National Academies Press: OpenBook

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

Chapter: Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States

« Previous: Appendix E: Overview of Recycled Plastics Supply and Demand: Identifying the Critical Market Bottlenecks for Closing the Loop
Page 253
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 253
Page 254
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 254
Page 255
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 255
Page 256
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 256
Page 257
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 257
Page 258
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 258
Page 259
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 259
Page 260
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 260
Page 261
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 261
Page 262
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 262
Page 263
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 263
Page 264
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 264
Page 265
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 265
Page 266
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 266
Page 267
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 267
Page 268
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 268
Page 269
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 269
Page 270
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 270
Page 271
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 271
Page 272
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 272
Page 273
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 273
Page 274
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 274
Page 275
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 275
Page 276
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 276
Page 277
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 277
Page 278
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 278
Page 279
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 279
Page 280
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 280
Page 281
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 281
Page 282
Suggested Citation:"Appendix F: The Use of Plastic Scrap in Transportation Applications in the United States." National Academies of Sciences, Engineering, and Medicine. 2023. Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities. Washington, DC: The National Academies Press. doi: 10.17226/27172.
×
Page 282

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

253 Appendix F The Use of Plastic Scrap in Transportation Applications in the United States Jenna Jambeck University of Georgia With contribution from: Jenny Liu Missouri University of Science and Technology PLASTIC PRODUCTION AND USE Global plastics production in 2017 was estimated at 438 million metric tons (MMT) (348 MMT of polymer resins, 62 MMT of polymer fibers, and 27 MMT of additives) (Geyer 2020). Resins alone in 2020 were estimated at 367 MMT (Plastics Europe 2021). Total cumulative primary plastics production between 1950 and 2017 was estimated as 9.2 billion tonnes, which means half of all plastic ever made by humankind was produced in 13 years (Geyer 2020). The highest proportion of polymer produced for use is polyethylene (both low density and high density combined) and polypro- pylene (PP) (see Figure F-1). The year 2020 was the first time that global production dropped or plateaued for resins since the recession, with 368 MMT produced in 2019 and 367 MMT produced in 2020 (these quanti- ties do not include the production of recycled plastics). European plastics production dropped from 64.4 to 56 MMT from 2017 through 2020, not including recycled plastics (Plastics Europe 2021).

254 RECYCLED PLASTICS IN INFRASTRUCTURE Plastics are extremely useful, which is one reason why production across market sectors (see Figure F-2) has grown so sharply since being recorded in 1950. Plastics are also an inexpensive material produced as a re- sult of refining oil or natural gas extraction followed by cracking, processes FIGURE F-1 Global annual primary plastics production (in Mt) by material type from 1950 to 2017. NOTE: Mt = MMT = million metric tons. SOURCE: Geyer 2020. FIGURE F-2 Global annual primary plastics production (in Mt) by consuming sec- tor from 1950 to 2017. NOTE: Mt = MMT = million metric tons. SOURCE: Geyer 2020.

APPENDIX F 255 that are needed for fuels and specialty chemicals. For example, ethene, an olefin monomer created from natural gas or refining oil, is used to make specialty chemicals like ethanol and ethylene glycol. However, with a finite demand for specialty chemicals, excess ethene can be polymerized to create polyethylene and, beyond the creation of ethylene glycol, polyesters can be created. Since 1950, the global market trend has been to use plastics pri- marily for packaging. In the most recent data available, packaging accounts for 40.5 percent of the use in 2020 (Plastics Europe 2021). Nineteen percent of plastic resins were produced in North America Free Trade Agreement countries, which is about 70 MMT of resins (Plas- tics Europe 2021). In 2021, the National Academies of Sciences, Engi- neering, and Medicine estimated from available data that a total of 41.1 MMT of plastic resins was produced in North America in 2020, excluding polyethylene (PET) (NASEM 2021). The PET Resin Association reports 2.8 MMT of PET production in North America, and no specific year is noted (Heller et al. 2020; PET Resin Association 2015). The largest quan- tities produced were linear low-density polyethylene (LLDPE) and high- density polyethylene (HDPE), at 10.4 MMT each (NASEM 2021). The National Academies also found that plastic production trends in North America over the past two decades have varied for different plastic resins. LLDPE steadily increased in domestic production over the past 20 years. For polyvinyl chloride (PVC), other than a dip in domestic production in 2008 and the following few years (likely due to a period of recession), production remained consistent over the past 10 years. Around the same time period as the dip in production (2008), domestic sales decreased, but exports increased, keeping production relatively consistent. The total supply of polystyrene (PS) has had an overall decreasing trend since 2005, with a consistent decrease over the past 10 years. Most of the supply is used domestically, with exports of PS being consistently relatively low (NASEM 2021). The Organisation for Economic Co-operation and Development (OECD) has made estimates of plastic use in the United States that are higher than data found by the National Academies (which did not in- clude PET, a significantly used polymer): 84.31 MMT was estimated to be used in the United States in 2019, second only to China (94 MMT), then growing to 166 MMT by 2060 (see Figure F-3). The categories of use are shown in Table F-1, with packaging leading the use at 32 percent followed by other (not categorized) uses at 16 percent and then building and construction and other transportation applications (outside of tires) both at 12 percent.

256 RECYCLED PLASTICS IN INFRASTRUCTURE FIGURE F-3 Plastics use (MMT), baseline scenario from OECD, 2019-2060. NOTE: Data from OECD 2022. TABLE F-1 Use of Plastics in the United States in 2019 Use (2019) MMT Percentage (%) Packaging 27.16 32 Other 13.44 16 Building and construction 10.14 12 Transportation (other) 10.12 12 Consumer and institutional products 9.09 11 Textile sector—clothing 5.48 6.5 Electrical/electronics 3.42 4.1 Textile sector—other 2.96 3.5 Transportation (tires) 1.65 2.0 Industrial machinery 0.61 0.7 Marine coatings 0.12 0.1 Road marking 0.11 0.1 Personal care productsa 0 0 Total 84.3 a Reported as 0, but this seems unlikely, so it might be an unknown fraction of “Other.” SOURCE: OECD 2022.

APPENDIX F 257 PLASTICS WASTE Generation Similar to production and use, the annual trend over time of plastics waste generation is increasing from 1950 through 2018, primarily driven by the polymers polyethylene and polypropylene (see Figure F-4). Waste is also overwhelmingly generated by the packaging sector over time (see Figure F-5). Of primary plastics waste, 6,900 MMT was estimated to be gener- ated globally by the end of 2018 (Geyer 2020). This quantity is composed of 5,600 MMT of polymer resin, 900 MMT of polymer fibers, and 400 MMT of additives (Geyer 2020). The polymer resin categories are primar- ily polyethylene (2,300 MMT, or 41.1 percent), followed by polypropylene (1,300 MMT, or 23.2 percent), PET (800 MMT, or 14.3 percent), PS (400 MMT, or 7.14 percent), PVC (300 MMT, or 5.35 percent), polyurethanes (PURs) (300 MMT, or 5.35 percent), and others (200 MMT, or 3.57 per- cent) (Geyer 2020). The United States has the highest municipal solid waste (MSW) genera- tion rate in the world, per person and total (NASEM 2021). While plastics waste generation rates for the United States have also followed the global trend of overall increasing from 1960 through 2018 (see Figure F-6), there is some discrepancy over the plastics waste generation rates in the United FIGURE F-4 Global annual primary plastics waste generation (in Mt) by polymer type from 1950 to 2018. NOTE: Mt = MMT = million metric tons. SOURCE: Geyer 2020.

