Permanent Deformation Model Based on Shear Properties of Asphalt Mixtures

A permanent deformation model of asphalt concrete based on shear properties is developed and calibrated. This model is extended and improved from previous work with the use of laboratory test results. Triaxial compressive strength and repeated-load permanent deformation (RLPD) tests on three types of asphalt mixtures are performed at various loads and temperatures to correlate the shear properties of asphalt mixtures with rutting performance. Test results indicate that the cohesion and friction angle of a given asphalt mixture decrease with increased temperature. Also, the results of RLPD tests indicate that loading and environmental conditions such as deviatoric stress, confining pressure, test temperature, and load frequency significantly affect the permanent deformation of asphalt mixtures and must be incorporated into the prediction model. Three versions of the permanent deformation model based on different input levels are proposed and verified by the test data. Then, the model is calibrated by an accelerated pavement testing data set conducted on a typical pavement structure at various temperatures. The proposed model can successfully predict the permanent deformation of various asphalt mixtures under a wide range of loading and temperature conditions without changing model coefficients.