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Density and Moisture Content Measurements by Nuclear Methods Interim Report NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT 14. DENSITY AND MOISTURE CONTENT MEASUREMENTS BY NUCLEAR METHODS INTERIM REPORT HIGHWAY RESEARCH BOARD NATIONAL ACADEMY OF SCIENCES - NATIONAL RESEARCH COUNCIL HIGHWAY RESEARCH BOARD 1965 Officers DONALD S. BERRY, Chairman J. B. McMORRAN, First Vice Chairman EDWARD G. WETZEL, Second Vice Chairman GRANT MICKLE, Executive Director W. N. CAREY, JR., Deputy Executive Director Executive Committee REX M. WHrrrON, Federal Highway Administrator, Bureau of Public Roads (ex officio) A. E. JOHNSON, Executive Secretary, American Association of State Highway Officials (ex officio) LOUIS JORDAN, Executive Secretary, Division of Engineering and Industrial Research, National Research Council (ex officio) C. D. CURTISS, Special Assistant to the Executive Vice President, American Road Builders' Association (ex officio, Past Chairman 1963) WILBUR S. SMITH, Wilbur Smith and Associates (ex officio, Past Chairman 1964) W. BAUMAN, Managing Director, National Slag Association DONALD S. BERRY, Chairman, Department of Civil Engineering, Northwestern University MASON A. BUTCHER, County Manager, Montgomery County, Md. J. DOUGLAS CARROLL, JR., Executive Director, Tn-State Transportation Committee, New York City HARMER E. DAVIS, Director, Institute of Transportation and Traffic Engineering, University of California DUKE W. DUNBAR, Attorney General of Colorado JOHN T. HOWARD, Head, Department of City and Regional Planning, Massachusetts Institute of Technology PYKE JOHNSON, Retired LOUIS C. LUNDSTROM, Director, General Motors Proving Grounds BURTON W. MARSH, Executive Director, Foundation for Traffic Safety, American Automobile Association OSCAR T. MARZKE, Vice President, Fundamental Research, U. S. Steel Corporation J. B. McMORRAN, Superintendent of Public Works, New York State Department of Public Works CLIFFORD F. RASSWEILER, Retired M. L. SHADBUTRN, State Highway Engineer, Georgia State Highway Department T. E. SHELBURNE, Director of Research, Virginia Department of Highways DAVID H. STEVENS, Chairman, Maine State Highway Commission JOHN H. SWANBERG, Chief Engineer, Minnesota Department of Highways EDWARD G. WETZEL, The Port of New York Authority, New York City C. WOMACK, State Highway Engineer, California Division of Highways B. WOODS, Head, School of Civil Engineering, and Director, Joint Highway Research Project, Purdue University NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Advisory Committee DONALD S. BERRY, Northwestern University, Chairman A. E. JOHNSON, American Association of State Highway Officials LOUIS JORDAN, National Research Council B. McMORRAN, New York State Department of Public Works WILBUR S. SMITH, Wilbur Smith and Associates EDWARD G. WETZEL, The Port of New York Authority REX M. WHITTON, Bureau of Public Roads Advisory Panel on Materials and Construction JOHN H. SWANBERG, Minnesota Department of Highways, Chairman R. L. PEYTON, State Highway Commission of Kansas R. E. BOLLEN, Highway Research Board Section on Specifications, Procedures, and Practices (FY '63 and FY '64 Register) WILLIAM B. DRAKE, Kentucky Department of Highways ALFRED F. FAUL, Iowa State Highway Commission CHARLES R. FOSTER, National Bituminous Concrete Association HERBERT W. HUMPHRES, Washington Department of Highways DONALD R. LAMB, University of Wyoming T. F. McMAHON, Bureau of Public Roads FRANK P. NICHOLS, JR., Virginia Department of Highways GORDON K. RAY, Portland Cement Association GEORGE M. WILLIAMS, Bureau of Public Roads Program Staff W. A. GOODWIN, Program Engineer H. H. BISSELL, Projects Engineer W. HENDERSON, JR., Projects Engineer HERBERT P. ORLAND, Editor M. EARL CAMPBELL, Advisor NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT 1 4 DENSITY AND MOISTURE CONTENT MEASUREMENTS BY NUCLEAR METHODS INTERIM REPORT BY L. F. BALLARD AND R. P. GARDNER, RESEARCH TRIANGLE INSTITUTE DURHAM, NORTH CAROLINA HIGHWAY RESEARCH BOARD OF THE DIVISION OF ENGINEERING AND INDUSTRIAL RESEARCH NATIONAL ACADEMY OF SCIENCES - NATIONAL RESEARCH COUNCIL 1965 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerat- ing growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported an a continuing basis by Highway Planning and Research funds from participating member states of the Association and it