Permanent Deformation Characteristic of Asphalt Mixture Considering Pavement Temperature Distribution

Abstract

Permanent deformation(PD) of asphalt mixture caused by high temperature (above 50°C), instead of the accumulative deformation caused by moderate temperature (20°C to 50°C), attracts more attention. First, distributions of pavement temperature based on continued hourly average pavement temperature data in Shanghai and Wilson County were introduced. The result indicated that percentage frequency of pavement temperature below 50°C is more than 90%, and that above 50°C is less than 5. Second, PD of two asphalt mixtures measured by APA (asphalt pavement analyzer), dynamic stability (DS) of four mixtures tested by wheel tracking device and shear strength of five mixtures tested by uniaxial penetration test were introduced. The results show that PD at 40°C is almost 50 percent of that at 60°C, and that the ranking of high temperature performance for the same mixture changes with temperatures. At last, result of rutting depths calculated by the Mechanistic-Empirical Pavement Design Guide (MEPDG) suggests that rutting depth for high temperature months is almost two to three times of that for moderate temperature months. Therefore, PD of asphalt mixtures should be evaluated considering pavement temperature distribution. INTRODUCTION Rutting of asphalt pavements is a serious concern for a long time due to the increased traffic and wheel loads in China. Thus, it is necessary to predict the PD of a mixture before construction. Several test methods are in practice to assess the PD. The commonly used test methods include diametral tests, uniaxial tests, triaxial tests, shear tests, empirical tests, simple shear tests and simulative tests which are basically accelerated laboratory PD prediction tests (Sousa et al., 1991). However, almost all the tests evaluate the PD at constant high temperature such as 60°C or PG (performance grade) high temperature, while PD at moderate temperature was ICCTP 2009: Critical Issues in Transportation Systems Planning, Development, and Management ©2009 ASCE 2793