Characterization of Evotherm Warm Mix Binder - Petersen Asphalt ...

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Characterization of Evotherm Warm Mix Binder - Petersen Asphalt ...

Characterization of Evotherm

Warm Mix Binder

Koichi Takamura, Ph.D.

BASF Corporation

Charlotte, NC USA

koichi.takamura@basf.com


Plant Mixing Temperature

170

Plant Mixing Temperature, °C

160

150

140

130

120

110

Hot Mix

Evotherm

• Harder the asphalt, higher

the mixing temperature with

Hot Mix

• Independent on the asphalt

hardiness with Evotherm

• The thin water film acts

as the lubricant, as the

curling stone slides on

the ice

100

58 64 70 76 82

PG grading

2


Emulsion based Warm Mix

Emissions from Stack

80

60

46%

63%

58%

McAsphalt Trial in Oct. 4-5, 2005

Plant Production

Aggregate Asphalt Compaction

Hot Mix 155 o C 155 o C 145 o C

Warm Mix 125 o C *95 o C 85 o C

40

20

81%

* Emulsion temp.

Av. Stack Gas Temperature

Hot Mix

162 o C

Warm Mix

121 o C

0

CO 2

x10, % CO, ppm NO x

, ppm SO 2

, ppm

Warm Mix

Hot Mix

Fuel Oil Consumption

Litres/Tonne

Hot Mix 11.4

Warm Mix 5.2

• Significant reduction in CO, NO x and SO 2 emissions

from stack

3


Emulsion based Warm Mix

CO Emission

NO x Emission

SO 2 Emission

120

80

18

Hot mix (10/04/2005)

70

Hot mix (10/04/2005)

16

Hot mix (10/04/2005)

100

60

14

Concentration, ppm

80

60

Concentration, ppm

50

40

30

Warm Mix(10/05/2005)

Concentration, ppm

12

10

8

40

Warm Mix(10/05/2005)

6

20

4

Warm Mix(10/05/2005)

20

10

2

0

8:40 8:50 9:00 9:10 9:20 9:30

Time, minute

0

8:40 8:50 9:00 9:10 9:20 9:30

Time, minute

0

8:40 8:50 9:00 9:10 9:20 9:30

Time, minute

4


Residue Recovery

Procedure for Warm Mix

Asphalt Emulsion


Temperature profile of emulsion

based Warm Mix

Location Temp., °C

Mixing temperature 130

Discharge temperature 100

In hopper of paver 97

Just behind the screed of paver 92

at edge of mat 87

at center of mat 92

After pneumatic roller 73

Pavement 4 hrs after lay down* 52

*25mm below the surface

• Recovery Procedure for Asphalt Emulsion Residue

• Need to represent the mixing and paving

conditions

6


Evotherm trial by McAsphalt

Penetration at 25°C, dmm

120

100

80

60

40

Base AC

Rec'd AC from HMA

63% of

original

Rec'd AC from WMA

86%

• Base asphalt had a

penetration of 124dmm at

25°C, 5s.

Asphalt cement recovered

from field core samples

• Recovered AC from Hot

Mix asphalt = 81dmm

(63% of original value)

• Recovered AC from

Warm Mix asphalt =

107dmm (86% of original

value)

• Less heat aging of

asphalt cement at the

mix plant

7


Residue recovery procedure

Emulsion Residue

with 3% SBR Latex

100m

• Dry the emulsion at 80°C for 20 hours

• 80g emulsion in a PAV pan (~ 50g

residue)

• Maintain stable polymer network

• Recovered residue = Equivalent of

RTFOT sample of the hot mix AC

• RTFOT simulate heat oxidation of AC at the

hot mix plant

• SHRP and other binder

characterizations of recovered

residue

8


Residue recovery procedure

Ramada trial

Binder characterization

120

86%

100

89%

Penetration at 25°C, dmm

100

80

60

63% of

Base AC

Penetration at 25°C, dmm

80

60

40

20

56% of

Base AC

40

Base AC

Rec'd AC from

HMA

Rec'd AC from

WMA

0

Base AC

Base after

RTFOT

Rec'd WM

residue

• The new procedure closely simulate heat hardening of

Evotherm warm AC as penetration values

9


Residue recovery procedure

Emulsion Residue with 3% SBR Latex

Recovered residue

Residue after PAV

Asphalt binder becomes brittle

upon oxidation in the field

• Reduce fatigue and cold fracture

resistance of pavement

• PAV: Laboratory simulation of

oxidative aging of asphalt binder

• 100°C at 2.1MPa pressure for 20

hours

• Stable polymer network even after

the PAV-aging

100m

10


Before and After PAV (FTIR)

