Use of polymers to modify asphalt binder, even at a minority of the pavement structure, improves longevity and allows for higher traffic without rutting or cracking failures. We discuss two topics: the historical development of ethylene-based polymers in this application space and how they can successfully compatibilize recycled plastics.<br/><br/>The polymer chemistries to be reviewed include the most basic structure with polyethylene through more complex copolymers incorporating glycidyl side chains. Polyethylene is a poor choice as a modifier due to both its non-polar nature and plastomeric properties that are incompatible with the asphalt binder and fail to meet required performance properties. Copolymers such as more advanced systems, including Reactive Elastomeric Terpolymers, RET, have been demonstrated to be highly compatible and offer significant performance enhancements, including resistance to rutting and cracking failure modes.<br/><br/>Asphalt pavement is the most recycled material in the United States. In the last 30 years, there have been well over 100 field projects attempting to incorporate waste plastics as modifiers. These efforts have met with limited success both emotionally and technically. The view of pavements as linear landfills has met stiff resistance from the construction industry. As discussed in topic one, polyethylene is incompatible with asphalt, and its plastomeric properties do not meet performance standards. RET has been successfully used to compatibilize PE-rich recycled materials while meeting key AASHTO M320 and M332 standards. We will review both lab and field-testing results that have guided the development of these hybrid RET/recycled PE systems. These results include asphalt binder and Balanced Mix Design (BMD) testing, theoretical pavement structural analysis showing improvements over styrenic-based elastomers and multi-year field monitoring results.

Ethylene-based copolymers in infrastructure applications

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.