This test method covers the recovery of residue and oil distillate in emulsified asphalts composed principally of a semisolid or liquid asphaltic base, water and an emulsifying agent.
The standard is needed because many polymer modified emulsions suffer degradation of the polymer as a result of the high temperature of recovery during the distillation procedure even when the distillation temperature is reduced to 400F. In other cases the residue properties of some polymer containing emulsions are improved because of cross-linking that occurs at the elevated temperatures during the distillation procedure. Regardless of the impact of the high distillation temperature the recovered residue properties of these emulsions do not reflect the properties of the emulsion residue that ultimately is put in service on pavement. This procedure, recovered at a temperature reflective of the curing temperature that emulsions experience in service, will provide a more accurate measure of the in-service binder properties on the road. It is anticipated that this procedure can be used to obtain sufficient residue to enable determination of the high temperature PG grade of the binder at the climatic temperature of the pavement. Also the MSCR non recovered compliance and % recovery can be obtained on the vacuum recovered residue which will provide a more correct evaluation of the elastomeric properties of the emulsion residues compared to those properties determined after distilling the emulsion to 400F or higher. I will also be possible with test procedures currently under evaluation to use a 4 mm DSR parallel plate test conducted at temperatures as low as -40C to determine the low temperature PG grade of the binder that is placed in service on the pavement. The users are anticipated to be emulsion producers and purchasing agencies
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top