258 RECYCLED PLASTICS IN INFRASTRUCTURE FIGURE F-5 Global annual primary plastics waste generation (in Mt) by sector from 1950 to 2018. NOTE: Mt = MMT = million metric tons. SOURCE: Geyer 2020. FIGURE F-6 U.S. annual plastics waste generation from 1960 to 2018 in million tonnes. NOTE: Mt = MMT = million metric tons. SOURCE: USEPA 2020.

APPENDIX F 259 States, depending on what references are examined. In 2018, the U.S. Envi- ronmental Protection Agency (USEPA) estimated plastics waste generation at 32.4 Mt, while Law et al. (2020) estimated the 2016 value at 42 Mt. Milbrandt et al. (2022) estimated the total plastics waste generated in the United States in 2019 at 44 Mt. OECD has the highest estimate for plastics waste generation in the United States at 72.84 MMT and then categorizes the waste generation quantities by sector (see Table F-2), with the highest waste-generating sector as packaging (37 percent), followed by other (17 percent), consumer and institutional products (12 percent), then transportation (other) (11 percent), and other smaller sectors. Table F-2 also includes the percentage of used plastic (from Table F-1) that was estimated to become waste for each sec- tor. The lowest rate is for building and construction at 38 percent, followed by industrial machinery at 66 percent and transportation applications (83 to 84 percent). The other applications are all 90 percent or higher, with packaging being the highest, at 99 percent, meaning nearly 100 percent of packaging becomes waste the year it is used. The future trends and projec- tion for plastics waste generation in the United States is estimated by OECD to increase over time and to reach 142 MMT by 2060 (see Figure F-7). TABLE F-2 Plastics Waste Generation in the United States in 2019 Waste (2019) MMT Percentage of Total (%) Percentage of Use (%) Packaging 26.97 37 99 Other 12.21 17 91 Consumer and institutional products 8.4 12 92 Transportation (other) 8.35 11 83 Textile sector—clothing 5.19 7 95 Building and construction 3.81 5 38 Electrical/electronics 3.11 4 91 Textile sector—other 2.81 4 95 Transportation (tires) 1.39 2 84 Industrial machinery 0.4 1 66 Marine coatings 0.11 0 92 Road marking 0.1 0 91 Personal care products 0 0 0 Total 72.85 SOURCE: OECD 2022.

260 RECYCLED PLASTICS IN INFRASTRUCTURE Management Geyer (2020) estimated the global quantities of plastic as recycled and in- cinerated from 1980 through 2018 (see Figure F-8). The discarded fraction is the difference of the total plastics waste generated minus the fractions that are recycled or incinerated. “Discarded” is likely, more often than not, disposed of into a landfill or dumpsite. In some cases, waste materi- als, including plastics, might be discarded into the environment, including waterways (see subsequent section on Leakage). FIGURE F-7 Projected U.S. annual plastics waste generation from 2018 to 2060 in million tonnes. NOTE: Data from OECD 2022. FIGURE F-8 Estimated global recycling, incineration, and discard rates for nonfiber plastics. SOURCE: Geyer 2020.

APPENDIX F 261 To manage plastics waste, it first must be collected. And plastics waste is collected along with other MSW in the United States. The 2021 National Academies report provides a good overview of the types of collection in the United States, ranging from curbside to drop-off locations, to hiring private contractors. While technically nearly 100 percent of community members in the United States have a way to manage their waste through a collection system, the variety of methods of collection create a relatively variable sys- tem where collection efficiency can vary, impacting management scenarios like recycling (NASEM 2021). Collection is also one of the most expensive (without direct return) parts of the waste management system. In the United States in 2018, 50 percent of all MSW was landfilled, 24 percent recycled, 8.5 percent composted, and 12 percent combusted (USEPA 2020). As summarized by the National Academies in 2021, 76 percent of plastics in MSW were landfilled (comprising 18.5 percent of all landfilled materials, by mass), 8.7 percent were recycled, and 16 percent were combusted with energy recovery. While both recycling and combus- tion capacity expanded in the 1980s and 1990s, these percentages have remained relatively consistent over the past 15 years (NASEM 2021) (see Figure F-9). Because of how U.S. policy is constructed, state and local gov- ernments primarily bear the growing costs and challenges of managing in- creasing amounts of waste. Plastic products disposed of as waste (reported by USEPA in durable goods, nondurable goods, and containers and pack- aging categories) consist of a wide variety of plastic polymers containing FIGURE F-9 U.S. plastics waste management of municipal solid waste from 1960 to 2018 per year. NOTE: Composted levels are zero during this period. SOURCE: USEPA 2020.

262 RECYCLED PLASTICS IN INFRASTRUCTURE mixtures of chemical additives that allow for an array of properties; thus, the composition of plastics in MSW is incredibly diverse, which creates challenges in waste management systems, especially when sorting materials for appropriate recycling or composting (NASEM 2021). Landfilling is described as follows (NASEM 2021): None of the highest-production plastics (PET, HDPE, PVC, low-density polyethylene, polyethylene [PE], PS) biodegrade in a landfill, and they are considered contamination in compost. Since plastic products also contain an array of additives, this diversity of plastics waste can challenge recovery and recycling. In addition, plastics can be mixed with food waste, most of which goes to landfills (only 6.3 percent of food waste is composted, as compared with 69.4 percent of yard waste, which is restricted from landfills). With the vast majority (76 percent) of managed plastics waste disposed of in landfills (24.5 MMT in 2018), according to the National Academies (2021), there are opportunities to reduce this amount and conserve nonrenewable resources, increase energy efficiency, and provide economic and environmental benefits through effective source reduction, recycling, and composting. These options are in line with U.S. policy to prevent and reduce pollution at the source whenever feasible (Pol- lution Prevention Act). These principles are expressed in the Resource Conservation and Recovery Act (RCRA), where the order of preference in managing materials is source reduction, reuse, recycling, and disposal (NASEM 2021). The OECD estimate for landfilled plastics waste in the United States is more than double the USEPA estimate for 2018, at 53.1 MMT (73 percent) in 2019 (see Figure F-10) (OECD 2022). For com- bustion of plastics waste in the United States, in 2018, USEPA estimated the quantity at 5.1 MMT (16 percent) and OECD estimated it for 2019 at 13.9 MMT (19 percent) (see Figure F-10). Table F-3 contains the FIGURE F-10 Plastics waste management as estimated by OECD for the United States in 2019. NOTE: Data from OECD 2022.

263 T A B L E F -3 P la st ic in M SW M an ag ed in t he U ni te d St at es in 2 01 9 Pl as ti cs W as te b y R es in T yp e T ot al P la st ic M an ag ed Pl as ti cs W as te L an dfi lle d Pl as ti cs W as te C om bu st ed Pl as ti cs W as te R ec yc le d D ur ab le (% ) N on du ra bl e (% ) C on ta in er s an d Pa ck ag in g (% ) kt % kt % kt % kt % L D PE /L L D PE 15 ,1 39 34 13 ,2 90 88 1, 52 4 10 32 5 2 10 3 88 PP 8, 18 9 19 7, 20 2 88 71 6 9 27 1 3 41 6 53 H D PE 7, 91 0 18 6, 44 8 82 69 3 9 76 8 10 14 3 8% PE T 5, 98 6 14 4, 55 4 76 53 3 9 89 9 15 8 4 89 O th er 3, 11 5 7 2, 79 6 90 27 8 9 41 1 88 7 5 PS E PS 3, 09 4 7 2, 81 5 91 26 3 9 16 1 33 43 24 PV C 69 9 2 61 4 88 66 9 18 3 25 13 62 To ta l 44 ,1 31 10 0 37 ,7 20 86 4, 07 3 9 2, 33 9 5 24 7 70 N O T E S: k t = 1, 00 0 m et ri c to ns . B ec au se o f da ta r ou nd in g, s om e to ta l v al ue s m ay s ho w a s m al l d is cr ep an cy t o th e su m o f pr es en te d da ta . SO U R C E : M ilb ra nd t et a l. 20 22 .

