:t€ SIiNiTiIiIESIS F1H t f U U L1 TRANSPORTATION RESEARCH BOARD EXECUTIVE COMMITTEE 1991 Officers Chairman C. MICHAEL WALTON, Bess Harris Jones Centennial Professor of Natural Resource Policy Studies and Chairman, Civil Engineering Department, University of Texas at Austin Vice Chairman WILLIAM W. MILLAR, Executive Director, Port of Allegheny County Executive Director THOMAS B. DEEN, Transportation Research Board Members JAMES B. BUSBY IV, Federal Aviation Administrator, US. Department of Transportation (ex officio) GILBERT E. CARMICHAEL, Federal Railroad Administrator, U.S. Department of Transportation (ex officio) BRIAN W. CLYMER, Urban Mass Transportation Administrator, US. Department of Transportation (ex officio) JERRY R. CURRY, National Highway Traffic Safety Administrator, U.S. Department of Transportation (ex officio) TRAVIS P. DUNGAN, Research & Special Programs Administrator, US. Department of Transportation (ex officio) FRANCIS B. FRANCOIS, Executive Director, American Association of State Highway and Transportation Officials (ex officio) JOHN GRAY, President, National Asphalt Pavement Association (ex officio) THOMAS H. HANNA, President and Chief Executive Officer, Motor Vehicle Manufacturers Association of the United States. Inc. (ex officio) HENRY J. HATCH, Chief of Engineers and Commander, U.S. Army Corps of Engineers (ex officio) THOMAS D. LARSON, Federal Highway Administrator, US. Department of Transportation (ex officio) GEORGE H. WAY, JR., Vice President for Research and Test Department, Association of American Railroads (ex officio) ROBERT J. AARONSON, President, Air Transport Association of America JAMES M. BEGGS, Chairman, Spacehab, Inc. J. RON BRJNSON, President and Chief Executive Officer, Board of Commissioners of,The Port of New Orleans L. GARY BYRD, Consulting Engineer, Alexandria, Virginia - A. RAY CHAMBERLAIN, Executive Director, Colorado Department of Highways L. STANLEY CRANE, Consultant, Boynton Beach, Florida RANDY DOI, Director, IVHS Systems, Motorola Incorporated EARL DOVE, President, Earl Dove Company LOUIS J. GAMBACCINI, General Manager, Southeastern Pennsylvania Transportation Authority (past chairman, 1989) THOMAS J. HARRELSON, Secretary, North Carolina Department of Transportation KERMIT H. JUSTICE, Secretary of Transportation, State of Delaware LESTER P. LAMM, President, Highway Users Federation DENMAN K. McNEAR, Vice Chairman, Rio Grande Industries ADOLF D. MAY, JR., Professor and Vice-Chair, University of California Institute of Transportation Studies WAYNE MURI, Chief Engineer, Missouri Highway & Transportation Department (past chairman, 1990) ARNOLD W. OLIVER, Engineer-Director, Texas State Department of Highways and Public Transportation DELLA M. ROY, Professor of Materials Science, Pennsylvania State University JOSEPH M. SUSSMAN, Director, Center for Transportation Studies, Massachusetts Institute of Technology JOHN R. TABB, Director, Chief Administrative Officer, Mississippi State Highway Department FRANKLIN E. WHITE, Commissioner, New York State Department of Transportation JULIAN WOLPERT, Henry G. Bryant Professor of Geography, Public Affairs and Urban Planning, Woodrow Wilson School of Public and International Affairs, Princeton University NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Transportation Research Board Executive Committee Subcommittee for NCHRP C. MICHAEL WALTON, University of Texas at Austin (Chairman) WILLIAM W. MILLAR, Port Authority ofAllegheny County FRANCIS B. FRANCOIS, American Association of State Highway and WAYNE MURI, Missouri Highway & Transportation Department Transportation Officials THOMAS B. DEEN, Transportation Research Board THOMAS D. LARSON, US. Department of Transportation L. GARY BYRD, Consulting Engineer, Alexandria, Va. Program Staff Field of Special Projects ROBERT J. REILLY, Director, Cooperative Research Programs Project Committee SP 20-5 LOUIS M. MACGREGOR, Program Officer VERDI ADAM, Gulf Engineers & Consultants DANIEL W. DEARASAUGH, JR., Senior Program Officer ROBERT N. BOTHMAN, Oregon Dept. of Transportation IAN M. FRIEDLAND, Senior Program Officer JACK FREIDENRICH, New Jersey Dept. of Transportation CRAWFORD F. JENCKS, Senior Program Officer RONALD E. HEINZ, Federal Highway Administration KENNETH S. OPIELA, Senior Program Officer JOHN J. HENRY, Pennsylvania Transportation Institute DAN A. ROSEN, Senior Program Officer BRYANT MATHER, USAE Waterways Experiment Station HELEN MACK; Editor THOMAS H. MAY, Pennsylvania Dept. of Transportation EDWARD A. MUELLER, Morales and Shumer Engineers, Inc. TRB