0.06

Absorption

0.05

0.04

0.03

0.02

COOH

R-CO-R'

R-CHO

R-SO-R'

0.01

Unmodified

After PAV

0

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

Wavenumber, cm -1

Absorption

0.06

0.05

0.04

0.03

0.02

COOH

R-CO-R'

R-CHO

R-SO-R'

Bd

0.01

0

1800

1700

1600

3% SBR polymer modified

1500

1400

1300

1200

1100

After PAV

1000

900

Wavenumber, cm -1

• Polymer modification does not prevent asphalt oxidation

11


Oxidative Hardening (Base asphalt/Unmodified residue)

Base asphalt

Unmodified Residue

Unmodified Residue

1000

1000

1000

100

100

100

10

10

10

Complex modulus, MPa

1

0.1

0.01

after

RTFOT

After PAV

Complex modulus, MPa

1

0.1

0.01

after PAV

Complex modulus, MPa

1

0.1

0.01

Rec'd residue

after PAV

0.001

0.001

0.001

0.0001

Neat asphalt

0.0001

Rec'd residue

0.0001

Base asphalt

after RTFOT

0.00001

-30 -15 0 15 30 45 60 75

Temperature, °C

0.00001

-30 -15 0 15 30 45 60 75

Temperature, °C

0.00001

-30 -15 0 15 30 45 60 75

Temperature, °C

• Base asphalt shows sharp increase in complex modulus, G*, after PAV

• Less significant hardening with Evotherm warm mix

• Base asphalt after RTFOT Evotherm warm mix after PAV

12


Before and After PAV (Physics)

(a)

Unmodified residue

(b)

SBR latex modified

1000

1000

0.4 Hz

100

100

Complex Modulus [G*], MPa

10

1

0.1

0.01

0.001

Oxidative hardening

Before PAV

After PAV

Complex Modulus [G*], MPa

10

1

0.1

0.01

0.001

After PAV

Before PAV

0.0001

-30 -15 0 15 30 45 60 75 90

Temperature, °C

0.0001

-30 -15 0 15 30 45 60 75 90

Temperature, °C

• Modification with SBR latex-polymer reduces negative

effects of hardened asphalt at wide temperature range

13


Before and After PAV

(a)

Unmodified

(b)

3% SBR Latex

100

100

T g =-16°C

T g =-11°C

T g =-23°C

T g =-18°C

0.4 Hz

Loss Moulus (G"), MPa

After

PAV

Loss Modulus (G"), MPa

After PAV

10

-30 -25 -20 -15 -10 -5 0 5

10

-30 -25 -20 -15 -10 -5 0 5

Temperature, °C

Temperature, °C

• 7°C reduction in T g with 3% SBR latex polymer

• 5°C increase in T g after PAV, both unmodified and modified residues

14


Cold Fracture Resistance: Stiffness with BBR

1000

-18°C

Creep Stiffiness, MPa

Base Asphalt after

PAV: m-value = 0.31

Rec'd Residue after PAV:

m-value = 0.35

Base Asphalt after

RTFOT: m-value = 0.38

100

1 10 100 1000

Time, s

• Improved Cold Fracture Resistance with Evotherm warm mix

• Base asphalt after RTFOT Evotherm warm mix after PAV

15


Bending Beam Rheometer

1000

-18°C

Creep Stiffness, MPa

Unmodified

residue

Base Asphalt

• All binder samples are after

the PAV-aging

• Even unmodified residue is

lower creep stiffness than the

base asphalt used to make

the emulsion

100

3% SBR

modified

residue

• SBR latex polymer further

reduce the stiffness, thus

maintain low temp. flexibility

1 10 100 1000

Time, s

16


Fatigue Resistance under Repeated Stresses

Unmodified Binders

Base AC, after RTFOT

Unmodified Residue

Unmod. Res., after PAV

100

1% strain

100

100

7°C

Complex modulus, MPa

10

1

0.1

5%

strain

0.1% strain

10%

strain

Complex modulus, MPa

10

1

0.1

1%

strain

5%

strain

0.1% strain

10%

strain

Complex modulus, MPa

10

1

0.1

0.01

0 30 60 90 120

Cumulative time, minutes

0.01

0 30 60 90 120

Cumulative time, minutes

0.01

0 30 60 90 120

Cumulative time, minutes

• Base asphalt after RTFOT Evotherm warm mix after PAV

17


SBR Polymer Modified Residue

1.5% SBR modified

1.5% SBR, After PAV

3.0% SBR, After PAV

100

100

1% strain

100

7°C

10

10

10

Complex modulus, MPa

1

Complex modulus, MPa

1

5% strain

Complex modulus, MPa

1

0.1

20%

strain

0.1

0.1

0.01

10%

strain

0.01

0 30 60 90 120


Cumulative time, min.

