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From page 101... ... 101 6 Applications of Recycled Plastics in Pavements One of the greatest opportunities for using recycled plastics in infrastructure may be as a component material in pavements. Although some articles in the press and social media have claimed that "plastic roads" are a win-win and a solution to both the growing plastics waste problem and a means to achieve better roads and highways (Friedrich 2021; Lee 2021) Read the entire page →
From page 102... ... 102 RECYCLED PLASTICS IN INFRASTRUCTURE and development on the use of recycled plastics has been undertaken for this application. Some preliminary studies have been conducted on the use of recycled plastic in Portland cement concrete for general construction applications; a summary of those studies is provided in Chapter 7 and in Appendix F Read the entire page →
From page 103... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 103 The possible quantity of plastics that could be consumed in asphalt pavement applications will depend on the cost of the recycled plastic supply relative to other additives that provide similar benefits, the dosage rate (which will depend on the method of adding the recycled plastic, described in this section) , and the benefits to pavement performance, if any. Read the entire page →
From page 104... ... 104 RECYCLED PLASTICS IN INFRASTRUCTURE resistance to damage caused by heavily loaded trucks and extreme weather conditions. The most common polymer used to modify asphalt binders for high-grade applications is the block copolymer styrene-butadiene-styrene (SBS) Read the entire page →
From page 105... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 105 When considering the potential use of recycled plastics, or any other new material, in an asphalt pavement, one of the first questions is how it will impact pavement performance and service life. All state DOTs evaluate the condition of their highway network on an annual or semiannual basis using vans equipped with sensors and imaging systems to collect data on pavement health. Read the entire page →
From page 106... ... 106 RECYCLED PLASTICS IN INFRASTRUCTURE There are numerous options for the types of pavement preservation treatment or rehabilitation needed to restore a distressed pavement to good condition. By far, the most common approach to asphalt pavement rehabilitation is to cold mill the top couple of inches of the existing pavement (partial depth removal) Read the entire page →
From page 107... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 107 an asphalt mix containing 20 percent RAP reduces the cradle-to-gate greenhouse gas (GHG) emissions by 12 percent (Shacat 2023) Read the entire page →
From page 108... ... 108 RECYCLED PLASTICS IN INFRASTRUCTURE to eyes and throat, but are not currently regulated as an emission health hazard. Mix temperatures below 149°C (300°F) Read the entire page →
From page 109... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 109 polymer-modified asphalt binders that use virgin polymers to enhance the cracking- and deformation-related properties of asphalt binders. More than 260 million scrap tires are generated each year in the United States. Read the entire page →
From page 110... ... 110 RECYCLED PLASTICS IN INFRASTRUCTURE large states for decades, which indicates that no significant issues have been identified that would challenge the circularity of RTR-modified mixtures. However, some studies (Alavi et al. Read the entire page →
From page 111... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 111 FIGURE 6-5 Sustainability elements associated with pavement life-cycle states. SOURCE: Adapted from FHWA 2019. Read the entire page →
From page 112... ... 112 RECYCLED PLASTICS IN INFRASTRUCTURE FIGURE 6-6 Novophalt blending unit used to blend LDPE and other polymers into asphalt binder. SOURCE: Advanced Asphalt Technologies LLC. Read the entire page →
From page 113... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 113 BOX 6-1 Field Trials of Asphalt Mixes with Recycled Plastics in New York City In August 2022, Rice Avenue and Royal Oak Road, in the New York City (NYC) Borough of Staten Island, were the locations of the first field trials of asphalt mixes containing waste plastic in NYC. Read the entire page →
From page 114... ... 114 RECYCLED PLASTICS IN INFRASTRUCTURE to be used in asphalt mixture production at dosages of 6 to 8 percent by weight of the asphalt binder. It is unknown if the use of recycled plastics has a positive or negative impact on performance of the highway network in India. Read the entire page →
From page 115... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 115 FIGURE 6-7 Illustrations of wet and dry processes at an asphalt plant. TABLE 6-2 Summary of Advantages of Wet and Dry Methods for Adding Plastics to Asphalt Mixtures Method Advantages Disadvantages Unknowns Wet • Types of plastic and dosages can be optimized to achieve enhanced asphalt binder properties. Read the entire page →
