Determining thermal properties of asphalt concrete using field data and laboratory testing

Recently developed pavement design guide, Mechanistic-Empirical Pavement Design Guide (MEPDG), uses thermal properties such as Coefficient of Thermal Contraction or Expansion (CTC or CTE), thermal conductivity (k) and specific heat capacity (C) as inputs to predict pavement distresses such as thermal cracking and aging. To this day, thermal properties of asphalt concrete have been determined based on laboratory testing. This study determines CTC and CTE using field collected strain and temperature data from an instrumented pavement section on Interstate 40 at mile post 141 near Albuquerque, New Mexico, USA. Average CTC and CTE values of asphalt concrete are determined to be 2.69 × 10−5 per °C and 2.42 × 10−5 per °C in fall (October-November) and 2.47 × 10−5 per °C and 2.77 × 10−5 per °C in winter (December-February) respectively. For validation, CTC and CTE values of asphalt concrete are measured in the laboratory and found to be 2.64 × 10−5 per °C and 2.28 × 10−5 per °C respectively. In addition, C value is measured in laboratory and k value is determined by developing Finite Element Model (FEM). The measured C and the FEM determined k values are validated using real field data.