Preparation process of bio-oil and bio-asphalt,their performance,and the application of bio-asphalt:A comprehensive review

The objective of this paper is to establish the state of knowledge on fast pyrolysis of bio-oil and bio-asphalt binder and to facilitate efforts in improving the overall perform ance of bioasphalt and maximizing its road application.On the basis of reviewing the relevant literature recently,the fast pyrolysis(FasP) preparation process of bio-oil and its main properties,the preparation process of bio-asphalt and its performance and the application of bio-asphalt have been summarized.Due to the variations in raw materials,the adopted methods of FasP to prepare bio-oil could be different,and the properties of bio-oil from different sources are also different.At present,the plant-based bio-oil(mainly derived from wood waste and sawdust) has been widely used to prepare the bio-asphalt.Research on the low-temperature flexibility,high-temperature rheology,workability and other performance of biological asphalt showed that the workability and high-temperature performance of most asphalt are improved after adding bio-oil.However,the low-temperature performance is found to relatively reduce.Also,with regards to its application as a rejuvenator,bio-oil can considerably rejuvenate the aged asphalt’s mixture performance.By far,most of research on bio-asphalt is still focused on the performance of bio-asphalt binder in the laboratory;its application in practical road engineering is still to be examined.This review also provides an outlook for the future,for example,establishing an integrated preparation process from bio-oil to bio-asphalt,and evaluating the properties of bioasphalt by new standards.