A comprehensive review of bio-oil, bio-binder and bio-asphalt materials: Their source, composition, preparation and performance

To promote the application of bio-materials and provide a direction for their further re-searches, this paper comprehensively summarizes the research progress of biomaterials in recent years. The review results show that bio-oil is a mixture obtained from different biomasses through pyrolysis, alcoholysis, acidolysis, high liquefaction, etc., and those biomasses mainly include wood fiber type, waste oil type and animal manure type. Bio-binder refers to the product of bio-oil processed by distillation, extraction oxidation and polymer modification, and it can be served as a modifier, diluent or substitute material of asphalt; the main chemical components of bio-oil include ethers, esters, aldehydes, ke-tones, phenols, organic acids, alcohols and sugars. Bio-asphalt is obtained by adding bio-binder into the petroleum asphalt for modification or blending, and the shear temperature and shear rate of bio-asphalt derived from wood fiber type and waste oil type are usually higher than that of bio-asphalt derived from swine manure. Compared with petroleum asphalt, bio-asphalt binder usually shows lower high-temperature performance as well as higher low-temperature performance and aging resistance. Also, bio-asphalt mixture generally exhibits lower high-temperature stability, higher low-temperature crack resis-tance and water stability than petroleum asphalt mixture. Future studies should be con-ducted combining with the source, composition, preparation, properties and oil production rate of bio-oil. First, how to raise the bio-binder content in bio-asphalt as much as possible while ensuring the sufficient performance becomes the focus of future researches. Second, the micro reaction mechanism between bio-binder and petroleum asphalt should be illustrated in depth. Moreover, developing a complete and unifying technical standard and application specification of bio-asphalt technology is necessary for future researches. Furthermore, determining the optimum bio-binder potentially used as the substitute of petroleum asphalt is also an interesting topic. (c) 2022 Periodical Offices of Chang'an University. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).