Cutback bitumen is a range of binders that are produced by adding a hydrocarbon solvent such as paraffin or mineral turpentine to the penetration grade bitumen and mixing them.
as the solvent evaporates, the binder returns to its original form (penetration grade) to stick the particles with one another. Cutback bitumen gets the name from the solvent which is used in the process, because the solvent cuts back or evaporates, leaving the binder on the surface to do the rest of the work. The solvent used is called the cutter or flux.
Three types of solvents, based on the time of evaporation, are used in the mixture: slow-curing, medium-curing and rapid-curing solvents. A rapid-curing (RC) solvent will disappear faster than a medium-curing (MC) solvent and the same relation works between MC and SC. Evaporation rate of the solvent which effects the setting time of the bitumen, determines the curing. The viscosity of the cutback how ever, is dependent on the proportion and amount of solvent added: the higher the amount, the lower the viscosity of the cutback.
The ability to reshape is a great advantage the cutbacks have over the common penetration grade bitumen. It also requires less heat to liquefy which makes cutback grades easier to use at lower temperatures.

Advantage of cutback bitumen can be easily applied at lower temperatures than penetration grades because of its lower Bitumen Solvents viscosity. A disadvantage is that cutback bitumen consumes non-renewable energy resources which are eventually lost during evaporation.

BS group products in this bitumen type are classified below: