Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities (2023)

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Committee on Repurposing Plastics Waste in Infrastructure Consensus and Advisory Studies Division Transportation Research Board Board on Chemical Sciences and Technology Division on Earth and Life Studies Board on Infrastructure and the Constructed Environment Division on Engineering and Physical Sciences Recycled Plastics in Infrastructure Current Practices, Understanding, and Opportunities Consensus Study Report

Transportation Research Board Special Report 347 Subscriber Categories: Transportation, general; policy; materials; economics; environment Transportation Research Board publications are available by ordering individual publications directly from the TRB Business Office, through the Internet at www.TRB.org or nationalacademies.org/trb, or by annual subscription through organizational or individual affiliation with TRB. Affiliates and library subscribers are eligible for substantial discounts. For further information, contact the Transportation Research Board Business Office, 500 Fifth Street, NW, Washington, DC 20001 (telephone 202-334-3213; fax 202-334-2519; or e-mail TRBsales@nas.edu). Copyright 2023 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and National Academies Press and the graphical logos for each are all trademarks of the National Academy of Sciences. All rights reserved. Printed in the United States of America. This publication was reviewed by a group other than the authors according to the procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the National Academy of Medicine. Cover: Photograph from Advanced Drainage Systems. This study was sponsored by the U.S. Department of Transportation and the U.S. Environmental Protection Agency. International Standard Book Number-13: 978-0-309-70726-8 International Standard Book Number-10: 0-309-70726-9 Digital Object Identifier: http://doi.org/10.17226/27172 Library of Congress Control Number: 2023944065

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v COMMITTEE ON REPURPOSING PLASTICS WASTE IN INFRASTRUCTURE David A. Dzombak (NAE) (Chair), Hamerschlag University Professor Emeritus, Carnegie Mellon University Janie Chermak, Professor of Economics, University of New Mexico David Cornell,1 Principal, DD Cornell Associates LLC Jennifer Harper, Research Director, Missouri Department of Transportation Thomas Kazmierowski, Principal and Senior Consultant, T2JK Consulting Emmanuel “Cris” B. Liban, Chief Sustainability Officer, Los Angeles County Metropolitan Transportation Eric C. Macfarlane, First Deputy Commissioner, New York City Department of Design and Construction Debra Reinhart, Pegasus Professor Emerita, University of Central Florida Joseph Robinson, Chief Materials Engineer, Pennsylvania Department of Transportation Delmar Salomon, President, Pavement Preservation Systems LLC Shoshanna Saxe, Associate Professor of Civil and Mineral Engineering, University of Toronto Randy West, Director, National Center for Asphalt Technology, Auburn University Karen L. Wooley (NAS), W.T. Doherty-Welch Chair in Chemistry and University Distinguished Professor, Texas A&M University, College Station Consensus and Advisory Studies Division, Transportation Research Board Staff Monica A. Starnes, Study Director Thomas R. Menzies, Jr., Director Brittany Bishop, Program Officer Timothy Marflak, Program Coordinator Board on Chemical Sciences and Technology, Division on Earth and Life Studies Staff Liana Vaccari, Program Officer 1 David Cornell passed away during completion of the study. NOTE: See Appendix B for the Disclosure of Unavoidable Conflict of Interest.

vi Board on Infrastructure and the Constructed Environment, Division on Engineering and Physical Sciences Staff Cameron Oskvig, Director Brittany Segundo, Program Officer Consultant Sebastian Blanco, Technical writer and editor

vii Dedication We dedicate this report to Mr. David Cornell, who served as a committee member and passed away during this study. Mr. Cornell brought tremen- dous experience in plastics manufacturing and recycling to the committee. He was a pioneer in defining the formulations and manufacturing processes to produce bottle-grade polyethylene terephthalate (PET) and a champion of plastics recycling. After 28 years at Eastman Chemical, he joined the Association of Plastic Recyclers, where he was a technical director for 20 years. He was inducted into the Plastics Hall of Fame in 2018. His perspec- tives were highly valuable, and his dedication to the committee’s work was inspirational to all involved with the study.

