Replacement of Elastic Recovery (AASHTO T301) and Force Ductility
(AASHTO 300) Tests by DSR-Based Tests
LTRC Project No. 11-2B (Emulsions)
Southern Plains Transportation
Center (SPTC) Project No. 14.1-80
(Binders)
By
N. Wasiuddin
Louisiana Tech University
Objectives:
• Characterization of asphalt emulsion residues with
DSR tests:
• Strain sweep
• Frequency sweep
• Temperature sweep
• Multiple Stress Creep and Recovery (MSCR)
• Evaluation of correlations with:
• Elastic recovery • Force ductility
Why PG-Plus tests:
To identify the presence of polymers and quantify its
beneficial effects
PG-Plus tests:
• Elastic Recovery
• Force Ductility
• Phase Angle
• Toughness and Tenacity, etc.
are being used by
LA DOTD
Elastic Recovery Test (AASHTO T301) and
Force Ductility Test (AASHTO T300)
Ductility Bath
Elastic Recovery and
Force Ductility molds
Elastic Recovery
sample after severing Force Ductility sample
under test
20 cm
After pulling apart
Sever at the middle
after 5 minutes
(20- X) cm
After 1 hour
Elastic Recovery % = (20 – X) *100
20
Primary shape of briquette
Elastic Recovery Measurements:
Force Ductility Measurements:
The ratio of f2/f1 or f2 at 30 cm
f1
f2
In case of two maximum points
f1
f2
In case of one maximum point
Survey of Elastic Recovery Test Methods:
State Modified PG Binder Modified Emulsion
Asphalt
California AASHTO
T301(20cm&25°c)
AASHTO T51(25°c)
West Virginia AASHTO
T301(20cm&25°c)
-
Kentucky AASHTO
T301(10cm&25°c)
AASHTO
T301(10cm&4°c)
New Jersey ASTM
D6084(20cm&25°c)
AASHTO
T301(20cm&10°c)
Tennessee AASHTO
T301(20cm&25°c)
AASHTO
T301(20cm&10°c)
Texas ASTM
D6084(20cm&10°c)
TEX-539-C(20cm&10°c)
Louisiana AASHTO
T301(10cm&25°c)-2016
AASHTO
T301(20cm&10°c)
Survey of Force Ductility Test Methods (Illinois):
Test
SBS PG 64-28
SBS PG 70-22
SBS PG 70-28
SBS PG 76-22
SBS PG 76-28
Force Ratio (f2/f1),
4⁰c, 50mm/min.,
300 mm
elongation,
minimum
0.3 0.35
Survey of Force Ductility Test Methods (Louisiana):
Test PG 76-22m PG 70-22m
CRS-2P SS-1P PAC 15
Force Ratio
(f2/f1), 4⁰c,
50mm/min., 300
mm elongation,
minimum
0.3 _ 0.3 0.15 0.3
Force Ductility,
4⁰c, 50mm/sec,
300 mm
elongation, kg,
minimum
_ 0.23 - - -
MSCR Test Parameters (ASTM D7405):
Stress Levels of 100 and 3200 Pa, 10 Cycles, Creep Stress 1s, Recovery
9s
0
10
20
30
40
50
60
70
0 2 4 6 8 10 12
Str
ain
(%
)
Time (s)
One Cycle of MSCR Test
Ƴp peak strain
Ƴr recovered strain
Ƴu unrecovered strain
Percent of Recovery (%) = (Ƴr / Ƴp ) x 100 Non-Recoverable Creep Compliance (Jnr) = Ƴu /ơ
Why MSCR test instead of PG-Plus tests:
• Different states apply different methods and criteria for Elastic
Recovery and Force Ductility tests
• MSCR Test uses the same DSR device : No additional cost
• Easy and time saving
• Repeatability
• Less variability due to operator
• Small
• Mechanistic
20 Asphalt Emulsions were investigated
• Polymer Modified Emulsions:
PME
CHFRS-2P
CRS-2P (E)
CRS-2P (B)
CMS-1P
SS-1L
• Hard Pen Base Emulsions:
SS-1H (B)
SS-1H (U)
NTSS-1HM (C)
NTSS-1HM (B)
NTSS-1HM (U)
FOG SEAL
• Polymer Modified Hard Pen Base Emulsions:
CSS-1HP
SS-1HP
• Non Polymer Modified Non Hard Pen Base Emulsions:
CRS-2 (E)
CRS-2 (B)
CRS-2 (U)
SS-1 (E)
SS-1 (B)
SS-1 (U)
Emulsions Strain
Sweep
Freq. Sweep Temp. Sweep MSCR Elastic
Recovery
and Force
Ductility
SS-1 (E)
Temp.: 52°C
and 70°C
Strain:
2%, 12%,
22%, 32%,
42% and
52%
3 mat
samples
Temp.: 10°C, 25°C, 58°C
and 70°C
Ang. Freq.:
0.1 rad/s – 100
rad/s
3 mat samples
Temp.: from 52°C to
94°C at 6°C
intervals
Strain and
Ang. Freq.:
12% and 10
rad/s
3 mat samples
and
3 DSR mold
samples
Temp.: 10°C, 25°C, 58°C,
70°C and one
equal-stiffness
temperature (2.2
kPa stiffness)
Stress:
0.1kPa, 3.2 kPa
(0.1kPa, 0.2 kPa,
0.5 kPa and 3.2
kPa at 2.2 kPa
stiffness temp.)
