## 2 Materials, Specimens, and Experimental Program
### Experimental Program
#### 2.3.2 Pre-Heating Treatment and Heating Regime  
Prior to subjecting the specimens to the prescribed heating regime, all of them were inserted in an electrical oven at a constant temperature of 40 \({}^{\circ}\)C for 24 h with the aim of bringing them to a state of approximately equal moisture content. Upon removal from the oven and until their exposure to elevated temperatures, specimens were wrapped in a PVC membrane in order to prevent moisture exchange with the atmosphere. For heating to 120 \({}^{\circ}\)C and 200 \({}^{\circ}\)C, the electrical oven (the same used for the drying sequence) was preheated prior to specimens' placement at a temperature higher than the target one in order to counterbalance the heat loss due to door opening. Each specimen rested in the oven for 1 h under the target temperature and remained undisturbed after turning the oven off until its temperature reached the ambient one. All heated specimens were tested upon completion of the heating-cooling regime. Figure 3 presents the time history of the specimens' preparation and treatment. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Specimen**} & **Temperature** & **Tex Strip** & **TKLE** & **TKLE** & **TKM** & \(\sigma_{\text{max}}\) & \(\sigma_{\text{max,average}}\) & \(d_{\text{cmax}}\) & \(d_{\text{cmax,average}}\) & \(s_{\text{max}}\) \\  & **(\({}^{\circ}\)C)** & **\#** & (\({}^{\circ}\)C) & (\({}^{\circ}\)C) & (\({}^{\circ}\)C) & (\({}^{\circ}\)C) & (MPa) & (MeV) & (mm) & (cm) & (CoV) & **(mm)** \\ \hline T2051N01 & 20 & 1 & & & & & 313.28 & & 0.26 & 0.28 & \\ T2051N02 & 20 & 1 & - & - & - & 335.91 & & 0.22 & 0.28 & [29\%] & \\ T2051N03 & 20 & 1 & & & & 383.88 & & 0.38 & & 0.38 & & 0.07 \\ \hline T2052N01 & 20 & 2 & & & & & 340.72 & & 0.72 & & 0.48 & 0.66 & \\ T2052N02 & 20 & 2 & - & - & - & 305.58 & & 0.90 & & 0.61 & [32\%] & \\ \hline T2052N03 & 20 & 2 & & & & & 345.30 & & 0.61 & & 0.05 \\ \hline T2051L01 & 20 & 1 & & & & & 375.32 & & 0.377.57 & & 0.13 & 0.11 & \\ T2051L02 & 20 & 1 & - & - & - & 355.49 & & 0.09 & & 0.11 & [17\%] & \\ T2051L03 & 20 & 1 & & & & 401.90 & & 0.11 & & & \\ \hline T2052L01 & 20 & 2 & & & & 341.48 & & 0.66 & & 0.04 \\ T2052L02 & 20 & 2 & - & - & - & 391.14 & & 0.83 & & 0.69 & \\ T2052L03 & 20 & 2 & & & & 375.86 & & 0.59 & & 0.59 & & \\ \hline T12051N01 & 120 & 1 & 51 & 45 & 63 & 337.66 & & 341.74 & & 0.28 & 0.38 & \\ T12051N02 & 120 & 1 & [8\%] & [9\%] & [20\%] & [339.19 & & 0.36 & & 0.49 & \\ \hline T12051L01 & 120 & 1 & 49 & 49 & 53 & 316.27 & & 331.55 & 0.39 & 0.46 & \\ T12051L02 \({}^{*}\) & 120 & 1 & [1\%] & [17\%] & [11\%] & - & - & 6\% & - & [22\%] & \\ T12051L03 & 120 & 1 & & & 346.83 & & 0.54 & & 0.54 & & 0.10 \\ \hline T20051N01 & 200 & 1 & & & 345.30 & & 0.49 & & 0.48 & & 0.10 \\ T20051N02 & 200 & 1 & & [14\%] & [13\%] & [2\%] & 319.33 & & 0.47 & & 0.48 & \\ T20051N03 & 200 & 1 & & & 287.24 & & 0.48 & & 0.48 & & \\ \hline T20052N01 & 200 & 2 & & & 121 & 102 & 118 & 300.23 & & 0.74 & 0.56 & \\ T20052N02 & 200 & 2 & [7\%] & [9\%] & [4\%] & 359.82 & & 0.38 & & 0.38 & \\ \hline T20051L01 & 200 & 1 & & & & 238.35 & & 0.49 & & 0.06 \\ T20051L02 & 200 & 1 & [4\%] & [7\%] & [3\%] & 282.66 & & 0.51 & & 0.37 & & 0.40 & \\ T20051L03 & 200 & 1 & & & 233.77 & & 0.33 & & 0.33 & & 0.08 \\ \hline T20052L01 & 200 & 2 & & & 125 & 111 & 133 & 233.00 & & 0.79 & & 0.59 & \\ T20052L02 & 200 & 2 & [12\%] & [3\%] & [4\%] & 305.58 & & 0.42 & & 0.55 & & \\ \hline \hline \end{tabular} \({}^{*}\) Machine stopped working unexpectedly during testing.  
\end{table} 
Table 2: Experimental results. For specimens subjected to the previously described heating-cooling regime, the free part of the wallette surface furnished with the composite overlay had been covered with the same mortar used for the TRM so that real-life conditions were simulated during heating. For these specimens, the protection of the projecting bare textile was achieved using a combination of ceramic wool insulation and rock mineral wool insulation with aluminum coating, as depicted in Figure 4a.