Value-added application of waste PET based additives in bituminous mixtures containing high percentage of reclaimed asphalt pavement (RAP)

The use of reclaimed asphalt pavement (RAP) in road pavement construction has been widely encouraged due to its environmental and economic benefits. However, the percentage of RAP is usually capped at low percentages as studies have shown that a high percentage of RAP might be detrimental to overall pavement performance. Recent research has shown that the addition of waste plastic materials such as Polyethylene Terephthalate (PET) or their functionalized additives into asphalt pavement may potentially improve the durability of pavement and also help alleviate the environmental problems caused by plastic. The main objective of this study is to investigate the feasibility of using the additives, derived from waste PET through an aminolysis process, to improve the performance of bituminous mixtures containing RAP, by characterising the binder properties. To achieve this objective, binder samples composed of virgin bitumen, aged bitumen at various percentages, and PET derived additives, were prepared. These samples were then characterized through various laboratory tests, including dynamic shear rheometer, bending beam rheometer, moisture susceptibility, infrared red spectroscopy and fluorescence microscopy tests. The results indicated that the samples containing RAP and PET derived additives provided better overall performance compared to the conventional binder, increasing the rutting resistance by at least 15% and fatigue cracking resistance by up to 60%. Usage of such waste PET based additives as an additive for RAP mixtures represents an approach to deal with a relevant recycling problem while simultaneously recovering two value-added materials.