EFFECT OF PHOTOOXIDATION ON MOLECULAR WEIGHT DISTRIBUTIONS OF CORBETT ASPHALT FRACTIONS BY GEL PERMEATION CHROMATOGRAPHY

ABSTRACT

Oxidation of asphalt is believed to be one of the major contributing factors to the failure of asphalt pavement. Due to molecular complexity, the oxidation mechanism of asphalt is complicated by interactions among the molecules of different types. To minimize the interactions, the asphalt sample was separated into saturates, naphthalene aromatics, polar aromatics, and asphaltenes. These Corbett fractions were then oxidized under ultraviolet irradiation. Gel permeation chromatography was used to analyze the molecular weight changes of the Corbett fractions during photooxidation. All Corbett fractions have shown significant increase in molecular weight. The oxidized saturates have the highest weight average molecular weight and the most complicated molecular size profiles among the oxidized Corbett fractions