Tar

The residual product obtained by destructive distillation of organic matter such as coal, oil, wood, etc. is known as tar.

The road tar contains 72 to 95% of bituminous contents. The properties of tar depend upon the type of raw materials used for manufacture, the method of distillation, and the proportion of the residual matter contained by it.

The Indian Standard The institution has specified the following 5 grades of road tar for its use for different bituminous road construction under suitable climatic conditions.

-RT₁ = for painting road pavements under cold weather.

-RT₂= for painting rod pavements under normal climatic conditions.

-RT₃= for surface painting and renewal coats, premixed top course, and light carpets.

-RT₄= for premixed macadam in base course.

-RT₅= for grouted macadam.

It is used for roofing, road making, as a preservative for timber, etc.