Falling Weight Deflectometer Usage (2008)

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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway ad ministrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments indi- vidually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation devel- ops 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 and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full coopera- tion and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Research Council was requested by the Association to administer the research program because of the Board’s recognized objectiv- ity 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 transportation subject may be drawn; it possesses avenues of communication and cooperation with federal, state, and local governmental agencies, universities, and industry; its relationship to the National Research Council 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. The program is developed on the basis of research needs iden- tified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the Ameri- can Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement rather than to substitute for or duplicate other highway research programs. NOTE: The Transportation Research Board of the National Academies, the National Research Council, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, and the individual states participating in the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of this report. nchrp sYnThesis 381 Project 20-5 (Topic 38-15) ISSN 0547-5570 ISBN 978-0-309-09810-6 Library of Congress Control No. 2008906007 © 2008 Transportation Research Board copYriGhT perMission Authors herein are responsible for the authenticity of their manuscripts 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. Per- mission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMSCA, FTA, or Transit Development Corporation endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this docu- ment for educational and not-for-profit uses will give appropriate ac- knowledgment of the source of any development or reproduced material. For other uses of the material, request permission from CRP. noTice The project that is the subject of this report was a part of the National Cooperative Highway Research Program conducted by the Transpor- tation Research Board with the approval of the Governing Board of the National Research Council. Such approval reflects the Governing Board’s judgment that the program concerned is of national importance and appro- priate with respect to both the purposes and resources of the National Research Council. The members of the technical committee selected to monitor this proj- ect and to review this report were chosen for recognized scholarly compe- tence and with due consideration for the balance of disciplines appropri- ate to the project. The opinions and conclusions expressed or implied are those of the research agency that performed the research, and, while they have been accepted as appropriate by the technical committee, they are not necessarily those of the Transportation Research Board, the National Research Council, the American Association of State Highway and Transpor- tation Officials, or the Federal Highway Administration of the U.S. Depart- ment of Transportation. Each report is reviewed and accepted for publication by the techni- cal committee according to procedures established and monitored by the Transportation Research Board Executive Committee and the Governing Board of the National Research Council. Published reports of the naTionaL cooperaTiVe hiGhWaY research proGraM are available from: Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet at: http://www.national-academies.org/trb/bookstore Printed in the United States of America