Guidelines for the Selection of Snow and Ice Control Materials to Mitigate Environmental Impacts (2007)

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TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2007 www.TRB.org 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 577 Subject Areas Energy and Environment • Maintenance Guidelines for the Selection of Snow and Ice Control Materials to Mitigate Environmental Impacts LEVELTON CONSULTANTS LIMITED Richmond, BC 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 577 Project 6-16 ISSN 0077-5614 ISBN: 978-0-309-09880-9 Library of Congress Control Number 2007925771 © 2007 Transportation Research Board COPYRIGHT PERMISSION 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. Such approval reflects the Governing Board’s judgment that the program concerned is of national importance and appropriate with respect to both the purposes and resources of the National Research Council. The members of the technical committee selected to monitor this project and to review this report were chosen for recognized scholarly competence and with due consideration for the balance of disciplines appropriate 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 Transportation Officials, or the Federal Highway Administration, U.S. Department of Transportation. Each report is reviewed and accepted for publication by the technical committee according to procedures established and monitored by the Transportation Research Board Executive Committee and the Governing Board of the National Research Council. 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.

CRP STAFF FOR NCHRP REPORT 577 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Christopher J. Hedges, Senior Program Officer Eileen P. Delaney, Director of Publications Hilary Freer, Senior Editor NCHRP PROJECT 6-16 PANEL Field of Maintenance—Area of Snow and Ice Control Daniel P. Johnston, South Dakota DOT, Pierre, SD (Chair) Jeanne Hewitt, New York State DOT, Albany, NY Robert Chenier, Environment Canada, Hull, QC Edward Fink, Colorado DOT, Grand Junction, CO G. Michael Fitch, Virginia DOT, Charlottesville, VA Rod Frederick, U.S. Environmental Protection Agency (Retired) Jeanne Hewitt, New York State DOT, Albany, NY Deborah J. O’Bannon, University of Missouri–Kansas City, Kansas City, MO Leland D. Smithson, Iowa DOT, Ames, IA Paul Pisano, FHWA Liaison Frank N. Lisle, TRB Liaison 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 report herein was performed under NCHRP Project 06-16 by Levelton Consultants, Ltd., in cooperation with Ice and Snow Technologies; Dr. William M. Lewis, Jr.; and Dr. Brian Chollar. The work undertaken by Ice and Snow Technologies, Dr. William M. Lewis, Jr., and Dr. Brian Chollar was under subcontract with Levelton Consultants Ltd. The Principal Investigator for this report was Brent T. Mussato, Levelton Consultants, Ltd. The other authors for this report were Oliver K. Gepraegs, Phil T. Seabrook, John P. Davidson, and Robert S. Char- lton, Levelton Consultants Ltd.; Richard D. Parker and Dale G. Keep, Ice and Snow Technologies; Dr. William M. Lewis, Jr., University of Colorado, Boulder; and Dr. Brian Chollar. The work was con- ducted under the general supervision of Wayne C. Edwards, P.Eng, Principal, Levelton Consultants Ltd.

This report presents guidelines for the selection of snow and ice control materials through an evaluation of their cost, performance, and impacts on the environment and infrastruc- ture. The guidelines should be useful in helping maintenance managers develop a program that will minimize the environmental impacts of snow and ice control without compromis- ing effective maintenance strategies. The Guidelines will help highway agencies fill their dual role of providing safe roadways for the driving public while serving as stewards to protect and enhance the natural environment. Every year, considerable quantities of snow and ice control products are applied to high- ways, and environmental and regulatory agencies have questioned the environmental impact of these products. Transportation agencies are asked to use “environmentally friendly” or less toxic alternatives wherever possible, but there is no commonly accepted guidance for determining which products are acceptable. The traditional use of roadsalt has been prohibited in some locations, leaving highway agencies uncertain about how traffic safety can be maintained in bad weather. For example, Environment Canada has concluded that inorganic chloride roadsalts are harmful to the environment under the Canadian Envi- ronmental Protection Act, thus requiring development and implementation of improved management practices. Studies of the most common chemical alternatives—sodium chloride (salt), magnesium chloride, calcium chloride, calcium magnesium acetate, potassium acetate, and urea—have focused on performance and cost under various weather conditions without evaluating their relative impacts on the environment. Several new chemical preparations, including some that are trademarked, have entered the market as snow and ice control chemicals for use by transportation agencies, but there is limited information about their environmental impacts. There is a need for rational decision-making guidelines to assist DOT maintenance managers in selecting the most appropriate snow and ice control materials for the condi- tions that exist in their jurisdictions. Under NCHRP Project 06-16, a research team led by Levelton Consultants Ltd. con- ducted an extensive review of relevant technical information, then conducted a program of analytical laboratory testing on a wide range of products currently available in the North American market. The results were used to develop three products for the end user: a deci- sion tool for the selection of the most appropriate snow and ice control materials to suit the specific needs of any given highway agency, a purchase specification that can be used by an agency once agency staff have selected materials for use, and a quality assurance monitor- ing program that includes procedures and standard test methods to characterize snow and ice control products before their purchase or use. F O R E W O R D By Christopher J. Hedges Staff Officer Transportation Research Board

There are two major components to this report. Chapters 1 through 11 (a) summarize the review of technical information on the performance and environmental impacts of cur- rently available snow and ice control materials, and (b) present the results of an analytical laboratory testing program designed to address gaps in the current literature and to develop a matrix of properties of 42 chemicals. The second component presents guidelines for the user with three products: a decision tool for the selection of materials, a purchase specifica- tion, and the quality assurance monitoring program. An electronic version of the decision tool and several appendixes to the final report can be downloaded from the TRB website at http://www.trb.org/TRBNet/ProjectDisplay.asp?ProjectID=883.

