## 4 Results and Discussion  
The chemical compositions, related to the binder and aggregates of the mosaic floor mortars samples, are detailed in Tables 2 and 3. The K-Means Cluster analysis of all samples identified two sets of samples in both major and trace elements, with MA1, MA4 and MD3 forming a cluster clearly separated from the remaining samples. The ANOVA 1-way analysis showed that the variables with significant statistical influence to define these two groups were Al\({}_{2}\)O\({}_{3}\), K\({}_{2}\)O, SiO\({}_{2}\), Ba, Cs, Ga, Nb, Rb, Sn (\(p\) = 0.00), MgO, Zr (\(p\) = 0.001), P\({}_{2}\)O\({}_{5}\) (\(p\) = 0.002), Ni (\(p\) = 0.003), Br, Sr (\(p\) = 0.006), Na\({}_{2}\)O (\(p\) = 0.007), and Fe\({}_{2}\)O\({}_{3}\) (\(p\) = 0.015). All samples were characterized by low CaO content (1.1-5.5%) and high concentration in F\({}_{2}\)O\({}_{3}\) (6.2-11.1%) and Al\({}_{2}\)O\({}_{3}\) (20.7-35.9%), when compared with the same elements from other studies on roman mortars [8; 10; 37]. A study on Pompeii mortars [38] found low percentages of CaO (3.81%) and attributed this low content to the high content of volcanic rock fragments as well as to the to the chemical composition of the binder composed by a mixture of lime and clay. Another possible explanation can be related to the degradation of those present study mortars (some cohesion loss was observed) as a result of the unfavorable humidity conditions to which the mosaic floor has been submitted that may lead to the leaching of the lime, as cohesion loss was observed during sampling [39]. The SiO\({}_{2}\) content was higher than Al\({}_{2}\)O\({}_{3}\) in all samples, although in samples MA4 (between _nucleus_ and _rudus_), MD3 (_rudus_) and MA1 (_statumen_), this difference was much more evident, with over 2X's. The highest SiO\({}_{2}\) content was found in samples MA4, MD3 and MA1, with 47.3%, 54.1% and 47.6%, respectively. These samples showed lower Al\({}_{2}\)O\({}_{3}\) and higher K\({}_{2}\)O content than nucleus ones (layers 1 and 2). MD3 showed the lowest Al\({}_{2}\)O\({}_{3}\) (20.7%) and \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline
**Sample** & **Na\({}_{2}\)O** & **MgO** & **Al\({}_{2}\)O\({}_{3}\)** & **SiO\({}_{2}\)** & **P\({}_{2}\)O\({}_{5}\)** & **SO\({}_{3}\)** & **Cl** & **K\({}_{2}\)O** & **CaO** & **TiO\({}_{2}\)** & **MnO** & **Fe\({}_{2}\)O\({}_{3}\)** & **LOI** \\ \hline MA2 & 0.34 & 1.10 & 30.93 & 35.42 & 2.98 & 0.24 & 0.13 & 2.60 & 5.11 & 1.25 & 0.06 & 8.38 & 11.24 \\ MA3 & 0.30 & 1.16 & 32.49 & 37.07 & 1.50 & 0.40 & 0.10 & 2.68 & 3.65 & 1.30 & 0.07 & 8.48 & 10.62 \\ MB1 & 0.27 & 1.35 & 32.68 & 38.53 & 3.45 & 0.86 & 0.04 & 3.43 & 2.14 & 1.35 & 0.13 & 8.62 & 6.93 \\ MC1 & 0.33 & 0.97 & 29.27 & 31.87 & 4.64 & 3.82 & 0.11 & 2.46 & 5.48 & 1.12 & 0.10 & 7.58 & 11.96 \\ MD1 & 0.43 & 1.11 & 33.02 & 32.90 & 4.57 & 0.41 & 0.19 & 2.76 & 3.85 & 1.27 & 0.11 & 8.63 & 10.53 \\ \hline MB2 & 0.18 & 1.28 & 34.97 & 36.16 & 3.46 & 0.35 & 0.03 & 2.86 & 1.52 & 1.37 & 0.09 & 8.91 & 8.59 \\ MC2 & 0.26 & 0.99 & 34.09 & 34.63 & 4.35 & 0.32 & 0.10 & 2.52 & 2.41 & 1.22 & 0.17 & 8.09 & 10.63 \\ MC3 & 0.22 & 1.14 & 34.03 & 35.65 & 3.87 & 0.26 & 0.03 & 3.35 & 1.46 & 1.62 & 0.10 & 11.07 & 6.84 \\ MC4 & 0.19 & 1.35 & 35.93 & 36.42 & 3.50 & 0.17 & 0.07 & 2.70 & 1.70 & 1.28 & 0.16 & 8.50 & 7.78 \\ MD2 & 0.43 & 1.47 & 34.08 & 34.91 & 3.39 & 0.23 & 0.15 & 3.26 & 2.41 & 1.38 & 0.08 & 8.69 & 9.22 \\ \hline MA4 & 1.11 & 2.25 & 22.27 & 47.31 & 0.74 & 0.21 & 0.07 & 6.70 & 5.60 & 1.37 & 0.10 & 7.01 & 4.83 \\ \hline MD3 & 1.74 & 1.70 & 20.71 & 54.06 & 1.98 & 0.07 & 0.03 & 7.07 & 2.01 & 1.22 & 0.07 & 6.22 & 2.76 \\ \hline MA1 & 0.23 & 1.56 & 26.11 & 47.56 & 0.86 & 0.13 & 0.03 & 4.73 & 1.11 & 1.54 & 0.13 & 7.80 & 7.77 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Chemical concentrations of the major components of the mortars samples (in %).