Abstract
Effect of moisture content on thermal conductivity of porous materials has been investigated. As the most ideal samples, calcarious sandstones of various kinds, different in porosity and small in content of water soluble matter, are chosen. For measuring the thermal conductivity, the comparison method was used. Temperature difference between two opposing faces of sample plate is kept as small as possible to lessen the influence of vapour diffusion in the sample caused by the difference in partial pressure of the vapour. The moisture content is represented by volume percentage of free water contained in the sample.
The thermal conductivity is obtained as a function of moisture content with the temperature as parameter. This functional form is found the same in trend for all the samples, formulation of which is difficult because of three dimensional irregularity of the sample structure.
The relation between thermal conductivity and porosity can be explained by a formula derived by the author if the empirical exponent n of the formula is taken as 2.
