# Carbon Fiber Traces in Cracked Surfaces of Mortar Prisms
## 4 Fiber Traces on the Cracked Surfaces
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & **CF-0.5-1** & **CF-0.5-2** & **CF-1.0-1** & **CF-1.0-2** & **CF-1.5-1** & **CF-1.5-2** & **CF-2.0-1** & **CF-2.0-2** \\ \hline \multirow{3}{*}{Urootedness} & I & 3 & 6 & 4 & 2 & & 1 & 1 & 1 \\ \cline{2-10}  & II & & 1 & 1 & 2 & 5 & & & 1 \\ \cline{2-10}  & sum & 10 & & 9 & & 6 & & 3 & \\ \hline \multirow{3}{*}{Avulsion} & I & & & 1 & 1 & & 2 & 3 \\ \cline{2-10}  & II & & 1 & 4 & 2 & 4 & 7 & 3 & 2 \\ \cline{2-10}  & sum & 1 & & 7 & & 12 & & 10 & \\ \hline \multirow{3}{*}{Separation} & I & & & & & & & & \\ \cline{2-10}  & II & & 3 & 3 & 4 & 3 & 2 & 4 & 2 \\ \cline{2-10}  & III & & & & 2 & & 1 & 1 & 2 \\ \cline{2-10}  & sum & 3 & & 9 & & 6 & & 9 & \\ \hline \multicolumn{2}{c}{Overlay} & & & & & & & & 1 \\ \hline \multirow{3}{*}{Dividedness} & I & 1 & 1 & 2 & & 1 & & & \\ \cline{2-10}  & II & & & 1 & 4 & 4 & 5 & 5 & 7 \\ \cline{2-10}  & sum & 2 & & 7 & & 10 & & 12 & \\ \hline \multirow{3}{*}{N. of Regions} & Number & 1 & 2 & 4 & 3 & 6 & 6 & 6 & 7 \\ \cline{2-10}  & Sum & 3 & & 7 & & 12 & & 13 & \\ \hline \end{tabular}
\end{table} 
Table 1: The total numbers of each trace and regions in each prism sample summarized. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Prism**} & \multicolumn{2}{c}{**CF-0.5**} & \multicolumn{2}{c}{**CF-1.0**} & \multicolumn{2}{c}{**CF-1.5**} & \multicolumn{2}{c}{**CF-2.0**} \\ \cline{2-10}  & \(-\)**1** & \(-\)**2** & \(-\)**1** & \(-\)**2** & \(-\)**1** & \(-\)**2** & \(-\)**1** & \(-\)**2** \\ \hline \multirow{2}{*}{Urootedness} & 3 & 7 & 5 & 4 & 5 & 1 & 1 & 2 \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Avulsion+ \\ Separation+ \\ Overlay \\ \end{tabular} } & & & & & & & & & \\ \cline{2-10}  & 1 & 3 & 4 & 5 & 5 & 5 & 7 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Numbers of combined traces. it is considered that the sample area of CF 0.5-2 is slightly bigger than that of CF 1.0-1 or 2, there will not be any difference between the two, but the number decreases sharply with the fiber percentage increase to 1.5 and 2.0. Since it is considered that the uprooted fiber strands/clusters are held more tightly by the surrounding mortar than the avulsion, separation and overlay, the strength of the prism samples will be reduced as the number of uprooted fiber clusters reduces and those of the three traces increase. 4. The growth of overlapping and clustering caused by the fiber content increase introduces a greater number of cemented fiber clusters/chunks, i.e., air pockets as indicated by the summed number of avulsions and separations. The numbers are 4, 16, 18 and 19 for CF 0.5, CF 1.0, CF 1.5 and CF 2.0, respectively. If the overlay is added, the number becomes 20 for CF 2.0. It is increasing as the fiber percentage increases. The greatest increment is 12 between CF 0.5 and CF 1.0. However, the increment is reduced more as the fiber percentage increases further. The increasing numbers of (avulsions + separations) will reduce the strength of the prism samples. 5. The numbers of dividedness are 2, 7, 10 and 12 for CF 0.5, CF 1.0, CF 1.5 and CF 2.0, respectively. In these numbers, type II prevails, except CF 0.5. The numbers of the type II are 0, 5, 9 and 12 for CF 0.5, CF 1.0, CF 1.5 and CF 2.0, respectively. The greatest increase in number comes to 5 between CF 0.5 and CF 1.0. As the fiber content increases further, type I disappears but type II increases. Due to this, more parts of the cracked surfaces become covered with fiber-laden mortars and cemented fiber chunks as shown by Figures 10 and 11 for CF 1.5 and CF 2.0, respectively. 6. The region number sum of the same percentage samples increases as the fiber percentage increases, though the difference between CF 1.5 and CF 2.0 is only 1. This number increase indicates that the cracked surface becomes bumpier as the percentage increases, though its roughness increment slows down as the content increases more.