In the context of a literature study for the Ministry of Transportation of Ontario, a survey was conducted on asphalt binder extraction and recovery, with government agencies and research laboratories in the United States, Canada and Europe participating, receiving 40 responses. Respondents from United States Departments of Transportation (DOTs) comprised the majority of responses. The survey covered three categories of test evaluation: apparatus type, performance and safety. The Centrifuge was found to be the most common extraction method, the Rotary Evaporator was found to be the most common method of recovery and Trichloroethylene was found to be the most common solvent. Only two respondents mentioned using bio-sourced solvents. The most common uses for extraction and recovery were for the analysis of RAP binder and the determination of binder content. The determination of binder content was found to be consistent by all of the respondents. About half of the respondents found that the recovered binder properties were modified during extraction and recovery process in a significant way while the others found issues with binder aging and solvent remaining in the binder. Concerns were raised about the testing of RAP and PMA binders, in terms of difficulty in breaking them down. The average extraction and recovery took around 5 hours. Operator safety concerns focused mostly on volatiles and handling at hot temperatures, while environmental safety concerns focused on toxic chemicals and waste disposal. A number of recommendations were provided by the respondents for improving the test methods.
Keywords: asphalt binder, extraction, recovery, solvent, HMA, RAP, safety.
Mikhailenko, P.
