Polymer Modified Asphalt Durability in Pavements

424 Pages·2007·8.52 MB·English

by  Texas Transportation Institute

Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FHWA/TX-07/0-4688-1

4. Title and Subtitle 5. Report Date
POLYMER MODIFIED ASPHALT DURABILITY IN PAVEMENTS November 2006
Published: July 2007

6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.
Won Jun Woo, Edward Ofori-Abebresse, Arif Chowdhury, Jacob Report 0-4688-1
Hilbrich, Zachary Kraus, Amy Epps Martin, and Charles J. Glover

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)
Texas Transportation Institute

The Texas A&M University System 11. Contract or Grant No.
College Station, Texas 77843-3135 Project 0-4688

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered
Texas Department of Transportation Technical Report:
Research and Technology Implementation Office September 2004-August 2006

P. O. Box 5080 14. Sponsoring Agency Code
Austin, Texas 78763-5080

15. Supplementary Notes
Project performed in cooperation with the Texas Department of Transportation and the Federal Highway
Administration.
Project Title: Development of a Long-Term Durability Specification for Modified Asphalt
URL: http://tti.tamu.edu/documents/0-4688-1.pdf

16. Abstract
This project was designed to develop 1) a better quantitative understanding of the relation between
laboratory accelerated binder aging and field aging, 2) a test procedure to measure properties of an aged
binder that relate to failure on the road, and 3) a proposed specification for estimating the relative durability
of binders in the presence of oxidative aging. Tests were conducted on original base and polymer modified
binders, laboratory compacted mixtures, and pavement-aged binders. The project necessarily evolved to a
more comprehensive approach to improving pavement service life.
Methods for significantly improving pavement durability should be implemented: 1) construct pavements
with the lowest possible accessible (interconnected) air voids, consistent with other best construction and
mix design practices; 2) use mix designs that have an inherently low decrease in fatigue life with binder
oxidation, coupled with an appropriately high initial fatigue life; 3) use binders with a minimum stiffness at
the PAV* 16 hour condition (consistent with the appropriate performance grade); 4) use the pavement aging
model for pavement design; 5) use binders that have inherently slow hardening rates kinetics; and 6) use
modifiers that provide the most reduction in the hardening rate. Items 1 and 2 have a dramatic impact on
pavement service life but require additional research for the most effective implementation: 1) determine the
parameters that govern the decline of mixture fatigue life with binder hardening; 2) determine methods to
reliably, and with minimal risk to other construction parameters, achieve very low accessible air voids in
pavements.

17. Key Words 18. Distribution Statement
Asphalt, Modified Asphalt, Asphalt Durability No restrictions. This document is available to the
Specification, Asphalt Concrete Long-Term public through NTIS:
Performance, Asphalt Hardening in Pavements, National Technical Information Service
Asphalt Fatigue Springfield, Virginia 22161
http://www.ntis.gov

19. Security Classif.(of this report) 20. Security Classif.(of this page) 21. No. of Pages 22. Price
Unclassified Unclassified 424
Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

POLYMER MODIFIED ASPHALT DURABILITY IN PAVEMENTS

by

Won Jun Woo
Graduate Research Assistant
Artie McFerrin Department of Chemical Engineering/Texas Transportation Institute

Edward Ofori-Abebresse
Graduate Research Assistant, Texas Transportation Institute

Arif Chowdhury
Research Engineer, Texas Transportation Institute

Jacob Hilbrich
Undergraduate Research Assistant, Artie McFerrin Department of Chemical Engineering

Zachary Kraus
Graduate Research Assistant
Artie McFerrin Department of Chemical Engineering/Texas Transportation Institute

Amy Epps Martin
Associate Research Engineer, Texas Transportation Institute

and

Charles J. Glover
Professor/Research Engineer
Artie McFerrin Department of Chemical Engineering/Texas Transportation Institute

Report 0-4688-1
Project 0-4688
Project Title: Development of a Long-Term Durability Specification for Modified Asphalt

Performed in cooperation with the
Texas Department of Transportation
and the
Federal Highway Administration

November 2006
Published: July 2007

TEXAS TRANSPORTATION INSTITUTE
The Texas A&M University System
College Station, Texas 77843-3135

