## 3 Results and Discussion
### Mechanical Characterization of Specimens
#### 3.1.4 Summary of Specim Results  
To evaluate the results obtained from exposing the materials to the considered environmental conditions, four ranges were defined, using a 20% change in properties as the critical value. This threshold was based on ASCE 7-16 [55], specifically, Chapter 17.8.4, Test Specim Adequacy, which allows up to a 20% change in the effective stiffness of tested prototypes.  
Initially, the results from each day of exposure were compared with the reference values. Then, for each type of exposure and each test, the values with the greatest change were selected, regardless of the test duration. This methodology was used to establish the nomenclature presented in Table 3.  
The criteria in Table 3 were applied to the sample results and are presented in Table 4. In general, it was observed that more properties of the UN-FREI specimens fell within the critical range, whereas a greater number of properties in the UR-FREI specimens were classified in the severe range. This suggests that UR-FREI, being a more rigid and heterogeneous material with particles bound by a binder, is less vulnerable to changes in its properties compared to UN-FREI in small specimens.  
A high shear modulus in the UN-FREI will increase the stiffness of the isolator, which in turn leads to a shorter period and higher accelerations, potentially increasing drifts and shear forces in the isolated building. Additionally, higher damping helps reduce the accelerations considered in the response spectrum [59].  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline  & \multicolumn{4}{c}{**UN-FREI**} & \multicolumn{4}{c}{**UR-FREI**} \\ \hline
*** Exposure** & **T** & **C** & **R.C.** & **G** & \(\beta\) & **T** & **C** & **R.C.** & **G** & \(\beta\) \\ \hline RH & \(\downarrow\downarrow\) & \(\downarrow\downarrow\) & \(\uparrow\uparrow\uparrow\) & \(\downarrow\downarrow\downarrow\) & \(\sim\downarrow\) & \(\sim\downarrow\) & \(\downarrow\downarrow\) & \(\uparrow\uparrow\) & \(\sim\downarrow\) & \(\downarrow\downarrow\) \\ UV & \(\uparrow\uparrow\uparrow\) & \(\downarrow\downarrow\) & \(\downarrow\downarrow\) & \(\downarrow\downarrow\) & \(\downarrow\downarrow\) & \(\uparrow\uparrow\) & \(\uparrow\uparrow\uparrow\) & \(\uparrow\downarrow\downarrow\) & \(\downarrow\downarrow\downarrow\) & \(\uparrow\uparrow\) & \(\sim\downarrow\) \\ SW & \(\uparrow\uparrow\uparrow\) & \(\downarrow\downarrow\downarrow\) & \(\uparrow\uparrow\uparrow\) & \(\uparrow\uparrow\uparrow\) & \(\downarrow\downarrow\downarrow\) & \(\downarrow\downarrow\downarrow\) & \(\downarrow\downarrow\) & \(\uparrow\uparrow\uparrow\) & \(\sim\uparrow\) & \(\downarrow\downarrow\) \\ \hline \end{tabular}  
* * **T—**tension, C—**monotonic compression, R.C.—**residual compression, G—**shear modulus, \(\beta\)—**damping ratio.  
\end{table}
Table 4: Evaluation of the test results of UN-FREI and UR-FREI specimens.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Range (\%)** & **State** & *** Increase** & *** Decrease** \\ \hline
0 & 5 & Slight & \(\sim\uparrow\) & \(\sim\downarrow\) \\
5 & 10 & Moderate & \(\uparrow\) & \(\downarrow\) \\
10 & 20 & Severe & \(\uparrow\uparrow\) & \(\downarrow\downarrow\) \\
20 & 50 & Critical & \(\uparrow\uparrow\uparrow\) & \(\downarrow\downarrow\) \\ \hline \end{tabular}  
* **T**/\(\downarrow\) indicate a moderate increase or decrease, \(\uparrow\uparrow\)/\(\downarrow\downarrow\) indicate a severe increase or decrease, \(\uparrow\uparrow\uparrow\)/\(\downarrow\downarrow\) indicate a critical increase or decrease, \(\sim\) indicates a negligible change.  
\end{table}
Table 3: Evaluation criteria.