NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT 1 38 INSTRUMENTATION FOR MEASUREMENT OF MOISTURE LITERATURE REVIEW AND RECOMMENDED RESEARCH HIGHWAY RESEARCH BOARD NATIONAL RESEARCH COUNCIL NATIONAL ACADEMY OF SCIENCES -NATIONAL ACADEMY OF ENGINEERING HIGHWAY RESEARCH BOARD 1973 Officers WILLIAM L. GARRISON, Chairman JAY W. BROWN, First Vice Chairman MILTON PIKARSKY, Second Vice Chairman W. N. CAREY, JR., Executive Director Executive Committee HENRIK E. STAFSETH, Executive Director, American Association of State Highway Officials (ex officio) RALPH R. BARTELSMEYER, Federal Highway Administrator, U.S. Department of Transportation (ex officio) FRANK C. HERRINGER, Urban Mass Transportation Administrator, U.S. Department of Transportation (ex officio) ERNST WEBER, Chairman, Division of Engineering, National Research Council (ex officio) CHARLES E. SHUMATE, Executive Director-Chief Engineer, Colorado Department of Highways (ex officio, Past Chairman 1971) ALAN M. VOORHEES, President, Alan M. Voorhees and Associates (ex officio, Past Chairman 1972) HENDRIK W. BODE, Professor of Systems Engineering, Harvard University JAY W. BROWN, Director of Road Operations, Florida Department of Transportation W. J. BURMEISTER, Executive Director, Wisconsin Asphalt Pavement Association DOUGLAS B. FUGATE, Commissioner, Virginia Department of Highways WILLIAM L. GARRISON, Professor of Environmental Engineering, University of Pittsburgh ROGER H. GILMAN, Director of Planning and Development, The Port Authority of New York and New Jersey NEIL V. HAKALA, President, Esso Research and Engineering Company ROBERT N. HUNTER, Chief Engineer, Missouri State Highway Commission GEORGE KRAMBLES, Operating Manager, Chicago Transit Authority SCHEFFER LANG, Office of the President, Association of American Railroads SAUNDERS MAC LANE, Department of Mathematics, The University of Chicago HAROLD L. MICHAEL, School of Civil Engineering, Purdue University GRANT MICKLE, President, Highway Users Federation for Safety and Mobility JOHN T. MIDDLETON, Consultant JAMES A. MOE, Director, California Department of Public Works ELLIOTT W. MONTROLL, Professor of Physics, University of Rochester MILTON PIKARSKY, Commissioner of Public Works, Chicago DAVID H. STEVENS, Chairman, Maine Department of Transportation R. STOKES, General Manager, San Francisco Bay Area Rapid Transit District ROBERT N. YOUNG, Executive Director, Regional Planning Council, Baltimore, Maryland NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Advisory Committee WILLIAM L. GARRISON, University of Pittsburgh (Chairman) JAY W. BROWN, Florida Department of Transportation MILTON PIKARSKY, City of Chicago HENRIK E. STAFSETH, American Association of State Highway Officials RALPH R. BARTELSMEYER, U.S. Department of Transportation ERNST WEBER, National Research Council CHARLES E. SHUMATE, Colorado Dpartment of Highways ALAN M. VOORHEES, Alan M. Voorhees and Associates W. N. CAREY, JR., Highway Research Board General Field of Soils and Geology Area of Instrumentation and Testing Advisory Panel E 21-1 GEORGE W. McALPIN, New York Department of Transportation (Chairman) PAGE FISHER, Geotechnical Engineering JACK L. MICKLE, Iowa State University JAMES P. SALE, U.S. Waterways Experiment Station THOMAS H. THORNBURN, University of Illinois ELDON J. YODER, Purdue University RICHARD A. McCOMB, Federal Highway Administration JOHN W. GUINNEE, Highway Research Board Program Staff K. W. HENDERSON, JR., Program Director LOUIS M. MACGREGOR, Administrative Engineer HARRY A. SMITH, Projects Engineer JOHN E. BURKE, Projects Engineer DAVID K. WITHEFORD, Projects Engineer GEORGE E. FRANGOS, Projects Engineer HERBERT P. ORLAND, Editor ROBERT J. REILLY, Projects Engineer ROSEMARY M. MALONEY, Editor NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT 138 INSTRUMENTATION FOR MEASUREMENT OF MOISTURE LITERATURE REVIEW AND RECOMMENDED RESEARCH L. F. BALLARD RESEARCH TRIANGLE INSTITUTE RESEARCH TRIANGLE PARK NORTH CAROLINA RESEARCH SPONSORED BY THE AMERICAN ASSOCIATION OF STATE HIGHWAY OFFICIALS IN COOPERATION WITH THE FEDERAL HIGHWAY ADMINISTRATION AREAS OF INTEREST MATERIALS AND CONSTRUCTION SOILS, GEOLOGY, AND FOUNDATIONS HIGHWAY RESEARCH BOARD DIVISION OF ENGINEERING NATIONAL RESEARCH COUNCIL NATIONAL ACADEMY OF SCIENCES -NATIONAL ACADEMY OF ENGINEERING 1973 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP Report 138 Systematic, well-designed research provides the most ef- Project 21-1 FY '70 fective approach to the solution of many problems facing ISBN 0-309-02023-9 highway administrators and engineers. Often, highway L. C. Catalog Card No. 72-9486 problems are of local interest and can best be studied by highway departments individually or in cooperation with Price $4.00 their state universities and others. However, the