Bitumen emulsifiers are surfactants mainly used in the bitumen emulsification process. They significantly reduce the surface tension of water, alter the interfacial properties and state of the system, thereby producing a series of effects such as wetting, emulsification, foaming, washing, dispersion, antistatic properties, lubrication, and solubilization to meet the requirements of practical applications.

1. Mechanism of Action of Emulsifiers
Emulsifiers form a contact film at the oil-water phase boundary, preventing the two phases from repelling each other. This allows the oil to be stably dispersed in the water as fine particles, forming an emulsion. This emulsion is difficult to separate even after standing, thus achieving the emulsification effect.
2. Classification of Emulsifiers
By Ionic Type: Emulsifiers can be classified into anionic, cationic, amphoteric, and nonionic emulsifiers.
By Demulsification Rate: Emulsifiers can also be classified according to their demulsification rate into fast-breaking, medium-breaking, and slow-breaking types. Fast-breaking emulsifiers are suitable for applications requiring rapid traffic reopening, such as road repairs; medium-breaking emulsifiers are suitable for new road construction and maintenance; slow-breaking emulsifiers are suitable for projects requiring longer construction times, such as slurry seals.
3. Preparation Process of Emulsified Bitumen Emulsified bitumen is produced by combining bitumen and emulsifiers under specific technological processes to create a water-in-oil or oil-in-water liquid bitumen. Typically, high-temperature road bitumen is diffused into water through mechanical stirring and chemical stabilization, liquefying into a road construction material with very low viscosity and excellent fluidity at room temperature. When the emulsified bitumen breaks down and solidifies, it reverts to continuous bitumen and all water is removed, allowing the road material to achieve its final strength.