# Experimental Evaluation of the Durability of Concrete Repair Materials
## 3 Results and Discussion
### Accelerated Carbonation  
Table 3 and Figures 6 and 7 show the carbonation depths and velocity rates. The measurements were taken after one and four weeks to examine any changes. The carbonation depths of the intact specimens with target strengths of 20 and 40 MPa were 9.4 and 4.4 mm, respectively. For the repaired specimens with 2 and 5 mm notches and a target strength of 20 MPa, the impregnant specimens exhibited the smallest carbonation depths at one week, 8.7 and 8.9 mm, respectively. However, after four weeks, the epoxy/impregnant specimens exhibited the smallest carbonation depths, 9.9 and 11.7 mm, respectively, approximately \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Target Strength** & **Notch Width** & **Repair Method** & **Compressive Strength** & **Flexural Strength** \\ \cline{3-5}
**(MPa)** & **(mm)** & **(MPa)** & **(MPa)** & **(MPa)** \\ \hline \multirow{8}{*}{20} & \multirow{8}{*}{2} & - & Intact (no notch)-NN & 21.3 \(\pm\) 0.45 & 3.7 \(\pm\) 0.52 \\ \cline{3-5}  & & \multicolumn{2}{c}{Notched (unrepaired)-N} & 20.1 \(\pm\) 0.77 & 1.3 \(\pm\) 0.09 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy-E} & 20.2 \(\pm\) 0.69 & 2.3 \(\pm\) 0.16 \\ \cline{3-5}  & & \multicolumn{2}{c}{Impregnant-I} & 19.6 \(\pm\) 0.33 & 1.1 \(\pm\) 0.49 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy/impregnant-E and I} & 19.9 \(\pm\) 0.36 & 2.2 \(\pm\) 0.34 \\ \cline{3-5}  & & \multicolumn{2}{c}{Notched (unrepaired)-N} & 18.8 \(\pm\) 2.15 & 1.5 \(\pm\) 0.2 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy-E} & 19.6 \(\pm\) 0.24 & 2.0 \(\pm\) 0.33 \\ \cline{3-5}  & & \multicolumn{2}{c}{Impregnant-I} & 18.7 \(\pm\) 0.43 & 1.3 \(\pm\) 0.06 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy/impregnant-E and I} & 19.2 \(\pm\) 0.12 & 1.3 \(\pm\) 0.60 \\ \cline{3-5}  & & \multicolumn{2}{c}{-} & Intact (no notch)-NN & 39.1 \(\pm\) 3.09 & 5.3 \(\pm\) 0.37 \\ \cline{3-5}  & & \multicolumn{2}{c}{Notched (unrepaired)-N} & 35.1 \(\pm\) 2.16 & 2.2 \(\pm\) 0.25 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy-E} & 35.5 \(\pm\) 1.55 & 2.4 \(\pm\) 0.25 \\ \cline{3-5}  & & \multicolumn{2}{c}{Impregnant-I} & 33.9 \(\pm\) 0.84 & 1.8 \(\pm\) 0.21 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy/impregnant-E and I} & 35.0 \(\pm\) 0.78 & 3.1 \(\pm\) 0.18 \\ \cline{3-5}  & & \multicolumn{2}{c}{Notched (unrepaired)-N} & 33.0 \(\pm\) 1.79 & 2.0 \(\pm\) 0.31 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy-E} & 33.5 \(\pm\) 1.15 & 2.7 \(\pm\) 0.52 \\ \cline{3-5}  & & \multicolumn{2}{c}{Impregnant-I} & 32.5 \(\pm\) 0.52 & 1.9 \(\pm\) 0.22 \\ \cline{3-5}  & & \multicolumn{2}{c}{Epoxy/impregnant-E and I} & 33.5 \(\pm\) 0.25 & 3.3 \(\pm\) 0.12 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Compressive and flexural strength test results for various concrete specimens. These results show that the carbonation depth decreased as the concrete strength increased [32]. The accelerated carbonation test results confirm that the repair methods that included impregnant, i.e., impregnant repair or epoxy/impregnant repair, were more effective at reducing the carbonation depth and carbonation velocity. However, carbonation depth in the repaired specimens degraded between week one and week four. As such, for carbonation resistance, it will be more effective in the long term to repair the epoxy/impregnant simultaneously rather than separately. Furthermore, it would be most effective to apply it to roads with high traffic and structures exposed to the atmosphere for a long period of time. If carbon dioxide penetrates along the crack, it causes corrosion of