Influence of asphalt binder on time-temperature shift function for asphalt concrete at large strains

This paper presents a study of the time-temperature superposition principle for asphalt concrete. The idea behind the timetemperature superposition principle is to allow the construction of master curves representing the material viscoelastic behaviour at a given reference temperature in a range of reduced loading times which is wider than that tested in the laboratory. In addition, the asphalt concrete stiffness is in fact assumed to be a function of temperature and time. A penetration number is an empirical parameter and it could be linked to the viscosity of asphalt. This research has been extended upon previous studies on the viscoelastic behavior of asphalt concrete made from different penetration gradation of asphalt binder. The total 96 experiments were run through the unconfined compression and indirect tensile tests under various temperatures and different strain rates. The results obtained from both unconfined compression and indirect tensile tests can be used to construct the stress-reduced time master curve and timetemperature shift function for each asphalt concrete. The analysis results show that the time-temperature shift function can be simplified as a single function for both compressive and tensile modes at large stains and it can also be employed for multiple penetration-graded asphalts.