264 RECYCLED PLASTICS IN INFRASTRUCTURE plastics waste management data produced by Milbrandt et al. (2022) for the seven different plastic resin types. Low-density polyethylene (LDPE)/ LLDPE comprises most of the plastic discarded (34 percent), followed by PP (19 percent) and then HDPE (18 percent) and PET (14 percent). The highest recycling rate is for PET at 15 percent (the only recycling rate above 10 percent), followed by HDPE at 10 percent. PP and LDPE/LLDPE are at 3 and 2 percent, respectively. Recycling of discarded plastic (e.g., plastic “scrap”; it is not con- sidered waste if intended for recycling) consists of a relatively complex system of collection, initial separation and densification (often begin- ning at local facilities where either source-separated materials are baled or plastics are separated both mechanically and manually at material recovery facilities and then baled), transportation, processing (e.g., wash- ing and re-pelletizing), compounding (adding additives), and reusing in manufacturing. Directly related to recycling, the National Academies report (NASEM 2021) found that Although recycling is technically possible for some plastics, little plastic waste is recycled in the United States. Barriers to recycling include the wide range of materials (plastic resins plus additives) in the waste stream; increasingly complex products (e.g., multi-layer, multi-material items); the expense of sorting contaminated, single-stream recycling collections; and the low cost of virgin plastics paired with market volatility for reprocessed materials. In addition, the committee found that “Chemical recycling processes that strive toward material circularity, such as depolymerization to mono- mers, are in early research and development stages. Such processes remain unproven to handle the current plastic waste stream and existing high- production plastics.” When considering areas where recycling could be increased, as well as polymer types available (and potential for use in a predictive model for use in transportation), Milbrandt et al. (2022) presented data on the relative quantities of plastic materials landfilled in each state, as well as their polymer characterization (see Figures F-11 and F-12). The larg- est quantities of plastics being landfilled are in California, Florida, and Texas, followed by another tier of states like Georgia, Illinois, Indiana, Michigan, Ohio, Pennsylvania, South Carolina, and Virginia. The more detailed graphic in Figure F-12 shows the higher quantities of plastic materials landfilled by each site in each state, providing a more distinct picture where plastics could be captured for diversion from landfills and increased recycling.

APPENDIX F 265 FIGURE F-11 Plastics waste landfilled in 2019 by resin type and state. NOTES: Pie charts correspond to total amount landfilled in each state. kt = 1,000 metric tons. SOURCE: Milbrandt et al. 2022. FIGURE F-12 Total plastics waste landfilled on site in 2019. NOTE: kt = 1,000 metric tons. SOURCE: Milbrandt et al. 2022.

266 RECYCLED PLASTICS IN INFRASTRUCTURE LEAKAGE (MISMANAGED PLASTICS IN THE UNITED STATES) The 2021 National Academies report describes “leaked” waste as “Plastics waste not making it into (e.g., illegal dumping, litter) or leaking out of (e.g., blowing litter or unregulated leaking or discharge) our management systems is categorized as ‘mismanaged’ plastics waste.” Figure F-13, from the National Academies report, represents ways waste may leak, even from a solid waste management system reaching 100 percent of the population. Once in the environment, wastes are more difficult to recover for later treatment or disposal. Because USEPA data on MSW do not quantify mismanaged solid waste that leaks into the environment, researchers have derived estimates, draw- ing on USEPA-reported data and other data sources. Law et al. (2020) quantified the U.S. contribution of mismanaged plastics waste to the en- vironment as 1.13 to 2.24 MMT in 2016. This total mismanaged waste included estimated quantities of litter, illegal dumping, and estimates of exported plastics collected for recycling that were inadequately managed in the importing country. Litter (solid waste that is intentionally or uninten- tionally disposed of into the environment despite the availability of waste management infrastructure) was estimated as 2 percent of plastic solid waste generation equaling 0.84 MMT in 2016 and 0.14 to 0.41 MMT of plastics were estimated to be illegally dumped in 2016 (Law et al. 2020). Last, Law et al. (2020) estimated that 0.15 to 0.99 MMT of exported plastic scrap (in plastic and paper bales) was inadequately managed in the importing country. Law et al. (2020) found that the United States was the 3rd to 12th largest contributor of plastics waste into the coastal environment, with 0.51 to 1.45 MMT in 2016. OECD (2022) has made other estimates, including a total mismanaged plastics waste in the United States at 2.45 FIGURE F-13 Points of plastic leakage for municipal solid waste in the United States. NOTE: Black box with red outline denotes leakage potential. SOURCE: NASEM 2021.

APPENDIX F 267 MMT and uncollected litter at 0.14 MMT. However, total leakage is reported as two different values: in one case, as 0.24 MMT for plastic leakage from mismanaged waste and litter, and then as 0.56 MMT for all mismanaged and littered macroplastics (see Table F-4). Total leakage calculated by OECD for the United States includes both macroplastics and microplastics and was a total of 0.95 MMT in 2019 (see Table F-4). This is projected to grow over time to 1.23 MMT in 2060 (see Figure F-14) (OECD 2022). OECD also estimates that, as of 2019, the United States contributed to an accumulated stock of plastic in the ocean of 3.35 MMT and accu- mulated stock in rivers of 10.85 MMT and 0.11 MMT transported to the ocean (OECD 2022). But not every item is created equal in terms of risk to leakage, around the world and in the United States. Litter surveys and community science efforts have shown that while plastics make up a large percentage (about 70 to 80 percent) of what is found in the environment as litter, the majority of plastic items are single use, including packaging, TABLE F-4 OECD Data from 2019 on Plastic Leakage from the United States Category MMT Macroplastics, mismanaged 0.42 Macroplastics, littering 0.14 Macroplastics, marine 0 Macroplastics, total 0.56 Microplastics, primary pellets 0.03 Microplastics, microbeads 0 Microplastics, textile wash 0 Microplastics, tire abrasion 0.1 Microplastics, brake dust 0.01 Microplastics, road markings 0.03 Microplastics, marine coatings 0.01 Microplastics, artificial turf 0.01 Microplastics, microplastics dust 0.03 Microplastics, wastewater sludge 0.17 Microplastics, total 0.39 Total Leakage 0.95 SOURCE: OECD 2022.

268 RECYCLED PLASTICS IN INFRASTRUCTURE as well as tobacco-related (e.g., cigarette filters, product packaging, and e- cigarette cartridges) and unidentified fragments from larger items (NASEM 2021). Table F-5 contains examples of commonly leaked items and per- centage of plastic found from projects also highlighted in the National Academies report (NASEM 2021). Materials flows of plastics in the United States are complex (see the materials flow diagram in Figure F-15 developed by Heller et al. 2020). But the data presented so far provide an overview on the complexity, vari- ability, and differing estimates of plastic materials from production through leakage into the environment. Heller et al. (2020) also stated, the data challenges encountered in characterizing plastics material flows are a call for improved data collection, coordination and transparency. Improved understanding of plastic material production and usage in various product sectors can promote further coordination between prod- uct design and manufacturing and material recovery and reprocessing efforts. The National Academies report (NASEM 2021) also found: The complex international system of plastic production, trade, and use complicates efforts to fully quantify the role of the United States in plastic FIGURE F-14 Plastics waste leakage in the United States, baseline scenario from OECD, 2019-2060. NOTE: Mt = MMT = million metric tons. SOURCE: OECD 2022.

