Comparative analysis of the dynamic vapor sorption (DVS) technique and the traditional method for sorption isotherms determination - Exemplified at autoclaved aerated concrete samples of four density classes

The paper assesses two research techniques for the determination of moisture sorption isotherms. On the one hand, in the time and labor-intensive traditional method the relative humidities are set in desiccators or climatic chambers by saturated water solutions of properly selected salts. On the other hand, the automated dynamic vapor sorption technique (DVS) is based on a humidity generating device. To compare both methods sorption isotherms were determined for autoclaved aerated concrete samples of four different density classes. The results obtained indicate good compatibility for all tested concretes within the humidity range from 0% to 75-85%. In the case of high humidity ranges between 75-85% and 98%, the sorption isotherms differ significantly. From the two series of experiments it can be concluded that for the materials tested the quick DVS measurement method can be used to determine sorption isotherms up to about 80% relative humidity.