ix Reviewers This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manu- script remain confidential to protect the integrity of the deliberative process. We thank the following individuals for their review of this report: Annick Anctil, Michigan State University Frank Bates (NAS/NAE), University of Minnesota, Twin Cities Matthew Eckelman, Northeastern University Jim Frey, Resource Recycling Systems (RRS) Lt. Gen. Henry Hatch (NAE), U.S. Army Chief of Engineers (retired) Mohan Qin, University of Wisconsin–Madison Cristina Serrat, Dow David Wilson, Virginia Department of Transportation Hao Yin, New Mexico Department of Transportation Although the reviewers listed above provided many constructive com- ments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft be- fore its release. The review of this report was overseen by Chris Hen- drickson (NAE), Carnegie Mellon University, and Jerome Hajjar (NAE),

x REVIEWERS Northeastern University. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.

xi Acknowledgments The committee appreciates the support of the U.S. Department of Transpor- tation (USDOT) and the U.S. Environmental Protection Agency (USEPA) for the study and USDOT and USEPA staff for providing background in- formation about their respective research and policy programs related to recycling plastics waste and the use of recycled plastics in transportation and other infrastructure. Monica A. Starnes, Senior Program Officer, Transportation Research Board (TRB), directed the study and assisted the study committee in the preparation of this report under the guidance of Thomas R. Menzies, Jr., Director of Consensus and Advisory Studies, TRB. The following National Academies of Sciences, Engineering, and Medicine staff members also as- sisted the committee in its information gathering and provided other pro- fessional support and insight during committee meetings and deliberations: Brittany Bishop, Program Officer, TRB; Cameron Oskvig, Director, Board on Infrastructure and the Constructed Environment (BICE); Brittany Segundo, Program Officer, BICE; and Liana Vaccari, Program Officer, Board on Chem- ical Sciences and Technology. Timothy Marflak of TRB provided support to the committee in arranging meetings and other logistics. Sebastian Blanco, consultant, assisted with technical editing of the report. Karen Febey, Senior Report Review Officer, TRB, managed the report review process. The committee thanks the following individuals for sharing their knowledge with the committee (see also Appendix C): David Allaway, Oregon Department of Environmental Quality Tony Aloisio, ecologiQ

xii ACKNOWLEDGMENTS Gregg Beckham, National Renewable Energy Laboratory Rick Bohan, Portland Cement Association Greg Bohn, Advanced Drainage Systems, Inc. (ADS) Ashley Buss, Iowa Department of Transportation William Buttlar, University of Missouri–Columbia Halil Ceylan, Iowa State University Fred Chuck, Geosynthetic Materials Association Alexis Davison, Major Road Projects Victoria C. J. Dubois, Dow Daniel Figola, Advanced Drainage Systems, Inc. (ADS) Filippo Giustozzi, Royal Melbourne Institute of Technology Ross Guppy, Austroads John Harvey, University of California, Davis Simon Hesp, Queen’s University Marc Hollahan, Tangent Shawn Johnson, USDOT Alli Kingfisher, Washington State Department of Ecology Reid Lifset, Yale University Jennifer Lynch, National Institute of Standards and Technology (NIST) William Mainwaring, Sicut Enterprises Rachel Meidl, Rice University Ganesh Nagarajan, WM Andrew Peters, Louisiana Tech Michael Pluimer, University of Minnesota Duluth Tom Pyle, California Department of Transportation Cristina Serrat, Dow Nena Shaw, USEPA Thomas Spear, Schrader Co. Scott Taylor, Major Road Projects Victoria Chris Wacinski, Ecologic Materials Corp. Nazimuddin Wasiuddin, Louisiana Tech Patrick Weaver, Solterra Materials Inc. Julie Zaniewski, Dow As part of the information-gathering activities, on September 21, 2022, the committee toured ADS’s recycling facilities in Pandora, Ohio, as well as a materials testing laboratory and pipe production facility in Findlay, Ohio. The committee is grateful for the opportunity to see the operations and learn firsthand how the plastic recycling and pipe manufacturing pro- cesses are carried out. Staff from Rumpke Waste and Recycling, an ADS recycling partner from Ohio, also participated in the tour and provided insightful information from a materials recovery facility perspective. The

