The objective of this research was to identify or develop a simple, rapid, and accurate laboratory procedure suitable for routine use for determining the mixing and compaction temperatures of both unmodified and modified asphalt binder. The research was performed by the National Center for Asphalt Technology, Auburn University, Auburn, Alabama with the support of Malvern Instruments Inc., Westborough, Massachusetts. In the course of the research, the project team evaluated existing and emerging methods to determine temperatures that will provide satisfactory aggregate coating during laboratory mixing and appropriate laboratory specimen compaction without degrading the asphalt binder and identified two improved, equally effective test methods. These tests, termed the phase angle method and the steady shear flow viscosity (SSFV) method, provide reasonable, consistent mixing and compaction temperatures that correlate well with the results of HMA coating, workability, and compactability tests for both binder types. The phase angle and SSFV measurements are made with the dynamic shear rheometer (DSR), already widely used in asphalt laboratories for measuring binder stiffnesses over a range of temperatures and frequencies. (Author/publisher)
Samenvatting