APPENDIX F 269 production, export, import, use, and the country’s contribution to plastic pollution. Concluding that regular, standardized, and systematic data col- lection is critical to understanding the extent and patterns of plastics waste inputs to the environment, including the ocean, and how they change over time. (NASEM 2021) TABLE F-5 Top 10 Items Tallied from Specific Leakage Documenting Projects in the United States Data Set Date Range (n = number of litter items counted) Top 10 in Rank Order Ocean Conservancy’s International Coastal Cleanup (U.S. only) 2015 to July 2021 (n = 18,565,446), 82% plastic items Cigarette butts, food wrappers, bottle caps (plastic), beverage bottles (plastic), straws, stirrers, other trash, beverage cans, grocery bags (plastic), beverage bottles (glass), bottle caps (metal), lids (plastic). Marine Debris Monitoring and Assessment Project (MDMAP) Accumulation of items 2.5-30 cm 2009 to 2021 (n = 895,417), 84% plastic items Hard plastic fragments, foamed plastic fragments, plastic rope/net, bottle/ container caps, filmed plastic fragments, plastic other, cigarettes, plastic beverage bottles, food wrappers. Marine Debris Tracker (U.S. only) 2011 to July 2021 (n = 2,333,337), 71% plastic items Plastic or foam fragments, cigarettes/cigars, plastic food wrappers, plastic caps or lids, other (trash), plastic bottle, plastic bags, paper and cardboard, aluminum or tin cans, foam or plastic cups or plates, straws. Mississippi River Plastic Pollution Initiative (MRPPI) March 15 to April 25, 2021 (n = 75,184), 74% plastic items Cigarette butts, food wrappers, plastic beverage bottles, foam fragments, aluminum cans, hard plastic fragments, plastic bags, plastic/foam cups, paper and cardboard, film fragments. (Note: PPE was 1% to 2% of all litter found.) SOURCE: NASEM 2021.

270 FI G U R E F -1 5 Pr od uc ti on , i m po rt s, e xp or ts , u se , d is po sa l, an d le ak ag e of p la st ic s in t he U ni te d St at es in 2 01 7. SO U R C E : H el le r et a l. 20 20 .

APPENDIX F 271 RECYCLING IN TRANSPORTATION Environmental Considerations While use in various recycling applications is one way to create a demand for plastics that are currently being landfilled, an increase in recycling does not necessarily create a demand for plastics that are currently mismanaged or leaking into the environment. If the increase in recycling from a new ap- plication was great enough to accept all of the plastics in the waste stream or close to it, it might then also promote enough value that it could cause demand for plastics that are leaking out. However, the leakage components in the United States may not change unless there is true incentive or value to communities and community members, since littered items currently still include items that are recyclable. However, when a deposit return scheme is in place, those items (e.g., a beverage bottle) were found to have 40 percent less (by count) leaking out of the system (Schuyler et al. 2018). Previous research has shown that reduction of production is required to “bend the curve” of plastic entering the environment and ocean, so that waste management alone, which recycling is only one part of, cannot re- duce the quantities projected to leak into the environment based on current projection models (Borrelle et al. 2020; Lau et al. 2020). In addition, more scientists are acknowledging that plastic pollution starts with production, when fossil fuels are extracted (oil and gas) and refined and petrochemicals are produced. These components of the plastics life cycle impact the com- munities surrounding the production facilities, which are often marginal- ized and already burdened with other pollution as well, and recycling does not reduce any of this impact (Syberg 2022). Microplastic emissions from both asphalt and concrete roadways have been raised as a potential concern, and only one paper was found that quantified microplastic generation from plastic-modified asphalt roads for the first time (Enfrin et al. 2022). Microplastics were released following a logarithmic trend ranging from 2 to 40 µm in size depending on percentage of plastic included in the mix (see Figure F-16), with colder and more acidic conditions exacerbating microplastics release (Enfrin et al. 2022). Other mi- croplastics that have been identified related to roadways and roadway use are tire particles and road paint particles, which are significant, although mostly concentrated in urban runoff, traffic areas, and not areas that are more remote from roadways (Goßmann et al. 2021; Sommer et al. 2018; Werbowski et al. 2021). Although no literature was found, in a similar vein, microplastics emis- sions from abrasion of plastic lumber from use could also be a concern, along with the fact that composite lumber (made up of plastics and wood components) cannot be recycled again and so eventually will need to be

272 RECYCLED PLASTICS IN INFRASTRUCTURE disposed of. Research is currently being conducted on the incorporation of recycled (e.g., shredded or pelletized used plastics) into stabilization for granular roads. The plastic is being tested for incorporation into the soils at about 4 percent by weight. Other plastic stabilization and/or drainage materials include geogrid, geotextiles, and erosion control grids. In this case, the recycled plastic materials are incorporated directly into the soils. Evaluation is being conducted for potential leaching from the plastics to test potential environmental impacts from leachable contaminants. It does not appear that any microplastic generation is being evaluated at this time, so the potential for microplastic generation, and in comparison with other products made from plastics, is unknown (Ceylan 2022). Asphalt Wet Process The amount (or dosage) of scrap plastic incorporated into asphalt binders through the wet process plays an important role in the properties of scrap plastic–modified asphalt binders. According to previous research, there is an optimum waste plastic dosage for waste plastic–modified asphalt binders (Brasileiro et al. 2019). Too much or too little scrap plastic added may ad- versely affect the properties of asphalt binder (Ameri et al. 2012; Karmakar and Roy 2016). In the wet process, the plastic tends to separate from the asphalt binder owing to the different densities and viscosity between the two components. According to Singh and Kumar (2019), some modified FIGURE 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. NOTE: cPE/PP = commingled PE and PP; rABS = recycled acrylonitrile butadiene styrene; rLDPE/LLDPE = recycled LDPE and LLDPE; rPET = recycled PET. SOURCE: Efrin et al. 2022.

APPENDIX F 273 asphalt was not storage-stable, with a high concentration of scrap plastic at high temperatures. In contrast, some low plastic concentration–modified binders have issues related to underutilization of polymer modification. A multitude of studies have investigated the effects of modified asphalt containing scrap plastics at various dosages on properties and pavement performance. Based on these studies, 5 percent of scrap HDPE is recom- mended based on stiffness and rutting resistance (Suksiripattanapong et al. 2022). Mashaan et al. (2021) reported that the optimum content of PET scrap plastic is 6 to 8 wt.% based on rutting and aging resistances. Naskar et al. (2010) found that modified asphalt with 5 wt.% waste plastic has the highest thermal stability. Fuentes-Audén et al. (2008) mentioned that low recycled polyethylene content blends (0 to 5 wt.%) could potentially be used for road paving applications, whereas high-polymer-content blends (percent weight recycled polyethylene >15) are suitable for roofing mem- branes in building construction. A review article summarized past studies’ recommended dosages for different waste plastics, as presented in Figure F-17 (Vargas and El Hanan- deh 2021). On average, the content recommended is 4.5 percent. The optimum percentages of scrap LDPE, HDPE, PET, PVC, and PP are 4.37, 4.43, 3.57, 6.25, and 4.38 percent, respectively. Overall, the dosage of waste plastic concentration varies from ap- proximately 2 to 8 wt.% by the weight of asphalt binder (Vargas and El Hanandeh 2021; Willis et al. 2020). Given this, the average binder content is approximately 5 wt.%. This dosage corresponds to about 2 to 8 pounds FIGURE F-17 Optimum dosages of waste plastic used for asphalt (wet process). SOURCE: Vargas and El Hanandeh 2021.