From page 116... ... 116 RECYCLED PLASTICS IN INFRASTRUCTURE Additional Background Information from a Literature Review In 2021, NCAT at Auburn University completed a comprehensive literature review as part of study funded by the National Cooperative Highway Research Program (NCHRP) Read the entire page →
From page 117... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 117 funded by Australia and New Zealand) was completed under the title Use of Road-Grade Recycled Plastics for Sustainable Asphalt Pavements. Read the entire page →
From page 118... ... 118 RECYCLED PLASTICS IN INFRASTRUCTURE to include the melting point and size of the plastic particles, the temperature profile and sequence of materials addition, and compatibility characteristics of the asphalt binder and plastics. Plastics that do not melt are assumed to become an inert part of the aggregate matrix. Read the entire page →
From page 119... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 119 assessments. Other references included literature reviews, cost analyses, pavement design, production information, technical guidance, environmental impact assessment, or agency specifications. Read the entire page →
From page 120... ... 120 RECYCLED PLASTICS IN INFRASTRUCTURE Several projects that do have experimental value for assessing the effect of the added plastics include projects in Alabama, Minnesota, Missouri, New York, Pennsylvania, and Virginia (see Boxes 6-1, 6-2, and 6-3 for brief summaries of projects in New York City, Pennsylvania, and Missouri, respectively) Read the entire page →
From page 121... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 121 BOX 6-2 Pennsylvania's Experience with Post-Consumer Plastics in Asphalt The Pennsylvania Department of Transportation (PennDOT) in collaboration with Pennsylvania State University (PSU) Read the entire page →
From page 122... ... 122 RECYCLED PLASTICS IN INFRASTRUCTURE and (2) developing tests to optimize the blend for plastic type, content, degradation status, and existing modification processes. Read the entire page →
From page 123... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 123 BOX 6-3 Missouri's Experience with Post-Consumer Plastics in Asphalt In the summer of 2021, the Missouri Department of Transportation and the Missouri Center for Transportation Innovation undertook the first project in the state to use post-consumer recycled waste plastic in asphalt. The project is located in Columbia, Missouri, on a section of roadway that sees more than 8,000 vehicles per day. Read the entire page →
From page 124... ... 124 RECYCLED PLASTICS IN INFRASTRUCTURE accelerated pavement testing facility located near Auburn, Alabama, that serves as a national proving ground for asphalt pavement technologies. One of the test sections containing recycled plastics used the dry process and the other test section used the wet process. Read the entire page →
From page 125... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 125 The 1-mi test sections utilized two different proprietary recycled plastic products added by the dry process to the mixtures used for the 1.5-in. overlay. Read the entire page →
From page 126... ... 126 RECYCLED PLASTICS IN INFRASTRUCTURE State of Practice and Research Multiple research projects have conducted laboratory testing exploring the inclusion of recycled plastic for soil stabilization. No field trials were found in published documentation, although a new project led by Iowa State plans to conduct field test sections in future years. Read the entire page →
From page 127... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 127 test sections will be constructed to assess the performance. At the end of the project, a practitioner's guide will be developed to document best practices and accelerate implementation. Read the entire page →
From page 128... ... 128 RECYCLED PLASTICS IN INFRASTRUCTURE FINDINGS • Numerous marketing claims and media reports suggest that using recycled plastics in asphalt pavements is a win-win, solving both an environmental problem of plastics waste while lowering the cost of and improving the life of asphalt pavements. However, there is essentially no evidence at this time to support the claims that the addition of recycled plastics will extend the life of asphalt pavements, and the purported cost savings have not been adequately documented. Read the entire page →
From page 129... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 129 generated from the wear of pavement surfaces containing recycled plastics will have negative consequences on air quality or stormwater runoff from real projects. There is also very limited information on the recyclability of asphalt pavements containing plastics waste. Read the entire page →
From page 131... ... APPLICATIONS OF RECYCLED PLASTICS IN PAVEMENTS 131 The White House. Read the entire page →

From page 101...

... 101 6 Applications of Recycled Plastics in Pavements One of the greatest opportunities for using recycled plastics in infrastructure may be as a component material in pavements. Although some articles in the press and social media have claimed that "plastic roads" are a win-win and a solution to both the growing plastics waste problem and a means to achieve better roads and highways (Friedrich 2021; Lee 2021)