## 5 Results
### Petrophysical Properties  
The following physical and mechanical properties were determined: real and bulk density, porosity open to helium and water, porosity closed to water, wetting coefficient by weight, water saturation index, PLT strength, compressive and tensile strengths (theoretical parameters calculated indirectly by Point Load Test data). Physical and mechanical tests were performed in all but one lithologies; indeed, the limestones used as mosaic tesserae in the Roman temple were not analysed since their scarcity did not allow performance of laboratory tests. In addition to rock samples from the monuments, outcropping metadolostone from the Roman quarries were tested. Since the sandstone outcrop was not precisely identified, it was not possible to perform tests on this material. All the data are reported in Table 2.  
The investigations showed three main sample populations with significantly different physical-mechanical characteristics and corresponding to the main lithologies, i.e., metadolostone, sandstone, \"sandstone\" _s.l._ (Figures 11-13). Even within each population, some differences between the subgroups could be observed, with some overlapping trends in physical properties. From these populations we can distinguish the samples of marly limestone and siltstone, which have at least partly different behaviours. The metasilstone, represented by a single sample, was not present in the studied monument but its petrophysical characterization could provide a reason why Romans decided not to use this material, outcropping very close to the monument, in building the temple. The sample population of the three types of metadolostones (laminated, brecciated and massive) differ from the other two populations (sandstone and \"sandstone\" _s.l._), as they are less porous and more resistant (Figures 11 and 12). The average helium open porosity varied between 8.4 \(\pm\) 5.7% in laminated metadolostones and 12.9 \(\pm\) 3.2% in brecciated metadolostones, while in massive metadolostones the average value was 11.6 \(\pm\) 2.7% (Table 2). The metasilstone had a porosity value of 18.8%, which is one of the lowest values among metamorphic rocks. The sandstone showed much greater porosity, with an average value of 33.5 \(\pm\) 5.0%. \"Sandstone\" _s.l._ had intermediate values between the two previous populations, with an average of 24.5 \(\pm\) 2.1%. Marly limestone, due to high compactness, showed a low average value of helium open porosity (3.5%) and a slower absorption compared to the other lithologies. Sandstone and \"sandstone\" _s.l._, by virtue of their greater open porosity, showed faster water absorption than metadolomite and metasilstone. Figure 11: (a) Helium open porosity (\(\Phi_{\rm O}\) H\({}_{2}\)O) vs. bulk density (\(\rho_{\rm B}\)); (b) real density (\(\rho_{\rm R}\)) vs. bulk density (\(\rho_{\rm B}\)); (c) real density (\(\rho_{\rm B}\)) vs. water closed porosity (\(\Phi_{\rm C}\) H\({}_{2}\)O). Figure 12: (**a**) Helium open porosity (\(\Phi_{\rm O}\) He) vs. water open porosity (\(\Phi_{\rm O}\) H\({}_{2}\)O); (**b**) kinetic of water absorption shown by imbibition coefficient (IC\({}_{\rm W}\)) over 192 h.  
Observing the data as a whole, the bulk density showed a clear linear negative correlation with porosity (Figure 11a) and no evident positive correlation with the real density (Figure 11b) due to the presence of populations of the sandstone and especially \"sandstone\" _s.l._ samples, which had different physical properties with respect to the metadolostone, showing a clear linear positive correlation coefficient (R\({}^{2}\) = 0.6, Figure 11b). The bulk density had average values ranging from a minimum of 2.40 \(\pm\) 0.07 g/cm\({}^{3}\) in the samples of breciated dolomite, an intermediate value of 2.44 \(\pm\) 0.10 g/cm\({}^{3}\) in the samples of massive dolomite, to a maximum of 2.56 \(\pm\) 0.20 g/cm\({}^{3}\) in the laminated dolomite samples (Table 2).