DISCLAIMER

The contents of this report reflect the views of the authors, who are responsible for the
facts and the accuracy of the data presented herein. The contents do not necessarily reflect the
official view or policies of the Federal Highway Administration (FHWA) and the Texas
Department of Transportation (TxDOT). This report does not constitute a standard,
specification, or regulation, nor is it intended for construction, bidding, or permit purposes. The
Unites States Government and the State of Texas do not endorse products or manufacturers.
Trade or manufacturers’ names appear herein solely because they are considered essential to the
object of this report. The engineers in charge were Charles J. Glover, P.E. (Texas No. 48732)
and Amy Epps Martin, P.E. (Texas No. 91053).
v
ACKNOWLEDGMENTS

This project was conducted for TxDOT, and the authors thank TxDOT and FHWA for
their support in funding this research project. In particular, the guidance and technical assistance
provided by the project director (PD) Darren Hazlett of TxDOT, the project coordinator (PC)
German Claros of the Research and Technology Implementation (RTI) office, and the project
monitoring committee (PMC). Special thanks also go to Lee Gustavus and Rick Canatella of the
Texas Transportation Institute (TTI) for their help in specimen and sample preparation. The
various TxDOT district offices that provided assistance in material and pavement core
procurement are also thanked. Finally, we thank Ben Worrel of the MnRoad Test Site for
providing the MnRoad pavement cores, binder, and hot mix materials, as well as MnRoad data.

vi
TABLE OF CONTENTS
Page

LIST OF FIGURES.....................................................................................................................xiv
LIST OF TABLES.......................................................................................................................xxi
LIST OF ABBREVIATIONS AND SYMBOLS......................................................................xxiii

CHAPTER 1. INTRODUCTION AND BACKGROUND.........................................................1-1
PROBLEM STATEMENT....................................................................................................1-1
BACKGROUND AND SIGNIFICANCE OF WORK..........................................................1-1
A Brief Review of Binder Oxidation and Hardening Kinetics........................................1-2
Binder Oxidation and Embrittlement – Conventional Binders........................................1-4
Binder Oxidation and Embrittlement – Polymer-Modified Binders................................1-6
TxDOT Project 0-4468 – Fatigue Resistance of Rut-Resistant Mixtures......................1-13
SUMMARY OF DURABILITY ISSUES...........................................................................1-14
OUTLINE OF THE REPORT.............................................................................................1-15

CHAPTER 2. DURABILITY EFFECTIVENESS OF SELECTED POLYMER-ASPHALT
SYSTEMS....................................................................................................................................2-1
INTRODUCTION.................................................................................................................2-1
RESEARCH OBJECTIVES..................................................................................................2-1
METHODOLOGY................................................................................................................2-2
Materials..........................................................................................................................2-2
Aging Methods.................................................................................................................2-3
Analytical Measurements.................................................................................................2-3
RESULTS AND DISCUSSION............................................................................................2-4
Asphalt Composition and Changes in Composition with Oxidative Aging....................2-4
Effect of Aging on Ductility and Rheological Properties................................................2-7
Oxidative Hardening Rates............................................................................................2-17
GPC Spectra...................................................................................................................2-22
Effect of Polymer Modifier on Elongational Properties................................................2-26
Some Important Binder Measures Related to Durability...............................................2-32
vii
TABLE OF CONTENTS (CONT.)
Page

SUMMARY.........................................................................................................................2-36

CHAPTER 3. EFFECTIVENESS OF POLYMER MODIFIER AFTER AGING.....................3-1
INTRODUCTION.................................................................................................................3-1
RESEARCH OBJECTIVES..................................................................................................3-2
METHODOLOGY................................................................................................................3-2
Material Preparation.........................................................................................................3-2
Test Methods....................................................................................................................3-3
RESULTS AND DISCUSSION............................................................................................3-3
Effect of Aging on Ductility and Rheological Properties................................................3-3
Effect of Polymer Modifier on Elongational Properties..................................................3-5
Rheological and Elongational Properties of Rejuvenated Heavily Aged PMA..............3-8
CONCLUSION....................................................................................................................3-12

