Bitumen emulsion is a combination of three basic ingredients, Bitumen, water, and small amount of an emulsifying agent. These ingredients are introduced into a process which shears the bitumen into tiny droplets. The emulsifier, which is a surface-active agent, keeps the Bitumen droplets in a stable suspension and controls the breaking time. The final product is a liquid product with a consistency ranging from that of milk to heavy cream and can be used in cold processes for road construction and maintenance.
Bitumen emulsion does not require a petroleum solvent to make it liquid and in most cases Bitumen emulsions can be used without additional heat. Both of these factors contribute to energy savings. Additionally, Bitumen emulsions offer great flexibility in their application since they offer the end-user a great variety of characteristics not found in other paving and maintenance materials. Bitumen emulsions are environmentally friendly. There are little or no hydrocarbon emissions created with their use.
Bitumen emulsions were first prepared in the early part of the 20th century and today they are used all over the world. The use of Bitumen emulsions is growing and 10-20% of all Bitumen is used in the form of Bitumen emulsions.
MS (Medium Set), SS (slow set), and
QS (Quick Set)
have been adopted to simplify and standardize this classification.
Additionally, trailing numbers are used to delineate the relative viscosity if the emulsion and the letters "h" and "s" indicate whether a hard or soft base Bitumen is used to make the Bitumen emulsions.
Thus, a CSS-1h is a cationic slow set emulsion with a relatively low Bitumen emulsion viscosity made with a hard base Bitumen.