Certain relationships between chemical composition and properties of petroleum asphalts from different origin

Asphalts are classified according to three most commonly measured properties: ductility,, penetration and the ring and ball softening point. The present study shows through many examples that these physical characteristics are not discriminating enough. It was revealed that the chemical composition sheds more light on the physical properties of the various grades of asphalt. There were significant differences between the chemical composition of asphalts having the same softening point and from the same origin. Increase in ductility has been accounted for by the high content of resins while lower penetration is due to high asphaltene content. The correlation of two asphalt indices with the composition shows that the Gaestel index (I-C) proves to be a more adequate quality parameter than the asphaltene index (I-A) for the characterization of asphalts. Both indices can be comparatively used to distinguish between asphalts of narrow softening point ranges.