Properties of bitumen modified by polyethylene and polyethylene glycol with different molecular weights

Abstract

ABSTRACT Polyethylene (PE) and polyethylene glycol (PEG) with three different molecular weights are employed to modify bitumen, which is denoted as the polymer-modified bitumen (PMB). The samples, PMB-L, PMB-M and PMB-H, indicate PE/PEG modified bitumen in which PEG molecular weight is from low to high. PEGs and PMBs exhibit different crystallisation and melting behaviours measured by a differential scanning calorimeter. Rutting resistance and elastic property of PMBs under high temperature are studied by a rheometer. By analysing the complex modulus variation with temperature increment, it is found that the rheological stability is better for PMB-L and PMB-H, revealing a non-monotonous relationship with PEG molecular weight. The mechanical property of PMBs under low temperature is detected by their tensile behaviour and glass transition temperature, both of which reflect the weak ductility and low-temperature property of PMB-H. The reason for different properties of PMBs is interpreted by the phase structure and their stability, especially by the size and location of the PEG-rich phase.