AUTHOR=Suo Zhi , Chen Huan , Yan Qiang , Tan Yitian , Li Xinghai , Zhang Ao TITLE=Laboratory Performance Evaluation on the Recovering of Aged Bitumen With Vegetable Oil Rejuvenator JOURNAL=Frontiers in Materials VOLUME=8 YEAR=2021 URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2021.650809 DOI=10.3389/fmats.2021.650809 ISSN=2296-8016 ABSTRACT=

Generally, the conventional rejuvenator contains many mineral oils to supply the missing components of aged bitumen. The mineral oils could recover the performance of aged bitumen go through a long-term aging process. However, the mineral oils are easy to volatilize at higher recycling temperature. The higher volatilization will reduce the effect of rejuvenator and limit proportion of reclaimed asphalt pavement (RAP) in recycled asphalt mixture (RAP contents less than 30%). The main components of vegetable oil are straight chain higher fatty acids and glycerides. The esters of straight chain higher fatty acids and glycerol are not volatile at high temperature. Therefore, they can be used to recover the micro chemical composition of bitumen and a change in colloidal stability of asphaltene. In this research, two newly kinds of bitumen rejuvenator were developed by replacing mineral oil with waste cooking corn and soybean oil. The two kinds of vegetable and a mineral bitumen rejuvenators were utilized to recover aged bitumen with 2–10% by weigh. The objectives of the research are evaluating the rheological properties, high temperature and fatigue performance of the recovered bitumen. The Dynamic Shear Rheometer Test and Rotational Viscosity Test were conducted according to the AASHTO and ASTM standards. Additionally, the crack resistance of bitumen was evaluated by using the bending beam rheometer (BBR) test at −12 and −18°C. The result of laboratory test and statistical analysis of ANOVA showed that the vegetable oil rejuvenators effectively reduce the viscosity and stiffness of aged bitumen. It will improve both the fatigue resistance and low temperature crack resistance. In addition, when the content of vegetable oil is higher, the rejuvenating agent can make the recovered bitumen have lower viscosity and stiffness. Considering that the rutting resistance under high temperature, it is suggested that 6 and 8% vegetable oil be used to recover the aged bitumen.