Plastic waste is considered amongst the most harmful waste materials that pollute the environment and pose serious health hazards to human and animals. Unfortunately, it is extremely resistive against natural decay. Its unplanned disposal raises significant global concern. This research work was aimed at investigating the potentials of using waste plastic, specifically the commonly wasted Low Density Polyethylene (LDPE), in a useful and sustainable manner, like flexible pavements. The common rheological properties and viscosity-temperature susceptibility (VTS) of the recycled waste plastic-modified asphalt binder, and the stability properties of related hot mix asphalt (HMA), were critically evaluated. This research has indicated that consistency, temperature susceptibility, stiffness, and other rheological properties of asphalt binder and the stability of the HMA could be improved by adding waste plastic to asphalt binder. Although the study sought to determine the optimal dosage of plastic, the results are inconclusive due to the complexity of the parameters involved. The waste plastic-modified asphalt was found to have improved characteristics in terms of traditional and advanced asphalt characterization tests. While using the waste plastic-modified asphalt in HMA mixes, the outcomes of the volumetric analysis and Marshall Stability test are inconclusive in the range of test parameters used. The HMA mixes prepared with the waste plastic-modified asphalts were found to behave more like the gap-graded mix, which is common for a few other modified asphalt concretes such as the crumb rubber-modified asphalt concrete mixtures.