USING HIGH PRESSURE-GEL PERMEATION CHROMATOGRAPHY TO EVALUATE THE CHEMICAL COMPOSITION OF BLENDED ASPHALTS (PULSE VELOCITY, ASPHALT CONCRETE MIXES, INDIRECT TENSILE TEST, RESILIENT MODULUS)

Many problems have been associated with changes in the asphalt industry over the last decade. Research is needed to study the effects of these changes in order to eliminate undesirable consequences and to optimize potential benefits from technological advances. Concurrently, new research tools are needed to characterize the composition of asphalts. One recent innovation in the asphalt industry is the production of asphalts from the products of residuum oil supercritical extraction (ROSE) systems. The main purpose of this project was to evaluate such blended ROSE asphalts in order to determine the effects of chemical composition on asphalt properties, and to determine if blended asphalts are significantly different from asphalts produced by more traditional methods. An additional objective was to investigate a new procedure for characterizing the chemical composition of asphalts. High pressure-gel permeation chromatography (HP-GPC) was selected for this purpose. Products from two different ROSE plants were blended in the laboratory to produce asphalts of different composition. The physical properties of these asphalts and of commercial asphalts were then determined. In addition, tests were conducted on asphalt concrete mixes of these asphalts. High pressure-gel permeation chromatography was used to characterize the chemical composition of the asphalts. It was determined that chemical composition has a significant effect on the properties of asphalt and of asphalt concrete mixes. However, the results of this study do not support the contention that blended, ROSE asphalts are different in any essential manner from asphalts produced by more traditional methods. The results also show that high pressure-gel permeation chromatography is suitable for use in characterizing asphalts. Good correlations were established between HP-GPC parameters and various physical properties of asphalts and of asphalt concrete mixes for the asphalts used in this study