C O N T E N T S 1 Summary 8 Chapter 1 Introduction 8 1.1 Problem Statement and Research Approach 8 1.2 Scope of Study 10 Chapter 2 Operational and Performance Considerations 10 2.1 Products Used and Properties 10 2.1.1 Chloride Salts 11 2.1.2 Organic Products 13 2.1.3 Sand or Abrasives 13 2.2 Storage 13 2.2.1 Solid Snow and Ice Control Materials 13 2.2.2 Liquid Snow and Ice Control Materials 13 2.2.3 Sand or Abrasives 13 2.3 Handling and Application Methods 13 2.4 Agency Survey—Current and Future Status of Use in the United States and Canada 14 2.4.1 Product Use and Methods of Application 15 2.4.2 Natural Environment Concerns 16 2.4.3 Corrosion Concerns 16 2.4.4 Purchasing Issues 18 2.5 Application Strategies 18 2.5.1 Anti-Icing 19 2.5.2 Deicing 19 2.5.3 Pre-wetting 20 2.5.4 Dry Abrasive/Chemical Mixes 20 2.5.5 Abrasive Use 20 2.5.6 Stockpile Treatment 21 2.5.7 Application Strategy Studies 22 2.6 Materials Loading 22 2.6.1 Product Selection 23 2.6.2 Application Amounts 23 2.6.3 Strategy Selection 25 CHAPTER 3 Impacts to the Natural Environment 25 3.1 Environmental Pathways 25 3.1.1 Soil Transport 27 3.1.2 Air Transport 27 3.1.3 Water Transport 27 3.2 Framework for Protection of Environmental Systems 27 3.2.1 U.S. Regulations 28 3.2.2 Canadian Regulations 29 3.2.3 Others

29 3.3 Components of Concern 30 3.3.1 Ferrocyanides 30 3.3.2 Radioactivity 30 3.4 Aquatic Environments 30 3.4.1 Protection of Aquatic Resources 32 3.4.2 Potential Types of Impairment of Aquatic Resources by Snow and Ice Control Materials 42 3.4.3 Evaluation of Specific Snow and Ice Control Materials 46 3.4.4 Overview of Specific Snow and Ice Control Materials 46 3.4.5 Conclusions 47 3.5 Soils 48 3.5.1 Chloride 48 3.5.2 Sodium 49 3.5.3 Calcium 49 3.5.4 Magnesium 49 3.5.5 Potassium 50 3.5.6 Acetates 50 3.5.7 Organic Products 50 3.5.8 Urea 51 3.5.9 Abrasives 51 3.5.10 Ferrocyanide Products 51 3.5.11 Conclusion 51 3.6 Soil Biotic 51 3.6.1 Chloride-Based Salts 52 3.6.2 Urea and Potassium Acetate 52 3.6.3 Ferrocyanides 53 3.6.4 Conclusion 53 3.7 Vegetation 53 3.7.1 Aerial Deposition 54 3.7.2 Ion Uptake and Accumulation from Soil 54 3.7.3 Osmotic Stress 55 3.7.4 Species Sensitivities 55 3.7.5 Other Factors Affecting Impacts to Vegetation 56 3.7.6 Specific Effects Associated with Select Snow and Ice Control Materials 59 3.7.7 Conclusion 59 3.8 Air Quality 60 3.9 Animals 60 3.9.1 Wildlife 61 3.9.2 Birds 61 3.9.3 Toxic Effects 61 3.9.4 Bioaccumulation of Heavy Metals 62 3.9.5 Conclusions 62 3.10 Human Health and Exposure 63 CHAPTER 4 Impacts to Infrastructure and Vehicles 63 4.1 Concrete and Concrete Infrastructure 64 4.1.1 Corrosion of Concrete-Embedded Reinforcing Steel 68 4.1.2 Effects of Snow and Ice Control Materials on Cement Paste 70 4.1.3 Concrete-Embedded Reinforcing Steel and Concrete Paste Conclusions