Stafffor. NCHRP Project 20-5 EARL SHIRLEY, California Dept. of Transportation JON UNDERWOOD, Texas Dept. of Highways and Public Transportation ROBERT E. SKINNER, JR., Director for Special Projects THOMAS WILLETF, Federal Highway. Administration HERBERT A. PENNOCK, Special Projects Engineer RICHARD A. McCOMB, Federal Highway Administration (Liaison) JUDITH KLEIN, Editor ROBERT E. SPICHER, Transportation Research Board (Liaison) CHERYL CURTIS, Secretary NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM *169 SYNTHESIS OF HIGHWAY PRACTICE REMOVING CONCRETE FROM BRIDGES DAVID G. MANNING Georgetown, OntarIo Canada Topic Panel JAMES E. BARNHART, Ohio Department of Transportation DENNIS CARLSON, New Jersey Department of Transportation BILL S. HANSHEW, West Virginia Department of Highways (Retired) CHARLES KLINE, Pennsylvania Department of Transportation FRANK N. LISLE, Transportation Research Board ROBERT H. MORECOCK, Virginia Department of Transportation GEORGE P. ROMACK, Federal Highway Administration RESEARCH SPONSORED BY THE AMERICAN I ASSOCIATION OF STATE HIGHWAY AND I TRANSPORTATION OFFICIALS IN COOPERATION I WITH THE FEDERAL HIGHWAY ADMINISTRATIOJ TRANSPORTATION RESEARCH BOARD NATIONAL RESEARCH COUNCIL WASHINGTON, D.C. JUNE 1991 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP SYNTHESIS 169 Systematic, well-designed research provides the most effective Project 20-5 FY 1988 (Topic 20-07) approach to the solution of many problems facing highway ad- ISSN 0547-5570 ministrators and engineers. Often, highway problems are of local ISBN 0-309-04918-0 interest and can best be studied by highway departments individ- Library of Congress Catalog Card No. 90-72084 ually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation Price $8.00 develops increasingly complex problems of wide interest to high- way authorities. These problems are best studied through a coor- Subject Areas dinated program of cooperative research. Structures Design and Performance In recognition of these needs, the highway administrators of Construction the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research Mode Highway Transportation 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 re- NOTICE search program because of the Board's recognized objectivity and understanding of modern research practices. The Board is The project that is the subject of this report was a part of the National Cooperative Highway Research Program conducted by the Transportation Research Board uniquely suited for this purpose as: it maintains an extensive with the approval of the Governing Board of the National Research Council. Such committee structure from which authorities on any highway approval reflects the Governing Board's judgment that the program concerned is of national importance and appropriate with respect to both the purposes and transportation subject may be drawn; it possesses avenues of resources of the National Research Council. communications and cooperation with federal, state, and local The members of the technical committee selected to monitor this project and to governmental agencies, universities, and industry; its relation- review this report were chosen for recognized scholarly competence and with due consideration for the balance of disciplines appropriate to the project. The opinions ship to the National Research Council is an insurance of objectiv- and conclusions expressed or implied are those of the research agency that per- ity; it maintains a full-time research correlation staff of specialists formed the research, and, while they have been accepted as appropriate by the in highway transportation matters to bring the findings of re- technical committee, they are not necessarily those of the Transportation Research Board, the National Research Council, the American Association of State Highway search directly to those who are in a position to use them. and Transportation Officials, or the Federal Highway Administration of the U.S. The program is developed on the basis of research needs identi- Department of Transportation. fled by chief administrators of the highway and transportation Each report is reviewed and accepted for publication by the technical committee according to procedures established and monitored by the Transportation Research departments and by committees of AASHTO. Each year, specific Board Executive Committee and the Governing Board of the National Research areas of research needs to be included in the program are pro- Council. The National Research Council was established