The structure of the rig from inside to outside is formed by substrate, bonding layer, insulation layer, reinforced base coat, and finishing coat (see Figure 3).
To monitor the distribution of the temperature at different positions and structural layers along the horizontal and vertical directions of the test wall surface, the strain gauges and temperature sensors in preparing ETICS GHB should be installed at the same positions as the concrete base, the insulating layer (outer surface), and the finishing coat. Seven strain gauges and six temperature sensors were installed in each layer (see Figures 2-4).
(1) As shown in Figure 7, the temperature changing trend at different measuring points on the surfaces of the finishing coat and the insulating layer are similar and have a shape of a rectangular wave.
(2) As shown in Figure 7(a), the test chamber caused a progressively top-down decline in the temperature of the finishing coat, insulating layer, and bonding layer along the vertical direction of the wall surface.
(1) As shown in Figure 9, for each period at the temperature rising and maintaining phases, the strain of the finishing coat changes synchronously with the temperature in the external layer.
The finishing coat shrinks at early stage and expands after a number of cycles.
(2) Figures 9 and 10 show the results of the strains on the surfaces of the finishing coat and insulating layer.
The most, second to most, and less significant shrinkage are located in the finishing coat, insulating layers, and bonding layers, respectively.
In these two instants, the cracks and swells on the finishing coat appeared as lines and circles.
(1) On the surface of the finishing coat (see Figure 15), most of the cracks are in the horizontal direction, the second to most of the cracks are vertical ones, and very few of the oblique cracks appeared.
(2) As shown in Table 4, the number, the length, and width of the cracks on the surface of the finishing coat gradually increase with the increase in the number of cycles.
In this study, the temperature and strain in three various structural layers (i.e., finishing coat, insulating layer, and the bonding layer) of the ETICS GHB under the hygrothermal cycles were investigated.