Cutback Bitumen

Solvent-Thinned Liquid Binder

Cutback Bitumen is manufactured by dissolving base bitumen in a volatile petroleum solvent (e.g., kerosene or naphtha) to temporarily reduce its viscosity. This allows the binder to be applied in a liquid form at lower temperatures. After application, the solvent evaporates ("cuts back") into the atmosphere, leaving the residual bitumen to perform the binding function.

Key Features & Applications :

Application Temperature

Applied at lower temperatures than HMA, but higher than emulsions.

Classification

Rapid Curing (RC) using naphtha, Medium Curing (MC) using kerosene, and Slow Curing (SC) using oils.

Primary Use

Prime Coats for non-bituminous base layers, road patching, and light surface treatments where ambient temperature application is necessary.

Note

Due to environmental and safety concerns regarding solvent evaporation, cutback bitumen is increasingly being replaced by Emulsion Bitumen, though it remains critical for specific applications.