Cutback Bitumen ( Liquid Bitumen ) is Bitumen that is dissolved in a solvent . Typical solvents include Naptha, gasoline and kerosene, white spirit etc. The type of solvent controls the curing time while the amount determines the viscosity of the Cutback Bitumen.
The advantage Cutbacks have over Emulsions is a much higher residual Bitumen percent, typically over 80% compares with over 40-65% for Bitumen emulsions. The result is more Bitumen left on the roadway after curing, for the same volume of binder applied.
Cutback bitumen’s suitable for primer sealing can also be used in the manufacture ofpre-mix asphalt, which is used in patch repairs.Cutback bitumen’s are used extensively in sprayed sealingapplications, particularly in cooler weather where theyprovide improved initial stone retention due to their lower viscosity. Typically, a single application of the appropriate cutback bitumen is sprayed onto the primed pavement ontowhich aggregate is laid.
Cutbacks are divided into two classifications, Rapid-Curing (RC) and Medium-Curing (MC) depending on the solvent used. They are further defined by a number which indicates the minimum kinematic viscosity (fluidity) of the cutback.