ACKNOWLEDGMENTS xiii committee thanks the following individuals who contributed to the tour visit and discussions: Greg Bohn, ADS Andrew Bright, ADS Johnathon Brown, ADS Adam Elsea, ADS Steve Farrow, ADS Daniel Figola, ADS Scott Fredrickson, ADS Ryan McKinnis, ADS Marc Mullholland, ADS Kristen Rinehart, ADS Michael Sanders, ADS Jeff Snyder, Rumpke Waste and Recycling Bill Vanhoose, ADS Randall Weyant, ADS Kash White, ADS The next day, on September 22, the committee held a closed meeting in Westerville, Ohio, at the headquarters of the National Ground Water As- sociation (NGWA). The committee thanks NGWA’s Chief Executive Officer, Terry Morse, for graciously sharing their facilities with the National Acad- emies for the meeting. The committee also appreciates all the coordinating help from Trisha Freeman, NGWA Director of Membership. The committee also expresses appreciation to the authors of the white papers presented in the appendixes of this report, for their work and their discussions with the committee about their papers: Karan Bhuwalka, Massachusetts Institute of Technology (MIT) (Appendix E) Stephanie Bolyard, North Carolina Department of Environmental Quality (Appendix D) Jenna Jambeck, University of Georgia (Appendix F) Randolph Kirchain, MIT (Appendix E) Michael Lepech, Stanford University (Appendix G) Zhiye Li, Stanford University (Appendix G) Elizabeth Moore, MIT (Appendix E) Milena Rangelov, VitalMetrics (Appendix H) Basuhi Ravi, MIT (Appendix E) Paul Rikhter, VitalMetrics (Appendix H) Hasini Siriwardana, VitalMetrics (Appendix H) Sangwon Suh, VitalMetrics (Appendix H)

xiv ACKNOWLEDGMENTS Joshua Kneifel and Kathryn Beers from NIST provided valuable help with identification of several of the white paper authors. The committee is grateful for their assistance. The committee also thanks Gretchen Baier (Dow), Scott Collick (Du- Pont), Thomas Nosker (Rutgers University), and Joel Tickner (University of Massachusetts Lowell) for suggesting several of the experts who presented in open session.

xv Contents PREFACE xxvii ACRONYMS AND ABBREVIATIONS xxix SUMMARY 1 1 INTRODUCTION 9 Study Charge, 10 Study Approach and Scope Decisions, 11 Report Organization, 17 References, 18 2 PLASTICS PROPERTIES, PRODUCTION, AND MARKETS 19 Polymers and Plastics, 20 Processability and Properties, 21 Plastic Types, 24 Plastics Production and Use, 26 Market Drivers, 28 Findings, 29 References, 29 3 MANAGEMENT AND SOURCING OF PLASTICS WASTE 33 Plastics Waste Management in the United States, 34 Plastics Recycling in the United States, 38

xvi CONTENTS Types of Recycled Plastics Processing, 45 History of Recycling in the United States, 51 Recycled Plastics Supply and Demand in the United States, 56 Findings, 60 References, 61 4 LIFE-CYCLE CONSIDERATIONS 65 Life-Cycle Assessment of Recycled Plastics Use in Infrastructure: Benefits and Costs, 66 Framing a Life-Cycle Assessment for Use of Recycled Plastics in Infrastructure: Selected Important Holistic Questions, 70 Findings, 81 References, 82 5 IMPACT OF POLICY AND REGULATION ON THE USE OF PLASTICS WASTE IN INFRASTRUCTURE IN THE UNITED STATES 85 Plastics Recycling Policies and Regulations in the United States, 86 Policies for Increasing Demand for Recycled Plastics, 92 Some State Policies to Promote Plastics Waste Collection and Recycling, 94 Some Industry Initiatives to Promote Plastics Waste Collection and Recycling, 96 Findings, 97 References, 98 6 APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 101 Recycled Plastics in Asphalt Pavements, 102 Recycled Plastics in Subbase of Pavements, 125 Findings, 128 References, 129 7 APPLICATIONS OF RECYCLED PLASTICS IN OTHER INFRASTRUCTURE 133 Products and Applications, 134 Role of Public Agencies and Other Infrastructure Owners, 164 Findings, 165 References, 167