274 RECYCLED PLASTICS IN INFRASTRUCTURE of scrap plastics in a ton of asphalt mixture (1-4 kg/tonne). Most often the optimum content is referenced as approximately 5 wt.% (Fuentes-Audén et al. 2008; Kalantar et al. 2012; Naskar et al. 2010; Vargas and El Hanandeh 2021), which corresponds to about 5 pounds of scrap plastics in a ton of asphalt mixture (2.5 kg/tonne). Dry Process The dosage is also an important factor that affects asphalt mixtures’ per- formance in the dry process. Shankar et al. (2013) used shredded waste plastic in asphalt mixture by dry process: 6 wt.% (by weight of binder) was selected as the optimum plastic dosage based on Marshall Stability and indirect tensile strength. Up to 10 wt.% of scrap plastics (by weight of binder) were tested, and 8 wt.% was recommended as the optimum dosage (Mishra and Gupta 2018). Janshedpur (India) reported 7 wt.% shredded recycled plastic as the optimum ratio by dry process (PTI 2015). Similarly, Naghawi et al. (2018) reported that the optimum shredded PET was 7.5 wt.% of the binder based on Marshall Stability and indirect tensile strength. Barrasa et al. (2014) found that the optimum plastic content was 1 wt.% to aggregates. Vasudevan et al. (2012) reported that for paving 1 km with 25 mm thickness and 3.75 m width in India, 1 ton of waste plastic is used. Movilla- Quesada et al. (2019) estimated using approximately one to two tons of plastic scrap per kilometer, assuming a 5-cm-thick paved surface layer with two lanes. Overall, the dosage of recycled plastics commonly reported in the lit- erature varies from approximately 0.2 to 1 percent by weight of aggregate, which corresponds to about 4 to 19 pounds of recycled plastics in a ton of asphalt mixture (Awwad and Shbeeb 2007; White and Reid 2018; Willis et al. 2020). More specifically, the optimum plastic content was about 8 wt.% (by weight of binder). This dosage corresponds to about 8 pounds of recycled plastics in a ton of asphalt mixture (4 kg/tonne) (Mishra and Gupta 2018). With an unknown application of wet/dry processes, a range of values was used to calculate the quantity of plastic scrap that can be utilized annu- ally. Since the optimum quantity in dry is 4 kg and the maximum in wet is 4 kg, with a typical value of 2.5 kg per tonne of asphalt, the range used is 2.5 to 4 kg of plastics per tonne of asphalt. According to the National Asphalt Pavement Association (NAPA), approximately 350 MMT of asphalt are produced each year (NAPA 2011). This level of asphalt production could utilize 0.88 to 1.4 MMT of scrap plastics each year, or 1.6 to 2.3 percent of what is being currently landfilled (depending on if using the Milbrandt or OECD estimate) or at the higher end, 2.6 to 3.7 percent. Utilizing plastics

APPENDIX F 275 in asphalt could increase the plastics recycling rate from 5 to 8.5 percent at the maximum (using Milbrandt data) and if all plastic that was leaked was used in roads, it would be close to meeting or exceed what is estimated to leak out annually by OECD in 2019 (0.95 Mt), so 92 to 147 percent (see Table F-6). Concrete Numerous studies have been conducted to explore the optimum content of scrap plastics in concrete, a content that does not negatively influence the engineering properties of concrete (Bajracharya et al. 2014; Ragaert et al. 2017). The content of plastics affects the workability, compressive strength, flexural strength, splitting tensile strength, and modulus of elastic- ity (Akçaözoğlu et al. 2010; Araghi et al. 2015; Rahmani et al. 2013; Saikia and De Brito 2014; Sharma and Bansal 2016; Usman et al. 2015). Various types and forms of plastics in concrete were investigated by previous stud- ies, such as PET particles, flakes, and fibers (Araghi et al. 2015; Foti 2013; Ingrao et al. 2014); HDPE (Naik et al. 1996); and PVC (Kou et al. 2009). PET is the most commonly studied plastic in concrete; 5, 10, and 15 percent (by volume of fine aggregates or sand) are some typical dosages of PET tested in concrete (Albano et al. 2009; Araghi et al. 2015; Rahmani et al. 2013). Other researchers used different ratios based on the volume percentage of total aggregates or sand (Saikia and De Brito 2014). Besides these two ratios, some researchers used different weight ratios based on the weight of sand used in concrete (Frigione 2010; Reis et al. 2011). Rahmani et al. (2013) found that concrete with 5 percent (volume of fine aggre- gates) PET particles yielded the optimum compressive strength. However, the compressive and tensile strength was decreased with a further increase in PET content. Albano et al. (2009) reported that 10 percent of 0.26-cm TABLE F-6 Potential for Annual Plastic Scrap Utilization in Asphalt kg per Tonne of Asphalt Usea Asphalt Produced per Year (MMT)b Total Plastic Scrap Use Potential (MMT/ yr) Resin Landfilled (MMT) in 2019c Percentage of Landfilled Quantity Recycling Increase Percentage of Leakage (0.95 MMT) All Plastic Scrap 2.5-4 350 0.88-1.4 37.72 (M) 53.09 (OE) 2.3-3.7% 1.6-2.6% From 5% to 8.5% 92%- 147% NOTE: (M) indicates data from Milbrandt et al 2022; (OE) indicates data from OECD 2022. SOURCES: a Ranges from the literature: Awwad and Shbeeb 2007; Mishra and Gupta 2018 White and Reid 2018; Willis et al. 2020. b NAPA 2011. c Milbrandt et al. 2022; OECD 2022.

