Incorporating Recycled Plastics in Asphalt Binders and Mixtures
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Authors
Arunthavabalan, siththarththan
Issue Date
2021
Type
Thesis
Language
Keywords
compatibilizer , pavement engineering , Plastics , wet process
Alternative Title
Abstract
Plastic has become an unavoidable material in modern life, and its existence spans from food packaging to transporting goods. Due to the low cost and durability of plastic products, the growth in plastic production has been increasing exponentially. The increased production increased plastic waste. The awareness for plastic waste management also grew due to unmanaged plastic waste and its pollution for the environment. Plastic recycling has become a significant problem worldwide due to ever-increasing plastic waste. Due to the lack of recycling, approximately 75 percent of plastic waste ended up in landfills in 2018. In the U.S., recycled plastic has been tested in different construction materials such as soil, concrete, and pavement materials to enhance the engineering properties of those materials and reduce the amount of plastic accumulating in landfills. Plastics have been tested in pavement materials as binder modifiers, binder replacement, and aggregate replacement or additive. Due to plastics' plastomeric nature, the addition of plastic makes the asphalt binder and asphalt mixture stiffer�"the incorporation of plastic shifts the performance grade temperature of asphalt binder and plastic blends towards the warmer side. The development of compatibilizers mitigated the drawbacks caused by incorporating recycled low-density polyethylene (rLDPE) in asphalt binder. Compatibilizers with polyisoprene (PI) and polybutadiene (PBD) backbones synthesized with polyethylene-block-polyethylene (glycol) (PEPEG) at two different molecular weights were tested. The effect of unreacted Maleic anhydride (MAH) in the compatibilizers was also evaluated.Polyisoprene (PI) and polybutadiene (PBD) were found effective in 1 percent and 2 percent rLDPE blends, respectively, and polybutadiene was considered an effective compatibilizer. PBD grafted with lower molecular weight PEPEG and a low level of unreacted MAH helped maintain the high-temperature performance grade while reducing the lower temperature grade of the asphalt plus 2 percent rLDPE blend.