Plastic waste as strength modifiers in asphalt for a sustainable environment

This research took the form of an investigation into the applicability of polyethylene terephthalate (PET) as strength modifiers in asphalt road construction. Samples of thoroughly washed, naturally dried and shredded PET wastes were collected. The optimum binder content (OBC) of the unmodified asphalt mix was determined. The bitumen used for the control mix was replaced with PET waste in 1, 3 and 5% proportions. Another sample was prepared with the addition of 1, 3 and 5% of PET waste while the OBC was fixed. The samples were subjected to Marshall Stability (MS) and Marshall Flow (MF) tests. Bulk density (BD), void in total mix (VTM), and void filled with bitumen (VFB) were determined. The results were compared with standards. The PET content obtained that conforms to the specification in AASHTO, ASTM and Nigeria Federal Ministry of Works standards was found to be 1% addition to OBC by weight of aggregate. This percentage PET content was 15% by weight of bitumen with BD, VTM, VFB, MF and MS being 2.38 kg/m3, 3.33%, 82.20%, 4.00 mm and 17.01 kN, respectively. The 1% PET modified asphalt was found to be useful for pavement construction and reduces the quantity of plastic waste in our environment.