3 mat samples for
0.1 and 3.2 kPa
and 3 mat
samples2 for 0.2
and 0.5 kPa
Temp.
Elastic
Recovery: 10°C and
25°C
Temp.
Force
Ductility: 4°C
2 mat
Samples
for Elastic
Recovery
and 2 mat
samples
for Force
Ductility
SS-1 (B)
SS-1 (U)
SS-1H (B)
SS-1H (U)
SS-1HP
SS-1L
CRS-2 (E)
CRS-2 (B)
CRS-2 (U)
CRS-2P (E)
CRS-2P (B)
CHFRS-2P
CMS-1P
CSS-1HP
PME
NTSS-1HM (B)
NTSS-1HM (C)
NTSS-1HM (U)
Fog Seal
Experimental Plan
Recovering Residue from Emulsified Asphalt:
• Low temperature evaporative technique (ASTM D7497)
• Elastic Recovery Test : 24 hours at 25⁰C forced oven + 24 hours at
60⁰C forced oven
• DSR-based Test : 24 hours at 25⁰C forced oven + 24 hours at
60⁰C forced oven
•Force Ductility Test : 6 hours at 60⁰C forced oven
Strain Sweep Test:
• Strain Sweep Test was conducted at two temperatures, 52⁰C and 70⁰C,
and six strains , 2%, 12%, 22%, 32% , 42% and 52%
• Drop from Initial G*% = 100* (G*2% - G*52%)/(G*2%)
• The lower the drop, the higher the strain tolerance
• Indication of linearity
•Drop from initial G* can be used as a criteria to estimate aggregate loss in
chip seals
•Polymer Modified
Emulsions:
PME
CHFRS-2P
CRS-2P (E)
CRS-2P (B)
CMS-1P SS-1L
Strain Sweep Test:
• The maximum of tolerance at 52⁰C and 70 ⁰C are 12.9% and
16.4% respectively for SS-1L
• The minimum of tolerance at 52⁰C and 70 ⁰C are 3.4% and 1.9%
respectively for CMS-1P
•Hard Pen Base
Emulsions:
SS-1H (B)
SS-1H (U)
NTSS-1HM (C)
NTSS-1HM (B)
NTSS-1HM (U)
FOG SEAL
Strain Sweep Test:
• NTSS-1HM(C), NTSS-1HM(B) and FOG SEAL could not reach 52% strain at 52⁰C
• The maximum of tolerance at 52⁰C and 70 ⁰C are 44.2% and 43.3%
respectively for NTSS-1HM(U) and NTSS-1HM(B) • The minimum of tolerance at 52⁰C and 70 ⁰C are 15% and 1.2%
respectively for SS-1H(U)
•Polymer Modified and
Hard Pen Base Emulsions:
CSS-1HP
SS-1HP
Strain Sweep Test:
• The maximum of tolerance at 52⁰C and 70 ⁰C are 22.5% and 7.5%
respectively for CSS-1HP
• The minimum of tolerance at 52⁰C and 70 ⁰C are 9.6% and 3.7%
respectively for SS-1HP
•Non Polymer Modified and
Non Hard Pen Base
Emulsions:
CRS-2 (U)
CRS-2 (E)
CRS-2 (B)
SS-1 (E)
SS-1 (B)
SS-1 (U)
Strain Sweep Test:
• The maximum of tolerance at 52⁰C and 70 ⁰C are 6.7% and 3.8%
respectively for SS-(E)
• The minimum of tolerance at 52⁰C and 70 ⁰C are 2.7% and 0.4%
respectively for CRS-2(B) and SS-1(B)
Strain Sweep Test:
In Summary:
• Higher drop from initial G* or lower strain tolerance will result in
increase of aggregate loss in chip seals
• Asphalt emulsions prepared of hard pen base asphalt have higher
drop from initial G* or lower strain tolerance
Frequency Sweep Test:
• Master curve was constructed at 25⁰ C based on conducted
frequency sweep tests at 10⁰C, 25⁰C, 58⁰C and 70⁰C. • Master curve is used to understand the overall rheological behavior
of asphalt emulsions.
