Study on Heat Insulation of Diatomite Asphalt Concrete in Permafrost Regions

Abstract

A key problem in road construction in cold regions is keeping permafrost stable, a requirement that cannot be satisfied by common asphalt concrete pavement. In this study, experiments on the thermal conductivity of diatomite asphalt concrete were performed, and the thermal conductivity coefficient and heat capacity per volume were determined. With these parameters and the FE method, variations in the temperature field of permafrost were analyzed. Indoor experiments show that the conductivity of asphalt concrete decreases when diatomite is added in the asphalt mix. In particular, at a diatomite content of 55%, the conductivity coefficient decreases to 15% but the heat capacity per volume only slightly changes. FEM analysis confirms that the temperature field of the permafrost varies with pavement surface temperature. When diatomite asphalt concrete is used, the top of the permafrost becomes colder. As diatomite content reaches 25%, the temperature at the top of the permafrost decreases to 1.5 °C. Hence, diatomite asphalt concrete has good heat insulation properties and keeps permafrost stable.