## 4 Discussion
### Short Beams
All of the beams displayed a brittle fracture, with a crack that is typical of a shear fracture (Figure 5). There were no differences between the types of fracture in the beams reinforced with both types of fiber. A crack formed between the load application point and the edge of the support, which was more open in the lower area and gradually narrowed as it reached the load application point. In the central area of the beam, the crack took on a step-like shape, but on joining the two ends of the crack, a straight line was obtained which cut the steps roughly in half. In the beams which were not reinforced with fibers, the type of fracture was very similar, appearing as a crack which, as in the aforementioned case, spanned from the edge of the support to the load application point; however, in this case, the shape of the crack was not a straight line, but rather a curve, which is typical of shear cracking in unreinforced concrete elements. Cracking occurs when the principal tensile stress in the concrete exceeds the tensile strength of the concrete. Due to the non-existence of stirrups and fibers that can contribute to the resistance to shear stress, when the tensile strength of the concrete is reached, the crack becomes larger and the central zone slides downwards with respect to the zone that remains in the supports. In the beam BHM8, the pin effect of the tensile reinforcement could be verified. \begin{table}
\begin{tabular}{c c} \hline \hline
**Compared Levels** & \(p\)**-Value** \\ \hline BHM-BHR & 0.854 \\ BHM-BRF & 6.98 \(\times\) 10\({}^{-5}\) *** \\ BHR-BRF & 5.79 \(\times\) 10\({}^{-5}\) *** \\ \hline \hline \end{tabular} \({}^{***}\) The \(p\)-value is \(<\) than 10 \(\times\) 10\({}^{-3}\).  
\end{table} 
Table 7: Results of the analysis ANOVA for the breaking load. \begin{table}
\begin{tabular}{c c} \hline \hline
**Compared Levels** & \(p\)**-Value** \\ \hline BHM-BHR & 0.27495 \\ BHM-BRF & 0.00513 \({}^{**}\) \\ BHR-BRF & 0.00155 \({}^{**}\) \\ \hline \hline \end{tabular} \({}^{**}\) The \(p\)-value is \(<\)10 \(\times\) 10\({}^{-2}\) and \(>\)10 \(\times\) 10\({}^{-3}\).  
\end{table} 
Table 8: Results of the analysis ANOVA for the displacement. Figure 6 shows the increases in the average values achieved by the reinforced beams compared to the benchmark beams. Figure 5: Images of the beams after flexural strength testing. Figure 6: Increases in the average values of the properties of reinforced beams. The data in Figure 6 show once again that both types of reinforcement are highly effective because they brought about a highly significant improvement in the structural response of reinforced elements. Furthermore, the results obtained were very similar and, excluding the case of rigidity, the increases achieved using HR fibers were slightly higher than those achieved using HM fibers. A significant increase in the load capacity of the beams was observed when the beams were reinforced using either of the two procedures. Both with the HR fibers and with HM fibers, increases in load were achieved which more than doubled (2.5 and 2.4 times, respectively) the load for the benchmark beams. In the case of the energy absorbed during the test, the increases were even higher: 3.9 times higher with HR fibers and 3.5 times higher with HM fibers. The displacements of the reinforced beams also exhibited significant increases, recorded at 1.6 times higher (HR) and 1.5 times higher (HM). In the case of rigidity, the same results were obtained with both types of fabric, 50% more than those for the unreinforced beam. The analysis of a beam such as that tested cannot be carried out using the Bernoulli beam model since all regions of the beam are in D regions and, as such, they do not fulfil the assumption of having flat sections both before and after the strain. The analysis must be performed using the rods and straps method [76; 77].