BACKGROUND: The properties of asphaltic binders used in preservation surface treatments are very important to the performance of the treatment in which they are used. However, asphaltic binders used in such treatments are often selected based on availability and other factors that are not necessarily related to the performance of the final product. Often distress, such as stripping and raveling of these treatments, can be traced directly to improper binder selection and use. Clearly, proper binder selection is necessary for attaining desired performance. Performance-related specifications (PRS) that specify quality in terms related to long-term performance will help in the selection of the proper binder for a specific application. Although such PRS have been developed for the constituents of hot-mix asphalt mixtures used in pavements, PRS are not readily available for binders used in preservation surface treatments. Therefore, research is needed to (1) evaluate existing binder tests and, if necessary, identify new tests that relate to performance and (2) develop PRS for preservation surface treatments that provide a direct relationship between key quality characteristics of asphaltic binders and performance. These specifications will help highway agencies specify binder characteristics that will provide the desired performance of preservation treatments.
OBJECTIVE: The objective of this research is to develop recommended performance-related specifications (PRS) for asphaltic binders used in preservation surface treatments. For the purpose of this research, preservation surface treatments are treatments that are applied to a large surface area of an existing roadway to slow future deterioration and maintain or improve its functional condition (without increasing structural capacity) such as chip seals, microsurfacing, and slurry seals.