EXPERIENCES WITH THE CORBETT-SWARBRICK PROCEDURE FOR SEPARATION OF ASPHALT INTO FOUR GENERIC FRACTIONS

The Corbett-Swarbrick procedure for separation of asphalt into four generic fractions is evaluated. This procedure, currently accepted as an ASTM standard (ASTM D 4124-82), has been submitted to the ASTM committee for revision. The revised procedure involves considerable modifications to the existing standard. Oregon State University and the Oregon State Highway Division have implemented both procedures (the current ASTM standard and the revised procedure) and routinely used them in an ongoing research program. A number of difficulties have been experienced with both procedures. Some of these difficulties are related to interpetation of the standard and some were due to the inexperience of the research team with the test procedures. The purpose of this paper is to present some of the ways the research team solved the major difficulties encountered with the implementation of the test. Several aspects of the test procedure are analyzed: method used for asphaltene precipitation, filtration, solvent concentration, and some problems related to the use of alumina and the chromatographic column.