As indicated by Specifications D 977 and D 2397, emulsified asphalts are classified by type (rapid medium or slow setting) and by grade within type (viscosity in the case of the rapid-setting type or characteristic of the residual asphalt in the case of the medium and slow-setting types). Selection for use of a particular type and grade is controlled by type of construction (whether an application or a mix type), properties of the mineral aggregate (both grading and mineral composition), and environmental conditions during construction. For surface treatments and seals, emulsions are formulated to set rapidly upon contact with the mineral aggregate or pavement surface. When used in mix types, slower breaking is required to allow time for mixing and laydown. If the mix aggregate is open graded without appreciable fines, a medium-setting emulsion may be used that deposits a relatively hard asphalt. If the aggregate is dense-graded but does not contain a large amount of very fine material (dust), a medium-setting emulsion with a soft residue may be a good choice. However, if the dense-graded aggregate contains a large amount of very fine mineral matter, a slow-setting emulsion may be required.

1.1 This practice covers the selection of emulsified asphalts for various paving and allied uses.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Practice