etd-tamu-2005C-CVEN-Gatchal

115 Pages·2005·1.38 MB·English

CHARACTERIZATION OF AGGREGATE RESISTANCE TO DEGRADATION
IN STONE MATRIX ASPHALT MIXTURES

A Thesis
by
DENNIS GATCHALIAN

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE

December 2005

Major Subject: Civil Engineering
CHARACTERIZATION OF AGGREGATE RESISTANCE TO DEGRADATION
IN STONE MATRIX ASPHALT MIXTURES

A Thesis
by
DENNIS GATCHALIAN

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE

Approved by:

Chair of Committee, Eyad Masad
Committee Members, Dallas Little
Ibrahim Karaman
Head of Department, David Rosowsky

December 2005

Major Subject: Civil Engineering
iii
ABSTRACT

Characterization of Aggregate Resistance to Degradation in
Stone Matrix Asphalt Mixtures. (December 2005)
Dennis Gatchalian, B.S., Washington State University
Chair of Advisory Committee: Dr. Eyad Masad

Stone matrix asphalt (SMA) mixtures rely on stone-on-stone contacts among
particles to resist applied forces and permanent deformation. Aggregates in SMA should
resist degradation (fracture and abrasion) under high stresses at the contact points. This
study utilizes conventional techniques as well as advanced imaging techniques to
evaluate aggregate characteristics and their resistance to degradation. Aggregates from
different sources and types with various shape characteristics were used in this study.
The Micro-Deval test was used to measure aggregate resistance to abrasion. The
aggregate imaging system (AIMS) was then used to examine the changes in aggregate
characteristics caused by abrasion forces in the Micro-Deval.
The resistance of aggregates to degradation in SMA was evaluated through the
analysis of aggregate gradation before and after compaction using conventional
mechanical sieve analysis and nondestructive X-ray computed tomography (CT). The
findings of this study led to the development of an approach for the evaluation of
aggregate resistance to degradation in SMA. This approach measures aggregate
degradation in terms of abrasion, breakage, and loss of texture.
iv
DEDICATION

This thesis is dedicated to my father and mother, Donald and Cynthia Gatchalian.
They have supported me through all facets of my life, especially during my graduate
studies. The thesis is also dedicated to my sister Denille and brother Dustin. Thank you
all for the love, support, and endless encouragement you have given me.
v
ACKNOWLEDGMENTS

Most importantly, I would like to thank Dr. Eyad Masad for giving me the
opportunity to pursue my graduate studies here at Texas A&M University. He has
provided endless encouragement and insight into civil materials as he assisted me
through my time in graduate school and at Washington State University. His passion for
research and encouraging others to learn has greatly influenced my motivation to be a
hard worker and obtain a well-rounded education. I would also like to thank Dr. Dallas
Little for his invaluable insight into civil materials through his coursework and endless
work experience. Thanks are also due to Dr. Ibrahim Karaman for serving as a
committee member and for his review of this thesis.
I would also like to thank the International Center for Aggregates Research
(ICAR) for the funding they provided during the completion of my graduate studies here
at Texas A&M University. Thanks to Mr. Arif Chowdhury and Mr. Rick Canatella for
their continuous help in the asphalt laboratory when I had any questions or concerns.
Thanks also go to Dr. Richard Ketcham and his associates at the high-resolution X-Ray
computed tomography facility at The University of Texas at Austin.
I also express my many thanks to those who helped with the progression of this
research. Thanks to Jay Jenkins, Daniel Gibson, Steven Swindell, and Jonathan Howson
for their help in the laboratory. Last but not least, I would like to thank Mr. Corey
Zollinger and Ms. Edith Arambula for being mentors and assisting me during my time
here at Texas A&M.
vi
TABLE OF CONTENTS
Page

ABSTRACT..................................................................................................................iii
DEDICATION...............................................................................................................iv
ACKNOWLEDGMENTS...............................................................................................v
TABLE OF CONTENTS...............................................................................................vi
LIST OF TABLES.......................................................................................................viii
LIST OF FIGURES.......................................................................................................ix
CHAPTER