Master
Curve
Master Curve:
• NTSS-1HM (C), NTSS-
1HM (U) and Fog Seal
show high G* values in a wide range of frequencies
Frequency Sweep Test:
In Summary:
• Hard Pen Base Emulsions show higher G* value and lower strain
tolerance
Temperature Sweep Test:
• Temperature Sweep Test of DSR was conducted on emulsion residues
from 52⁰C to 94⁰C at 6⁰C intervals.
• Results of Temperature Sweep Test include:
Diagram of G*/Sin(δ) versus Temperature
Diagram of Phase Angle(δ) versus Temperature
Temperature Sweep Test: G*/Sin(δ) versus Temperature
• Hard Pen Base emulsions
including NTSS-1HM (B) and
CSS-1HP have the higher
G*/Sin δ than other emulsions.
NTSS-1HM (B)
CSS-1HP
Temperature Sweep Test: G*/Sin(δ) versus Temperature
• Hard Pen Base emulsions such
as NTSS-1HM (C), NTSS-1HM
(U) and Fog Seal have the higher
G*/Sin δ than other emulsions.
.
FOG SEAL
NTSS-1HM (C)
NTSS-1HM (U)
Temperature Sweep Test: Phase Angle(δ) versus
Temperature
• When temperature increases,
phase angle increases to a
maximum and then decreases.
• the maximum phase angle of all
the non-hard pen polymer modified
asphalt emulsion residues fall between 75⁰ to 85⁰.
Temperature Sweep Test: Phase Angle(δ) versus
Temperature
• When temperature increases,
phase angle increases to a
maximum and then decreases.
• the maximum phase angle of all
the non-hard pen polymer modified
asphalt emulsion residue falls between 75⁰ to 85⁰.
Elastic Recovery Test (AASHTO T301):
10⁰C 25⁰C
Average Elastic
Recovery (%)
Modified
Emulsions
Modified
Emulsions
MSCR Test Results:
Emulsions
Percent Recovery (MSCR)
Creep Stress 0.1 kPa Creep Stress 3.2 kPa
10°C 25°C 58°C 70°C 10°C 25°C 58°C 70°C
Polymer Modified Emulsions
CMS-1P 58.8 46.9 35.1 29.0 57.8 45.1 12.6 -1.9
CRS-2P (B) 60.2 48.1 25.9 21.7 58.1 46.2 9.8 0.9
CRS-2P (E ) 76.0 63.0 29.7 30.3 65.9 62.7 9.5 2.2
SS-1L 66.7 58.2 53.1 35.6 62.9 56.8 13.9 0.7
PME 79.5 60.0 36.0 32.0 67.4 60.0 12.2 0.4
CHFRS-2P 72.7 67.5 36.8 38.1 72.8 67.4 17.1 5.2
Polymer Modified and Hard Pen Base Asphalt Emulsions
CSS-1HP 99.9 81.4 56.7 76.3 73.3 76.9 36.2 10.4
SS-1HP 75.9 68.7 24.1 8.7 73.2 68.7 12.9 1.3
MSCR Test Results:
Emulsions
Percent Recovery (MSCR)
Creep Stress 0.1 kPa Creep Stress 3.2 kPa
10°C 25°C 58°C 70°C 10°C 25°C 58°C 70°C
Non-Polymer Modified and Non-Hard Pen Base Asphalt Emulsions
SS-1 (B) 66.1 44.2 3.7 -1.8 66.1 43.4 0.0 -2.7
SS-1 (E ) 66.1 39.8 4.9 -1.1 67.4 37.6 -0.1 -2.6
SS-1 (U) 54.4 41.1 5.4 -0.1 52.8 38.5 -0.1 -2.7
CRS-2 (U) 51.1 34.9 2.9 -1.9 51.7 38.5 -0.2 -2.9
CRS-2 (B) 55.5 37.9 7.7 0.6 52.4 37.3 0.2 -2.6
CRS-2 (E ) 59.9 49.0 7.1 0.5 63.1 51.0 0.4 -2.6
MSCR Test Results:
Emulsions
Percent Recovery (MSCR)
Creep Stress 0.1 kPa Creep Stress 3.2 kPa
10°C 25°C 58°C 70°C 10°C 25°C 58°C 70°C
