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.