FRACTIONATION OF ASPHALT MATERIALS BY USING SUPERCRITICAL CYCLOHEXANEAND PENTANE

Fractionation of asphalt materials by using supercritical cyclohexane and pentane has been successfully conducted. Each of three asphalts wa s fractionated into ten fractions. These asphalts and their fractions were then characterized by a variety of analyses including Corbett chr omatographic separation, infrared analysis, refractive index- and intr insic viscosity-size exclusion chromatography (gel permeation chromato graphy), and elemental analysis by atomic absorption. The fractions we re then reblended to produce materials of typical asphalt consistency. These blends were then subjected to oxidative aging in a pressure oxi dation vessel and were found, in some cases, to have improved aging ch aracteristics in the sense that they did not harden in response to a g iven carbonyl formation (oxidatian) as much as normal asphalt material s. Hence, the supercritical fractionation technique is considered to h ave great potential for producing improved asphalt materials.