Hard Pen Base Asphalt Emulsions
SS-1H (U) 72.1 59.0 6.5 2.4 73.5 58.5 3.4 -0.1
SS-1H (B) 96.6 63.4 11.6 4.0 80.7 63.6 5.3 0.2
NTSS-1HM
(U) >100 67.5 12.8 8.8 90.0 68.9 9.7 1.6
NTSS-1HM
(C ) >100 >100 25.8 13.5 >100 72.1 24.2 10.2
NTSS-1HM
(B) >100 >100 39.7 33.0 >100 >100 45.1 28.1
FOG SEAL >100 >100 27.0 14.3 96.9 >100 26.8 12.1
MSCR Test Results:
Emulsions
2.2 kPa
Stiffness
(G*/sinδ)
Temperatures
°C)
Creep Stresses (kPa) R2 Value for
Log(stress)
vs. Percent
Recovery
0.1 0.2 0.5 3.2
Polymer Modified Emulsions
CRS-2P (E) 63°C 27.5 24.6 13.9 1.5 0.98
SS-1L 61°C 60.6 55.4 38.8 7.4 0.99
CHFRS-2P 67°C 34.3 29.8 18.6 2.2 0.99
CMS-1P 55°C 43.0 45.6 37.5 23.3 0.91
CRS-2P (B) 59°C 16.5 19.0 13.1 3.7 0.88
PME 62°C 44.2 39.7 26.1 4.1 0.99
Polymer Modified and Hard Pen Base Asphalt Emulsions
CSS-1HP 80°C 92.2 86.7 47.5 1.1 0.98
SS-1HP 66°C 11.4 8.7 5.5 0.8 0.99
MSCR Test:
Emulsions
2.2 kPa
Stiffness
(G*/sinδ)
Temperatures
°C)
Creep Stresses (kPa) R2 Value for
Log(stress)
vs. Percent
Recovery
0.1 0.2 0.5 3.2
Non-Polymer Modified and Non Hard Pen Base Asphalt Emulsions
CRS-2 (U) 56°C 6.2 4.1 1.9 -0.3 0.95
CRS-2 (B) 57°C 7.7 6.0 3.4 0.0 0.99
CRS-2 (E) 57°C 5.7 3.9 2.0 -0.2 0.96
SS-1 (U) 57°C 8.4 5.7 2.5 -0.3 0.95
SS-1 (B) 57°C 5.9 5.8 3.2 0.5 0.96
SS-1 (E) 57°C 8.7 6.0 2.6 -0.3 0.94
MSCR Test Results:
Emulsions
2.2 kPa
Stiffness
(G*/sinδ)
Temperatures
°C)
Creep Stresses (kPa) R2 Value for
Log(stress)
vs. Percent
Recovery
0.1 0.2 0.5 3.2
Hard Pen Base Asphalt Emulsions
SS-1H (U) 68°C 4.2 2.8 1.2 -0.3 0.95
SS-1H (B) 68°C 10.7 7.6 3.6 0.0 0.95
Fog Seal 94°C 8.6 6.4 3.2 0.2 0.96
NTSS-1HM
(U) 79°C 13.3 9.2 3.8 -0.4 0.94
NTSS-1HM
(B) 96°C 21.1 15.7 7.5 0.3 0.96
NTSS-1HM
(C) 90°C 15.7 12.3 6.8 0.6 0.98
Correlation between MSCR parameters and Elastic
Recovery
Coefficient of Determination (R2) for Linear Correlation Between
Percent Recovery (MSCR) and Elastic Recovery (AASHTO
T301)
MSCR Temperature MSCR Creep
Stress
Elastic Recovery
Temperature (AASHT
T301)
10°C 25°C
58°C 0.1 kPa 0.961 0.798
3.2 kPa 0.938 0.843
70°C 0.1 kPa 0.957 0.872
3.2 kPa 0.516 0.493
2.2 kPa Stiffness
Temperature
0.1 kPa 0.908 0.692
3.2 kPa 0.409 0.487
Correlation between MSCR parameters and Elastic
Recovery
Coefficient of Determination (R2) for Linear Correlation Between
Non-Recoverable Creep Compliance, Jnr (MSCR) and Elastic
Recovery (AASHTO T301)
MSCR Temperature MSCR Creep
Stress
Elastic Recovery
Temperature
(AASHTO T301)
10°C 25°C
58°C 0.1 kPa 0.737 0.623
3.2 kPa 0.604 0.472
70°C 0.1 kPa 0.169 0.696
3.2 kPa 0.502 0.391
2.2 kPa Stiffness
Temperature
0.1 kPa 0.734 0.682
3.2 kPa 0.078 0.139
Force Ductility Test:
Emulsions Max. Force, f1
(lb)
Force at 30 cm, f2
(lb) f2/f1
Force at 35 cm
(lb)
Avg. St. Dev. Avg. St. Dev. Avg. St. Dev. Avg. St. Dev.
