Performance of waste plastic bio-oil as a rejuvenator for asphalt binder

Pavement recycling is actively applied on asphalt roads due to ageing problems associated with bituminous binders when exposed to weathering and trafficking during their service life. Recycling of asphalt occurs through rejuvenator agents. This study utilised bio-oil produced from hydrothermal liquefaction of waste plastic films (linear low-density polyethylene - LLDPE) to rejuvenate laboratory-aged bitumen. Initially, the neat bitumen was aged through thermal ageing (Pressure Ageing Vessel - PAV) and then the aged binder was mixed with bio-oil from waste plastics at 5% and 8% bio-oil (BO) by weight of aged binder. All four binders including neat bitumen, aged bitumen, aged bitumen/BO-5% and aged bitumen/BO-8% were analysed for thermogravimetric analysis, Fourier Transform InfraRed analysis, rheology in the linear viscoelastic region, multiple stress creep and recovery analysis, and linear amplitude sweep analysis. The ageing of neat binder resulted in hardening of the binder, however, the bio-oil rejuvenator softened the aged binder significantly. The thermo-chemical and rhcological performance of aged binder was significantly improved after the addition of bio-oil. The outcomes suggest how bio-oil produced from hydrothermal liquefaction of waste plastics (possibly non-recyclable) may serve as potential rejuvenator for aged asphalt binders in an effort to recycle more using non-recyclable material.

Automated summary

Pavement recycling is a promising solution for addressing the ageing problems of asphalt roads, and this study investigates the use of bio-oil from waste plastics as a rejuvenator for aged bitumen. The results show that the addition of bio-oil significantly softens the aged binder and improves its thermo-chemical and rheological performance. This has important implications for recycling more asphalt using non-recyclable materials.