Comparative Evaluation of MSCR Tests on Warm-Mix

Technologies

Zelelew H., Paugh C., Corrigan M., and Belagutti S.

FHWA Office of Pavement, Construction, and Asset Management 1200 New Jersey Ave. SE

Washington DC 20590

2nd International Warm-mix ConferenceSt. Louis Missouri

October 11-13, 2011

Outline Project Descriptions

Binder Testing

Performance Testing

Relating MSCR to Performance

Summary of Findings

Project Descriptions Location: Pleasant Gap, PA

Duration: May to June 2009

Five Plant Produced 9.5mm NMAS Asphalt Mixtures

o HMA (Control Mix)

o WMA (Advera®)

o WMA (LEA)

o WMA (Gencor)

o WMA (Sasobit®)

Surface Layers

Mixture Production: Counter-flow Drum Mix Plant

PG 64-22Foaming Process

Wax Additive

Lab Mixing

o Silverson High Shear Mixer

Binder ID Source Dosage Rates (%) Remark

PG 64-22 - - -

Advera® Lab Prepared (LP) 0.25 by weight (Total Mix)

Sasobit® Plant Supplied (PS) 1.50

by weight (Binder) LEA Lab Prepared (LP) 0.20

Gencor Plant Supplied (PS) 1.25

Binder Testing

PG Verification AASHTO M320-10

Binder ID M320 Continuous

Effects

PG High Temp. PG Low Temp.

PG 64-22 PG 65.2-23.5 - -

Advera® PG 65.9-23.5 Slightly Increased No Change

Sasobit® PG 71.2-24.5 Increased by +6°C Slightly Decreased

LEA PG 64.9-23.7 Slightly Decreased Slightly Decreased

Gencor PG 66.3-26.9 Slightly Increased Decreased by -3.4°C

0

2

4

6

8

10

12

14

16

0 100 200 300 400 500 600 700 800 900 1000

Stra

in (%

)

MSCR (TP 70-11) Determines the Presence of Elastic Response using DSR

Temperature Selection

o LTPPBind V3.1

o 52 - 70C

Duration (10 Cycles)

o 1 sec (Creep)

o 9 sec (Recovery)

Stress Mode

o 0.025 to 2.56 kPa

o 0.1 & 3.2 kPa Example: 0.025 kPa

23

10

1

MSCR Test Parameters Using 0.1 & 3.2 kPa Stress Levels

o Non-recoverable Creep Compliance (Jnr)

o Percent Difference in Jnr (Jnrdiff)

o Percent Recovery (R)

o Difference in R (Rdiff)

Jnrdiff = Jnr (3.2) – Jnr (0.1) x 100

Jnr (0.1)

Rdiff = R(0.1) – R (3.2) x 100

R (0.1)

Computations

…..

…..

0.00

0.20

0.40

0.60

0.80

1.00

0.01 0.1 1 10 100

J nr(1

/kPa

)

Shear Stress (kPa)

PG 64-22

Advera

Sasobit

LEA

Gencor

Stress Sensitivity(52 °C)

0.00

0.75

1.50

2.25

3.00

0.01 0.1 1 10 100

J nr(1

/kPa

)

Shear Stress (kPa)

PG 64-22

Advera

Sasobit

LEA

Gencor

.....(58 °C)

0.00

1.50

3.00

4.50

6.00

0.01 0.1 1 10 100

J nr(1

/kPa

)

Shear Stress (kPa)

PG 64-22

Advera

Sasobit

LEA

Gencor

…..(64 °C)

0.00

3.00

6.00

9.00

12.00

0.01 0.1 1 10 100

J nr(1

/kPa

)

Shear Stress (kPa)

PG 64-22

Advera

Sasobit

LEA

Gencor

…..(70 °C)

0.00

3.00

6.00

9.00

12.00

0.01 0.1 1 10 100

J nr(1

/kPa

)

Shear Stress (kPa)

52 C

58 C

64 C

70 C

Summary

0.00

2.00

4.00

6.00

8.00

10.00

46 52 58 64 70 76

J nr(1

/kPa

)

Temperature (C)

PG 64-22

Advera

Sasobit

LEA

Gencor

Jnr vs. Temperature

(0.1 kPa)

0.00

2.00

4.00

6.00

8.00

10.00

46 52 58 64 70 76

J nr(1

/kPa

)

Temperature (C)

PG 64-22

Advera

Sasobit

LEA

Gencor

…..

