The first consideration in selecting the right type and grade of bitumen emulsion is the application in which it will be used. Once a group of emulsions have been selected for a particular use, some other factors must be considered. The decision should account for the properties of the aggregate and the ability of the emulsion to coat the aggregate. The suitablity of a cationic or anionic emulsion with a particular aggregate must be evaluated. Usually, cationic emulsions are more versatile with regard to different aggregates. Medium and slow set emulsions, being more stabilized, depend less on the aggregate type although the same basic principals for selection of an anionic or cationic emulsion type still apply.

Weather expected during construction is important. Some important conditions are air temperature humidity, wind velocity and possibility of precipitation. Emulsions depend on evaporation of water for development of breaking and adhesion characteristics. Although surface and atmospheric conditions are less critical for cationic emulsions, these types still depend some what on weather conditions for optimum results.