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8326990 
Journal Article 
Effects of asphaltenes on asphalt recycling and aging 
Lin, MS; Davison, RR; Glover, CJ; Bullin, JA 
1995 
1 
Transportation Research Record
ISSN: 0361-1981
EISSN: 2169-4052 
National Research Council 
Washington, DC, United States 
1507 
86-95 
English 
Blends made using n-hexane asphaltenes from asphalts, SHRP AAG-1 AAD-1, and AAK-2 and maltenes from SHRP AAG-1 and AAD-1 were laboratory-aged to study the effects of asphaltenes on rheological properties. For comparison, maltenes from SHRP AAG-1 and AAD-1 as well as their parent asphalts were aged at the same aging conditions as those of blends. The laboratory oxidation conditions were pure oxygen pressure at 20.7 bar absolute, temperatures of 71.1, 82.2, and 93.3°C with aging times from 1 to 24 days depending on aging temperature. The changes due to oxidative aging were monitored by asphaltene precipitation in n-hexane, Fourier transform infrared spectroscopy, and dynamic mechanical analysis at 60°C. Oxidative aging of asphalts and maltenes results in the formation of carbonyl compounds, the production of asphaltenes, and an increase in viscosity. The change in asphaltene content with respect to the change in carbonyl content is quantified by defining the asphaltene formation susceptibility (AFS). The type of asphaltenes, regardless of their sources, have no effect on AFS. Therefore, it appears that AFS is a strong function of maltene composition. However, the effect of asphaltenes on viscosity is only moderately dependent on the asphalt source of the asphaltenes. The results of this study show that the maltene composition has the dominant effect on the oxidation behavior of an asphalt. For recycling of road pavement, the results also suggest that a recycling agent should be chosen so that the mixture of the recycling agent and the maltene from the old pavement possesses good oxidation properties.