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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2013. Methods for Evaluating Fly Ash for Use in Highway Concrete. Washington, DC: The National Academies Press. doi: 10.17226/22483.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2013. Methods for Evaluating Fly Ash for Use in Highway Concrete. Washington, DC: The National Academies Press. doi: 10.17226/22483.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2013. Methods for Evaluating Fly Ash for Use in Highway Concrete. Washington, DC: The National Academies Press. doi: 10.17226/22483.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2013. Methods for Evaluating Fly Ash for Use in Highway Concrete. Washington, DC: The National Academies Press. doi: 10.17226/22483.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2013. Methods for Evaluating Fly Ash for Use in Highway Concrete. Washington, DC: The National Academies Press. doi: 10.17226/22483.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2013. Methods for Evaluating Fly Ash for Use in Highway Concrete. Washington, DC: The National Academies Press. doi: 10.17226/22483.
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N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP REPORT 749 Methods for Evaluating Fly Ash for Use in Highway Concrete Lawrence Sutter Michigan Technological UniversiTy Houghton, MI R. Douglas Hooton UniversiTy of ToronTo Toronto, ON Scott Schlorholtz iowa sTaTe UniversiTy Ames, IA Subscriber Categories Materials • Pavements TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2013 www.TRB.org Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration

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 accelerating 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 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 cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies 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 transportation subject may be drawn; it possesses avenues of communications 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 identified 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 American 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. 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 NCHRP REPORT 749 Project 18-13 ISSN 0077-5614 ISBN 978-0-309-28355-7 Library of Congress Control Number 2013950227 © 2013 National Academy of Sciences. All rights reserved. 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, or Transit Development Corporation 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. NOTICE 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 with the approval of the Governing Board of the National Research Council. The members of the technical panel selected to monitor this project and to review this report were chosen for their special competencies and with regard for appropriate balance. The report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the Governing Board of the National Research Council. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board, the National Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, and the sponsors of 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 the report.

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. C. D. Mote, Jr., is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, on its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. C. D. Mote, Jr., are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Board’s varied activities annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individu- als interested in the development of transportation. www.TRB.org www.national-academies.org

C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 18-13 by the Michigan Tech Trans- portation Institute at Michigan Technological University (MTU). MTU was the contractor for this study, with the Michigan Tech Transportation Institute serving as fiscal administrator. Administrative and tech- nical support was provided by the University Transportation Center (UTC) for Materials in Sustainable Transportation Infrastructure at MTU. Dr. Lawrence Sutter, professor and director of the Michigan Tech Transportation Institute, was the Principal Investigator. The other authors of this report were Dr. R. Douglas Hooton, P.E., Professor of Civil Engineering at the University of Toronto and Co-principal Investigator, and Dr. Scott Schlorholtz, Adjunct Assistant Professor of Civil, Construction and Environmental Engineering at Iowa State Uni- versity and Co-principal investigator. Other contributors to the research were Dr. David Hand, P.E., Professor of Civil and Environmental Engineering at MTU; Dr. Karl Peterson, Assistant Professor of Civil Engineering at the University of Toronto; Melanie Kueber, P.E., Ph.D. student at MTU; Zeyad Ahmed, P.E., Ph.D. student at MTU; Andre de Groot, M.S. student at the University of Toronto; and Benja- min Longmire, B.S. student at MTU. The work was done under the general supervision of Drs. Sutter, Schlorholtz, and Hooton. CRP STAFF FOR NCHRP REPORT 749 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Amir N. Hanna, Senior Program Officer Andréa Parker, Senior Program Assistant Eileen P. Delaney, Director of Publications Natalie Barnes, Senior Editor NCHRP PROJECT 18-13 PANEL Field of Materials and Construction—Area of Concrete Materials Daniel P. Johnston, Pierre, SD (formerly with South Dakota DOT) (Chair) Mostafa Jamshidi, Nebraska DOR, Lincoln, NE Wesley Glass, Kentucky Transportation Cabinet, Frankfort, KY Donald J. Janssen, University of Washington, Seattle, WA Patricia I. Miller, Pennsylvania DOT, Harrisburg, PA Thomas A. Pyle, California DOT, Sacramento, CA Deniz Sandhu, New York State DOT, Albany, NY Gina Ahlstrom, FHWA Liaison Frederick Hejl, TRB Liaison

