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Bitumen Chemomechanics Related to Pavement Performance

Troy Pauli, Will Grimes, Alec Cookman, Ryan Boysen, Shin-Che Huang, Mike Farrar, Mike Harnsberger, James

Beiswenger, Pam Coles and Bruce Thomas

51st Petersen Asphalt Research Conference and Pavement Performance Prediction Symposium

Innovations for Predicting Pavement PerformanceMeasurements and Models

Hilton Garden Inn & University of Wyoming Conference CenterJuly 17, 2014, Laramie, Wyoming

Acknowledgments

The authors gratefully acknowledge the Federal Highway Administration, U.S. Department of Transportation, for financial support of this project under contract no. DTFH61-07-H-00009 (ARC).

Delft University of TechnologyTom Scarpas, Sybrand van de Zwaag and Alexander Schmets

Asphalt Research Consortium Partners

Outline

• Introduction• Bitumen Composition• Asphalt Macrostructure Modeling• Bitumen Chemomechanics

• Properties of the Oil Phase • Viscous Flow• Diffusion and Molecular Mass• Thermal Fatigue

• Properties of the Maltene and Asphalt Phase• Viscous Flow• Healing

• Asphalt Macrostructure and RAP Blending• Wax Surface Freezing

• Sectorization and Rippling• Healing

• Conclusions

0

10

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30

40

50

60

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90

100

Per

cent

Of F

ract

ion

Asphalt

AsphaltenesResinsWaxNeutrals

Asphalt Composition(SARA/IEC/WAX)

Asphalt Microstructure Modeling

Damage-Healing: Entropy Production

Nosonovsky, M, and B. Bhushan, 2010, Surface Self-organization: From Wear to Self-healing in Biological and Technical Surfaces. Applied Surface Science, 256, 3982-3987.

Nosonovsky, M., and S. K. Esche, 2008, A Paradox of Decreasing Entropy in Multiscale Monte Carlo Grain Growth Simulations. Entropy, 10(2), 49-54.

Nosonovsky, M., 2010, Entropy in Tribology: in the Search for Applications. Entropy, 12(6), 1345-1390.

Nosonovsky, N., R.Amano, J. M. Lucci and P. K. Rohatgi, 2009, Physical Chemistry of Self-organization and Self-healing in Metals. Phys. Chem. Chem. Phys., 11, 9530-9536.

The net entropy production of a damage-healing systems

Entropy Production in Damage-Healing

Pauli, A. T., 2014, Chemomechanics of Damage Accumulation and Damage Recovery Self-Healing in Bituminous Asphalt Binders. Dissertation, Printed by Sieca Repro, Delft, The Netherlands. ISBN 978-94-6186-269-3.

Entropy Production in Damage-Healing

Properties of the Oil Phase:

Viscous FlowDiffusion, Molecular Weight and Thermal

Fatigue

Entropy Production in Damage-Healing

Viscous Flow of Model Oils

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 100 200 300 400 500 600 700

n-P

araf

fin v

isco

sity

, cen

tipoi

se

n-Paraffin molecular mass, g/mol

90°C

120°C

150°C

180°C

HPLC-Gel Permeation Chromatography

Thermal Gravimetric Analysis

Tvol vs. Molecular Mass

Viscous Flow of Neutral Oils

Rajbongshi, P., and A. Das, 2009, Estimation of Temperature Stress and Low-Temperature Crack Spacing in Asphalt Pavements. Journal of Transportation Engineering © ASCE, October 2009, 745-752.

Rajbongshi, P., and A. Das, 2008, Thermal Fatigue Considerations in Asphalt Pavement Design. Int. J. Pavement Res. and Technol., 1(4), 129-134.

Stress Build-up: Thermal Fatigue

Stress Build-up: Thermal Fatigue

a. b.

R² = 0.9561

0

0.0005

0.001

0.0015

0.002

0.0025

0 10 20 30

AB

S C

hang

e in

spe

cific

vol

ume

(-15°

C)

Percent Wax from IEC Neutrals

AAM-1

R² = 0.9483

0

0.0005

0.001

0.0015

0.002

0.0025

500 700 900 1100 1300A

BS

Cha

nge

in s

peci

fic v

olum

e (-1

5°C

)

IEC Neutrals Molecular Mass (Da)

AAG-1

AAM-1

Oils Molecular Mass vs. α

*Bahia, H. U., 1991, Low-Temperature Isothermal Physical Hardening of Asphalt Cements. PhD Dissertation.Civil Engineering Department, Penn State University. University Park, PA.

*

Thermal Stress vs. α

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50

100

150

200

250

MN1-2 MN1-3 MN1-4 MN1-5

Nor

mal

ized

Tra

nsve

rse

Cra

ck L

engt

h, (2

009)

(Lft)

Asphalt Source

2008 2009

Thermal Fatigue in Pavement

Thermal Fatigue in Pavement

Pauli, A. T., M. J. Farrar, and P. M. Harnsberger, 2012, Material Property Testing of Asphalt Binders Related to Thermal Cracking in a Comparative Site Pavement Performance Study. In Scarpas, A., N. Kringos, and I. Al-Qadi (Eds.), 2012, 7th RILEM International Conference on Cracking in Pavements Mechanisms, Modeling, Testing, Detection and Prevention Case Histories. Springer, The Netherlands, pp. 233-243.

