Your question is unclear... do you mean Tar bitumens?... Tar bitumens (bitumen is the brown or black viscous residue from the vacuum distillation of crude petroleumare) are increasingly being used as a binder in road works and consists of a standard product of about 70% bitumen and 25-30% tar. Tar bitumens are classifiable as the pyrolysis products of organic materials and are applied hot. (source: Journal of Higway Engineering)