Effect of Moisture Movement on Tested Thermal Conductivity of Moist Materials

Abstract

Thermal conductivity measurements are based on temperature gradients within the tested material. When testing nonsaturated moist porous materials, this gradient causes redistribution of the enclosed moisture and, as a result, the apparent (measured) conductivity is smaller than the actual one. This paper analyzes the dynamic processes and the development of thermal and moisture fields during the test, and shows that changes in the moisture field increase as the ratio of the vapor diffusivity to the hydraulic modulus of the material decreases. It shows, however, that for a wide range of concretes (dry density between 340 and