Chemical surfactants that act as emulsifiers are classified according to the electrochemical charge obtained when they are separated in a water solution. In the case of ANIONIC EMULSIONS, the chemical charge is NEGATIVE. The chemical type and amount of surfactant used in the production process determines the process in which the resulting asphalt emulsion can be used.

In MS-1, MS-2, MS-4 and MS-5 bitumen, called Medium Setting, the breakage is slow enough to allow the emulsion to be mixed with coarse aggregate containing a high proportion of fines.