## 3 Experimental Results and Discussion
### Dynamic Compressive Strength
#### 3.3.1 Effect of the Strain Rate on the Dynamic Compressive Strength  
The stress-strain curve is an index reflecting the comprehensive performance of concrete. The characteristics of the curve reflect the characteristics of each stage of the whole process of internal structure failure of the concrete under an impact load. The dynamic impact test data of the two concretes under three loading rates of 5.8, 7.8, and 9.8 m/s are shown in Tables 12-17. \begin{table}
\begin{tabular}{c c c c c} \hline
**Temperature/\({}^{o}\)C** & **High/mm** & **Mass/g** & **Strength/Mpa** & **Strain Rate/s\({}^{-1}\)** \\ \hline \multirow{2}{*}{25} & 40.0 & 436 & 52.5 & 132 \\  & 40.2 & 428 & 51.6 & 127 \\  & 39.9 & 427 & 55.9 & 136 \\ \hline \multirow{2}{*}{200} & 40.1 & 388 & 62.5 & 137 \\  & 40.3 & 395 & 60.8 & 135 \\  & 40.0 & 392 & 63.7 & 139 \\ \hline \multirow{2}{*}{400} & 40.1 & 382 & 37.5 & 151 \\  & 40.3 & 397 & 39.9 & 154 \\  & 40.1 & 378 & 38.2 & 159 \\ \hline \multirow{2}{*}{600} & 39.9 & 378 & 28.6 & 163 \\  & 40.7 & 357 & 26.9 & 167 \\  & 40.2 & 361 & 27.8 & 175 \\ \hline \multirow{2}{*}{800} & 40.5 & 317 & 11.8 & 187 \\  & 40.2 & 321 & 12.3 & 186 \\ \end{tabular}
\end{table} 
Table 13: The dynamic impact test of ordinary concrete on a loading rate of 7.8 m/s. \begin{table}
\begin{tabular}{c c c c c} \hline
**Temperature/\({}^{o}\)C** & **High/mm** & **Mass/g** & **Strength/Mpa** & **Strain Rate/s\({}^{-1}\)** \\ \hline \multirow{2}{*}{25} & 40.1 & 427 & 46.5 & 102 \\  & 40.3 & 429 & 42.3 & 98 \\  & 40.0 & 427 & 45.5 & 103 \\ \hline \multirow{2}{*}{200} & 40.2 & 391 & 57.9 & 117 \\  & 40.4 & 398 & 63.5 & 121 \\  & 40.1 & 395 & 49.5 & 113 \\ \hline \multirow{2}{*}{400} & 40.2 & 385 & 32.1 & 125 \\  & 40.4 & 400 & 34.2 & 147 \\  & 40.2 & 381 & 30.5 & 129 \\ \hline \multirow{2}{*}{600} & 40.0 & 381 & 25.8 & 146 \\  & 40.8 & 360 & 20.9 & 137 \\  & 40.3 & 364 & 18.5 & 115 \\ \hline \multirow{2}{*}{800} & 40.6 & 320 & 9.3 & 156 \\  & 40.3 & 324 & 7.6 & 158 \\  & 40.0 & 333 & 7.9 & 153 \\ \hline \end{tabular}
\end{table} 
Table 12: The dynamic impact test of ordinary concrete on a loading rate of 5.8 m/s. It can be seen from Tables 12-17 that the strain rate significantly influences the strength of the specimen, regardless of the type of concrete and the impact velocities. Table 12 illustrates that the strength increases with the increase of the strain rate for the normal concrete. For the normal concrete at different impact velocities, i.e., Tables 13 and 14, the experimental results come to the same conclusion. In addition, for the basalt fiber-reinforced concrete, it also demonstrates the same strain rate effect on strength. Through the above experimental data, the stress-strain curves under various loading rates and at room temperature (25 \({}^{\circ}\)C), 200 \({}^{\circ}\)C, and 400 \({}^{\circ}\)C are found as follows. It can be seen from Figures 18 and 19 that the dynamic compressive strength of the two concretes increases with the increase of the loading rate. When the loading rate is 5.8 m/s, the strength of ordinary concrete at room temperature improves by 43.9% compared to the static load at the same temperature. The strengths of ordinary concrete improve 65.8% and 51% at 200 and 400 \({}^{\circ}\)C, respectively, compared with the static load at the same temperature, while the strengths of basalt fiber-reinforced concrete improve by 32%, 61.6%, and 41.7% at room temperature (25 \({}^{\circ}\)C), 200, and 400 \({}^{\circ}\)C, respectively, compared with the static load at the same temperature. When the loading rate is 7.8 m/s, the strength of ordinary concrete improves by 62.5%, 69.5%, and 56.9% at room temperature, 200, and 400 \({}^{\circ}\)C, respectively,