Various emulsions are classified based on two main factors: particles’ electrostatic charge and breaking or setting time.
In an emulsion, if the particles’ charge be negative, the bitumen emulsion is called Anionic and introduces itself wit letter “A”. Otherwise, the bitumen is known as cationic and have the “C” letter.
The second grading system of bitumen emulsion is closely related to the application. When applied to a surface, bitumen emulsion must break and set. Technically, breaking means the evaporation of water, which makes bitumen strong enough for sticking to aggregates and setting on the place of application.
The time that is needed for bitumen emulsion to lose water and behave like an ordinary bitumen, is called the reactivity rate. This parameter determines whether the bitumen is rapid setting emulsion, medium setting emulsion, and slow setting medium.
Another factor that can affect the reactivity of bitumen emulsion is the temperature of the surface onto which it is applied. In a hot weather, evaporation of water can accelerate.