An improved laboratory test procedure for measuring thermal conductivity of asphalt concrete (AC) pavement is proposed. In this preliminary work, a simple device for thermal diffusivity of AC is developed and the corresponding thermophysical properties are measured. The measurement results indicate that the thermal conductivity and thermal diffusivity of AC are functions of compaction degree, degree of moisture saturation, and temperature. From the estimated thermal conductivity and the measured thermal diffusivity, the transient temperature response to changes in environmental conditions of an AC pavement is analyzed numerically with an incremental recursive method by applying the energy balance principle and the Fourier heat transfer equation. The analysis results show that an AC pavement undergoes diurnal temperature cycles whose amplitude decreases with depth and changes sharply at the pavement surface. In addition, with the changing frequency of the temperature, thawing and refreezing effects of the AC pavement increase progressively from January to March in New Brunswick, Canada.
Abstract