Tar is the viscous liquid obtained by the destructive distillation of coal or wood in the absence of. Generally, the colour of the road tar is black and it contains 72 to 96% bituminous contents.
5 Types of Road Tar
There are 5 types(grades) of road tars viz RT-1, RT-2, RT-3, RT-4, RT-5 based on their viscosity and other properties.
RT-1 has the lowest viscosity and used for surface painting under exceptionally cold weather. The specific gravity of this road tar is 1.26
RT-2 is recommended for standard surface painting under normal Indian climate condition. Specific gravity 1.26
RT-3 may be used for surface painting, renewal coats and premixed top course and light carpets. The specific gravity of this tar is 1.28
RT-4 is generally used for premixing tarmacadam in base course. Specific gravity 1.28
RT-5 has the highest viscosity and may be used for grouting purpose. Sp.g 1.28