METHODOLOGY FOR DEFINING LMS PORTION IN ASPHALT CHROMATOGRAM

A procedure for defining the appropriate relative quantity for the large molecular size (LMS) fraction in asphalt was developed based on the correlation between chromatogram and selected physical properties. The physical properties and chromatogram of two viscosity grades of three asphalt cements, conditioned at three artificial aging times, were analyzed. Each chromatogram was divided into 30 equal-time slices and the relative quantity of each slice was calculated. Correlation between relative quantity of LMS and each physical property was evaluated through regression analysis. The relative quantity of individual slices was also analyzed to establish correlation with each physical property. The results of analyses using the procedure suggested in this study indicated that in the front part of the chromatogram there was a portion that had a high correlation with selected asphalt properties. It was therefore suggested that generally accepted LMS should be defined by this portion. It was also found that there was an individual slice, within the LMS portion, by which the three properties could be best predicted.