Physicochemical properties of bitumen coal-tar mixtures

The miscibility of bitumen-coal tar mixtures has been investigated. Bitumen-coal tar mixtures containing 10 to 50 wt% of coal tar were examined by differential scanning calorimetry and optical microscopy to determine the threshold of miscibility. A solid-like precipitate was observed 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. microprobe. This indicated that a new distribution takes place between aromatics and aliphatic-like compounds. Copyright (C) 1996 Elsevier Science Ltd.