CATIONIC Bitumen EMULSIONS When asphalt is milled into microscopic particles and dispersed in water with a chemical emulsifier, it becomes an asphalt emulsion. The tiny droplets of asphalt remain uniformly suspended until the emulsion is used for its intended purpose. In the emulsion state, the emulsifier molecules orient themselves in and around droplets of asphalt. The chemistry of the emulsifier/asphalt/water system determines the dispersion and the stability of the suspension. When emulsions are used in the field, the water evaporates into the atmosphere, and the chemical emulsifier is retained with the asphalt.