0.01

0 30 60 90 120

Cumulative time, min.

0.001

0 30 60 90 120 150 180

Cumulative time, min.

Evotherm with 3.0% SBR latex maintains excellent fatigue resistance

even after PAV --- Extended service life with >2% latex

18


Pavement Longevity

• 4, 20, 44 and 94 hours PAV-aging

• FTIR for Chemistry

• DSR for rheological measurements

Binder samples were too brittle to do the

BBR measurements after 44 hrs PAVaging

19


Accelerated oxidative aging test (PAV)

McAsphalt PG58-28, Unmodified Evotherm Residue

0.3

Absorption

0.2

0.1

R-COOH

R-CO-R'

R-CHO

24 hr PAV

44 hr

94 hr R-SO-R'

Neat asphalt

0

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

Wave number, cm -1

McAsphalt PG58-28, 3% SBR Latex Modified Residue

0.3

Butadiene

Absorption

0.2

0.1

94hr

44hr

0

6hr PAV

Neat asphalt

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

Wave number, cm -1

• SBR polymers remain even after 94 hrs PAV

20


Accelerated oxidative aging test (PAV)

After 94hrs PAV-aging

McAsphalt PG58-28, Unmodified Evotherm Residue

Absorption

0.3

0.2

0.1

R-COOH

R-CO-R'

R-CHO

24 hr PAV

44 hr

94 hr R-SO-R'

Neat asphalt

0

1800

50m

1700

1600

1500

1400

1300

Wave number, cm -1

1200

1100

1000

900

0.3

McAsphalt PG58-28, 3% SBR Latex Modified Residue

Absorption

0.2

0.1

0

1800

1700

6hr PAV

1600

94hr

1500

Neat asphalt

1400

44hr

1300

1200

1100

Butadiene

1000

900

Wave number, cm -1

• SBR polymers remain even after 94 hrs PAV-aging

21


Pavement Longevity: Ergon/Valero in Texas

12

65

Complex Modulus [G*] at 25°C, MPa

9

6

3

Base Asphalt

Unmod. Residue

3% SBR Mod. Residue

SHRP Procedure

Phase Angle, degree

55

45

35

Valero PG64-22

0

1 10 100

Hours in PAV-aging

25

1 10 100

Hours in PAV-aging

• Reduced Oxidative hardening of SBR latex modified residue.

22


Pavement Longevity: McAsphalt in Canada

Complex Modulus at 19 °C, MPa

20

15

10

5

0

Base asphalt

Unmod. Residie

3% SBR Mod. Residue

1 10 100

Hours in PAV-aging

Phase angle, degree

65

55

45

35

25

McAsphalt PG58-28

1 10 100

Hours in PAV-aging

• Reduced Oxidative hardening of SBR latex modified residue,

even after >20 years of service

23


Pavement Longevity: Shell China

20

Base Asphalt

65

Complex Modulus at 13°C, MPa

15

10

5

Unmodified Residue

3% SBR Mod. Residue

Phase Angle at 13°C, degree

55

45

35

Shell China PG64*-22

0

25

1 10 100

1 10 100

Hours in PAV-aging

Hours in PAV-aging

• Reduced Oxidative hardening of SBR latex modified residue

• Consistent conclusion with 3 widely different asphalt

24


Conclusions

• Potential Pavement Longevity with Warm

Mix System

• Reduced oxidative hardening of asphalt binder during

the mixing and paving processes

• D. Newcomb, the Vice President-Research & Technology,

National Asphalt Pavement Association, states

• “Binder aging is directly related to the production temperature of the

mixture. The majority of binder hardening due to aging takes place in

the hot-mix plant. If the plant temperature is reduced, the oxidative

hardening of the binder will be reduced. Less hardening of the binder

during construction could mean more flexibility and resistance to

cracking in service. ---”

25


Reference

• Davidson, J.K., Lubbers, C., Takamura, K., Proc.

Canadian Technical Asphalt Assoc. 52, 297-324

(2007)

• Takamura, K., Road Materials and Pavement

Design 9, 87-102 (2008)

26

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