receives the full cooperation and support of the Bureau of Public Roads, United States Department of Commerce. The Highway Research Board of the National Academy of Sciences-National Research Council was requested by the Association to administer the research program because of the Board's recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as: it maintains an extensive committee structure from which authorities on any highway transpor- tation subject may be drawn; it possesses avenues of com- munications and cooperation with federal, state, and local governmental agencies, universities, and industry; its rela- tionship to its parent organization, the National Academy of Sciences, a private, nonprofit institution, is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. This report is one of a series of reports issued from a continuing The program is developed on the basis of research needs research program conducted under a three-way agreement entered identified by chief administrators of the highway depart- into in June 1962 by and among the National Academy of Sciences- National Research Council, the American Association of State High- ments and by committees of AASHO. Each year, specific way Officials, and the U. S. Bureau of Public Roads. Individual fiscal areas of research needs to be included in the program are agreements are executed annually by the Academy-Research Council, the Bureau of Public Roads, and participating state highway depart- proposed to the Academy and the Board by the American ments, members of the American Association of State Highway Association of State Highway Officials. Research projects This report was prepared by the contracting research agency. It has to fulfill these needs are defined by the Board, and qualified been reviewed by the appropriate Advisory Panel for clarity, docu- research agencies are selected from those that have sub- mentation, and fulfillment of the contract. It has been accepted by the Highway Research Board and published in the interest of an mitted proposals. Administration and surveillance of re- effectual dissemination of findings and their application in the for- search contracts are responsibilities of the Academy and mulation of policies, procedures, and practices in the subject its Highway Research Board. problem area. The opinions and conclusions expressed or implied in these reports The needs for highway research are many, and the are those of the research agencies that performed the research. They National Cooperative Highway Research Program can are not necessarily those of the Highway Research Board, the Na- tional Academy of Sciences, the Bureau of Public Roads, the Ameri- make significant contributions to the solution of highway can Association of State Highway Officials, nor of the individual transportation problems of mutual concern to many re- states participating in the Program. sponsible groups. The program, however, is intended to NCHRP Project 10-5 FY '64 complement rather than to substitute for or duplicate other NAS-NRC Publication 1213 highway research programs. Library of Congress Catalog Card Number: 65-60076 The application of nuclear principles to the measurement of soil moisture content FOREWORD and density continues to be of interest, and research efforts are being directed to By Staff refining existing techniques and equipment or to develop new techniques and equipment. Although nuclear devices have been in use for several years in com- Highway Research Board paction control of highway materials, acceptance among highway engineers has been limited because of doubts concerning the accuracy of test results. If these doubts can be erased, a materials control technique possessing the distinct advan- tages of being nondestructive and rapidly executed will be available for widespread use in highway construction. These advantages will impart economic benefits in terms of reduced operating costs and ultimate performance of the completed road- way. Toward the objective of erasing the current doubts, this study provides data from an evaluation of the accuracy of the nuclear gauges in comparison with the currently used non-nuclear methods of determining soil density and moisture con- tent. The information in this report will be of particular interest to soil and materials engineers, contractors, and other researchers who have
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