71 4.1.4 Atmospheric Corrosion Costs 71 4.1.5 Forms of Corrosion 72 4.1.6 Atmospheric Corrosion of Motor Vehicles, Roadside Infrastructure, and Metal Bridges 73 4.1.7 Motor Vehicle, Roadside Infrastructure, and Bridge Materials 74 4.1.8 Snow and Ice Control Chemicals 74 4.1.9 Corrosion Inhibitors 75 4.1.10 Discussion of Atmospheric Corrosion of Snow and Ice Control Chemicals 76 4.2 Other Impacts to Infrastructure 76 4.2.1 Railway Traffic Control Signaling 77 4.2.2 Power Distribution Lines 79 CHAPTER 5 Analytical Methods Used to Measure Attributes of Snow and Ice Control Materials 79 5.1 Specification Sources 79 5.1.1 Pacific Northwest Snowfighters (PNS) 79 5.1.2 Strategic Highway Research Program (SHRP) 80 5.1.3 American Society for Testing and Materials (ASTM) 80 5.1.4 American Association of State Highway and Transportation Officials (AASHTO) 80 5.2 Physical Attributes 80 5.2.1 Specific Gravity 80 5.2.2 Freezing Point and Eutectic Temperature 80 5.2.3 Gradation 80 5.2.4 Particle Degradation 81 5.2.5 Settleability 81 5.3 Chemical and Environmental Attributes 81 5.3.1 Active Ingredient 82 5.3.2 Metals 83 5.3.3 Total Phosphorus 83 5.3.4 Nitrogen 83 5.3.5 Organic Matter (BOD and COD) 83 5.3.6 pH 84 5.3.7 Cyanide 84 5.3.8 Aquatic Toxicity 85 5.4 Evaluation of Concrete-Related Test Methods 85 5.4.1 SHRP H-205.8, Test Method for Rapid Evaluation of Effects of Deicing Chemicals on Concrete 85 5.4.2 SHRP H-205.9, Test Method for Evaluation of Scaling Effects of Deicing Chemicals on Concrete Surfaces 86 5.4.3 SHRP H-205.12, Test Method for Evaluation of Corrosive Effects of Deicing Chemicals on Steel Reinforcement in Concrete 86 5.4.4 Summary of Concrete-Related Test Methods 87 5.5 Evaluation of Atmospheric Corrosion Testing 87 5.5.1 Immersion Testing 89 5.5.2 Poultice Corrosion Testing 89 5.5.3 Salt-Spray Testing 90 5.5.4 Electrochemical Testing 90 5.5.5 Test Track Testing 90 5.5.6 General Comments Regarding Laboratory Corrosion Tests

92 CHAPTER 6 General Assessment of Information 92 6.1 General Conclusion 92 6.1.1 Natural Receiving Environment 92 6.1.2 Infrastructure Corrosion 93 6.1.3 Other Infrastructure 94 6.2 Draft Material Selection Framework 94 6.2.1 Approach and Assumptions 95 6.2.2 Candidate Product Selection and Matrix of Significant Properties 96 6.2.3 Preliminary Qualification 96 6.2.4 Decision Tool 98 6.2.5 Product Selection 99 6.3 Information Gaps 99 6.3.1 Information Gaps—Natural Environment 101 6.3.2 Information Gaps—Infrastructure 102 6.3.3 Information Gaps—Materials 102 6.4 Revised Work Plan 102 6.4.1 Task 7 (Analytical Testing Program) 106 6.4.2 Task 8 (Matrix of Significant Properties) 106 6.4.3 Task 9 (Purchase Specification) 107 6.4.4 Task 10 (Decision Tool Guidelines) 107 6.4.5 Phase II Reporting 109 CHAPTER 7 Analytical Program Overview 111 CHAPTER 8 Chemical Analysis 111 8.1 Organic Matter (BOD and COD) 112 8.2 Nitrogen 112 8.3 Phosphorus 112 8.4 Cyanide 112 8.5 Heavy Metals 112 8.5.1 Arsenic 115 8.5.2 Cadmium 115 8.5.3 Chromium 116 8.5.4 Copper 116 8.5.5 Lead 117 8.5.6 Mercury 117 8.5.7 Nickel 118 8.5.8 Selenium 118 8.5.9 Silver 119 8.5.10 Zinc 119 8.6 Chemical Analysis Summary 122 CHAPTER 9 Aquatic Toxicity Testing 127 CHAPTER 10 Effects of Snow and Ice Control Materials on Reinforcing Steel Corrosion 127 10.1 Introduction 127 10.2 Background 128 10.3 Laboratory Program 128 10.3.1 Concrete Properties 128 10.3.2 Snow and Ice Control Materials 129 10.3.3 ASTM G 109 Exposure

131 10.3.4 Chloride Diffusion—ASTM C 1556 131 10.4 Results and Discussion 133 10.5 Conclusions and Recommendations 135 CHAPTER 11 Atmospheric Corrosion Testing 135 11.1 Introduction 136 11.2 Technology Overview 136 11.2.1 Electrochemistry 136 11.2.2 LPR 136 11.2.3 Weight Loss 136 11.3 Test Method 137 11.4 Test Program Evaluation 139 11.5 Data Assessment 140 11.5.1 Structural Steel, A36 140 11.5.2 Wrought Aluminum, AA6061-T6 141 11.5.3 Cast Aluminum AA356.2 142 11.5.4 Free Machining Brass, CDA 360 143 11.5.5 Magnesium Alloy, AZ91C-T6 143 11.6 Conclusions 145 11.7 Proposed Testing Program 146 References