## 2 Materials and Methods
### Dynamic Vapor Soprtion Tests  
The dynamic vapor sorption method (DVS) can be considered a novel technique and its application is still not commonly used in the building physics field. The device uses very sensitive scales with a high resolution, up to the microgram level. This allows to \begin{table}
\begin{tabular}{c c c} \hline \hline
**Density of Solution (kg m\({}^{-3}\))** & **Concentration of Sulfuric Acid in Solution** & **Relative Humidity Above** \\ \hline
1350 & 42\% & 50\% \\
1200 & 24\% & 80\% \\
1100 & 12\% & 95\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mixing ratio for sulfuric acid and demineralized water. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Relative Humidity at 23 \({}^{\circ}\)C** & **Name of Substance** & **Chemical Formula** \\ \hline
53.5\% & Magnesium nitrate & Mg(NO\({}_{3}\))\({}_{2}\) \\
75.4\% & Sodium chloride & NaCl \\
84.7\% & Potassium chloride & KCL \\
94.0\% & Potassium nitrate & KNO\({}_{3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Chemicals used for the preparation of the saturated solutions. reduce the sample size and speed up the whole measurement procedure. The sample is weighed continuously to track the real response of the material in real time and not just particular discrete points that are identified throughout several hours. The weighing dish of the sample has a diameter in the range of 10 to 30 mm and is placed on a hang down wire in the measuring chamber. The humidity of the environment is maintained by mixing dry and saturated humid air from a gas cylinder in the desired ratio. The air in the sample space has a large volume flow, which even allows the measurement of highly sorption active materials. Figure 3 shows details of the used DVS device. This study is specifically focused on the use of this system while determining the sorption characteristics of aerated concrete. For this purpose, it is necessary to capture the sample's weight response in multiple points with different relative humidities. The sample of the material is placed in the measuring chamber, and the relative humidity is precisely set for each point by mixing dry and saturated gas in the required ratios. The equilibrium humidity point is reached when the sample weight had stabilized. The measurement can take several days, and the DVS system is equipped with automated procedures that ensure continuity of the entire measurement without user intervention. The user selects individual equilibrium points of relative humidity by setting their parameters, and the system automatically performs the entire measurement. The equilibrium point is in a steady state when the derivative of mass over time is zero. With regard to the super sensitive and accurate scale and its specifics, the exact weight is practically unattainable. The DVS system therefore determines the duration of the sorption time (TIME method) or it allows to set the value for the mass derivation over time in which it is considered to reach a steady state (DMDT method). Both methods find their application. The TIME method, with a precisely set time, is especially suitable when comparing the overall response of the sorption kinetics for several materials. When using the DMDT method, measuring the same materials may have a different total experiment time. Translating generated graphs then makes data post-processing more complex. The DMDT mode is more suitable to measure the moisture equilibrium points, where the monitored value represents the change in weight over time. In addition to the limit value, which is considered to be a steady state, the DMDT mode contains three other parameters. The first parameter is the length of stability, which represents the time required for the mass derivative to become equal or lower than the pre-set DMDT value. When the value of the derivative falls below the limit value, the timer is set off.