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ACKNOWLEDGMENT This work was sponsored by the American Association of State Highway and Transportation Officials (AASHTO), in cooperation with the Federal Highway Administration, and was conducted in the National Cooperative Highway Research Program (NCHRP), which is administered by the Transportation Research Board (TRB) of the National Academies. COPYRIGHT PERMISSION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FTA, Transit Development Corporation, or AOC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. DISCLAIMER The opinion and conclusions expressed or implied in the report are those of the research agency. They are not necessarily those of the TRB, the National Research Council, AASHTO, or the U.S. Government. This report has not been edited by TRB.
iii CONTENT LIST OF TABLES .................................................................................................................. iv ACKNOWLEDGMENTS ....................................................................................................... v CHAPTER 1. INTRODUCTION AND RESEARCH APPROACH................................... 1 1.1 INTRODUCTION................................................................................................. 1 1.1.1 Problem Statement ................................................................................... 2 1.1.2 Research Objectives ................................................................................. 2 1.2 SCOPE OF STUDY .............................................................................................. 2 1.3 PROFICIENCY SAMPLES USED IN STUDY................................................... 2 CHAPTER 2. RESULTS OF ANALYSIS AND ESTIMATES OF PRECISION.............. 4 2.1 TEST DATA ......................................................................................................... 4 2.2 ANALYSIS OF THE DATA ................................................................................ 4 2.2.1 Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus, AASHTO T245...................................................................... 4 2.2.2 Preparation of Test Specimens of Bituminous Mixtures by Means of California Kneading Compactor, AASHTO T247................................... 6 2.2.3 Standard Practice for Preparation of Test Specimens of Bituminous Mixtures by Means of Gyratory Shear Compactor, ASTM D4013 ......... 8 2.2.4 Preparing and Determining the Density of the Hot-Mix Asphalt (HMA) Specimens by Means of the Superpave Gyratory Compactor, AASHTO T312 ....................................................................................................... 10 CHAPTER 3. COMPARISON OF AVAILABLE PRECISION ESTIMATES............... 13 CHAPTER 4. CONCLUSIONS AND RECOMMENDATIONS....................................... 14 4.1 CONCLUSIONS................................................................................................. 14 4.2 RECOMMENDATIONS .................................................................................... 15 REFERENCES:...................................................................................................................... 16 APPENDIX A: MARSHALL COMPACTION METHOD APPENDIX B: CALIFORNIA KNEADING COMPACTION METHOD APPENDIX C: GYRATORY SHEAR COMPACTION METHOD APPENDIX D: SUPERPAVE GYRATORY COMPACTION METHOD APPENDIX E: PRECISION STATEMENT FOR AASHTO T269
iv LIST OF TABLES Table 1-1- HMD Proficiency Samples Used in Analysis of T269 Precision Estimates ............ 3 Table 1-2- HMG Proficiency Samples Used in Analysis of T269 Precision Estimates............ 3 Table 2-1- Precisions of % Air voids based on Analysis of Air Void Data (Marshall Apparatus).................................................................................................................. 4 Table 2-2- Summary Table for Precisions of Gmm & Gmb (Marshall Apparatus) .................... 5 Table 2-3- Precisions of % Air Voids based on Analysis of Gmm & Gmb Data (Marshall Apparatus).................................................................................................................. 5 Table 2-4- Pooled Precisions for T269 using Precisions of % Air Voids and Precisions of Gmm & Gmb (Marshall Apparatus)............................................................................ 6 Table 2-5- Precisions of % Air Voids based on Analysis of Air Void Data (California Kneading Compactor) ............................................................................................... 6 Table 2-6- Summary Table for Precisions of Gmm & Gmb (California Kneading Compactor) ..................................................................................................................................... 7 Table 2-7- Precisions of % Air Voids based on Analysis of Gmm & Gmb Data (California Kneading Compactor) ............................................................................................... 7 Table 2-8- Pooled Precisions for T269 using Precisions of % Air Voids and Precisions of Gmm & Gmb (California Kneading Compactor) ....................................................... 8 Table 2-9- Precisions of % Air Voids based on Analysis of Air Void Data (Gyratory Shear Compactor)................................................................................................................. 9 Table 2-10- Summary Table for Precisions of Gmm & Gmb (Gyratory Shear Compactor) ..... 9 Table 2-11- Precisions of % Air Voids based on Analysis of Gmm & Gmb Data (Gyratory Shear Compactor)...................................................................................................... 9 Table 2-12- Pooled Precisions for T269 using Precisions of % Air Voids and Precisions of Gmm & Gmb (Gyratory Shear Compactor) ............................................................. 10 Table 2-13- Precisions of % Air Voids based on Analysis of % Air Void Data (Superpave Gyratory Compactor).............................................................................................. 11 Table 2-14- Summary Table for Precisions of Gmm & Gmb (Superpave Gyratory Method) . 12 Table 2-15- Precisions of % Air Voids based on Analysis of Gmm & Gmb Data (Superpave Gyratory Method).................................................................................................... 12 Table 2-16- Pooled Precisions for T269 using Precisions of % Air voids and Precisions of Gmm & Gmb (Superpave Gyratory Method) ........................................................... 12 Table 3-1- Summary of the Available Precision Estimates for T269..................................... 13
v ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 9-26 by the AASHTO Materials Reference Laboratory (AMRL). Special thanks are extended to the laboratories participating in the AMRL Proficiency Sample Programs used in this study. The research reported herein was performed under NCHRP Project 9-26 by the AASHTO Materials Reference Laboratory (AMRL). Dr. Haleh Azari and Mr. Robert Lutz were co- principal investigators on the study. Other AMRL employees, including Mr. Peter Spellerberg and Mr. Ron Holsinger played supporting roles and provided valuable comments in the study.
