Thermal conductivity coefficient of cement-based mortars as air relative humidity function

This paper presents results of tests and research conducted on three cement-based mortars. At first, moisture sorption was measured at 20A degrees C and six relative humidity levels of the air. The tests were completed with a mathematical description of obtained sorption isotherms. Then, thermal conductivity coefficients lambda were measured with stationary and non-stationary techniques on samples of various moisture degree. A linear dependence between coefficient lambda and material moisture was determined. Component results of these two stages of research helped determine a mathematical dependence of the thermal conductivity coefficient upon the relative humidity of the tested materials.