## 4 Results
### Wet Fringe  
The wet fringe was observed and measured by the naked eye during the capillary test. IRT allowed us to observe and quantify not only the wet fringe but also the water distribution within the outer layers of the studied stones. The main fact extracted from the IRT images was that porous and fissural rocks behaved differently. In both cases, three zones were defined (Figures 6 and 7):(i) The wet zone, where the water filled the void system almost instantly and the temperature between the fluid and the rock equilibrated rapidly. The rock surface was wet. (ii) The capillary zone, an area of inner water migration evidenced by a homogeneous mineral cooling. 1. In the sedimentary stones, this zone was also observed by the naked eye as wet. The upper part of the capillary zone corresponded to the visible wet fringe. 2. In the granites, this zone was dry although a strong mineral cooling produced only by water effect was observed by IRT. The bottom part of the capillary zone corresponded to the visible wet fringe. Figure 7: Subtracted IRT images of GA (Gris Alba granite) and GS (Golden Ski granite) at their initial state (**a-d,k-n**) and after 5 cycles of TF (Thermal Fatigue test) (200(5) \({}^{\circ}\)C) (**f–i,p–s**) obtained by subtracting thermograms at 1, 5, 10, and 30 min from the initial state. Vertical temperature profiles are plotted from the IRT images (**e,j,o,t**). (iii) The dry/evaporation zone, the upper part that was not invaded by water and cooled freely by air contact. In some cases, an evaporation zone when the water already reached the top of the sample. Vertical profiles were graphed to delimit these zones at different times of the capillary water uptake test (Figures 6 and 7). Figure 6 showed the three parts of the sedimentary stones behaviour during capillary water uptake. A homogeneous wet zone that cooled quickly, a capillary zone marked by the distribution of the dark colour, and an upper dry zone in which the cooling took place at a moderate rate. For the Chalons chalk, the IRT images revealed that for the fresh rock, after 1 min of water contact, the wet fringe was a thin dark line at around 1 cm height (Figure 6a). After 5 min, the wet zone was slightly spread at the mid-height of the sample, although the upper part of the dark line corresponded to the wet fringe observed visually around 2.2 cm. After 10 min, the water was well distributed in the whole sample in the IRT images (Figure 6a-e) and also observed by the naked eye. At the end of TT, the IRT images were similar to those from the same time-lapse at the initial state, with a slight difference due to the increase in the capillary zone height after 5 min. The thermal profile graphed a faster cooling in the tested sample and an evaporation phase at the upper part. During the last cycle of the TF test (Figure 6f-j), after 5 min, the wet fringe was measured slightly higher than the initial state and after 30 min, the sample saturation and an evaporation area were clearly observed. The water behaviour in Fontainebleau sandstone is shown in Figure 6k-t. After 1 min, no changes were perceived on the IRT image. Nevertheless, at 5 min the wet fringe was clearly observed with the naked eye at around 2 cm, that in the IRT image included the wet zone (of about 0.5 cm) and the capillary moist zone (1.5 cm), in which the water circulated and advanced to the top with the time (Figure 6o). In the TT test, the wet fringe appeared from minute 1, and its migration together with the rock cooling area to the upper part of the sample was observed. In the TF test (Figure 6p-t), the wet zone rose higher and the cooling of the capillary area to the top of the sample at the end of the test was evident. The profiles were more homogeneous and smoother than the chalk ones, so the combination of the naked eye, the profiles, and the IRT images were needed to establish the interpretation of the water migration. Figure 7 showed the three parts of granite behaviours.