## 2 Materials and Method
### Moisture Buffer Performance of Room
#### 2.2.2 Experimental Setting  
In the performance test of specimens, a small blender is used for preparing the test materials. However, there is a need for a large amount of composite hygroscopic mortar for the room test, so medium-sized equipment is used (Figure 3).  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{2}{c}{**Position**} & **Structure (From Inside to Outside)** \\ \hline \multirow{2}{*}{Roof} & \multicolumn{2}{c}{CM layer 20 mm + Steel Reinforced Concrete 100 mm + CM layer} \\  & & 20 mm + Waterproof layer + Plywood 25 mm + CM layer 20 mm \\ \hline \multirow{2}{*}{Room I} & Exterior wall & CM layer 20 mm + Porous brick 240 mm + CM layer 20 mm \\  & Interior wall & CM layer20 mm + Porous brick 190 mm + CM layer 20 mm \\ \hline \multirow{2}{*}{Room II} & Exterior wall & CHM-WSE 20 mm + Porous brick 240 mm + CM layer 20 mm \\  & Interior wall & CHM-WSE 20 mm + Porous brick 190 mm + CM layer 20 mm \\ \hline \multicolumn{2}{c}{Window} & Double Low-E glass window + Aluminum alloy frame \\ \hline \hline \end{tabular}
\end{table}
Table 4: Structural form of the building envelope.  
Figure 1: The tested building.  
Figure 2: Drawing of the test room.  
In order to ensure the performance of the porous material was not damaged, a multi-stage mixing method is also adopted in mixing the raw materials for the room test. Before mechanical stirring, manual pre-mixing is conducted to ensure the good mixing of the raw materials. The CHM-WSE was evenly plastered on the inner surface of the wall, except for the ceiling and floor. After 15 days of good ventilation, the primer and finish were plastered in sequence. After the construction was finished, test room was cross ventilated to dry the initial moisture to the mortar application. Tests are carried out independently in each room. Temperature sensors are fixed on the wall, ceiling and floor. The layout of the test room is shown in Figures 4 and 5. Temperature sensors are protected by silver paper from direct radiation. Data is recorded and stored by a 48-channel paperless recorder and a temperature and humidity automatic recorder. The outdoor temperature and humidity meter is arranged in an open space. The sealing performance of doors and windows which are closed during the test to reduce the influence of outdoor parameters on indoor humidity is good. Temperature and humidity are recorded every 0.5 h.  
Figure 4: Horizontal test point (h = 1.5 m).  
Figure 3: The experimental set-up of text. (**a**) Cement paste mixer (**b**) Electronic balance (\(\leq\)5 kg).  
The features of the measuring instruments used in this test are listed in Table 5.  
The test compares the indoor temperature and humidity change between the room with CHM-WSE and CM, and takes 24 h as the test duration. In the January test of air conditioning mode, during a 24 h air conditioned heating, humidification is divided into two time periods, daytime 8:30-16:30, with a total of 8 h humidification, and 16:30-8:30 the next day, for a total of 16 h without humidification. In April, tests of no air conditioning and humidifying mode is conducted.  
In the practical moisture buffering performance experiment, the moisture load consists of three parts:  
\[G(t)=G_{b}(t)+\Delta G_{o}(t)+\Delta G_{w}(t) \tag{4}\]  
where \(G_{b}(t)\) is the moisture load in the room, in kg/m\({}^{2}\); \(\Delta G_{0}(t)\) is the hourly humidity load caused by the difference of indoor and outdoor relative humidity, in kg/m\({}^{2}\); \(\Delta G_{w}(t)\) is the moisture transfer of the internal wall, in kg/m\({}^{2}\). The practical moisture buffering can be expressed as:  
\[MBV_{practical}=\frac{G(t)\times t_{p}}{A_{s}\times\varphi} \tag{5}\]  
where \(A_{s}\) is the used area of hygroscopic material, in m\({}^{2}\); \(t_{p}\) is the period; \(\varphi\) is the relative humidity, in %.