Abstract: The thermal properties of loess are important in the study of genetic mechanism of freezing-thawing hazard and thermal engineering calculation. However, temperature greatly impacts the thermal behaviors of loess. In this study, the thermal properties of loess samples with different water contents and dry densities are tested using Test Protocol Hot Disk TPS 2500S under different temperatures. The evolution of thermal properties of loess with temperature is discussed. The study reveals the following results. The thermal conductivity development of samples as temperature decreases can be divided into three stages: slowly increasing stage, rapidly increasing stage and stable stage. As temperature decreasing, the specific heat capacity of samples increases initially and then decreases, finally stabilizes. The thermal diffusivity of samples decreases at first and then increases with decreasing temperature. When the temperature is below ?20℃, the thermal diffusivity keeps stable. The larger the water content, the greater the influence of temperature on the thermal properties of samples. There exists large difference of thermal properties between unfrozen soil and frozen soil. Dry density impacts n the thermal properties mainly through the minerals and free water content of soil. In applications of freezing-thawing hazard and thermal engineering, thermal properties can be selected in accordance with soil temperature, water content and dry density. Determination of whether the soil is frozen or not is the key to determine the thermal properties.

Key words: loess, thermal properties, temperature, thermal conductivity, specific heat capacity, thermal diffusivity