# Structural Detection and Restoration Proposal for the Mardin Sahkulubey Cupola
## 4 Experimental Study
### Mechanical and Physical Experiments  
Compressive strength, density, and water absorption tests were performed on the samples taken from the east, west, north, and south facades of Sahkulubey Cupola. In addition, the average values obtained from the porosity and compaction tests are shown in bar graphs (Figures 8 and 9). The experiments can be carried out on cubes with sides of (50 \(\pm\) 5) mm or on right circular cylinders with a diameter and height of (50 \(\pm\) 5) mm. This study was carried out using cube samples. Three samples were used for all experiments. Since cube samples conforming to standards were used, no correction factor was used [27; 28; 29]. It has been observed that on windy facades, the stone wears out more with rain. On windless facades, the stone maintains its strength as it did on the first day.  
When the compressive strength results are examined, it is seen that different results are obtained in each direction. The highest compressive strength value was found in the south direction sample, with 22.71 MPa, and the lowest in the east direction sample, with 9.15 MPa. The value in the west direction sample was 15.18 MPa, and the value in the north direction sample was determined as 20.77 MPa. No samples were taken from the building using core drilling or any other method. The pieces are all different sizes and cannot be standardized. For this reason, if the conversion coefficient is used according to the dimensions, it is possible to obtain close values. For density, it was understood  
Figure 6: Model of Sahkulubey Cupola: North Facade (**left**), South Facade (**middle**), West Facade (**right**).  
Figure 7: Specimens taken.  
that the samples taken from the western facade had the highest value (2.42 g/cm\({}^{3}\)), while those taken from the northern facade had the lowest (2.37 g/cm\({}^{3}\)) value. According to the water absorption test (Figure 9), it was found that the samples taken from the northern facade had the lowest (8.01%) average value. The samples taken from the south facade had the highest (9.69%) average value. When the porosity test is examined, it is seen that the samples taken from the east and west facades have the lowest (0.19) porosity, and the samples taken from the south facade have the highest (0.21) porosity. According to the compactness test, it was understood that the samples taken from the east and west facades had the highest (0.81) average value. In contrast, the samples taken from the south facade had the lowest (0.79) average value. When thermal conductivity is examined, it was found that the samples taken from the eastern front had the highest mean value, and the samples taken from the west side had the lowest mean value. It is seen that the granite used in the construction of the eastern facade has significantly higher values than the materials used in the construction of the other facades in terms of all the examined properties.  
In this study, the Young's modulus of the material (19.8 GPa) and the Poisson ratio (0.21) were determined. Similar results were obtained in other studies on Mardin stone [30; 31].  
Figure 8: Compressive strength (**left**) and soaked in water (**right**).  
Figure 9: Average values of experimental study results.