276 RECYCLED PLASTICS IN INFRASTRUCTURE PET particles (by volume of fine aggregates) presented the best mechani- cal properties compared to the blends with greater or bigger particle sizes. Similarly, Araghi et al. (2015) reported that 15 percent (by volume of fine aggregates) of PET particles was the optimum dosage based on crushing load and weight loss. Ramadevi and Manju (2012) observed that the compressive strength, split tensile strength, and flexural strength increased when up to 2 percent (by weight of fine aggregates) of PET bottle fibers were incorporated. The strength gradually decreased when 4 and 6 percent of the fine aggregates were replaced. Thus, the replacement of 2 percent of the fine aggregates is reasonable. Similarly, Frigione (2010) found that the substitution of 5 per- cent (by weight of sand) of PET had the best performance based on work- ability, compressive strength, and splitting strength. Saikia and De Brito (2014) reported that 10 percent (by volume of total aggregates) of PET was the optimum dosage based on abrasion behavior. PET has a specific gravity of 1.11 g/cm3, and the specific gravity of fine aggregates was about 2.75 g/ cm3 (Araghi et al. 2015; Rahmani et al. 2013). Generally, fine aggregates consist of about 30 percent of concrete proportion by weight (Rahmani et al., 2013). Therefore, consider using 5 to 15 percent waste PET (by volume of fine aggregates), which is about 1.5 to 5 pounds of PET in a ton of con- crete (0.75 to 2.5 kg/tonne). Except for PET, limited studies investigated other types of plastics, such as HDPE and PVC. Malagaveli and Patura (2011) reported that the compressive and flexural strength increased when 3.5 percent (by volume of concrete) HDPE fiber was added. When more than 3.5 percent (by volume of concrete) was added, the strength of the concrete began to decrease. Naik et al. (1996) concluded that the compressive strength decreased with an increase in the amount of waste plastic, particularly above 0.5 percent (by weight of total mixture). Therefore, to maintain a particular compressive strength level, HDPE plastic must be controlled under 0.5 percent (by weight of total mixture). Therefore, about l pound of HDPE could be used in a ton of concrete (0.5 kg/tonne). Kou et al. (2009) reported 15 percent (by volume of fine aggregates) of PVC as the optimum dosage based on overall proper- ties, including compressive strength, tensile splitting strength, dry shrinkage, and modulus of elasticity. The dry density of concrete with 15 percent PVC was 1620 kg/m3, and the mix design showed the PVC was 45 kg/m3 (Kou et al. 2009). Therefore, about 5.5 pounds of PVC could be used in a ton of concrete (2.8 kg/tonne). In 2019, 370 million cubic yards of concrete was produced. Assuming a density of 150 pcf, this equates to 679.7 MMT of concrete in 2019. If all plastics waste was from current leakage rates, more than 100 percent (179 percent) of what is currently leaked could be utilized in concrete. Based on the information above, Table F-7 summarizes the po- tential use of plastics waste in concrete by polymer for 2019.

APPENDIX F 277 Plastic Lumber Plastic lumber has been in use for decades with the exploration of use in 2003 for landscaping (Stutz et al. 2033) along with a Healthy Building Network guide to plastic lumber published in 2005 (Platt et al. 2005). Plastic lumber can consist of single or multiple resins, as well as composite materials (resin, plus wood pulp, etc.). While use is projected to grow, the industry also experienced a surge during the COVID-19 pandemic with the high expense and lack of availability of natural wood (Hood 2021). Con- tinued use and growth is expected to continue into the near future. There is likely more room for this industry to receive/uptake more post-consumer resin than it currently is. According to data from Trex (private company), a regular 16-foot board will utilize 2,250 plastic bags (Noe 2021). Assuming each bag weighs 5.5 g each, this would be 0.77 kg of resin use per board- foot. According to lumber statistics, 98.802 million m3 of wood was used in construction in 2019. This is equal to 41,865 million board-feet of lumber. Converting this lumber all to “Trex style” lumber would utilize 32.4 MMT of plastics per year; however, it is likely that only a small fraction of this lumber could actually be plastic for use. For example, in 2019, 19.3 percent of the 990,000 new homes built had decks (Emrath 2021). With the aver- age size of 265 square feet and 1-inch thickness, this would correspond to TABLE F-7 Potential for Annual Plastic Scrap Utilization in Concrete Resin kg per Tonne of Concrete Usea Concrete Produced in 2019 (MMT)b Total Plastic Scrap Use Potential (MMT/ yr) Resin Landfilled (MMT) in 2019c Percentage of Landfilled Quantity Recycling Increase Percentage of Leakage (0.95 MMT) PET 0.75-2.5 679.7 0.51-1.7 4.554 11-37% From 15% to 24-43% HDPE 0.5 679.7 0.34 6.448 5.3% From 10% to 14% PVC 2.8 679.7 1.87 0.614 100%+ From 3% to 100% All Plastic Scrap 2.5 679.7 1.7 37.72 4.5% From 5% to 9.15% 179% NOTES: a Ranges from the literature: PET, Araghi et al. 2015; Frigione 2010; Rahmani et al. 2013; Saikia and Brito 2014; HDPE, Malagaveli and Patura 2011; Naik et al. 1996; PVC, Kou et al. 2009. b Margolies 2020. c Milbrandt et al. 2022.

278 RECYCLED PLASTICS IN INFRASTRUCTURE the use of 0.04 MMT of plastics. In addition, porches were also popular, with 65.3 percent of new homes constructing porches, and this would add another 0.06 MMT to use of plastics in lumber. The amount of plastic lum- ber that could be utilized by the transportation sector is unknown. There is projected growth in the plastic lumber industry, and it is likely there is growth in this space for more plastics usage; however, companies report challenges with getting LDPE/LLDPE back from consumers since film plas- tics are only collected by customer drop-off at retail stores. There are also challenges with the plastic materials being clean, dry, and uncontaminated by receipts and other materials. With current lumber use in transportation applications, a potential capacity for use in this sector could be further evaluated/calculated. Base Stabilization of Granular Roads Both shredded and pelletized plastics have begun to be explored for use in the stabilization of granular roads in Iowa (Ceylan 2022). While this work has been experimental and is still being explored for environmental impact as well (see Environmental Considerations, above), 4 percent of shredded PET and 4 percent of pelleted HDPE incorporated by soil weight provided some strength improvement (Ceylan 2022). Work is continuing to examine this application from both structural and environmental perspectives. Summary Plastic production reached more than 400 MMT globally in 2019 and is still projected to grow globally, and in the United States, plastics waste generation has continued to grow through time and is also expected to continue as is or grow: the United States generates the most plastics waste per person and as a country in the world. The highest mass of plastics waste generated in the United States is from packaging and the resins of LDPE/ LLDPE and PP. Plastic leakage continues to be an issue in the United States from especially problematic items (like food wrappers, cigarettes, cups, bottles, etc.) found in litter and other data-collection strategies. Plastic scrap can be used in asphalt in two different ways, wet and dry processes. Plastic scrap can also be used in concrete. Plastics have also found applications in plastic lumber and are being evaluated for use in granular road stabiliza- tion. While environmental issues still remain unanswered, use in asphalt can increase the recycling rate for plastic scrap from 5 to 8.5 percent, and use in concrete can increase recycling rates from 5 to 9.1 percent. When com- bined, recycling in roadway materials (concrete and asphalt) could reach 3.1 MMT, resulting in an incrementally increased recycling rate from 5 to 12 percent. However, these applications would be more than three times

