Key objectives of the Strategic Highway Research Project (SHRP) A-003A were to validate properties selected for inclusion in the binder specification and to develop accelerated performance tests (APTs) suitable for predicting pavement performance in terms of fatigue and low temperature cracking as well as permanent deformation. This paper specifically addresses the laboratory tests, measured engineering properties and their relationship to the SHRP binder specification and to performance for both unmodified and modified mixes.
Materials considered in this research included 8 to 16 binders, 5 modifiers, and 2 to 4 aggregates. For fatigue, mixes were tested in the controlled-strain mode of loading using a flexural beam test device. For permanent deformation both a wheel-tracking device and a simple shear repeated-load test apparatus was used. Low temperature thermal cracking was evaluated using the thermal stress restrained specimen test (TSRST).
Overall, the results indicate that the relationship between binder properties and mix performance, as measured by the recently developed APTs, is excellent for thermal cracking, but substantially less definitive for fatigue cracking and permanent deformation. Furthermore, the recently developed APTs and resulting engineering properties are suitable for predicting pavement performance of modified mixes as well.