## 3 Experimental Procedure  
### Preparation of Specimens  
For the study of compressive strength of rubberized concrete, 30 cubic specimens (\(100\text{ mm}\times 100\text{ mm}\times 100\text{ mm}\)) were produced according to the mix ratios presented in Table 2, as specified by the Standard for Test Method of Mechanical Properties on Ordinary Concrete (China National Standard GB/T 50081-2002), and three specimens per mixture. Cement, aggregate, high range water reducer, and water were mixed in a conventional laboratory mixer (Figure 3a) for 3 min, and the prepared concrete was poured into \(100\times 100\times 100\text{ mm}^{3}\) molds (Figure 3b). Then they were placed on the vibration table for vibration compaction (Figure 3c). Finally, they were demolded after 24 h (Figure 3d). All the specimens were cured at \(20\pm 2\)\({}^{\circ}\)C and 95% relative humidity for 28 days (Figure 3e). Figure 3f shows the partial prepared cubic specimens. Table 4 lists the types and the numbers of the specimens for the compression test.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Mix ID**} & \multirow{2}{*}{**Water (g)**} & \multirow{2}{*}{**Cement (g)**} & \multicolumn{3}{c}{**Aggregate(g)**} & \multicolumn{3}{c}{**Rubber Particle**} & \multirow{2}{*}{**HRWR (g)**} \\ \cline{3-3} \cline{5-10}  & & & **Fine** & **Coarse** & & **Size** & **Ratio (\%)** & **Weight (g)** \\ \hline C\({}_{\text{-J}}\) & 760 & 1440 & 2680 & 4480 & - & 0 & 0 & 10.08 \\ C\({}_{\text{-N}}\) & 760 & 1440 & 2412 & 4480 & 3–5 mm & 10 & 268 & 10.08 \\ C\({}_{\text{-N}}\) & 760 &  
For the investigation of the thermal insulation properties of rubberized concrete, four groups of 13 specimens were fabricated from rubberized concrete mixed according to the mix ratios presented above and one specimen for per mixture. The cylindrical specimens were all 40 cm in height and 60 cm in cross-sectional diameter. Materials were also mixed in the conventional laboratory mixer for 3 min, and then the prepared concrete was poured into molds (removed after 24 h). As shown in Figure 4a, four thermocouples were embedded at equal distances from the bottom to the top of each specimen successively when producing specimens. The thermocouple at the bottom was identified as #1, and then #2, #3, and #4. Numbered labels were successively attached to the wires connecting the thermocouples (Figure 4b). One prepared specimen is shown in Figure 4c. The specimens were also cured at 20 \(\pm\) 2 \({}^{\circ}\)C and 95% relative humidity for 28 days. Figure 5 shows the simplified flow-process diagram for sample preparation, and Table 5 lists the types and the numbers of the specimens for thermal insulation test.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Group** & \begin{tabular}{c} **Rubber Particle Size** \\ **and Content** \\ \end{tabular} & \
\begin{tabular}{c} **Number of** \\ **Specimens** \\ \end{tabular} &
\begin{tabular}{c} **Number of** \\ **Compression Tests** \\ \end{tabular} \\ \hline Reference & — & 3 & 3 \\ \hline Experimental group \#1 & 3–5 mm, 10\% & 3 & 3 \\ \hline Experimental group \#1 & 3–5 mm, 20\% & 3 & 3 \\ \hline Experimental group \#2 & 1–3 mm, 10\% & 3 & 3 \\ \hline Experimental group \#2 & 1–3 mm, 20\% & 3 & 3 \\ \hline Experimental group \#3 & 40 mesh, 10\% & 3 & 3 \\ \hline Experimental group \#3 & 40 mesh, 20\% & 3 & 3 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Grouping of the cubic specimens for compression test.  
Figure 3: Preparation process of concrete cubic specimens: (**a**) Concrete mixing, (**b**) concrete pouring, (**c**) vibration compaction of concrete cubic specimens on vibration table, (**d**) demolding after 24 h, (**e**) maintenance of concrete cubic specimens, and (**f**) partial concrete cubic specimens after 28 days of maintenance.