APPENDIX F 279 enough to take the 2019 estimated plastics that were leaked from the sys- tem (0.95 Mt). Plastic lumber materials are currently in high demand, with potential for growth; however, the full market size and capacity for recycled plastic scrap is currently unknown. Based on decking and porches, only 0.1 MMT of plastic scrap could be utilized, but use for other lumber materials (e.g., landscape timber, railroad ties, in transportation applications) could be significantly higher. For all plastic scrap recycling and use scenarios, the collection and capture of clean post-consumer materials remain a significant issue. Although these applications could technically utilize all of the plastics that leak from the system currently (polymer dependent), the challenge re- mains to capture and collect the plastics. Strategies to incentivize collection or other policy changes might work, but the overall system is currently not designed to accommodate this type of recycling. REFERENCES Akçaözoğlu, S., Atiş, C. D., and Akçaözoğlu, K. 2010. An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete. Waste Management 30(2):285-290. Albano, C., Camacho, N., Hernández, M., Matheus, A., and Gutierrez, A. 2009. Influence of content and particle size of waste PET bottles on concrete behavior at different w/c ratios. Waste Management 29(10):2707-2716. Ameri, M., Mansourian, A., and Sheikhmotevali, A. H. 2012. Investigating effects of ethylene vinyl acetate and gilsonite modifiers upon performance of base bitumen using Superpave tests methodology. Construction and Building Materials 36:1001-1007. Araghi, H. J., Nikbin, I. M., Reskati, S. R., Rahmani, E., and Allahyari, H. 2015. An ex- perimental investigation on the erosion resistance of concrete containing various PET particles percentages against sulfuric acid attack. Construction and Building Materials 77:461-471. Awwad, M. T., and Shbeeb, L. 2007. The use of polyethylene in hot asphalt mixtures. Ameri- can Journal of Applied Sciences 4(6):390-396. Bajracharya, R. M., Manalo, A. C., Karunasena, W., and Lau, K. T. 2014. An overview of mechanical properties and durability of glass-fibre reinforced recycled mixed plastic waste composites. Materials & Design (1980-2015) 62:98-112. Barrasa, R. C., Caballero, E. S., Fresno, D. C., Andrés, E. V., and Fernández, M. N. 2014. POLYMIX: Polymeric waste in asphalt mixes. Sustainability, eco-efficiency and conserva- tion in transportation. Infrastructure Asset Management 23-31. Borrelle, S. B., Ringma, J., Law, K. L., Monnahan, C. C., Lebreton, L., McGivern, A., Murphy, E., Jambeck, J., Leonard, G. H., Hilleary, M. A., Eriksen, M., Possingham, H. P., De Frond, H., Gerber, L. R., Polidoro, B., Tahir, A., Bernard, M., Mallos, N., Barnes, M., and Rochman, C. M. 2020. Predicted growth in plastic waste exceeds efforts to mitigate plastic pollution. Science 369(6510):1515. Brasileiro, L., Moreno-Navarro, F., Tauste Martínez, R., Matos, J., and Rubio-Gámez, M. D. C. 2019. Reclaimed polymers as asphalt binder modifiers for more sustainable roads: A Review. Sustainability 11(3):646. Ceylan, H. 2022. Base Stabilization of Iowa Granular Roads Using Recycled Plastics. Presen- tation to the Committee on Repurposing Plastics Waste in Infrastructure, Transportation Research Board, June 9, 2022.

280 RECYCLED PLASTICS IN INFRASTRUCTURE Emrath, P. 2021. Share of New Homes with Decks Drops Below 20 Percent. National Association of Home Builders, October 7. https://eyeonhousing.org/2021/10/share-of-new-homes-with- decks-drops-below-20-percent Enfrin, M., Myszka, R. and Giustozzi, F. 2022. Paving roads with recycled plastics: Micro- plastic pollution or eco-friendly solution? Journal of Hazardous Materials 437:129334. Foti, D. 2013. Use of recycled waste PET bottles fibers for the reinforcement of concrete. Composite Structures 96:396-404. Frigione, M. 2010. Recycling of PET bottles as fine aggregate in concrete. Waste Management 30(6):1101-1106. Fuentes-Audén, C., Sandoval, J. A., Jerez, A., Navarro, F. J., Martínez-Boza, F. J., Partal, P., and Gallegos, C. 2008. Evaluation of thermal and mechanical properties of recycled polyethylene modified bitumen. Polymer Testing 27(8):1005-1012. Geyer, R. 2020. Chapter 2—Production, use, and fate of synthetic polymers. In Plastic Waste and Recycling, edited by T. M. Letcher. Academic Press, pp. 13-32. Goßmann, I., Halbach, M., and Scholz-Böttcher, B. M. 2021. Car and truck tire wear particles in complex environmental samples—A quantitative comparison with “traditional” mi- croplastic polymer mass loads. Science of the Total Environment 773:145667. Heller, M. C., Mazor, M. H., and Keoleian, G. A. 2020. Plastics in the US: Toward a material flow characterization of production, markets and end of life, Environmental Research Letters 15:094034. Hood, L. L. 2021. A lumber shortage puts demand and prices for plastics at an all-time high. Is it sustainable? Next City, May 20. https://nextcity.org/urbanist-news/lumber- shortage-puts-demand-and-prices-for-plastics-at-an-all-time-high Ingrao, C., Giudice, A. L., Tricase, C., Rana, R., Mbohwa, C., and Siracusa, V. 2014. Recycled-PET fibre based panels for building thermal insulation: Environmental impact and improvement potential assessment for a greener production. Science of the Total Environment 493:914-929. Kalantar, Z. N., Karim, M. R., Mahrez, A. 2012. A review of using waste and virgin polymer in pavement. Construction Building Materials 33:55-62. Karmakar, S., and Roy, T. K. 2016. Effect of waste plastic and waste tires ash on mechanical behavior of bitumen. Journal of Materials in Civil Engineering 28(6):04016006. Kou, S. C., Lee, G., Poon, C. S., and Lai, W. L. 2009. Properties of lightweight aggregate concrete prepared with PVC granules derived from scraped PVC pipes. Waste Manage- ment 29(2):621-628. Lau, W. W. Y., Shiran, Y., Bailey, R. M., Cook, E., Stuchtey, M. R., Koskella, J., Velis, C. A., Godfrey, L., Boucher, J., Murphy, M. B., Thompson, R. C., Jankowska, E., Castillo Castillo, A., Pilditch, T. D., Dixon, B., Koerselman, L., Kosior, E., Favoino, E., Gutberlet, J., Baulch, S., Atreya, M. E., Fischer, D., He, K. K., Petit, M. M., Sumaila, U. R., Neil, E., Bernhofen, M. V., Lawrence, K., and Palardy, J. E. 2020. Evaluating scenarios toward zero plastic pollution. Science eaba9475. Law, K. L., Starr, N., Siegler, T., Jambeck, J., Mallos, N., and Leonard, G. 2020. The United States’ contribution of plastic waste to land and ocean. Science Advances 6(44). Malagavelli, V., and Patura, N. R. 2011. Strength characteristics of concrete using solid waste an experimental investigation. International Journal of Earth Sciences and Engineering 4(6). Margolies, J. 2020. Concrete, a Centuries-Old Material, Gets a New Recipe. The New York Times, August 11, 2020. https://www.nytimes.com/2020/08/11/business/concrete- cement-manufacturing-green-emissions.html Mashaan, N. S., Chegenizadeh, A., Nikraz, H., and Rezagholilou, A. 2021. Investigating the engineering properties of asphalt binder modified with waste plastic polymer. Ain Shams Engineering Journal 12(2):1569-1574.