CONTENTS xvii 8 PLASTICS REDESIGN FOR RECYCLING 175 Drivers and Rationale for Next-Generation Plastics and Plastic Products, 177 Considerations for Next-Generation Plastics and Plastic Products in Infrastructure Applications, 178 Diverse Directions for Next-Generation Plastics and Plastic Products, 180 Caveats, Risks, Upstream/Downstream Reality Checks, and Potential Adverse Effects of Next-Generation Plastics, 187 Findings, 188 References, 189 9 MAJOR FINDINGS AND RECOMMENDATIONS 193 Major Findings and Conclusions, 194 Recommendations, 196 References, 200 APPENDIXES A Study Committee Biographical Information 201 B Disclosure of Unavoidable Conflict of Interest 209 C Invited Speakers at Committee Meetings 211 D Utilization of Plastics Waste in Transportation Infrastructure in State Departments of Transportation 215 E Overview of Recycled Plastics Supply and Demand: Identifying the Critical Market Bottlenecks for Closing the Loop 219 F The Use of Plastic Scrap in Transportation Applications in the United States 253 G Durability and Life-Cycle Implications of Repurposing Plastics Waste in Infrastructure: A Case Study 283 H The Life-Cycle Environmental Benefits and Trade-Offs of Plastics Waste Recycling and Reuse in Infrastructure 325 I Glossary 363 J Overview of Plastics by Resin Identification Code (RIC) 367

xix Boxes, Figures, and Tables BOXES 1-1 Statement of Task, 12 1-2 Definitions, 15 3-1 Pyrolysis and Plastics Recycling, 50 4-1 Complicated Versus Complex, 67 4-2 Justice40 Initiative, 68 4-3 An Introduction to eLCA, 69 4-4 Circular Economy, 79 5-1 USEPA 2021 National Recycling Strategy, 87 5-2 A Recycling Model: Germany, 88 5-3 America Recycles Pledge, 97 6-1 Field Trials of Asphalt Mixes with Recycled Plastics in New York City, 113 6-2 Pennsylvania’s Experience with Post-Consumer Plastics in Asphalt, 121 6-3 Missouri’s Experience with Post-Consumer Plastics in Asphalt, 123 7-1 Fiber Composite Decking: A Case Study, 136

xx BOXES, FIGURES, AND TABLES 7-2 Corrugated Pipe Manufactured with Recycled HDPE: A Case Study, 148 7-3 HDPE Noise Wall Panel: A Case Study, 155 8-1 USEPA Green Chemistry and Engineering Programs, 181 8-2 Example of Federal Research and Development: Bio-Optimized Technologies to Keep Thermoplastics Out of Landfills and the Environment (BOTTLE™) Consortium, 184 FIGURES 2-1 Schematic of extrusion blow molding process, 24 2-2 Schematic of injection stretch blow molding process, 24 2-3 Global production of plastics by polymer, 27 2-4 Global annual primary plastics production by consuming sector from 1950 to 2017, 27 3-1 Plastics waste composition in the United States (percent by weight) by material type and resin code, 34 3-2 Historic global plastics waste disposal, 37 3-3 Value streams in a circular economy, 37 3-4 Post-consumer plastics recovered in the United States, 2010-2020, 40 3-5 Access to residential curbside recycling, 42 3-6 Recycling methods currently available, 46 3-7 Schematic of mechanical recycling process and new product development, 48 3-8 Strategies for PET chemical recycling, 49 3-9 Comparison of U.S. plastics waste, recycled plastics by type, and total plastic sales and captive use (2020), 57 3-10 Five-year pricing trend for recyclable container commodities, 58 3-11 Single-use plastic acceptance in U.S. MRFs, 59 4-1 Generic life cycle of infrastructure assets, 66 5-1 Number of state Extended Producer Responsibility (EPR) laws by state, 90 5-2 2019-2020 container redemption rates as related to the price paid per deposit in the United States and Europe, 91 5-3 Percentage of recycled content used in PET bottles in California by the five largest beverage producers in 2020 and 2021, 92

