10
0
0 0.0075
2.36
4.75
6.7
Sieve size (raised to power 0.45) [mm]
Slide 15
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13.2
Property
Test
Method
Performance requirements
HiMA
base
HiMA binder course
course
Workability
Gyratory
ASTM
compactor, air
D6926
Class 1
Class 2
Class 1
Class 2
Class 3
≤ 6.3%
≤ 3.8 %
3.2 to 6.3 % for D = 10,
2.5 to 5.7 % for D = 14
voids after 100
gyrations
Moisture
Modified
ASTM
Refer
Refer
Refer
Refer
Refer
sensitivity
Lottman
D4867
Table
Table
Table
Table
Table
10
10
10
10
10
Permanent
RSST-CH,
AASHTO
≤
deformation
55°C,
320
strain
strain
strain
strain
strain
≥
≥ 9 GPa
≥
≥
30 000
1.7%
≤
1.7%
≤
2.3%
≤
1.7%
≤
1.1%
reps
Dynamic
Dynamic
AASHTO
≥
14
14
modulus
modulus test at
TP 62
GPa
AASHTO
≥
T 321
με
for
με
for
με
for
με
for
με
for
10
E
6
10
E
6
10
E
6
10
E
6
10
E
GPa
14
GPa
14
GPa
10 Hz, 15°C
Fatigue
Beam
fatigue
test at 10 Hz,
10°C,
to
70%
stiffness
Slide 16
reduction
330
reps
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≥
reps
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430
≥
reps
360
≥
reps
330
≥
reps
330
6
Way forward:
• Validate improved mix design,
• Perform APT and LTPP,
• Finalize mix design and structural design guidelines
Slide 17
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Thank you