APPENDIX F 281 Milbrandt, A., K. Coney, A. Badgett and G. T. Beckham. 2022. Quantification and evaluation of plastic waste in the United States. Resources, Conservation and Recycling 183:106363. Mishra, B., and Gupta, M. K. 2018. A study on use of plastic coated aggregates (PCA) in bituminous concrete mixes of flexible pavement. International Journal of Engineering & Technology (UAE) 7(45):396-401. Movilla-Quesada, D., Raposeiras, A. C., Silva-Klein, L. T., Lastra-González, P., and Castro- Fresno, D. 2019. Use of plastic scrap in asphalt mixtures added by dry method as a partial substitute for bitumen. Waste Management 87:751-760. Naghawi, H., Al-Ajarmeh, R., Allouzi, R., AlKlub, A., Masarwah, K., Al-Quraini, A., and Abu-Sarhan, M. 2018. Plastic waste utilization as asphalt binder modifier in asphalt concrete pavement. International Journal of Civil and Environmental Engineering 12(5):566-571. Naik, T. R., Singh, S. S., Huber, C. O., and Brodersen, B. S. 1996. Use of post-consumer waste plastics in cement-based composites. Cement and Concrete Research 26(10):1489-1492. Naskar, M., Chaki, T. K., and Reddy, K. S. 2010. Effect of waste plastic as modifier on thermal stability and degradation kinetics of bitumen/waste plastics blend. Thermochimica Acta 509(1-2):128-134. National Academies of Sciences, Engineering, and Medicine (NASEM). 2021. Reckoning with the U.S Role in Global Ocean Plastic Waste. Washington, DC: The National Academies Press. https://doi.org/10.17226/26132 National Asphalt Paving Association (NAPA). 2011. https://www.asphaltpavement.org/ uploads/documents/GovAffairs/NAPA%20Fast%20Facts%2011-02-14%20Final.pdf Noe, R. 2021. Eco-Friendly, Low-Maintenance Deck Boards Use 2,250 Plastic Bags per Board. Core77.com, https://www.core77.com/posts/107168/Eco-Friendly-Low-Maintenance- Deck-Boards-Use-2250-Plastic-Bags-per-Board Organisation for Economic Co-operation and Development (OECD). 2022. Global Plastics Outlook: Economic Drivers, Environmental Impacts and Policy Options. https://www. oecd-ilibrary.org/sites/de747aef-en/index.html?itemId=/content/publication/de747aef-en PET Resin Association. 2015. PET by the Numbers. http://www.petresin.org/news_PETby- thenumbers.asp Plastics Europe. 2021. Plastics: The Facts. https://plasticseurope.org/wp-content/uploads/2021/12/ Plastics-the-Facts-2021-web-final.pdf Platt, B., Lent, T., and Walsh, B. 2005. The Healthy Building Network’s Guide to Plastic Lumber. Institute of Local Self-Reliance (ILSR), Washington, DC, June. https://www. greenbiz.com/sites/default/files/document/CustomO16C45F64528.pdf PTI. 2015. Jamshedpur’s Plastic Roads Initiative is a lesson for all Indian cities! India Times. http:// www.indiatimes.com/news/india/everyindian-city-needs-to-learn-from-juscos-plastic- roads-in-jamshedpur-232246.html Ragaert, K., Delva, L., and Van Geem, K. 2017. Mechanical and chemical recycling of solid plastic waste. Waste Management 69:24-58. Rahmani, E., Dehestani, M., Beygi, M. H. A., Allahyari, H., and Nikbin, I. M. 2013. On the mechanical properties of concrete containing waste PET particles. Construction and Building Materials 47:1302-1308. Ramadevi, K., and Manju, R. 2012. Experimental investigation on the properties of concrete with plastic PET (bottle) fibres as fine aggregates. International Journal of Emerging Technology and Advanced Engineering 2(6):42-46. Reis, J. M. L., Chianelli-Junior, R., Cardoso, J. L., and Marinho, F. J. V. 2011. Effect of recycled PET in the fracture mechanics of polymer mortar. Construction and Building Materials 25(6):2799-2804.

282 RECYCLED PLASTICS IN INFRASTRUCTURE Saikia, N., and De Brito, J. 2014. Mechanical properties and abrasion behaviour of concrete containing shredded PET bottle waste as a partial substitution of natural aggregate. Construction and Building Materials 52:236-244. Schuyler, Q., Hardesty, B. D., Lawson, T. J., Opie, K., and Wilcox, C. 2018. Economic incen- tives reduce plastic inputs to the ocean. Marine Policy 96:250-255. Shankar, A. U., Koushik, K., and Sarang, G. 2013. Performance studies on bituminous con- crete mixes using waste plastics. Highway Research Journal 6(1). Sharma, R., and Bansal, P. P. 2016. Use of different forms of waste plastic in concrete—a review. Journal of Cleaner Production 112:473-482. Singh, B., and Kumar, P. 2019. Effect of polymer modification on the ageing properties of asphalt binders: Chemical and morphological investigation. Construction and Building Materials 205:633-641. Sommer, F., Dietze, V., Baum, A., Sauer, J., Gilge, S., Maschowski, C., and Gieré, R. 2018. Tire abrasion as a major source of microplastics in the environment. Aerosol and Air Quality Research 18(8):2014-2028. Stutz, J., Donahue, S., Mintzer, E., and Cotter, A. 2003. Plastic Lumber in Landscaping Ap- plications. Tellus Institute, May 12. https://www.csu.edu/cerc/researchreports/documents/ PlasticLumberinLandscapingApplications.pdf Suksiripattanapong, C., Uraikhot, K., Tiyasangthong, S., Wonglakorn, N., Tabyang, W., Jomnonkwao, S., and Phetchuay, C. 2022. Performance of asphalt concrete pavement reinforced with high-density polyethylene plastic waste. Infrastructures 7(5):72. Syberg, K. 2022. Beware the false hope of recycling, Outlook. Nature 611:S6. https://doi. org/10.1038/d41586-022-03645-0 U.S. Environmental Protection Agency (USEPA). 2020. Advancing Sustainable Materials Management: 2018 Assessing Trends in Material Generation, Recycling, Composting, Combustion with Energy Recovery and Landfilling in the United States. Washington, DC: USEPA. Usman, M., Javaid, A., and Panchal, S. 2015. Feasibility of waste polythene bags in concrete. International Journal of Engineering Trends and Technology 23(6):317-319. Vargas, C., and El Hanandeh, A. 2021. Systematic literature review, meta-analysis and artifi- cial neural network modelling of plastic waste addition to bitumen. Journal of Cleaner Production 280:124369. Vasudevan, R., Sekar, A. R. C., Sundarakannan, B., and Velkennedy, R. 2012. A technique to dispose waste plastics in an ecofriendly way—Application in construction of flexible pavements. Construction and Building Materials 28(1):311-320. Werbowski, L. M., Gilbreath, A. N., Munno, K., Zhu, X., Grbic, J., Wu, T., Sutton, R., Sed- lak, M. D., Deshpande, A. D., and Rochman, C. M. 2021. Urban stormwater runoff: A major pathway for anthropogenic particles, black rubbery fragments, and other types of microplastics to urban receiving waters. ACS ES&T Water 1(6):1420-1428. White, G., and Reid, G. 2018. Recycled waste plastic for extending and modifying asphalt binders. In 8th Symposium on Pavement Surface Characteristics (SURF 2018), Brisbane, Queensland, Australia (pp. 2-4). Willis, R., Yin, F., and Moraes, R. 2020. Recycled Plastics in Asphalt Part A: State of the Knowledge. Greenbelt, MD: National Asphalt Pavement Association.

Next: Appendix G: Durability and Life-Cycle Implications of Repurposing Plastics Waste in Infrastructure: A Case Study »
Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

In the U.S., most plastics waste is disposed in landfills, but a significant amount also ends up as litter on land, rivers, and oceans. Today, less than 10 percent of plastics waste is recycled in the U.S. annually. The use of recycled plastics in infrastructure applications has potential to help expand the market and demand for plastics recycling.

These are among the findings in TRB Special Report 347: Recycled Plastics in Infrastructure: Current Practices, Understanding, and Opportunities from the Transportation Research Board of the National Academy of Sciences, Engineering, and Medicine.

The report emphasizes that pursuing the recycling of plastics in infrastructure depends on goals, policy, and economics. To that end, life cycle economic and environmental assessments should be conducted to inform policies on plastics waste reuse.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!