Thermal Fatigue in Pavement

MN1-2

Thermal Fatigue in Pavement

Properties of the Maltene and Asphalt Phase:

Viscous Flow of Maltenes and Oils and Healing

Entropy Production in Damage-Healing

Viscous flow of maltenes

Viscous flow of asphalt

Viscous flow of asphalt (influence of temperature)

Viscous flow of asphalt (influence of temperature)

Lytton, R. L., C. W. Chen and D. N. Little, 2001, Microdamage Healing in Asphalt and Asphalt Concrete, Volume III: A Micromechanics Fracture and Healing Model for Asphalt Concrete, FHWA-RD-98-143. Federal Highway Administration, U. S. Department of Transportation, McLean, VA.

Flow Properties and Healing

Flow Properties and Healing

Entropy Production in Damage-Healing

Asphalt Microstructure and RAP Blending

Mix Model Mechanism

RAP-Asphalt Flow Properties

RAP-Asphalt Flow Properties

RAP-Asphalt Flow Properties

RAP-Asphalt Mixture Model

RAP-Asphalt Flow Properties

RAP-Asphalt Flow Properties

RAP-Asphalt Flow Properties

RAP-Asphalt Flow Properties

y = -288.05x2 + 36.892x + 87.192R² = 0.9067

0

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0.00 0.20 0.40 0.60

Pha

se A

ngle

Isooctane Asphaltene Mass Fraction

Viscous flow of asphalt

Surface Freezing and Crystallization in n-

ParaffinsA Model for Wax Surface Structuring in Bitumen

Entropy Production in Damage-Healing

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

Paraffin surface freezing “detected” byX-ray reflectivity and grazing incidence diffraction

X.Z. Wu, B.M. Ocko, E.B. Sirota, S.K. Sinha, M. Deutsch, B.H. Cao, M.W. Kim, Surface Tension Measurements of Surface Freezing in Liquid Normal Alkanes, Science, 261 (1993a) 1018-1020.

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

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surfa

ce te

nsio

n, d

yne/

cm

temperature, °C

hexadecanewax-oils highSTasphaltseicosanewax-oils lowSToils (waxless)

Surface tension versus temperature plots for material groups; asphalts, IEC neutral fraction oils and model paraffins.

Wax Surface-Freezing in Complex Media

Pauli, T., W. Grimes. J. Beiswenger and A. J. M. Schmets, 2014, Surface Structuring of Wax in Complex Media.

J. Mater. Civ. Eng., 10, Submitted August 27, 2013; doi:10.1061/(ASCE)MT.1943-5533.0001032.

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

Wax Surface-Freezing in Complex Media

1%

5%

10%

20%

Spin-cast, dried, then image

1%

5%

10%

20%

Wax Surface-Freezing in Complex Media

y = 0.5595x - 0.0142R² = 0.8947

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 2 4 6

Cry

tallin

e M

ater

ial v

ia D

SC

Γ, fitting coefficient

y = 1.1936x + 0.6833R² = 0.9711

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0 2 4 6

Per

cent

Wax

Ext

ract

ed fr

om IE

C N

eutra

ls

Γ, fitting coefficient

Wax Surface-Freezing in Complex Media

Sectorization and Rippling Morphologies in Paraffin

and Polymer Crystal Lamella

Why Bees?: CES, Sectorization, Tilt Angle

Why Bees?: CES, Sectorization, Tilt Angle

Why Bees?: CES, Sectorization, Tilt Angle

Why Bees?: CES, Sectorization, Tilt Angle

Cooling

Assemblage of

crystallites to micro single

crystals

Roughening in the crystal

Artificial Bees: Paraffin in paraffin oil

Paraffin micro-crystals present in different media

asphalt maltenes neutral oils

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0 5 10 15 20 25 30

Hea

ling

Rat

e In

dice

s

Mass % Wax per IEC Neutral

dh/dt

dh2/dt

Healing and Presence of Wax

Force-Flux Coupling

Conclusions

• The oils phase viscosity is driven by molecular weigh.• The maltene (i.e., the oils plus resins) may be considered a

polar associated solution, BUT, apparent molecular weight may be a big player in viscosity.

• The asphalt (maltene plus asphaltenes) is conveniently modeled as a nano-particle suspension. AGAIN, apparent molecular weight considerations may play a significant role in viscous flow.

• Activation energy models of viscosity work well to explain viscosity-temperature relationships of the nano-particle suspension model considered.

• The Oil’s molecular weight correlates with thermal contraction properties of asphalt, thus, thermal fatigue correlates with thermal contraction, ergo, oils molecular weight correlates with , thermal fatigue.

• Asphaltene content strongly contributes to stiffness of RAP mixtures.

Conclusions

• The “LIQUID” (behavior) of asphalt relates to fatigue-healing.

• Surface crystallization (Surface Freezing) of paraffin wax in complex media involves diffusion controlled crystallization. Bees are observed in both thermally and solvent treated materials.

• Crystals develop at a liquid-vapor interface due to lowering of the liquid-vapor surface free energy state relative to a liquid-solid + solid-vapor state.

• Oils and wax concentration are mutually related in terms of molecular weight, both of which relate to healing.

• Force-flux Coupling makes it difficult to pin-point a single compositional contributor to binder mechanical (rheological) behavior.

• IN SHROT: a chemomechanics model of bitumen behavior based in non-equilibrium statistical thermodynamics of asphalt microstructure is proposed to predict damage-