Multi-Damage Healing Ability of Modified Bitumen with Waste Plastics Based on Rheological Property

To explore the influence of waste plastics on the self-healing ability of bitumen, the healing effect of multiple damages, and enlarge the utility of waste plastic in pavement through dynamic shear rheology (DSR) tests, multiple repeated loading tests with fatigue-healing-fatigue as the basic cycle were conducted on modified bitumen samples containing five types of waste plastics (PET, HDPE, PP, PS, and PVC) with different dosages. The damage healing ability of bitumen of the same waste plastic with different dosage ratios and the same dosage of different waste plastics under the same healing time, loading strain, and damage degree through single and multiple loading were explored and analyzed. The results show that based on the three sets of data of the complex shear modulus, phase angle, and fatigue factor, the PS and PVC-modified bitumen have a better recovery performance than that of the other three types of modified bitumen, and the latter also has the best fatigue resistance property. To maximize the improvement effect on the healing index of bitumen, the recommended optimal dosages of PET, HDPE, PP, PS, and PVC are 2%, 2%, 2%, 6%, and 4%, respectively. PS has the best promoting effect on the damage healing ability of bitumen after undergoing multiple damages, while PET has the worst improvement effect. The findings can provide theoretical support and guidance for the wide application of waste plastic-modified bitumen pavement.