Manufacture of Road-Paving Asphalt Using Coal Tar

Coal tar is a ready source of asphaltenes needed in asphalt production. Coal tar pitch itself, however, is unsuitable for making road-paving asphalt, since the resulting material has low ductility, high temperature sensitivity, and low resistance to wear. For this reason, in England, where replacing imported petroleum with local products was important 10 to 20 years ago, it was required that no more than 10 to 20 percent coal tar pitch be incorporated in road pavement. At higher concentrations, the pitch separates from the petroleum-derived asphalt, causing brittleness and cracking. To make a good asphalt from coal tar pitch, chemical modification or blending with additives appears necessary. In this study, the potentials are for producing road-paving asphalt from coal tar and available inexpensive petroleum fractions are explored. The objective of the study is to develop new uses of coal tar for asphalt production and to free the petroleum residue for upgrading to gasoline and diesel fuels.