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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 INFORMATION 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 opinions and conclusions expressed or implied in this report are those of the researchers who performed the research. They are not necessarily those of the Transportation Research Board, the National Research Council, or the program sponsors. The information contained in this document was taken directly from the submission of the author(s). This material has not been edited by TRB.
CONTENTS LIST OF TABLES .................................................................................................................................... IV LIST OF FIGURES ................................................................................................................................... V ACKNOWLEDGMENTS ........................................................................................................................ VI ABSTRACT ............................................................................................................................................. VII CHAPTER 1. INTRODUCTION AND RESEARCH APPROACH ...................................................... 1 1.1. Background............................................................................................................................. 1 1.2. Problem Statement ................................................................................................................. 1 1.3. Research Objectives ............................................................................................................... 1 1.4. Scope of Study ........................................................................................................................ 1 CHAPTER 2. DESIGN AND CONDUCT OF THE ILS ......................................................................... 3 2.1. Materials Selection ................................................................................................................. 3 2.2. Preliminary Study of AASHTO T180 .................................................................................. 4 2.3. Participating Laboratories .................................................................................................... 7 2.4. Interlaboratory Sample Preparation and Shipping ............................................................ 7 2.5. Interlaboratory Study Instructions ...................................................................................... 7 CHAPTER 3. INTERLABORATORY TEST RESULTS AND ANALYSIS ........................................ 8 3.1. Test Data ................................................................................................................................. 8 3.2. Method of Analysis ................................................................................................................. 9 3.3. Precision Estimates ................................................................................................................ 9 3.4. Tests for Significance ........................................................................................................... 12 3.4.1. Maximum Dry Density ........................................................................................... 12 3.4.2. Optimum Moisture Content ................................................................................... 13 3.5. Precision Estimates based on the ILS data ........................................................................ 15
ii CHAPTER 4. ANALYSIS OF PROFICIENCY SAMPLE RESULTS ............................................... 16 4.1. Proficiency Sample Data...................................................................................................... 16 4.2. Description of Samples ........................................................................................................ 16 4.3. Testing Instructions ............................................................................................................. 17 4.4. Description of Equipment/Apparatus ................................................................................ 17 4.5. PSP Data ............................................................................................................................... 17 4.6. Statistical Data Summary .................................................................................................... 17 4.7. Precision Estimates based on the PSP data ....................................................................... 18 CHAPTER 5. PRECISION STATEMENT FOR AASHTO T180 ....................................................... 20 5.1. Comparison of the ILS and PSP Precisions ....................................................................... 20 5.2. Proposed Precision Estimates for AASHTO T180 ............................................................ 21 CHAPTER 6. CONCLUSIONS AND RECOMMENDATIONS ......................................................... 22 6.1. Summary ............................................................................................................................... 22 6.2. Conclusions ........................................................................................................................... 22 6.3. Recommendations ................................................................................................................ 23 REFERENCES .......................................................................................................................................... 24 APPENDIX A. INSTRUCTIONS AND DATA SHEET FOR INTERLABORATORY STUDY ..... 25 Testing of fine graded blends ......................................................................................................... 26 Testing of coarse graded blends .................................................................................................... 26 Calculation and Report .................................................................................................................. 27 APPENDIX B. MAXIMUM DENSITY AND OPTIMUM MOISTURE CONTENT OF ILS SAMPLES AND COMPUTED ASTM E691 STATISTICS ................................................................. 29 APPENDIX C. INSTRUCTIONS FOR TESTING SOIL CLASSIFICATION AND COMPACTION OF PROFICIENCY SAMPLES .............................................................................................................. 34 APPENDIX D. MAXIMUM DENSITY AND MOISTURE CONTENT OF PROFICIENCY
iii SAMPLES .................................................................................................................................................. 37 APPENDIX E. PRECISION STATEMENT FOR AASHTO T180 ..................................................... 44
iv LIST OF TABLES Table 2-1. Gradation of ILS fine and coarse blends and Grading E and A of AASHTO M147 .......... 4 Table 2-2. Sources and classifications of ILS soil-aggregate blends according to AASHTO M145 .... 4 Table 2-3. Specific gravities (Gsb) of the soil-aggregate components and blends ................................. 5 Table 2-4. Optimum moisture content and maximum density values from the preliminary study .... 6 Table 3-1. Summary of Statistics of maximum dry density (lb/cu. ft.) from ILS ................................ 12 Table 3-2. Summary of Statistics of optimum moisture content (% ) from ILS .................................. 12 Table 3-3. t-values on comparison of the average maximum dry densities of the blends in the ILS 13 Table 3-4. F-value on compar ison of var iability of maximum density of the blends in the ILS ........ 13 Table 3-5. t-values on comparison of average optimum moisture content of the blends in ILS ........ 14 Table 3-6. F-values on comparison of var iability of optimum moisture content of the blends in ILS .................................................................................................................................................. 14 Table 3-7. Precision estimates of maximum density and optimum moisture content from ILS ........ 15 Table 4-1. Sources and classifications of PSP soil blends according to AASHTO M 147 .................. 16 Table 4-2. Summary of Statistics of maximum dry density (lb/cu. ft.) from PSP ............................... 18 Table 4-3. Summary of Statistics of optimum moisture content (% ) from PSP ................................. 18 Table 4-4. Precision estimates of maximum density and optimum moisture content from PSP data .................................................................................................................................................. 19 Table 5-1. Summary of Statistics for compar ison of maximum dry density (lb/cu. ft.) and optimum moisture content (% ) of PSP and ILS samples .................................................................... 21 Table 5-2. Repeatability and reproducibility standard deviations of maximum dry density and optimum moisture content of sandy clay (PSP) and sand and gravel (ILS) mater ials ..... 21
v LIST OF FIGURES Figure 2-1. Compaction curves and 100% saturation line of samples in the preliminary study ......... 6 Figure 3-1. Maximum density values (lb/cu ft) and their corresponding er ror bands ......................... 8 Figure 3-2. Optimum Moisture Contents (% ) and their cor responding er ror bands .......................... 9 Figure 3-3. h and k consistency statistics of maximum density from ILS ............................................ 10 Figure 3-4. h and k consistency statistics of optimum moisture content from ILS ............................. 11
