This project is a follow up on IDEA Project 84 which developed simple single-edge notched three-point bend (SENB) and compact tension (CT) tests that can accurately measure fracture energy (GIc or Gf) and crack mouth opening displacement (CMOD) under realistic conditions of severe tensile constraint in a notched asphalt binder sample in the brittle state. Further, a simple double-edge notched tension (DENT) test was developed that can accurately measure the essential and plastic works of fracture in the ductile state (we and wp) as well as an approximate critical crack tip opening displacement (CTOD). It is hypothesized that a specification system based on these fracture mechanics-based properties (i.e., GIc, Gf and CMOD in the brittle and brittle-to-ductile states and we, wp, and CTOD in the ductile state) is able to provide superior performance prediction for all asphalt binders at low and ambient temperatures, irrespective of their composition or manufacturing process. The main products of this IDEA effort are four improved laboratory standard test methods for low-temperature and fatigue performance grading of asphalt binders. The new methods better recognize the importance of chemical and physical hardening as well as fatigue cracking as potential aggravating factors in low-temperature failure. An advantage of the methods is that no new equipment is required; all tests can be done with only slight modifications to the instruments originally purchased for the SHRP BBR and DTT. The product of IDEA Project 104 will be an accompanying binder specification which sets realistic limits on grade temperatures and fracture energies in both brittle and ductile states for a given location and traffic level. The final report is available from the National Technical Information Service (NTIS # PB2007-107317).
