Use of Ocean Plastic Waste in Road Construction

Roughly 8 million metric tons of plastic waste pollute the world’s oceans annually and detrimentally impact the environment. It is estimated that ocean plastic waste costs society up to $2.5 trillion/year. Abandoned fishing nets, one type of ocean plastic waste, are a major threat to marine habitats and biodiversity.These “ghost nets” account for 52% of the Great Pacific Garbage Patch where they snare, trap and kill commercial and endangered marine life. Ocean plastic waste is a diverse heterogeneous mixture of unsorted plastics that is severely damaged by the environment making it difficult to recycle. Efforts are being made to recycle ocean plastic into consumer products (e.g., clothing, footwear, eyewear). The average lifetimes of these products, however, are less than 3 years so the same plastic needs to be recycled frequently and the volumes are insufficient to match the outlet need.A more sustainable solution and higher volume outlet is needed. The problem will be addressed through the creation of an asphalt additive based on ocean plastic.The asphalt modifier can be easily incorporated into new road and re-pavement and increases road strength and durability. The asphalt road construction industry is one of the nation’s most sustainable industries. Nearly 100% of used asphalt in roads is recycled which is a very high rate compared to the plastic (9%), paper (66%), metals (33%), andglass (25%) industries. Asphalt roads last 25-35 years, so the recycled ocean plastic does not need to be revisited regularly. Asphalt formulations, additionally, are robust and do not require the pristine purity needed for plastic consumer products.This reduces recycling costs. In Phase I, the technical feasibility of an asphalt modifier that combines fibers from waste fishing nets with other ocean plastics using a compatibilizer will be created. The formulation will use traceable recovered fishing nets and ocean plastic and be evaluated using standard asphalt paving testing methods.The commercialization value chain involving ocean plastic suppliers, commercial plastic processing companies, and asphalt pavement manufacturers will be developed. In Phase II, intermediate and road performance trials of the best formulations will be conducted with the identified partners. The recycling of ocean plastic waste is a very sustainable solution. The commercialization of the product is expected to result in the recycling of 45,000 MT of ocean plastic waste over ten years. Successful commercialization of using ocean plastic waste into asphalt paving application has several anticipated public benefits: reduction of green-house gas emissions and non-renewable energy usage by replacing asphalt aggregate andasphalt binder with ocean plastic, U.S. developed technology for ocean plastic waste recycling that can be leveraged to locations around the globe where the problemis greater, reduction in landfill costs for disposal of ocean plastic waste, improved recreational, tourism and diving benefits from reduced gear on beaches and at sea, reduced safety risks for marine vessels when maneuverability is compromised by net entanglement, a new large potential avenue enabling low value “land based” plastic to be recycled into roads.