Field and Laboratory Investigation of the Influence of Fine Aggregate Angularity on Rutting of Flexible Pavement A Case study - Khartoum State

ABSTRACT 

The primary purpose of this study is to identify the causes of rutting in highway pavements in the form of channelization particularly on wheel tracks resulting from high traffic repetitions and environmental effects. The rutting reduces the required performance due to poor hot mix asphalt (HMA) components and construction to mention a few. The study focused on the impact of fine aggregate angularity (FAA) to increase Asphalt layer stability. AASHTO testing method (T 304) was applied at the expense of uncompacted void content as a measure to determine the fine aggregate angularity index. Through the selection of samples of fine aggregate natural and crushed used in the production of hot mixt asphalt in Khartoum State by adopting Asphalt Institute requirements as described in Superpave design method, in Relation between Angularity and Traffic volume (ESAL) . This study applied Marshall Design method in the evaluation of properties of asphalt mixture voids, stability and other indicators to assess the results in producing accepted mixture with good performance. The study also included data collection on producing crushed aggregate, quarry sources and suitability for hot mix asphalt within Khartoum state to study the cause of rutting in the Ring road and Elsteen Street as case study in order to link the angularity and texture with the both process of crushing aggregate and various type crushers available. Data analysis has shown the high FAA value increase the stability. For the proper matching between all mixes properties, the mix should not be design to optimize one particular property mixes. Also the finding from this study indicate that regarding the existing HMA in the Ring road the fine aggregate angularity with blended natural and crushed aggregate is suitable for the current ESAL according to Asphalt Institute requirements.

TABLE OF CONTENTS

Dedication I

Abstract-English ii

Abstract- Arabic iii

Acknowledgements iv

List of contents vi

List of Tables vii

List of Figures ix

Abbreviations xi

CHAPTER 1 INTRODUCTION AND LITERTURE REVIEW

1.1 Introduction 1

1.2 Problem Definition 3

1.3 Research Objectives 3

1.4 Literature Review 4

CHAPTER 2 THE INFLUENCE OF FAA IN RUTTING IN HMA

2.1 Introduction 12

2.2 Possible Causes of Rutting 12

2.3 Fine Aggregate Angularity 14

2.4 The Relation between the FAA and Shear Strength 18

2.5 Asphalt Mixture Requirement 19

CHAPTER 3 CRUSHED AGGREGATE PRODUCTION AND TYPE OF CRUSHER PLANTS

3.1 Introduction 22

3.2 Production of Crushed Aggregate 22

3.3 Type of Crusher Plants 23

3.4 Influence of Crushers Type 27

CHAPTER 4 SOURCES OF HOT MIX ASPHALT MATERIAL

4.1 Introduction 28

4.2 Crushed Aggregate Types and Sources 28

4.3 Sources of Natural Fine Aggregate 30

4.4 Sources of Sand in Khartoum 31

4.5 Sources of Mineral Filler 31

4.6 Bitumenious Materials 33

CHAPTER 5 LABORATORY TESTING

5.1 Introduction 34

5.2 Sampling of Fine Aggregates 34

5.3 Classification Testing 34

5.4 Natural Aggregate Tests 35

5.5 The Bitumenous Materials 36

5.6 Mineral Filler 37

5.7 Fine Aggregate angularty Results 37

5.8 Fine Aggregate Gradation 39

5.9 Marshal Tests 40

5.10 Proposed Blending 41

CHAPTER 6 DATA ANALYSIS

6.1 Introduction 43

6.2 The Results Summary 43

6.3 Effect of FAA on HMA Bulk Density 44

6.4 Effect of FAA on HMA Air Voids 45

6.5 Effect of FAA on HMA Void in Mineral Aggregate 45

6.6 Effect of FAA on HMA Void Filled with Asphalt 46

6.7 Effect of FAA on HMA On The Marshall Stability 47

6.8 Effect of FAA on HMA Marshall Flow 48

6.10 Blended Sample 49

CHAPTER 7 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS

7.1 Summery 50

7.2 Conclusions 50

7.3 Recommendations 51

References 52

APPENDIX (A) 55

APPENDIX (B) 70