CHAPTER 4. A PRELIMINARY INVESTIGATION OF POLYMER MODIFIED AND
UNMODIFIED ASPHALT USING IMAGING.........................................................................4-1
INTRODUCTION.................................................................................................................4-1
RESEARCH OBJECTIVES..................................................................................................4-2
METHODOLOGY................................................................................................................4-2
Material Preparation.........................................................................................................4-2
Test Methods....................................................................................................................4-2
RESULTS AND DISCUSSION............................................................................................4-3
SUMMARY...........................................................................................................................4-9

CHAPTER 5. TOWARDS AN OXYGEN AND THERMAL TRANSPORT MODEL OF
BINDER OXIDATION IN PAVEMENTS.................................................................................5-1
INTRODUCTION.................................................................................................................5-1
RESEARCH OBJECTIVES..................................................................................................5-3
viii
TABLE OF CONTENTS (CONT.)
Page

METHODOLOGY................................................................................................................5-3
Materials..........................................................................................................................5-4
Pavement Core Properties................................................................................................5-7
Binder Extraction and Recovery......................................................................................5-8
Binder Content.................................................................................................................5-8
Binder Analytical Measurements.....................................................................................5-8
Aging Methods.................................................................................................................5-9
RESULTS AND DISCUSSION..........................................................................................5-10
Texas and Minnesota Aging Rates................................................................................5-10
Model Development of Binder Aging in Pavements.....................................................5-21
MnRoad Pavements.......................................................................................................5-28
Summary of the Pavement Aging Model.......................................................................5-36
Oxidative Aging in Texas Pavements............................................................................5-37
Summary of Binder Aging in Texas Pavements............................................................5-46

CHAPTER 6. ESTIMATION OF POLYMER MODIFIED MIXTURE FATIGUE LIFE
BASED ON THE EFFECTS OF AGING...................................................................................6-1
INTRODUCTION.................................................................................................................6-1
Problem Statement...........................................................................................................6-1
Chapter Objectives...........................................................................................................6-2
Scope of the Chapter........................................................................................................6-2
Chapter Organization.......................................................................................................6-3
RESEARCH METHODOLOGY...........................................................................................6-3
Introduction......................................................................................................................6-3
Experimental Design........................................................................................................6-3
HMAC Specimen Fabrication..........................................................................................6-7
Hypothetical Pavement Structure and Traffic Parameters.............................................6-10
Analytical Measurements...............................................................................................6-11
ix
TABLE OF CONTENTS (CONT.)
Page

Analysis Procedure........................................................................................................6-15
LABORATORY TEST RESULTS AND ANALYSIS.......................................................6-17
Surface Energy Test Results..........................................................................................6-17
CMSE Test Results........................................................................................................6-20
Load Cycles to Crack Initiation (N)..............................................................................6-29
i
Load Cycles to Crack Propagation N ...........................................................................6-31
p
Statistical Analysis of Lab N Results............................................................................6-31
f
Discussion of N Results................................................................................................6-33
f
SUMMARY.........................................................................................................................6-34

CHAPTER 7. THE IMPACT OF MIXTURE VERSUS NEAT-FILM BINDER AGING
ON MIXTURE FATIGUE..........................................................................................................7-1
INTRODUCTION.................................................................................................................7-1
RESEARCH OBJECTIVES..................................................................................................7-2
METHODOLOGY................................................................................................................7-2
Materials..........................................................................................................................7-2
Aging Processes...............................................................................................................7-3
Test Methods....................................................................................................................7-4
RESULTS AND DISCUSSION............................................................................................7-5
Mixture versus Neat-Film Binder Oxidation and Hardening..........................................7-5
Mixture Oxidative Aging and Fatigue Resistance.........................................................7-13
The Impact of Binder Aging on Mixture Fatigue Life..................................................7-16
SUMMARY AND CONCLUSIONS..................................................................................7-21

CHAPTER 8. A PROTOCOL FOR ASSESSING POLYMER MODIFIED ASPHALT
DURABILITY IN PAVEMENT.................................................................................................8-1
BACKGROUND...................................................................................................................8-1
DETERMINE MEASURES OF MODIFIED BINDER PERFORMANCE.........................8-2
x