THE USE OF THE SUPERPAVE PG GRADING SYSTEM FOR SELECTING ASPHALT BINDERS FOR SEAL COATS

The primary purpose of this report is to summarize the analysis and evaluation of the use of PG-graded asphalt for seal coats. The adoption of the PG grades will obviate the need to continue the viscosity and/or penetration grades and will begin a specification system based on performance. Recommendations include the following: (1) The recommended selection criteria for the asphalt binder using the new PG Superpave grading system are based on high and low pavement design temperatures and on traffic levels. Information contained in this report should be used to determine the proper PG grade of asphalt to be utilized in the various areas of the state. It is recognized that additional field experience may require adjusting these recommendations. (2) Field personnel should evaluate the recommended PG grades in their region of the state to determine whether the grades are satisfactory. (3) Asphalt cements which must be heated to a temperature in excess of 190 deg C in order to spray should, instead, be emulsified. (4) Recommendations contained in Appendix B should be followed to maximize the probable success of the seal coat. (5) The contractor must submit a seal coat design for approval prior to beginning construction of the seal coat. These conditions should be addressed in follow-up evaluations of the use of the PG grading system.