Comparative Laboratory Tests of Thermal Conductivity of Road Materials Using Two Measurement Methods

The fundamental material parameter used in the thermal analysis of road pavement structures is the thermal conductivity. This parameter can be determined using various methods. The main objective of this paper is to compare and evaluate the thermal conductivity test results obtained using two different measurement methods. Thermal conductivity was determined using the steady-state and transient methods. The transient method is more cost-effective and faster but tends to produce a higher dispersion of results. In contrast, the steady-state method is more challenging to apply, particularly when testing large and heavy specimens of heterogeneous materials such as road pavement materials. For this reason, it is essential to assess the differences in results obtained by these two methods when applied to road materials. Two types of materials were tested in this study: an asphalt mixture and a cement concrete. The obtained results show statistically significant differences (α = 0.05), taking into account the two methods considered. The average difference can be estimated at 10% and 11% for asphalt mixtures and cement concretes, respectively. The obtained results are important for quantifying material parameters used in thermal and coupled thermal/structural analysis of pavement structures. This is particularly relevant in areas affected by urban heat islands and in road sections used as solar collectors.