BOXES, FIGURES, AND TABLES xxi 6-1 Cross-sections of flexible (asphalt) pavement, rigid (concrete) pavement, and composite pavement, 102 6-2 Photograph of a core from an asphalt pavement showing surface, intermediate, and base layers, 104 6-3 Photographs of common asphalt pavement distresses: (a) rutting, (b) load-related cracking, (c) environmental (thermal) cracking, and (d) reflection cracking, 105 6-4 Milling of an existing asphalt pavement, a common part of pavement rehabilitation, 106 6-5 Sustainability elements associated with pavement life-cycle states, 111 6-6 Novophalt blending unit used to blend LDPE and other polymers into asphalt binder, 112 6-7 Illustrations of wet and dry processes at an asphalt plant, 115 6-8 Illustrations of the material structure of standard asphalt (no recycled plastic), and plastic-modified asphalt by the dry and wet methods, 116 6-9 U.S. locations of pavement projects containing recycled plastic–modified asphalt mixtures, 120 7-1 Replacement of wooden fender with HDPE structural fender system at the Martin Downs Blvd (SR-714) Bridge over the South Fork of the St. Lucie River in Stuart, Florida, 139 7-2 Sign in Zwolle, the Netherlands, illustrating the cross-section of PlasticRoad panels, 151 7-3 Main materials used in sound barriers in the United States, 153 7-4 Nonwoven geotextile being installed at road construction site, 157 7-5 Photo of a ByFusion block, 162 7-6 BubbleDeck hollow HDPE plastic spheres installed in a floor slab prior to pouring of concrete, 163 8-1 Two distinct strategies for next-generation plastics and plastic products, designed for enhanced recyclability, which may operate divergently or synergistically and may result in unintended consequences or adverse effects, 176 8-2 Chemical upcycling with combination of petrochemically derived plastics and biomass to create new polymers, 187 D-1 Summary of state DOT responses, 216 E-1 U.S. plastics waste generation by source type, 221

xxii BOXES, FIGURES, AND TABLES E-2 Recycled fractions for various plastic types compared to generation volumes, 223 E-3 U.S. plastics waste generation and diversion by source, 224 E-4 MRF processing fees (in US$/tonne) per region, 227 E-5 Locations and reasons for curbside programs shutting down across the country between 2018 and 2023, 227 E-6 Plastic recycling value chain, 229 E-7 Distribution of end-use markets for (a) PET, (b) HDPE, and (c) film packaging, 235 E-8 Percentage of plastics waste collected for recycling domestically and exported outside the United States and Canada, 236 E-9 Comparing demand growth from 2020 to 2030 with recycled supply and disposal quantities, 239 E-10 (a) Prices for food-grade R-PET and virgin PET in the United States (West Coast) from 2018 to 2020. (b) Collection rate of post-consumer PET bottles from 2010 to 2020. (c) The percentage recycled content used in PET bottles in California by the five largest beverage producers in 2020 and 2021, 240 E-11 Left: Prices for natural and pigmented HDPE bales in the United States from 2009 to 2020. Right: Quantity of HDPE generation segmented by end use, 242 E-12 Quantity of films generated and recycled from various end-use applications, 243 F-1 Global annual primary plastics production (in Mt) by material type from 1950 to 2017, 254 F-2 Global annual primary plastics production (in Mt) by consuming sector from 1950 to 2017, 254 F-3 Plastics use (MMT), baseline scenario from OECD, 2019-2060, 256 F-4 Global annual primary plastics waste generation (in Mt) by polymer type from 1950 to 2018, 257 F-5 Global annual primary plastics waste generation (in Mt) by sector from 1950 to 2018, 258 F-6 U.S. annual plastics waste generation from 1960 to 2018 in million tonnes, 258 F-7 Projected U.S. annual plastics waste generation from 2018 to 2060 in million tonnes, 260 F-8 Estimated global recycling, incineration, and discard rates for nonfiber plastics, 260

