## 3 Results
The analysis of reflectivity measurements and their comparison with non-destructive investigations (e.g., Schmidt hammer) was conducted to validate the use of the laser scanner for morphological and topographical reconstruction and, as already presented for the other sites, also for zoning the rock's geomechanical conditions. The zoning is based on the characteristics of the rock wall surfaces, which, in a first approximation, can be distinguished into surfaces regularized due to mining and irregular surfaces characterized by fracture propagation (Figure 7). The zones of greater alteration are located below an aqueduct, orthogonal to the wall, where the weathering process was more intense, and phenomena of collapse and detachment of rock \"flakes\" had already occurred. The processing of reflectivity values (\(I\)), ranging between 37% and 58%, highlights the different levels of absorption of the rock. The lowest values, corresponding to the most intense weathering of the material, have been recorded in areas where the surface is uneven due to the collapse of the vault. The highest values correspond to areas regularized by mining. For these almost flat areas, the regularity of the walls has reduced the vulnerability of the material due to the lower specific surface  
Figure 5: Photo of the seven discontinuities chosen for the assessment of rebound and reflectivity values. Discontinuity 1–7 of the Figure 4. The arrow indicates the portion of discontinuity investigated. exposed to weathering agents. Rebound values (_r_) obtained from the Schmidt hammer range between 10 and 40. **Survey 5. ** The research also focused on the study of the columns at the main entrance of Palazzo Jung in Palermo. The lithotype, ammonitic red limestone, characterized by a nodular and sometimes \"flaser\" structure, undergoes alterations when exposed to outdoor conditions, highlighting textural non-uniformities and, in severe cases, causing surface fractures [51]. The column on the right (see Figure 8) is prominently exposed to marine spray, resulting in signs of selective weathering that affect not only the chromatic appearance but also the rock's state of aggregation. On the same column, different degrees of alteration can be observed depending on the orientation of the cylindrical surface to the marine spray. The column's surface experiences a general whitening phenomenon, with intensity progressively increasing from areas facing the wall. The column exhibits the most altered band along a generatrix exposed to the east, towards the sea. For the altered column, the values of rebound (_r_) are dispersed in a wide range between 20 and 71. The surface of the altered column was divided into four vertical strips based on the visible level of alteration. The measured reflectivity values ranged between 45% and 55% (4 points in Figure 9). For the intact column (on the left), the reflectivity values ranged between 52% and 57% (1 point in Figure 9). The processed data further highlight the influence of the intensity of alteration on both the reflectivity values (_I_) and the rebound values (_r_) simultaneously. Figure 6: Castronovo di Sicilia. Chosen zones within the quarry area. Figure 7: Latomiae del Paradiso (Syracuse). Photo of the investigated area. **Survey 6. ** This study, conducted in the laboratory, focused on surveys (both direct and indirect) on tuff from Naples and calcarenite from Palermo. In laboratory investigations, for the indirect surveys, the RIEGL LMS-Z210 laser scanner, with a scanning field of 80\({}^{\circ}\)\(\times\) 360\({}^{\circ}\), was employed. Eight points were obtained (see Figure 9), highlighting the linear dependency of reflectivity (_I_) and rebound values (_r_). Regarding the Latomie del Paradiso, there are no experimental points because the line is obtained by interpolating average reflectivity and rebound data related to the zoning conducted on the rock mass based on the degree of alteration.