SOURCE OF WATER-SOLUBLE PHOTOOXIDATION PRODUCTS IN ASPHALT

AN ASPHALT WAS FRACTIONATED INTO ASPHALTENES, RESINS, DARK OILS, AND WHITE OILS. THESE FOUR FRACTIONS WERE LABELED SEPARATELY BY EXCHANGING HYDROGEN FOR TRITIUM, AND THEIR RADIOACTIVITY WAS MEASURED. EXPERIMENTAL DETAILS ARE GIVEN FOR THE TRITIATING TECHNIQUE EMPLOYED. BY USE OF THE FOUR COMBINATIONS OF ONE LABELED FRACTION AND THREE UNLABELED FRACTIONS, FOUR ASPHALTS WITH COMPOSITION AND PHOTOOXIDATION ACTIVITY SUBSTANTIALLY THE SAME AS THE ORIGINAL WERE THEN PREPARED. THIN FILMS OF THESE RECONSTITUTED ASPHALTS WERE REPEATEDLY PHOTOOXIDIZED AND EXTRACTED WITH WATER, AND THE TRITIUM CONTENT OF THE WATER-SOLUBLES WAS DETERMINED. RESULTS INDICATED THAT MOST OF THE WATER-SOLUBLE PRODUCTS OF THE PHOTOOXIDATION ORIGINATED FROM THE LOWER MOLECULAR-WEIGHT FRACTIONS OF THE ASPHALT WITH THE LARGER DARK OIL FRACTION BEING MORE PRODUCTIVE THAN THE WHITE OIL FRACTION. THE ASPHALT SAMPLE USED IN THIS INVESTIGATION WAS A 40/50 PENETRATION ROAD ASPHALT OF MIDDLE EAST ORIGIN AND ONE OF SEVERAL BEING STUDIED BY THE ROAD RESEARCH LABORATORY, UNITED KINGDOM. /AUTHOR/