(3.2 kPa)

Jnrdiff vs. Temperature

PG Classification AASHTO MP 19 Table 3 (MSCR)

Traffic Loading Jnr (3.2 kPa) (1/kPa)

Jnrdiff (%)

Standard Grade (S) < 4.0

Maximum 75 %

Heavy Grade (H) < 2.0

Very Heavy Grade (V) < 1.0

Extremely Heavy Grade (E) < 0.5

.....

Temperature (°C) Binder ID Jnrdiff

(%) Jnr (3.2 kPa)

(1/kPa) PG Grade (Table 3)

58

PG 64 - 22 4.74 1.593 PG 58 - 22 H

Advera 4.55 1.493 PG 58 - 22 H

Sasobit 29.64 0.865 PG 58 - 22 V

LEA 3.56 1.782 PG 58 - 22 H

Gencor 8.01 1.391 PG 58 - 22 H

Temperature (°C):

4.4, 21.1, 37.8, and 54.4

Frequency (Hz):

0.016 to 25 (0.1 to 157.1 rad/s)

Master Curve

Generalized Logistic Function

Pellinen, Witczak, and Bonaquist (2004)

Binder Master Curve

.....

1.E+00

1.E+02

1.E+04

1.E+06

1.E+08

1.E+10

1.E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08

Shea

r M

odul

us, |G

*| (k

Pa)

Reduced Frequency (Hz) (TRef = 21.1C)

PG 64-22

Advera®

Sasobit®

LEA

Gencor

Mixture DesignParameter Control

HMA WMA

Advera® Sasobit® LEA Gencor

Sieve No. (mm) Percent Passing (%)

1/2 in (12.5 mm) 100.0

3/8 in (9.5 mm) 98.0

No. 4 (4.75 mm) 72.0

No. 8 (2.36 mm) 46.0

No. 16 (1.18 mm) 26.0

No. 30 (600 μm) 17.0

No. 50 (300 μm) 11.0

No. 100 (150 μm) 8.0

No. 200 (75 μm) 5.0

CAA (%) 100/100

FAA (%) 45.2

F & E (%) 0.2

SE (%) 78.0

…..

o < 3 x106 ESAL

Parameters Control HMA

WMA

Advera® Sasobit® LEA Gencor

Pb (%) 5.9

Va (%) 4.0

VMA (%) 16.3

VFA (%) 76.0

F/Pbe 0.90 Pb = percent binder content, Va= percent air voids, VMA= percent voids in mineral aggregates, VFA= percent voids filled with asphalt, F/Pbe = fine dust to effective binder ratio.

o NDesign = 75

Prod & In-Place Temp

Mixture ID Temperature (°C)

Production Difference 1 In-place Difference 2

Control HMA 148.0 - 136.1 -

Advera® 118.2 29.8 105.5 30.6

Sasobit® 123.2 24.8 117.4 18.7

LEA 103.4 44.6 89.7 46.4

Gencor 121.6 26.4 97.7 38.4 1 reduction in production temperature 2 reduction in in-place temperature

On-site Paving

Performance Test -TP 79

AMPT (IPC Global)

Asphalt Mixture Performance Tester (AMPT)

Measures the Engineering Properties of Asphalt Mixtures

o Dynamic Modulus (|E*|):Stiffness

o Flow Number (Fn):

Rutting under Cyclic Load

Dynamic Modulus Test Temperature (°C)

4.4, 21.1, 37.8, and 54.4

Frequency (Hz):

