Identification and Laboratory Assessment of Best Practices to Protect DOT Equipment from the Corrosive Effect of Chemical Deicers WA-RD 796.1 Xianming Shi March 2013 Yongxin Li Scott Jungwirth Yida Fang Nicholas Seeley Emily Jackson WSDOT Research Report Office of Research & Library Services IDENTIFICATION AND LABORATORY ASSESSMENT OF BEST PRACTICES TO PROTECT DOT EQUIPMENT FROM THE CORROSIVE EFFECT OF CHEMICAL DEICERS FINAL REPORT Prepared for Washington State Department of Transportation Xianming Shi Yongxin Li Scott Jungwirth Yida Fang Nicholas Seeley Emily Jackson Western Transportation Institute Montana State University March 31, 2013 1. REPORT NO. 2. GOVERNMENT ACCESSION NO. 3. RECIPIENTS CATALOG NO WA-RD 796.1 4. TITLE AND SUBTITLE 5. REPORT DATE Identification and Laboratory Assessment of Best Practices March 2013 to Protect DOT Equipment from the Corrosive Effect of 6. PERFORMING ORGANIZATION CODE Chemical Deicers 7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO. X. Shi, Y. Li, S. Jungwirth, Y. Fang, N. Seeley, and E. Jackson 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NO. Western Transportation Institute Montana State University 11. CONTRACT OR GRANT NO. Bozeman, MT 59717 GCA 6703 12. CO-SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED Washington State Department of Transportation Final Report 310 Maple Park Ave SE 14. SPONSORING AGENCY CODE Olympia, WA 98504-7372 Research Manager: Kim Willoughby 360.705.7978 15. SUPPLEMENTARY NOTES This study was conducted in cooperation with the U.S. Department of Transportation, Federal Highway Administration. 16. ABSTRACT This study has identified, evaluated and synthesized the best practices that can be implemented to minimize the corrosive effects of chloride deicers on DOT winter application equipment and vehicles. The practices identified include: design improvements, maintenance practices, anti- corrosion coatings, corrosion inhibitors, salt removers, etc. A comprehensive literature search was conducted to gather existing research documents that are relevant to the corrosion of metals by chloride salts, with a focus on corrosion under neutral pH conditions and under ambient temperature and pressure. A nationwide survey was conducted of stakeholder groups, in order to capture the current knowledge in: estimating the deicer corrosion costs to vehicles and equipment, defining the chloride deicer corrosion problem and identifying best practices or products for managing the problem. 17. KEY WORDS 18. DISTRIBUTION STATEMENT Chemical deicers, corrosion, equipment 19. SECURITY CLASSIF. (of this report) 20. SECURITY CLASSIF. (of this page) 21. NO. OF PAGES 22. PRICE None None 215 2 Acknowledgements The research reported herein was financially supported by the Washington State Department of Transportation (WSDOT) as well as the Research & Innovative Technology Administration (RITA) at the U.S. Department of Transportation (USDOT) through Alaska University Transportation Center (AUTC) and Western Transportation Institute (WTI). Montana State University was the contractor for this study and Xianming Shi, Ph.D., P.E. was the principal investigator. The authors are indebted to the AUTC project manager Billy Connor, WSDOT project manager Kim Willoughby, Monty Mills, Greg Hansen, and other technical panel members for their continued support throughout this project. We thank all the professionals who participated in the survey or provided products for testing. Part of the laboratory investigation (related to multi-electrode array sensors) undertaken by the SwRI team led by Dr. Hui Yu was under a subcontract with Montana State University. Disclaimer The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Washington State Department of Transportation (WSDOT) or the Federal Highway Administration. This report does not constitute a standard, specification or regulation. 3 Table of Contents Acknowledgements ................................................................................................................... 3 Table of Contents ...................................................................................................................... 4 List of Figures ........................................................................................................................... 5 List of Tables ............................................................................................................................ 8 Abstract ................................................................................................................................... 10 Implementation Recommendations .................................................................................... 12 CHAPTER 1 - INTRODUCTION .......................................................................................... 15 1.1. Problem Statement ....................................................................................................... 15 1.2. Study Objective ............................................................................................................ 17 CHAPTER 2 – METHODLOGY ........................................................................................... 18 2.1. Literature Review......................................................................................................... 18 2.2. Survey of Transportation Professionals ....................................................................... 18 2.3. Laboratory Investigation .............................................................................................. 19 2.4. Cost-Benefit Analysis .................................................................................................. 27 CHAPTER 3 – RESULTS AND DISCUSSION .................................................................... 28 3.1. Findings from the Published Literature ....................................................................... 28 3.2. Findings from the Survey............................................................................................. 30 3. 3. Findings from the Preliminary Lab Investigation ....................................................... 36 3.4. MAS Assessing Metallic Corrosion under Deicer Environments ............................... 47 3. 5. Findings from the Site Visit ........................................................................................ 72 3.6. Cost-Benefit Analysis of Mitigating Deicer Corrosion to DOT Equipment ............... 84 CHAPTER 4 - CONCLUSIONS ............................................................................................ 88 4.1. Conclusions .................................................................................................................. 88 4.2. Implementation Recommendations ............................................................................. 91 APPENDICES ......................................................................................................................... A Appendix A: Literature Review ............................................................................................ A-2 Appendix B: Survey of the Current Practices ..................................................................... A-88 4 List of Figures Figure 1. SEM evidence of selective attack of grain boundary (left) and Mg2Al3 precipitates (right) on Al specimens exposed to field chloride-based deicers [6] ......................................................................................................................... 16 Figure 2. MAS sensor (a) schematic representation and (b) close-up (cross-section) picture. ................................................................................................................. 22 Figure 3. Photographic illustration of the MAS sensors, separated by groups, before environmental exposure ....................................................................................... 23 Figure 4. Photographic illustration of sensor setup in the environmental chamber ................ 24 Figure 5. Photographic illustration of the cyclic corrosion chamber (Humid Stage) and control program ................................................................................................... 25 Figure 6. Photographic illustration of the cyclic corrosion chamber (Humid Stage) and MMA data acquisition system ............................................................................. 25 Figure 7. Photographic illustration of sensors during the exposure cycle (Humid Stage) ..... 26 Figure 8. Photographic illustration of sensors during the exposure cycle (Salt Application Stage) ............................................................................................... 26 Figure 9. Equivalent circuit used for fitting impedance spectra. ............................................ 37 Figure 10. EIS Nyquist diagrams for coupons soaked in ZRust Bullet coating solution for 20 minutes, and then waiting for 24 hours for the coatings to cure. After that, the coupon was soaked two weeks in a 3% MgCl2 solution. The black points are test data and blue points are simulation data. ...................................... 39 Figure 11. EIS Nyquist diagrams for coupons soaked in Krown inhibitor solution for 10 minutes. After that, the coupon was soaked two weeks in a 3% MgCl2 solution. The black points are test data