BOXES, FIGURES, AND TABLES xxiii F-9 U.S. plastics waste management of municipal solid waste from 1960 to 2018 per year, 261 F-10 Plastics waste management as estimated by OECD for the United States in 2019, 262 F-11 Plastics waste landfilled in 2019 by resin type and state, 265 F-12 Total plastics waste landfilled on site in 2019, 265 F-13 Points of plastic leakage for municipal solid waste in the United States, 266 F-14 Plastics waste leakage in the United States, baseline scenario from OECD, 2019-2060, 268 F-15 Production, imports, exports, use, disposal, and leakage of plastics in the United States in 2017, 270 F-16 Density of microplastics (MPs) released from asphalt binder exposed to simulated road driving wear depending on polymer and percentage of plastic in the mix, 272 F-17 Optimum dosages of waste plastic used for asphalt (wet process), 273 G-1 The ASTM International Resin Identification Coding (RIC) system facilitates recycling of plastics, 284 G-2 Production, imports, exports, use, disposal, and leakage of plastics in the United States in 2017, 285 G-3 U.S. flows of PET in million pounds, 286 G-4 (a) Global end use of recycled plastic in 2017 (Technavio 2018). (b) Patent filing stratified by application, polymer type, and before recycling (polymers being recycled) versus after recycling (application area for recycled polymers), 289 G-5 Dosages of plastic used for asphalt, 293 G-6 Photo of a small sample of SFMOMA GFRPs facade panel. (a) The top surface of the panel is covered by a protective gel coat. (b) The bottom surface is covered by polyester matrix resin; woven fiber yarn can be observed from this side, 299 G-7 Process flow diagram and system boundaries of GFRP panel production, 300 G-8 Normalized environmental impact scores associated with the use of recycled plastic pellets (RPPs) in the GFRP panels for various contents and various expected life spans, 302 G-9 Environmental impact scores associated with the use of recycled plastic pellets (RPPs) in the GFRP composite panels at various contents (25%, 50%, and 75% of polymer matrix) and for various expected life spans (40, 60, and 80 years), 303

xxiv BOXES, FIGURES, AND TABLES G-10 Finding durability reduction tolerance of using 75 percent RPP in polymer matrix by projection, comparison to reference case (no RPP used and no life-span increment case), 304 G-11 Roadway cross-section design, 307 G-12 System boundaries considered for modeling the roadway pavement, 307 G-13 System boundaries considered for modeling the mechanical plastic recycling system, 310 G-14 Products usage for referenced case: 1 mile of road using no asphalt binder additives in 50 years, 311 G-15 Environmental impact scores associated with the use of recycled plastic pellets (RPPs) and low-density polyethylene (LDPE) in the production of asphalt pavement according to various contents (2%, 4%, 6%, and 8%) of asphalt binder and various expected life spans, 312 G-16 Finding durability reduction tolerance of using 8 percent RPPs in asphalt binder by projection, compared to (a) reference case (no additive and no life-span increment) and (b) using 8 percent LDPE in asphalt binder and no life-span increment, 313 G-17 Comparison of normalized environmental impact scores between 1 tonne unsaturated polyester and 1 recycled post-consumer PET pellet, 321 G-18 SimaPro network model of GFRP panel using fossil fuel– based polymer in 100 years with expected life span of 60 years, 322 H-1 End-of-life pathways of plastics, 328 H-2 Timeline of the types of relevant literature found on the use of EoL plastics in infrastructure applications, 330 H-3 RAP use and the average percentage of RAP utilization by sector, 332 H-4 Evidence and agreement statements and their relationship to confidence, 361 TABLES 2-1 Resin Identification Code, 25 3-1 Plastics Waste Disposal in the United States, 35 3-2 Differences in Management of Plastics Waste Among Sources, 39

