## 3 Results and Discussion
### Evaluation of Impact Resistance  
In Table 6, the test results for the impact resistance of each specimen are summarized and Figure 10 also shows the number of blows for the first crack and the number of blows for final failure. As seen in Table 6 and Figure 10, it is obvious that the impact resistance is greatly improved compared to the PM specimen if SF and CF are incorporated. The improvement of the impact resistance can be mainly due to the randomly distributed fibers in the cement matrix. These fibers, each acting as a miniature energy-absorbing mechanism, support a certain percentage of the load during each impact event. Thus, MFRCM and HyFRCM specimens can bear more impact blows and improve the impact resistance to the first crack compared to PM specimens. After the first crack occurs and is followed by the others, the fibers across these cracks act not only as energy-absorbing mechanisms but also as load transfer mechanisms. The mechanisms may defend the cracked MFRCM and HyFRCM disks against the tendency to fall into different pieces, therefore, improving the failure impact resistance. However, SF showed better performance than CF, having smaller dimensions and the same volume fraction (%) due to higher elastic modulus and tensile stress. The impact resistance of the PM specimen turned out to be about 1 to 2 blows from the first crack to the final failure, revealing that the impact ductility in the specimen had little effect. On the other hand, although there was a slight difference depending on the amount of SF and CF mixture in the case of MFRCM and HyFRCM specimens, the average number of blows from the first crack to final failure reached 39 times in the case of HyFRCM specimen containing 0.75% SF and 0.25% CF, showing that the fiber and impact ductility acted on the specimen even after the first crack occurred, resulting in a slight increase of the number of blows. Therefore, it is judged that the HyFRCM specimen containing 0.75% SF and 0.25% CF is dispersed throughout the specimen due to the cross-linking action of the fibers, and the time from the first crack to the final failure is delayed. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Mixture ID** & \begin{tabular}{c} **No. of Blows for** \\ **First Crack (I)** \\ \end{tabular} & \begin{tabular}{c} **No. of Blows for** \\ **Final Failure (2)** \\ \end{tabular} & \begin{tabular}{c} **Increased** \\ **(2) – (1)** \\ \end{tabular} & \
\begin{tabular}{c} **Absorbed Energy** \\ **(First Crack) (N-m)** \\ \end{tabular} &
\begin{tabular}{c} **Absorbed Energy** \\ **(Final Failure) (N-m)** \\ \end{tabular} \\ \hline SC0-1 & 1 & 3 & 2 & 8.82 & 26.46 \\ SC0-2 & 2 & 3 & 1 & 17.64 & 26.46 \\ SC0-3 & 2 & 4 & 2 & 17.64 & 35.28 \\ Average & 2 & 3 & 2 & 14.70 & 29.40 \\ SC1-1 & 93 & 124 & 31 & 820.26 & 1093.68 \\ SC1-2 & 96 & 129 & 33 & 846.72 & 1137.78 \\ SC1-3 & 98 & 133 & 35 & 864.36 & 1173.06 \\ Average & 96 & 129 & 33 & 843.78 & 1134.84 \\ SC2-1 & 101 & 138 & 37 & 890.82 & 1217.16 \\ SC2-2 & 104 & 142 & 38 & 917.28 & 1252.44 \\ SC2-3 & 104 & 145 & 41 & 917.28 & 1278.90 \\ Average & 103 & 142 & 39 & 908.46 & 1249.50 \\ SC3-1 & 87 & 117 & 30 & 767.34 & 1031.94 \\ SC3-2 & 81 & 113 & 32 & 714.42 & 996.66 \\ SC3-3 & 72 & 105 & 33 & 635.04 & 926.10 \\ Average & 80 & 112 & 32 & 705.60 & 984.90 \\ SC4-1 & 40 & 67 & 27 & 352.80 & 590.94 \\ SC4-2 & 35 & 57 & 22 & 308.70 & 502.74 \\ SC4-3 & 32 & 51 & 19 & 282.24 & 449.82 \\ Average & 36 & 58 & 23 & 314.58 & 514.50 \\ SC5-1 & 13 & 18 & 5 & 114.66 & 158.76 \\ SC5-2 & 12 & 17 & 5 & 105.84 & 149.94 \\ SC5-3 & 12 & 16 & 4 & 105.84 & 141.12 \\ Average & 12 & 17 & 5 & 108.78 & 149.94 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Results obtained from the impact resistance test. Meanwhile, Figure 11 shows the crack and fracture patterns of the fractured surface after the impact resistance test.