Asphalt Mixture Design and Thermology Experiments on Heat-Resistant Surfaces in Permafrost Regions

Abstract

Abstract To reduce the permafrost thaw-induced damage to asphalt pavement caused by heat absorption in permafrost regions, a material with low thermal conductivity was introduced into the asphalt mixture. This altered the thermal conductivity of the aggregate and thereby reduced that of the asphalt mixture. First, the optimal asphalt–aggregate ratio for the asphalt mixture was determined. Then, the material composition of the asphalt mixture was designed to form a heat-resistant surface without changing the AC-13 aggregate gradation. Thermal tests were performed with a Thermal Conductivity Instruments (TCI) thermal property analyzer on asphalt concrete specimens, prepared by adding primary mineral vermiculite (abbreviated hereafter as ZS, from Chinese) in different mass percentages of 0 %, 4 %, 6 %, 8 %, and 10 %. Test results showed that the thermal conductivity decreases exponentially with increasing percentage of ZS mass. These tests on asphalt concrete specimens indicate that the thermal conductivity drops by up to 46.27 % for 10 % ZS. At a depth of 4 cm below the surface of a heat-resistant pavement, the temperature can be reduced by at most 1.8°C, compared to observations at the same depth in an ordinary pavement. These results show encouraging prospects for application in permafrost regions.