BOXES, FIGURES, AND TABLES xxv 3-3 Post-Industrial (Commercial) Plastics Waste/Scrap Annual Generation Rates in the United States (see Appendix E), 40 3-4 Estimate of Annual Tonnage of Residential Recycling Material Generation in the United States in 2019, 43 3-5 Post-Consumer Plastics Waste Recycling Potential and Challenges by Type, 55 4-1 Percentage (by Weight) of Plastics Recycled by Type in 2018, 75 6-1 Typical Costs (2022) of Raw Materials Used in Asphalt Mixtures, 105 6-2 Summary of Advantages of Wet and Dry Methods for Adding Plastics to Asphalt Mixtures, 115 7-1 Railroad Tie Installations (as Part of Capital Projects as Well as Maintenance) in the United States in 2018, 141 7-2 Available Geosynthetic Products in the United States and Manufactured with Recycled Plastic, 158 8-1 Potential Approaches, Examples, and Desired Outcomes of Designing and Utilizing Recycled Plastics Waste for Infrastructure, 179 D-1 Summary of Allowed Uses of Recycled Plastics in Transportation Infrastructure, 217 D-2 Summary of Concerns by State DOTs Around Approving the Use of Recycled Plastics in Transportation Infrastructure, 218 E-1 Practically Recyclable Residential Waste Generated in the United States by Resin/Product Type, 221 E-2 Commercial Plastics Waste Generation, 222 E-3 Average Costs of Curbside Collection by Collection Type, 225 E-4 Handling Fees in U.S. States That Have Deposit Return Systems, 226 E-5 Cost Estimates for Feedstock Recycling Technologies, 234 F-1 Use of Plastics in the United States in 2019, 256 F-2 Plastics Waste Generation in the United States in 2019, 259 F-3 Plastic in MSW Managed in the United States in 2019, 263 F-4 OECD Data from 2019 on Plastic Leakage from the United States, 267 F-5 Top 10 Items Tallied from Specific Leakage Documenting Projects in the United States, 269

xxvi BOXES, FIGURES, AND TABLES F-6 Potential for Annual Plastic Scrap Utilization in Asphalt, 275 F-7 Potential for Annual Plastic Scrap Utilization in Concrete, 277 G-1 Maintenance and Replacement Schedule in 100 Years, 301 G-2 Characteristics of the Road Pavement Section “California-Dry No Freeze Urban Interstate-HMA-8,000 AADTT-Mr 9,500psi- LDPE0” in Which the Asphalt Surface Layer Is Made Using Asphalt Binder Produced with Different Additive Contents (i.e., 0%, 2%, 4%, 6%, and 8%), 306 G-3 Binder Fatigue Performance and Estimated Service Lives of Different Mixtures, 309 G-4 Rehabilitation Schedule in 50 Years, 309 G-5 Comparison of Potential Environmental Impact Scores Between 1 Tonne Unsaturated Polyester (P) and 1 Recycled Post-Consumer PET Pellet, 321 G-6 Potential Environmental Impact Scores for Producing 1 Tonne of Recycled Plastic Pellets in Victoria, Australia, 323 H-1 Summary of LCA Studies on Asphalt Materials with EoL Plastics, 335 H-2 Summary of LCA Studies on Concrete and Cementitious Composite Materials with EoL Plastics, 337 H-3 Summary of Findings on Feasibility of EoL Plastics in Infrastructure Applications, 348 H-4 Summary of Findings on Sustainability of EoL Plastics in Infrastructure Applications, 348 H-5 Amounts and Types of EoL Plastics Used in Infrastructure, 357 H-6 Availability of Literature, 361

