Analysis of waste polyethylene (PE) and its by-products in asphalt binder

The use of waste plastics in partial asphalt binder replacement and substitute for polymer modification has the potential to contribute to the sustainability of road infrastructure as well as preservation of natural resources. In this study, two types of polyethylene (PE) waste plastics PE-pellets and PE-shreds (a by-product of the former, currently incinerated after production) were blended with a conventional asphalt binder in order to analyze their effect on the chemo-mechanical and thermal behavior. Particular attention was paid to the characterization of the waste PE as well as to the description of sample preparation, lacking in other studies. Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy and Environmental Scanning Electron Microscopy (ESEM) were used to assess the different types of PE and blended asphalt binder's thermal properties, chemical modification degree and quality of blending, respectively. The rheological performance of waste PE blended binder was obtained using the Dynamic Shear Rheometer (DSR). The results illustrated that compared to commercial polymer modified binders, the binder resistance against high temperature distresses such as rutting could improve substantially with adding waste PE. The modulus of the binders at low temperatures was comparable. However, the negative results of high temperature storage stability of the PE blended binders indicated that attention needs to be paid to the mixture preparation method.