accelerat- ing growth of highway transportation develops increasingly This report is one of a series of reports issued from a continuing research program conducted under a three-way agreement entered complex problems of wide interest to highway authorities. into in June 1962 by and among the National Academy of Sciences- These problems are best studied through a coordinated National Research Council, the American Association of State High- program of cooperative research. way Officials, and the Federal Highway Administration. Individual fiscal agreements are executed annually by the Academy-Research In recognition of these needs, the highway administrators Council, the Federal Highway Administration, and participating -state highway departments, members of the American Association of the American Association of State Highway Officials of State Highway Officials. initiated in 1962 an objective national highway research The study reported herein was undertaken under the aegis of the program employing modern scientific techniques. This National Academy of Sciences—National Research Council. The program is supported on a continuing basis by funds from National Cooperative Highway Research Program, under which this study was made, is conducted by the Highway Research Board participating member states of the Association and it re- with the express approval of the Governing Board of the NRC. ceives the full cooperation and support of the Federal Such approval indicated that the Board considered that the prob- lems studied in this program are of national significance; that solu- Highway Administration, United States Department of tion of the problems requires scientific or technical competence, Transportation. and that the resources of NRC are particularly suitable to the con- duct of these studies. The institutional responsibilities of the NRC The Highway Research Board of the National Academy are discharged in the following manner: each specific problem, be- of Sciences-National Research Council was requested by fore it is accepted for study in the Program, is approved as appro- the Association to administer the research program because priate for the NRC by the Program advisory committee and the Chairman of the Division of Engineering of the National Research of the Board's recognized objectivity and understanding of Council. modern research practices. The Board is uniquely suited The specific work to be performed in each problem area is defined for this purpose as: it maintains an extensive committee by an advisory panel that then selects a research agency to do the work, monitors the work, and reviews the final reports. Members structure from which authorities on any highway transpor- of the advisory panels are appointed by the Chairman of the Divi- tation subject may be drawn; it possesses avenues of com- sion of Engineering of the National Research Council. They are se- munications and cooperation with federal, state, and local lected for their individual scholarly competence and judgment, with due consideration for the balance and breadth of disciplines. governmental agencies, universities, and industry; its rela- Responsibility for the definition of this research project and for the tionship to its parent organization, the National Academy publication of this report rests with the advisory panel. However, of Sciences, a private, nonprofit institution, is an insurance the opinions and conclusion expressed or implied are those of the research agency that performed the research, and are not necessarily of objectivity; it maintains a full-time research correlation those of the Highway Research Board, the National Research Coun- staff of specialists in highway transportation matters to cil, the Federal Highway Administration, the American Association bring the findings of research directly to those who are in of State Highway Officials, nor the individual states participating in the Program. a position to use them. Although reports in this category are not submitted for approval to The program is developed on the basis of research needs the Academy membership nor to the Council, each report is re- viewed and processed according to procedures established and identified by chief administrators of the highway depart- monitored by the Academy's Report Review Committee. Such ments and by committees of AASHO. Each year, specific reviews are intended to determine, inter alia, whether the major areas of research needs to be included in the program are questions and relevant points of view have been addressed, and whether the reported findings, conclusions and recommendations proposed to the Academy and the Board by the American arose from the available data and information. Distribution of the Association of State Highway Officials.