F O R E W O R D By Amir N. Hanna Staff Officer Transportation Research Board This report presents recommended changes to coal fly ash specifications and test pro- tocols contained in AASHTO Standard Specifications for Transportation Materials and Methods of Sampling and Testing (AASHTO M 295). These changes include modifica- tions to the test methods currently specified for evaluating acceptability of fly ash for use in highway concrete as well as the introduction of new test methods for enhancing such evaluations. The modified specifications and test protocols will guide materials engineers and fly ash producers in evaluating fly ash and assuring that highway concrete is enhanced, and not deleteriously affected, by replacing a portion of the cement in the concrete mixture with fly ash. The information contained in the report will be of immediate interest to state materials engineers and others involved in specifying and evaluating concrete mixtures for use in highway pavements and structures. Fly ash—a byproduct of coal combustion—is widely used as a cementitious and pozzola- nic ingredient in hydraulic cement concrete. The use of coal fly ash in concrete is increasing because it improves some properties of concrete and often results in lower cost of concrete. However, concrete performance is influenced by the chemical and physical compositions of fly ash that are sometimes controlled by regulatory requirements. In addition, current specifications and test methods do not adequately characterize fly ash properties, address the effects of fly ash characteristics on fresh and hardened concrete properties, or consider the alkali content of the cement. Such inadequate characterization may lead to inappropri- ate use of some materials or unwarranted restrictions on the use of suitable materials. Previous research has dealt with the effects of fly ash characteristics on concrete proper- ties but not with the applicability of current specifications to the fly ashes that currently are produced. Also, existing test methods for sampling and testing fly ash used in concrete do not adequately address the characterization of fly ash or the performance aspects of highway concrete. Thus research was needed to develop recommendations for improving fly ash specifications and test protocols to help highway agencies better evaluate and use fly ash that will provide acceptable structural performance and durability. Under NCHRP Project 18-13, “Specifications and Protocols for Acceptance Tests of Fly Ash Used in Highway Concrete,” Michigan Technological University of Houghton, Michi- gan, worked with the objective of recommending potential improvements to the specifica- tions and test protocols used to determine the acceptability of fly ash for use in highway concrete. To accomplish this objective, the researchers reviewed the practices, specifications, and test methods currently used for evaluating fly ash and investigated their suitability for evaluating fly ash intended for use in highway concrete. The investigation included an exten- sive laboratory testing program that covered the types and ranges of fly ash currently used or

expected to be used in the future in the United States; considered the chemical, physical, and mineralogical characteristics of fly ash; and evaluated the properties of a large number of paste, mortar, and concrete specimens incorporating different types and amounts of fly ash. Based on analysis of test results, changes to AASHTO M 295, Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete (included as Attachment A), that provide guidance on the testing and acceptance of fly ash were recommended. The researchers also proposed new tests for (1) determining the foam index for a coal fly ash and portland cement slurry and (2) determining air-entraining admixture adsorption by coal fly ash (both included in Attachment B). In addition, the researchers proposed changes to ASTM D4607 dealing with the determination of coal fly ash iodine number (also included in Attachment B). Attachment C provides elaborations and detail on several aspects of the research; it is not published herein but is available by searching for NCHRP Report 749 on the TRB website (www.trb.org). The recommended new test methods and modifications to existing specifications and test methods would be particularly useful to highway agencies because their use would ensure use of fly ash that will provide the expected performance and durability of highway con- crete. Their adoption as part of the AASHTO Standard Specifications for Transportation Materials and Methods of Sampling and Testing is, therefore, suggested.

C O N T E N T S 1 Summary 5 Chapter 1 Introduction 5 Background 5 Objective 5 Research Approach 5 Report Organization 6 Chapter 2 Literature Review 6 CFA Properties 7 Coal Fly Ash in Concrete 7 Fly Ash Specifications and Tests 7 Survey of CFA Users and Producers 8 Chapter 3 Methodology 8 Overview 9 Materials 9 CFA Sources 9 Portland Cement Sources 9 Air-Entraining Admixtures 9 CFA and Cement Sample Processing 10 Other Materials 10 Characterization of Coal Fly Ash 12 Characterization of Strength Activity 12 Characterization of the Effects of Carbon on Air Entrainment 12 Foam Drainage Test 12 Foam Index Test 15 CFA Iodine Number Test 16 Direct Adsorption Isotherm Test 19 Mortar and Concrete Mixtures to Evaluate Developed Tests 21 Assessment of ASR Mitigation 23 Chapter 4 Findings 23 CFA Characterization Study 23 Chemical Tests 25 Physical Tests 30 X-ray Diffraction, Thermal Analysis, and CFA Mineralogy 30 Summary of Precision Estimates for the Methods 30 Discussion of Characterization Test Results 33 CFA Pozzolanic Reactivity 33 SAI Tests 34 KHI Tests

34 Effect of Carbon on Air Entrainment 36 Correlation among the Tests 40 Correlation with Mortar and Concrete 43 Influence on Air-Void System Parameters 43 Prediction of ASR Mitigation 43 Pyrex Mortar Bar Test (ASTM C441) 44 Concrete Prism Tests 45 Accelerated Mortar Bar Tests 47 Alkali Leaching Test 48 Comparison of ASR Test Results 49 Chapter 5 Conclusions and Suggested Research 49 Conclusions 49 Changes to Chemical Requirements 50 Changes to Physical Requirements 51 Changes to Testing Requirements 51 Suggested Research 52 References 54 Acronyms A-1 Attachment A Summary of Proposed Changes to AASHTO M 295-11, Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete B-1 Attachment B Draft Proposed New Test Methods C-1 Attachment C Details of the Research into Methods for Evaluating Fly Ash Use in Highway Concrete (NCHRP Project 18-13) Note: Many of the photographs, figures, and tables in this report have been converted from color to grayscale for printing. The electronic version of the report (posted on the Web at www.trb.org) retains the color versions.

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TRB’s National Cooperative Highway Research Program (NCHRP) 749: Methods for Evaluating Fly Ash for Use in Highway Concrete presents suggested changes to coal fly ash specifications and test protocols contained in American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Transportation Materials and Methods of Sampling and Testing (AASHTO M 295).

The changes suggested include modifications to the test methods currently specified for evaluating acceptability of fly ash for use in highway concrete as well as the introduction of new test methods for enhancing such evaluations.

Attachment C: Details of the Research into Methods for Evaluating Fly Ash Use in Highway Concrete is only available online.

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