Application of different transient sorption methods to evaluate moisture diffusion coefficients of building materials on the hygroscopic range

Abstract

Typically, moisture transport coefficients are determined either by stationary measurements, as standard cup set-up and modified cup method, or by dynamic measurements, as the means of the type $\sqrt{t}$ rule in the initial phase of adsorption processes, logarithmic procedure in the end stage of adsorption processes, the half-time method, the moment method, and the hybrid 1-term method.

The aim of this work was to test the usability of the five dynamic calculation methods to define the moisture diffusivity in the hygroscopic range of different building materials. The results obtained were compared in order to evaluate the discrepancies between the different calculation techniques. Advantages in time saving using each experimental technique were compared with the feasibility of each process.

Two commonly used building materials are considered in the study, gypsum board and gypsum plaster, for adsorptive measurement of the moisture diffusivity at three different temperatures in three different relative humidity ranges.