Determining Thermal Conductivity of Paving Materials Using Cylindrical Sample Geometry

A testing procedure was developed for determining thermal conductivity k using the same cylindrical specimen geometry that is commonly used for standard mechanical property testing. An experimental test apparatus was constructed with a calculated systematic uncertainty of ±0.021 W  m−1  ° C−1 ( ±5% ) for a k=0.42 W  m−1  ° C−1 . A cylindrical reference sample of ultrahigh molecular weight polyethylene resulted in a thermal conductivity of 0.441±0.022 W  m−1  ° C−1 ( ±5.1% ) with 95% confidence. Conventional specimens of hot-mix asphalt and portland cement concrete mixtures were tested and yielded k values of 0.896±0.023 W  m−1  ° C−1 ( ±2.6% ) and 1.719±0.048 W  m−1  ° C−1 ( ±2.8% ) , both at a 95% confidence interval. These results fall within common literature value ranges for these materials, and indicate an acceptable level of accuracy and repeatability for this new test method.