Preparation process to affect stability in waste polyethylene-modified bitumen

An analysis of waste polyethylene (WPE) modified bitumens prepared using a variety of approaches is described in this study. The WPE was obtained from commercially-available packaging bags. It has recently been shown that addition of WPE to bitumen enhances the high temperature stability of the modified bitumen. In this paper, WPE-modified bitumens were prepared using a high-speed shear mixer employing different processing parameters. High temperature storage stability tests and morphological analysis showed that a shear rate of 3750 rpm, at 150 °C and shear time of 1.5 h to be the optimal processing parameters of storage stability. In addition, differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to analyze the thermal stability of the WPE-modified bitumen. We found that the thermal stability of the modified bitumen surpassed that of the base bitumen, but was generally independent of the preparation parameters.