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Multi-Stress Creep and Recovery Test Method New Specification
John D’Angelo Federal Highway Administration
Phone 202-366-0121 fax 202-493-2070 John.D’[email protected]
Neat PG58-28 at multiple temperatures
0
0.5
1
1.5
2
2.5
3
10 100 1000 10000 100000Stress Pa
Jnr
58C64C70C
5
10
15
20
25
30
Neat binders are typically linear up to 3.2 kPa or higher
BBRS3 PG 64-22
0
2
4
6
8
10
0.01 0.1 1.0 10 100
stress kPa
J nr k
Pa-1
66.1 58 64 70
PG 82-22
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
10 100 1000 10000 100000stress Pa
Jnr
58C64C70C76C83C calc
1
2
3
4
5
6
7
8
9
10
Stress sensitivity increases with temperature. At 70C little
stress sensitivity at 82 very sensitive.
SBS PG 70-28 SBS
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
10 100 1000 10000 100000Stress Pa
Jnr
58C64C70C76C72C calc
1
2
3
4
5
6
7
8
9 Compliance values increase with
temperature and stress. The rate of increase with stress increases with
increased temperature.
ETG Wax study
ETG Wax study
0
2
4
6
8
10
12
0.01 0.1 1 10 100
Jnr 1
/kPa
Stress kPa
Chart Title
R-91-0 64C
R-91-1 64C
R-91-2 70C
R-91-3 64C
R-91-4 70C
R-91-5 70C
R-91-6 58C
R-91-7 70C
R-91-8 58C
R-91-9 58C
91-0 Lion Oil PG64-22 Control 91-1 Montan (lignite wax) 91-2 Asphaltan A (blend, possibly of montan, and EBS) 91-3 Asphaltan B (refined lignite wax) 91-4 Licomont BS100 (Ethylene bis-stearamided (EBS)) 91-5 Sasobit (Fischer-Tropsch) 91-6 Luxco Pitch (crude stearic acid pitch) 91-7 Alphamin GHP (polyethylene wax) 91-8 Montan LGE (ester wax) 91-9 Astra Wax 3816D (refined slack wax)
Highly modified binder MSCR stress sweep .1 to 6.4kPa
-50
150
350
550
750
950
1150
-50 50 150 250 350 450 550 650 750
% s
trai
n
time s
Jnr change with stress increase
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
0.1 1 10
Jnr
log stress kPa
Jnr vs stress
Correction of Jnr Diff
Increase the low stress from .1 to .8 kPa still in the linear range for most AC’s
Consider going to Jnr slope Arizona procedure. Keep original recommendation of waive Jnr diff
for E grades.
Jnr Slope
Jnr diff (Jnr3.2 – Jnr0.1)/Jnr0.1
Jnr diff slope (Jnr3.2 – Jnr0.1)/3.1 or (Jnr0.8 – Jnr3.2)/2.4
New Arizona State Procedure
Comparison of Jnr diff to slope
-3000.0
-2500.0
-2000.0
-1500.0
-1000.0
-500.0
0.0
500.0
1000.0
1500.0
2000.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
-0.10 0.10 0.30 0.50 0.70 0.90 1.10 1.30 1.50
Jnr d
iff
Jnr d
iff S
lope
Jnr 3.2
Next steps
Collect data on Jnr slope Collect data on Jnr0.8kPa to calculations of
both slope and Jnr diff
