# Experimental Study on Flexural Capacity of Corroded RC Slabs Reinforced with Basalt Fiber Textile
## 2 Experimental Program
### Strengthening Scheme  
During the test, the strengthening materials (BFRP or BTRM) were externally bonded to the bottom of the corroded RC slabs in a range of 2000 mm as shown in Figure 6. It should be emphasized that the strengthening layers did not extend into the support range and at the end of the strengthening layer there was no other special anchoring treatment. The different flexural performance was investigated by changing the experimental variables including the initial corrosion state, the strengthening materials (BFRP or BTRM) and the layers of basalt textile. Details of the specimens are shown in Table 3. The first letter in the specimen name (M or S) represents the specimen with a moderate or severe corrosion state, respectively. The 2 nd letter denotes the strengthening schemes. (C) represents non-strengthened slabs which served as control specimens, and letter (P or M) represents strengthened with BFRP or strengthened with BTRM, respectively. The last Arabic number (3 or 5) represents 3 or 5 layers of textile, respectively. For example, 'M-P-3' denotes that a moderately corroded RC slab was strengthened by 3 layers of BFRP.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Textile** & **Weight Per Area** & **Cross Section Area** & **No. of** & **Elasticity Modulus** & **Tensile Strength** & **Elongation** \\  & **(g/m2)** & **(mm2)** & **Yarns** & **(GPa)** & **(MPa)** & **(\%)** \\ \hline Basalt & 221 & 0.201 & 12 & 35.1 (0.068) * & 725.95 (0.062) & 2.07 (0.055) \\ \hline \hline \end{tabular} Note: * coefficient of variation.  
\end{table}
Table 1: Mechanical properties of the test basalt textile.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Types** & **Layers** & **Nominal Thickness * (n)** & **Tensile Strength** (mm)** & **Elongation Ratio** & **Elasticity Modulus (\%)** & **(GPa)** \\ \hline BFRP & 3 & 1.071 (0.043) ** & 147.53 (0.062) & 2.87 (0.053) & 4.964 (0.063) \\ BFRP & 5 & 1.785 (0.047) & 153.10 (0.069) & 3.00 (0.048) & 5.032 (0.059) \\ BTRM & 3 & 10.000 & 17.97 (0.071) & 2.21 (0.071) & 0.798 (0.070) \\ BTRM & 5 & 10.000 & 23.61 (0.066) & 2.45 (0.064) & 0.918 (0.076) \\ \hline \hline \end{tabular} Note: * The nominal thickness of BFRP was the mean value of specimen by measurement; the nominal thickness of BTRM was a 10 mm design thickness of the specimen. ** coefficient of variation.  
\end{table}
Table 2: Mechanical properties of BFRP and BTRM materials.  
The wet layup application was adopted, and the strengthening procedures included the following steps.  
1. The concrete surface was prepared as follows: firstly, marking out the areas where the BFRP or BTRM should be bonded; then, roughening the surface concrete with a bush hammer for to a depth of approximately 3 mm; and finally cleaning the dust with compressed air.
2. The procedure for BFRP-strengthened specimens included: brushing textile with adhesive layer by layer and then compacting the layers with a plastic roller. To satisfy the adhesive soaking sufficiently and remove the excess polymer, each layer of the composite material was rolled 5 times by using a plastic roller.  
Figure 5: Tensile test of strengthening materials. (**a**) Geometry of coupons (all dimensions in mm); (**b**) details of tensile test; (**c**) basalt fiber-reinforced polymer (BFRP) coupons; (**d**) basalt textile-reinforced mortar (BTRM) coupons; (**e**) failure mode of BFRP coupons; (**f**) failure mode of BTRM coupons.  
3. The procedure for BTRM-strengthened specimens included: (a) wetting the concrete surface with water; (b) paving mortar and textile layer by layer to ensure good impregnation of mortar for the textile; and controlling overall thickness of BTRM by 10 mm. In detail, the first and last layers of BTRM were mortar layers, the thickness of each being 2 mm. The thickness of intermediate layers was uniform and related to the number of textile layers. For example, if the BTRM contained 3 textile layers, the thickness of each intermediate layer would be 2 mm.