Zur Messung der Wärmeleitfähigkeit feuchter Stoffe

On the measurement of thermal conductivity of humid substances

. The thermal conductivity of building materials depends on a wide range of influencing variables, and a large number of articles have been published. The most thorough and knowledgeable compilation of these influences have probably been collected by W. F. Cammerer [1]. There has been a focus on the problem of moisture influence for nearly a hundred years. Until today the processes and correlating effects of thermal conductivity with simultaneous presence of dampness have not become fully clear. The reason for this is that the laws of coupled transient transportation of heat and water, which starts in the pores of the substance as soon as there is a thermal gradient, have only been treated in a more precise way in the last century. Also the properties necessary for calculation have only been completed recently. This allows a much better approach to the problem well known for a long time. This shall be demonstrated in the present study by theoretically reproducing, in the thermal conductivity apparatus, the moisture migration process during measurement. Thus, it is possible to work out the effects of moisture resulting from the dampness already present and the one which results from the moisture shifting during measurement.