This specification covers 14 grades of road tar as follows: RT-1, RT-2, RT-3, RT-4, RT-5, RT-6, RT-7, RT-8, RT-9, RT-10, RT-11, RT-12, RT.C.B.-5, and RT.C.B.-6. The tar shall conform to the requirements prescribed for (1) water content, (2) specific gravity, (3) specific viscosity, (4) distillate content, (5) softening point of residue from distillation, and (6) total bitumen soluble in carbon disulfide. The properties enumerated shall be determined by the specified test methods including Engler and float tests, distillation test, and ring-and-ball test.

1.1 This specification covers 14 grades of tar as follows: RT-1, RT-2, RT-3, RT-4, RT-5, RT-6, RT-7, RT-8, RT-9, RT-10, RT-11, RT-12, RT.C.B.-5, and RT.C.B.-6.