I INTRODUCTION...........................................................................................1
Problem Statement.....................................................................................1
Objectives of the Study..............................................................................3
Report Organization...................................................................................4
II BACKGROUND ............................................................................................6
Description of SMA...................................................................................6
Aggregate Requirements in Stone Matrix Asphalt......................................7
Measurements of Aggregate Structure in SMA..........................................9
Methods for Characterization of Aggregates for
SMA Mixtures.........................................................................................15
Summary.................................................................................................23

III EXPERIMENTAL DESIGN.........................................................................25
Introduction.............................................................................................25
Materials and Mixture Design..................................................................25
Resistance to Abrasion Using the Micro-Deval
Test and Imaging Techniques...................................................................36
Aggregate Degradation Due to Compaction.............................................39
Aggregate Degradation Due to Repeated
Dynamic Loading....................................................................................44
Summary.................................................................................................45
vii
CHAPTER Page

IV RESULTS AND DATA ANALYSIS............................................................46
Introduction.............................................................................................46
Aggregate Degradation Due to
Micro-Deval Abrasion Test......................................................................46
Aggregate Degradation Due to Compaction.............................................50
Aggregate Degradation Due to Repeated
Dynamic Loading....................................................................................62
Analysis of Results and Discussion..........................................................63
Approach for the Analysis of Aggregate
Breakage and Abrasion............................................................................67
V CONCLUSIONS AND RECOMMENDATIONS.........................................70

Future Research.......................................................................................71

REFERENCES.............................................................................................................73

APPENDIX A1.............................................................................................................77

APPENDIX A2.............................................................................................................88

APPENDIX A3.............................................................................................................92

APPENDIX A4.............................................................................................................93

APPENDIX A5...........................................................................................................101

VITA..........................................................................................................................105
viii
LIST OF TABLES

TABLE Page

2.1 Coarse Aggregate Quality Requirements....................................................8
3.1 SMA Mixture Specification for SGC.......................................................26

3.2 Proposed Aggregates Used in the Study...................................................27
3.3 SMA Gradation for River Gravel, Granite, Limestone 1,
Limestone 2, and Traprock.......................................................................29

3.4 SMA Gradation for Crushed Glacial Gravel.............................................29
3.5 Summary of Specimens Prepared.............................................................35
3.6 Mix Design Results..................................................................................35
4.1 Results for Degradation of Coarse Aggregate
via Micro-Deval Abrasion........................................................................47
4.2 CEI Results of Five Aggregates...............................................................58
ix
LIST OF FIGURES

FIGURE Page

2.1 Influence of Compaction on Change in Gradation....................................13

2.2 Influence of L.A. Abrasion Value on Aggregate Breakdown....................14

2.3 Influence of F&E Content on Aggregate Breakdown................................15

2.4 Aggregate Imaging System (AIMS).........................................................19

2.5 Correlation of Manual and AIMS Method for Measurement of
Shape Using Two Indices (a) Sphericity and (b) Shape Factor..................20

3.1 Mixture Design Gradations......................................................................30

3.2 Determination of Optimum Asphalt Content for Traprock........................33

3.3 Example of Trimmed Specimen for Flow Number
Test (Glacial Gravel)................................................................................35

3.4 Macro Used for AIMS Results.................................................................38

3.5 X-Ray Image of Limestone 1 at 250 Gyrations with
Circles Highlighting Areas with Crushed Particles...................................42

4.1 Results of AIMS Analysis for
(a) Angularity (b) Sphericity (c) Texture..................................................49

4.2 Sieve Analysis Results for Glacial Gravel................................................51

4.3 Sieve Analysis Results for Traprock........................................................52

4.4 Sieve Analysis Results for Limestone 1...................................................53

4.5 Sieve Analysis Results for Limestone 2...................................................54

4.6 Sieve Analysis Results for Granite...........................................................55

4.7 Sieve Analysis Results for Uncrushed River Gravel.................................55

4.8 Percent Change in 9.5 mm and 4.75 mm Sieves Using Sieve Analysis.....57
x
FIGURE Page

4.9 Recorded Shear Stress for Mixtures from the SGC...................................59

4.10 Results of Change in Gradation Using X-Ray CT Imaging.......................61

4.11 Percent Change in 9.5 mm and 4.75 mm
Sieves for the Flow Number Test.............................................................63

4.12 The Relationship between Change in Aggregate
Gradation and Micro-Deval Loss.............................................................69