Precision Estimates of AASHTO T148: Measuring Length of Drilled Concrete Cores (2010)

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Web-Only Document 165: Precision Estimates of AASHTO T148: Measuring Length of Drilled Concrete Cores National Cooperative Highway Research Program Haleh Azari National Institute of Standards and Technology Gaithersburg, MD Contractor’s Final Task Report for NCHRP Project 9-26A Submitted September 2010 NCHRP

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.

iii CONTENTS   LIST OF TABLES ..................................................................................................................................... V  LIST OF FIGURES .................................................................................................................................. VI  ACKNOWLEDGEMENTS ................................................................................................................... VII  ABSTRACT ……………………………………………………………………………………… VIII  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 EXECUTION OF THE ROUND ROBIN .............................................. 2  2.1  Test Specimens ........................................................................................................................ 2  2.2  Test Apparatus ......................................................................................................................... 2  2.3  Participating Laboratories ........................................................................................................ 3  2.4  Specimens’ Delivery ................................................................................................................ 3  2.5  Round Robin Study Instructions .............................................................................................. 3  CHAPTER 3- ROUND ROBIN TEST RESULTS AND ANALYSIS .................................................... 4  3.1  Test Data .................................................................................................................................. 4  3.2  Method of Analysis .................................................................................................................. 4  3.3  Analysis of Results ................................................................................................................... 4  3.4  Test of Statistical Significance ................................................................................................. 6  3.5  Precision Estimates .................................................................................................................. 8  CHAPTER 4- CONCLUSIONS AND RECOMMENDATIONS ......................................................... 10 

iv 4.1  Conclusions ............................................................................................................................ 10  4.2  Recommendations .................................................................................................................. 10  REFERENCES. ........................................................................................................................................ 11  APPENDIX A- INSTRUCTIONS AND DATASHEET FOR AASHTO T148 ROUND ROBIN STUDY ........................................................................................................................... 12  APPENDIX B- LENGTH OF DRILLED CONCRETE CORES AND COMPUTED ASTM E691 STATISTICS .................................................................................................................. 15  APPENDIX C- PRECISION STATEMENT FOR AASHTO T148 ..................................................... 20 

v LIST OF TABLES Table 2-1- Sample ID and dimensions of the LTPP drilled concrete cores ........................................... 2  Table 3-1- Summary of statistics of concrete core length measurements (mm) .................................... 6  Table 3-2- Results of F-test on comparison of within-laboratory variability of length measurements for 1 % level of significance ..................................................................................................... 7  Table 3-3- Results of F-test on comparison of between-laboratory variability of length measurements for 1 % level of significance ............................................................................ 8  Table 3-4- Precision estimates for measurement of drilled concrete cores based on AASHTO T148 9 

vi LIST OF FIGURES Figure 2-1- A 3-point caliper core measuring apparatus (courtesy of ASTM C 174 [3]) ..................... 3  Figure 3-1- Median length values (mm) and their corresponding error bands .................................... 5 

vii ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 9-26A by the AASHTO Materials Reference Laboratory (AMRL). Dr. Haleh Azari was the principal investigator on the study. Mr. Mohamed Tarawallie, the Research Technician, provided help by carrying the concrete cores to the participating laboratories and collecting the length measurement data. Mr. Boran Altun, the Research Engineer, assisted with the preparation of the report. Mr. Jean-Claude de-Sugny, the research assistant, helped with the reviewing the report. The author would like to thank Dr. Jussara Ramadan from FHWA for providing the drilled concrete cores for the study. The author wishes to acknowledge the laboratories that participated in this round robin study. Their willingness to volunteer their time and conduct the length measurements at no cost to the study is most appreciated. The laboratories include: State Department of Transportation Laboratories: Pennsylvania Department of Transportation, Harrisburg, Pennsylvania New Jersey Department of Transportation, Trenton, New Jersey Delaware Department of Transportation, Dover, Delaware Maryland Department of Transportation, Hanover, MD North Carolina Department of Transportation, Raleigh, NC Virginia Department of Transportation, Richmond, VA Other Participating Laboratories: Craig Testing Laboratories, Inc., Mays Landing, New Jersey ATC Associates, Burlington, New Jersey Specialized Engineering, Ijamsville, MD McKinney and Company, Ashland, VA Summit Engineering, Hillsborough, NC