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The conductive behavior of asphalt concrete can be improved with the addition of conductive materials, thus a multifunctional asphalt-based composite can be obtained. The conductive asphalt-based composite modified by graphite was studied extensively. Conductive materials percentages may have influences on performance of asphalt mixture. The performance of an asphalt pavement is significantly affected by its resistance to permanent deformation and its fatigue performance. The paper presents the results of a project aimed at investigating static and dynamic response as cracking and fatigue behaviors of conductive asphalt-based composite using the ITT. In particular ITT were performed in which the graphite percentages, loading mode was varied. As test results indicate that the addition of graphite shows positive influence on the indirect tensile strength, failure stiffness modulus in static loading test, especially in high loading speed. The number of load cycles to fatigue failure presents a bit decrease with graphite percentages in dynamic loading test. After adding discontinuous carbon fibers, conductive asphalt-based composite shows good fatigue property, which can prevent crack propagation. It can be concluded that the combined modification brings reinforcement effect to asphalt concrete and improves its mechanical and fatigue properties.

Flexible pavement plays an important role in the primary concrete bridges at present. However, climate environment, to which pavement is exposed, significantly impact pavement stability and long-term performance. Especially, low temperature cracking of asphalt pavement in cold region is a common existing problem. In order to improve the pavement’s crack resistance it is necessary to predict the temperature stress distribution within the asphalt layers. A two-dimensional finite element model of a concrete bridge in thermal and thermal-structural couple analysis is developed to predict temperature and temperature stress variation of asphalt layers in cold region. The temperature stress variation is analyzed at seasonal temperature, different cooling rate and the different thickness of asphalt layers. The model considers a set of primary thermal environmental conditions. Ultimately, the model is aimed at providing pavement engineers with an efficient computational tool that attempts to increase the prediction accuracy of temperature in asphaltic pavement of cold region for more reliable pavement design.

According to three-point bending test, this paper explores the influence of low temperature on the flexural strength, the tensile strain and bending stiffness modulus of the aged Stone Mastic Asphalt (SMA-13) concrete. The asphalt mixtures are aged according to the short-term aging (at 135°C, 4 hours), and long-term aging (asphalt concrete at 85°C, 120 hours) and natural aging (3 months, 6 months and 9 months). The result shows that, with the same loading rate, the tensile strain of specimens at -30°C are smaller than those at -10°C; but when temperature is certain, the tensile strain of specimens lager than those of aged specimens. The longer the aging time lasts, the more flexural strength differences between high and low temperatures can be found. A pretty well index variation can be found between the tensile strain and temperature. The same trend also appears between the bending stiffness modulus and temperature of SMA-13 asphalt concrete.

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