xxvii Preface The current management of plastics waste in the United States results in most of this material being disposed of in landfills, and a portion escapes management and results in pollution of land, water, and air. Less than 10 percent of plastics waste in the United States is recycled. Systems for col- lection and management of plastics waste are organized at the state and regional levels and are highly variable. Public- and private-sector activities in plastics waste management are not well coordinated. Research and de- velopment for capture and processing of plastics waste and use of recycled plastics in consumer products and in infrastructure is still not far advanced after decades of study, albeit at relatively low levels of funding and activity. In House Report 116-452 from 2020, the U.S. Department of Trans- portation (USDOT) was directed to enter into an agreement with the National Academies of Sciences, Engineering, and Medicine (the National Academies) on the use of recycled plastic materials in transportation infra- structure. Likewise, the Save Our Seas Act 2.0 (SOS 2.0) directed USDOT and the U.S. Environmental Protection Agency (USEPA) to enter into an arrangement with the National Academies to conduct a study on the uses of plastics waste in infrastructure. USDOT and USEPA joined together to work with the National Academies to develop the statement of task for the study reported herein. To carry out the study, the National Academies formed a committee of 13 individuals with expertise in infrastructure performance, asphalt pavements, construction engineering, chemical and materials engineer- ing, resource economics, plastics recycling and waste management, plas- tics manufacturing, environmental engineering, life-cycle assessment, and

xxviii PREFACE sustainability. The committee members, from the United States and Canada, brought perspectives from state and city infrastructure owners, academia, and the plastics industry. The committee held 12 open meetings to learn about the state of re- search and the practice of incorporating recycled plastics in transportation and other infrastructure, plastics recycling practices and policies, and ongo- ing efforts to develop new plastics more amenable to recycling. The com- mittee appreciates the time and commitment that expert presenters from USDOT, USEPA, and various other public- and private-sector organizations in the United States, Canada, Australia, and the United Kingdom made to openly share their knowledge. The committee also appreciates the research efforts and analyses carried out by the experts who authored Appendixes D through H in this report. The committee held nine closed meetings to deliberate and draft this report. The findings, conclusions, and recommendations in the report rep- resent the consensus views of the committee. The collegiality and com- mitment of all committee members, the expert guidance by the National Academies’ Study Director Dr. Monica Starnes, and the active involvement of other National Academies staff members noted in the Acknowledgments were critical to the success of the study. David A. Dzombak, Chair Committee on Repurposing Plastics Waste in Infrastructure

xxix Acronyms and Abbreviations AAR Association of American Railroads AASHTO American Association of State Highway and Transportation Officials AREMA American Railway Engineering and Maintenance-of-Way Association ASCE American Society of Civil Engineers CFR Code of Federal Regulations DOT Department of Transportation EBM extrusion blow molding eLCA environmental life-cycle analysis (or assessment) EoL end of life EPR Extended Producer Responsibility EU European Union EVA ethylene-vinyl acetate FDA U.S. Food and Drug Administration FHWA Federal Highway Administration FRA Federal Railroad Administration FRP fiber-reinforced polymer GHG greenhouse gas

xxx ACRONYMS AND ABBREVIATIONS HDPE high-density polyethylene HIPS high-impact polystyrene ISBM injection stretch blow molding LCA life-cycle analysis (or assessment) LCCA life-cycle cost analysis (or assessment) LDPE low-density polyethylene LLDPE linear low-density polyethylene MFI melt flow index MFR melt flow rate MRF materials recovery facility MSW municipal solid waste NCAT National Center for Asphalt Technology NEPA National Environmental Policy Act NIR near infrared NIST National Institute of Standards and Technology NOL No Objection Letter (FDA) NSF National Science Foundation OECD Organisation for Economic Co-operation and Development OSTP Office of Science and Technology Policy PAH polycyclic aromatic hydrocarbon PCR post-consumer recyclable PE polyethylene PET polyethylene terephthalate PETG polyethylene terephthalate glycol PHMSA Pipeline and Hazardous Materials Safety Administration PP polypropylene PS polystyrene PVC polyvinyl chloride R&D research and development RAP reclaimed asphalt pavement RCC residential curbside collection RIC Resin Identification Code RPL recycled plastic lumber RTR recycled tire rubber SEA sulfur extended asphalt

ACRONYMS AND ABBREVIATIONS xxxi THUD Transportation, Housing and Urban Development, and Related Agencies TPE thermoplastic elastomer UP Union Pacific USACE U.S. Army Corps of Engineers USDOD U.S. Department of Defense USDOE U.S. Department of Energy USDOT U.S. Department of Transportation USEPA U.S. Environmental Protection Agency UV ultraviolet VOC volatile organic compound WPC wood–plastic composite