Non-classical Wax in Bitumen

A new procedure for isolation of the wax fraction in bitumen has been proposed. The procedure consists of collecting the fraction SEC II by Size Exclusion Chromatography as suggested in the SHRP program, followed by precipitation at −20°C. The wax was isolated and washed by filtration. Chemical analysis of the wax has been made using TLC/FID, IR spectroscopy, GC/MS and UV/VIS spectroscopy. The results indicate that the material consists mainly of saturated compounds with very small amounts of n-alkanes. There are also small amounts of material present, which show a strong absorption in UV/VIS. To verify that the isolated wax has the ability to crystallise in bitumen, several mixes with bitumen were made. The mixes were analysed using DSC, which verified that the material crystallise in bitumen and thus is regarded as a true crystallising material. Not to confuse the material isolated by the procedure above with the wax isolated by classical procedures, we propose to call our fraction “crystallizing material”.