25, 10, 5, 1, 0.5, and 0.1

4 Replicates

Unconfined Mode

75-125 μstrain

10

100

1000

10000

100000

1.E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08

Dyn

amic

Mod

ulus

, |E*|

(MPa

)

Reduced Frequency (Hz) (TRef = 21.1C)

Control HMA

Advera®

Sasobit®

LEA

Gencor

Master Curve

Flow Number Test

Termination Criterion

10,000 Cycles or

50,000 Microstrain

Temperature (°C)

45.8, 51.8, and 57.8

4 Replicates

Confined Test

690/69 kPa

Load (0.1 sec) and Unload (0.9 sec)

Selection of Test Temperature

Adjustments

50% Reliability

20 mm Depth

PG Temp = 51.8 °C

LTPPBind V3.1

Weather Station

State College, PA

…..

Number of Cycles

AccumulatedStrain Primary Secondary Tertiary

SlopeIntercept

Flow Number (Fn)

0

2000

4000

6000

8000

10000

12000

Control HMA Advera® Sasobit® LEA Gencor

Flow

Num

ber (

Cyc

les)

45.8 °C 51.8 °C 57.8 °C

Fn

0

5

10

15

20

Control HMA Advera® Sasobit® LEA Gencor

Slop

e (M

icro

ns/C

ycle

s)

45.8 °C 51.8 °C 57.8 °C

Slope

0

10000

20000

30000

40000

Control HMA Advera® Sasobit® LEA Gencor

Inte

rcep

t (M

icro

ns)

45.8 °C 51.8 °C 57.8 °C

Intercept

10

100

1000

10000

100000

1.E-06 1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08

Dyn

amic

Mod

ulus

, |E*|

(MPa

)

Reduced Frequency (Hz) (TRef = 21.1C)

Control HMA

Advera®

Sasobit®

LEA

Gencor

Variations in Performance Binder Rheological Properties

Dosage Rates

Intrinsic Properties of WMA Technologies

Production Temperature

0

2000

4000

6000

8000

10000

12000

Control HMA Advera® Sasobit® LEA Gencor

Flow

Num

ber (

Cyc

les)

45.8 °C 51.8 °C 57.8 °C

Typical Trends

Jnr

Fn

Intercept Slope

|E*|Sin()

Jnr

Jnr

Jnr

300

400

500

600

700

0.8 1.0 1.2 1.4 1.6 1.8 2.0

|E*|/

sin

() (

MPa

), 5

Hz

and

54.4

C

Jnr at 3.2 kPa (1/kP)

Sasobit

GencorAdvera

HMA

LEA

Relating Jnr to |E*|/sin()

0

2000

4000

6000

8000

10000

0.8 1.0 1.2 1.4 1.6 1.8 2.0

Flow

Num

ber (

Cyc

les)

Jnr at 3.2 kPa (1/kP)

Sasobit

LEA

Gencor

Advera

HMA

Relating Jnr to Fn

0

4

8

12

16

20

0.8 1.0 1.2 1.4 1.6 1.8 2.0

Slop

e (M

icro

ns/C

ycle

)

Jnr at 3.2 kPa (1/kP)

Sasobit

Gencor

Advera

HMA

LEA

Relating Jnr to Slope

20000

25000

30000

35000

0.8 1.0 1.2 1.4 1.6 1.8 2.0

Inte

rcep

t (M

icro

ns)

Jnr at 3.2 kPa (1/kP)

Sasobit

Gencor

Advera

HMA

LEA

Relating Jnr to Intercept

Summary of Findings Binder Test (|G*| and MSCR)

Performance Test (|E*| and Fn)

MSCR Test: Temperature-Stress Dependent Test

Sasobit Produced the Lowest Creep Compliance Values at all Test Temperatures and Shear Stress Levels

Relating Jnr to AMPT |E*| and Fn Test Parameters

Acknowledgment

o PennDOT

o Tom Abbey and the Staff at Glenn O. Hawbaker Inc.

o RamakrishnaReddy (MATL PE)

o MATL/ABTL Techs

Thank You

Questions