PHYSICOCHEMICAL PROPERTIES OF BITUMEN COAL-TAR MIXTURES

The miscibility of bitumen-coal tar mixtures has been investigated. Bi tumen-coal tar mixtures containing 10 to 50 wt% of coal tar were exami ned by differential scanning calorimetry and optical microscopy to det ermine the threshold of miscibility. A solid-like precipitate was obse rved after blending bitumen with coal tar. Up to 20 wt% of added coal tar, only one liquid-like phase was detected by both techniques, while a second phase appeared at higher contents of coal tar. The chemical composition of demixed phases was investigated using an FT-i.r. microp robe. This indicated that a new distribution takes place between aroma tics and aliphatic-like compounds. Copyright (C) 1996 Elsevier Science Ltd.