Evaluation of rutting in HMA mixtures using uniaxial repeated creep and wheel tracker tests

Permanent deformation of asphaltic concrete depends on temperature, rate of loading and state of stress and significantly increases above 40 degree C. The deformation behavior of finer to coarser hot-mix asphalt (HMA) mixtures was investigated in the laboratory by varying stress level from 100 to 500 kPa at 40 degree C and 55 degree C. Uniaxial repeated creep and wheel tracker tests were carried out at the specified conditions and the results were correlated to seek relationships between test methods. Subsequently, shift factors and a correlation between the test methods are proposed to guide pavement engineers in the selection of rut resistant mixtures in future. The results show that intercept coefficients vary in a narrow range and an average shift of 0.48 makes both the tests data on a straight line. Uniaxial repeated load strain test do not show a clear ranking of the mixtures at the specified temperatures and the stress conditions. The slope of linear relationship between the tests reduces with an increase in temperature and stress level. (author)