This study compares the results of four asphalt extraction methods: the Quick (WSDOT 711), the Vacuum (AASHTO T-164 Method E-11), the Centrifuge (AASHTO T-164 Method A), and the Reflux (AASHTO T-164 Method D).
The methods are compared on the basis of the amounts of trichloroethane used, the exposure to trichloroethane while testing, the time needed to do the testing, and the accuracy of the asphalt content and aggregate gradation determinations (with the Reflux method serving as the standard of comparison).
It was concluded that the Quick method was still the best alternative to the Reflux method, based primarily on the speed of the test and its close agreement with the Reflux method on asphalt content and percent passing the #200 sieve. All methods provided exposure to trichloroethane vapor well below the recommended allowable levels.
Washington (State). Dept. of Transportation. Materials Laboratory.
Accuracy, Aggregate gradation, Alternatives analysis, Asphalt concrete, Asphalt content, Resource extraction.