Bitumen emulsion is produced by the suspension of ultra-fine particles of bitumen in water by the aid of emulsifier, a chemical additive, and is widely used in road construction – known as cold asphalt – and maintenance. In these products, after the gradual evaporation of water, the remaining layer of bitumen on the surface penetrates to the lower asphalt layers. The existence of water as the lubricant is accompanied with some advantages among which, compatibility with environment, energy saving, convenient transportation and warehousing, economic efficiency and safety at work could be referred to.
Bitumen emulsion is categorized in 3 groups:
Anionic
Cationic
Nanionic
Practically, 1st and 2nd groups are used widely in road construction and maintenance; however, the 3rd group is important in emulsion technology development.
According to their curing time, bitumen emulsion are also grouped as following:
Rapid Setting
Medium Setting
Slow Setting