## 5 Results
### Mechanical Analysis  
Every element of the rough-hewn rusticated blocks included in the construction site areas (368) has been verified with an in-depth ultrasonic and sclerometric analysis campaign. The integration of the two techniques allows one to overcome their respective limits and to obtain a more complete and thorough evaluation of the mechanical characteristics of the stone elements.  
From the rebound value (R) and the ultrasonic velocity (Vp), it is possible to obtain the evaluation of the material properties: high Vp and R values indicate a stone in good condition; on the contrary, low values indicate problems, which can affect the surface and/or the stone matrix in depth [46].  
The measurements were performed on the same points for both techniques, following a regular grid (Figure 8A), to compare the distribution of values within the case. According to the input logic provided by the data management system, each measuring point has also been assigned an ID and the date of the survey.  
The ultrasonic measurements were carried out in indirect mode, meaning that the transmitter and receiver were placed on the same surface; sclerometric measurements were performed on the same points, carrying out 10 measurements on each point. This allows us to interpolate points to estimate the Vp and R distribution in each block and compare the results obtained with the two techniques. All the values obtained from the surveys were processed using GIS software to create thematic maps of distribution of the values of Vp and R, based on the perspective drawing.  
In Figure 8, block CL4-21 shows, for example, high R values distribution but the Vp values are low in the lower portion where the convolute laminations of Pietrafore are very degraded. Another sample is given by the CL3-10 block, where the low Vp values of the  
Figure 8: (**A**) Measurement scheme followed for NDT, outlined on a block portion; the red dots represent the grid of measuring points where the ultrasonic and sclerometric measurements were performed (**B**) portion of rough-hewn rustication investigated; distribution maps of (**C**) Vp values and (**D**) R values processed through GIS software.  
right portion are due to the presence of an open calcite vein, while the block surface is in good condition as shown by the R values distribution.  
Considering the average values of Vp and R, it is possible to note that the values obtained with the ultrasonic test are between 400 and 4965 m/s. Additionally, the Schmidt hammer test recorded average results, with R values between 19 and 50.  
It is possible to observe that the blocks investigated are mostly in a good state of conservation. Vp values lower than 2000 m/s have a state of medium/high degradation because of the presence of open fractures, parts in detachment, or even superficial disintegration. Twenty-eight have Vp values below 2000 m/s. The average Vp values are distributed heterogeneously on both facades and indicate that the blocks have different internal mechanical characteristics (Figure 9).  
R values lower than 30 indicate that the surface is exfoliated or broken, or that the element under investigation has portions of loose material. Only 17 elements out of 368 have R values under 30. Although R values show that the investigated blocks are in a good state of conservation, it is possible to observe that the facade on Via Gori has better surface characteristics (Figure 10).  
Figure 9: Average Vp value maps processed through GIS software, related to blocks on (**A**) Via Gori and (**B**) Via Cavour.