Low density polyethylene for asphalt binder modification

Nowadays, the use of polyethylene (PE) for bitumen modification has become widespread due to the major advantage of environmental sustainability. For the application of PE modified binder, it is necessary to first study the compatibility of polyethylene and bitumen. In this study, low density polyethylene (LDPE) was blended with the binder in five different dosages (1, 2, 3, 4 and 5%) and PE wax (3% and 2% LDPE+1% Wax) was added to the binder in two dosages (3% and 2% LDPE+1%wax). The dispersion of polyethylene in binder was observed using an optical microscopy and images were captured at different time intervals of 30 and 150 minutes. It was noticed that the equivalent diameter of PE particles increased with time. When PE wax introduced to the blend, the total polymer content was maintained as 3%, because the polymer started forming large size agglomerates above 3% dosage. The addition of PE wax improved the polymer dispersity in blend. To understand the phase separation, viscosity-temperature profile of these binders were studied using temperature sweep experiment, in which the viscosity values were measured during temperature decrement from 160 to 100°C and increment from to 100-160°C. The higher difference in viscosity values represent the instability of binder and the binder with higher LDPE content was found to be more instable.