Polymer Modified Emulsions
CHFRS-2p 5.3 0.3 0.38 0.05 0.07 0.01 0.35 0.03
CMS-1p 1.8 0 0.22 0.02 0.12 0.01 0.26 0.01
CRS-2P (E ) 5.9 0.1 0.4 0.07 0.07 0.01 0.36 0.06
PME 4.1 0.2 0.1 0.04 0.03 0.01 0.07 0.03
SS-1L 5.3 0.2 0.19 0.04 0.04 0.01 0.15 0.02
Non-Polymer Modified and Non-Hard Pen Base Asphalt Emulsions
CRS-2 (U) 8.7 0.7 0.06 0.08 0.01 0.01 0.02 0.03
CRS-2 (E ) 4.2 0.1 0 0 0 0 0 0
SS-1 (U) 4.3 0.02 0 0 0 0 0 0
SS-1 (B) 6.2 0.02 0.04 0 0.01 0 0 0
SS-1 (E ) 2.7 1
sample 0.06
1
sample 0.02
1
sample 0.03
1
sample
Force Ductility Test:
Emulsions Max. Force, f1
(lb)
Force at 30 cm, f2
(lb) f2/f1
Force at 35 cm
(lb)
Avg. St. Dev. Avg. St. Dev. Avg. St. Dev. Avg. St. Dev.
Hard Pen Base Asphalt Emulsions
SS-1H (U) 19.4 0.6 0 0 0 0 0 0
SS-1H (B) 13.8 1.2 0 0 0 0 0 0
Fog Seal 4.3 1
sample 0 0 0 0 0 0
NTSS-1HM
(U) 41.2 7.4 0 0 0 0 0 0
NTSS-1HM
(B) 18.7 6.2 0 0 0 0 0 0
Polymer Modified and Hard Pen Base Asphalt Emulsions
CSS-1HP 11.2 1.6 0 0 0 0 0 0
SS-1HP 9.2 0.05 2.13 0.11 0.23 0.01 0.89 1.26
Force Ductility Test:
Linear Correlation with Phase Angle
Force Ductility
Test Parameter
Phase Angle Testing Temperature
58°C 70°C 2.2kPa Temp. Average R2
Force at 30 cm, f2
(lb) 0.71 0.52 0.62 0.62
f2/f1 0.47 0.74 0.47 0.56
Force at 35 cm
(lb) 0.69 0.61 0.62 0.64
Average R2 0.62 0.62 0.57 0.61
Linear Correlation with Percent Recovery
Force Ductility
Test Parameter
Percent Recovery (at 0.1 kPa Creep
Stress) Testing Temperature
58°C 70°C 2.2kPa Temp. Average R2
Force at 30 cm, f2
(lb) 0.46 0.65 0.31 0.47
f2/f1 0.43 0.54 0.38 0.45
Force at 35 cm
(lb) 0.46 0.66 0.33 0.48
Average R2 0.45 0.62 0.34 0.47
Recommendations:
• MSCR (ASTM D7405) has been recommended to replace Elastic
Recovery test (AASHTO T301) to identify the presence of polymer.
Residue should be prepared according to ASTM D7497.
Test Specifications
Minimum Percent Recovery,
58⁰C, 0.1 kPa creep stress 25
Minimum Percent Recovery,
MSCR, 58⁰C, 3.2 kPa creep
stress 9
Recommendations:
• Percent recovery of MSCR and phase angle can be used to
replace force ductility requirements (AASHTO T300).
Test Specifications
Minimum Percent Recovery, MSCR at
58⁰C, 0.1kPa creep stress
&
Maximum Phase angle, 58⁰C, 12% strain,
10 rad/sec
30
81⁰