# Experimental Study on Flexural Capacity of Corroded RC Slabs Reinforced with Basalt Fiber Textile
## 3 Experimental Results and Discussion
### Load-Deflection Curves  
The load was applied incrementally at a rate of 2.5 kN per step until the tensile reinforcement yielded. The loading process was then controlled by deflection, and the increment was 2.5 mm per step. The load versus mid-span deflection is shown in Figure 9. The control specimens M-C and S-C presented the typical flexural failure by yielding of the tensile reinforcing bars, followed by concrete crushing in the compression zone. However, the bearing capacity and ultimate elongation of specimen S-C were significantly reduced due to severe corrosion.  
The differences between the curves of the strengthened slabs and the control slabs are attributed to the contribution of strengthening materials to the flexural performance of the slabs (refer to Figure 9). Before reaching the load peak, the load-deflection curves of the strengthened slabs increased monotonously. At this stage, the curves consisted of three segments with two turning points, indicating the initial cracking in concrete and the yielding of the tensile reinforcement. When the peak point of the curves was reached, a sudden drop of load occurred due to the strengthening layers fracturing or debonding near the mid-span. At the post-peak stage, the loading capacity of the strengthened slabs dropped to the value which was higher than or close to that of the control specimens. The major effect of the strengthening layers had almost been lost at this stage, and the load remained almost constant due to the tensile reinforcing bars yielding. The tests were terminated when the compressive concrete zone was crushed, which indicated that the slabs had reached their ultimate limit state. At the post-peak stage, most of the strengthened specimens underwent large deformation before failing. However, the deformation stage of M-P-5 was extremely short because the slab failed shortly after it reached the peak load.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Specimen ID**} & \multirow{2}{*}{\begin{tabular}{c} **Expected** \\ **Corrosion Ratio** \\ **(\%)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Actual** \\ **Corrosion Period** \\ **(days)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Measured** \\ **Corrosion Ratio * \\ **(\%)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Mean** \\ **Corrosion Ratio * \\ **(mm)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Maximum** \\ **Corrosion Crack Width** \\ **(mm)** \\ \end{tabular} } \\ \hline M-C & 8\% & 118 & 8.83 & 0.268 & 0.704 \\ M-P-3 & 8\% & 115 & 7.68 & 0.320 & 0.680 \\ M-P-5 & 8\% & 115 & 9.55 & 0.322 & 0.735 \\ M-M-3 & 8\% & 115 & 8.37 & 0.217 & 0.490 \\ M-M-5 & 8\% & 115 & 9.14 & 0.228 & 0.522 \\ H-C & 16\% & 200 & 16.25 & 0.363 & 0.845 \\ H-P-3 & 16\% & 210 & 15.81 & 0.446 & 1.210 \\ H-P-5 & 16\% & 210 & 14.94 & 0.434 & 1.250 \\ H-M-3 & 16\% & 215 & 16.43 & 0.410 & 1.381 \\ H-M-5 & 16\% & 215 & 14.27 & 0.432 & 1.169 \\ \hline \hline \end{tabular}  
* Measured corrosion ratio is an average steel mass loss of five longitudinal steel bars in a slab.  
\end{table}
Table 4: Accelerated corrosion results of test specimens.  
Figure 9: Load–deflection relationship of test specimens: (**a**) moderate corrosion; (**b**) severe corrosion.