COMPOSITION STUDIES ON ASPHALT CEMENTS- A PROGRESS REPORT

A BRIEF REVIEW IS PRESENTED OF PERTINENT INFORMATION LEADING TO THE DEVELOPMENT OF A NEW ADSORPTION PROCEDURE FOR THE SEPARATION OF THE PETROLENES EXTRACT OBTAINED FROM A NORMAL HEXANE EXTRACTION OF ASPHALT CEMENTS. THE PROPERTIES OF THE RECOVERED FRACTIONS WERE STUDIED FOR DENSITY, REFRACTIVE INDEX, CARBON-HYDROGEN RATIO AND SULFUR CONTENTS. THESE VALUES WERE UTILIZED IN EVALUATION OF THE CARBON DISTRIBUTION BY CHEMICAL FORM. A COMPARISON WAS SHOWN OF THESE EVALUATIONS FOR TWELVE SELECTED ASPHALT CEMENTS OF 85- 100 PENETRATION OBTAINED FROM VARIOUS SOURCES, AND A PARTIAL EVALUATION OF THE SAME TYPE WAS MADE ON TWELVE DIFFERENT AC- 20 ASPHALTS FROM THE BPR STUDY GROUP OF ASPHALT CEMENTS. THE MATERIAL IS A PROGRESS REPORT TO PRESENT DATA OF INTEREST TO OTHER PEOPLE WORKING WITH SIMILAR ASPHALTS OR WITH THE SAME ASPHALTS OF THE BPR STUDY GROUP. A STUDY WAS MADE TO EVALUATE THE CHEMICAL STRUCTURES THAT ARE OBTAINED FOR THE FOUR DIFFERENT COMPONENTS SEPARATED BY THE PRESCRIBED TECHNIQUE. THESE FOUR COMPONENTS ARE DESIGNATED AS PARAFFINIC-NAPHTHENIC (PN), LIGHT AROMATIC (LA), HEAVY AROMATIC (HA) AND HEXASPHALTENES (HX). IT WAS FOUND THAT THE VAN NES-VAN WESTEN METHOD HAD LIMITATIONS PROBABLY BECAUSE OF ITS EMPIRICAL NATURE, BUT THE CORBETT DENSIMETRIC PROCEDURE WAS SOMEWHAT MORE USEFUL. A LIMITED COMPARISON OF DATA AVAILABLE AT THIS TIME ON THE BPR AC-20 SAMPLES WITH THAT BY THE ROSTLER METHOD IS GIVEN. /AUTHOR/