Bitumen emulsions are oil-in-water dispersions where fine bitumen droplets are suspended in water, with bitumen content ranging between 30% and 70%.
These emulsions allow for easy application without the need for heating, unlike traditional cutbacks or paving-grade bitumen. During production, hot bitumen is rapidly mixed with water and an emulsifier, creating tiny, stabilized bitumen particles that remain dispersed in the water phase.
When applied, the water in the emulsion either evaporates or separates from the bitumen due to surface chemistry, a process known as “breaking.” Thanks to the close density of bitumen and water, sedimentation is minimal, and any separation during storage can be remedied by gentle stirring.
Types of Bitumen Emulsions
Bitumen emulsions are categorized into two main types: cationic (designated by “C”) and anionic (designated by “A”), with varying setting rates (rapid, medium, or slow) and binder compositions. The main grades include:
Cationic Bitumen Emulsion: Produced by adsorbing positive ions (cations) onto bitumen droplets, leaving negative ions in the water. These emulsions, particularly rapid-setting types, are widely used in the field.
Anionic Bitumen Emulsion: Made using fatty acid or resin acid salts derived from Tall-Oil, a by-product of the paper pulp industry. The negatively charged (anionic) particles are adsorbed by the bitumen, while positive ions remain in the water phase.
The characteristics of bitumen emulsions—classified as rapid (R), medium (M), or slow (S) setting—are designed to suit various pavement and surface dressing applications. At Black Castle Petro, we ensure top-quality bitumen emulsions tailored to meet specific project requirements efficiently and reliably.
