Development of Permanent Deformation Master Curves of Asphalt Mixtures by Load-Temperature Superposition

Abstract

The optional multiple repeated load (OMRL) test, which involves multiple load levels, is a more promising test method to simulate actual traffic load conditions on pavements. The presented study developed the load-temperature master curve for asphalt mixtures based on the OMRL test under four loading levels with varying temperatures (5 and 6°C) and confining stresses (, 69, and 138 kPa). The effects of temperature and confining stress on the permanent strain of pavement mixtures were evaluated. Results show that higher temperatures increased the permanent strain and load sensitivity significantly. Higher confining stress dramatically improved the multiple flow numbers of the four asphalt mixtures with a consistent ranking. Likewise, the load sensitivity of asphalt mixtures was increased under lower confining stress. A load-temperature master curve for the slope of strain growth could be established by shift factors, which means the OMRL test conducted under one temperature and confining stress level can be used to accurately predict permanent deformations under all other temperatures or confinements.