## 3 Results and Discussion
### Mechanical Properties  
#### 3.3.1 Strength and Stiffness Bending Properties  
In general, the FRP-LVL samples glued with ER adhesive presented the highest results in stiffness (MOE) and strength (MOR). In the flatwise position (Figure 4), the sample ER-CF (MOE: 8190 MPa; MOR: 86.27 MPa) presented an increase, about 30.53% and 37.61%, in MOE and MOR, respectively. For the rest of the samples, there were no statistically significant differences in comparison to the control sample. In the edgewise position (Figure 5), there was an increase in MOE values, between \(\sim\)14% and 35.93%, in the samples ER-CF; PVAc-CF (9626 MPa; 9754 MPa) and ER-BF (11,476 MPa), respectively. The MOR of the sample ER-BF (76.08 MPa) increased by 28.65%, while for the rest of the samples, in the MOR case, there were no statistically significant differences in comparison to the control sample. In the investigations of [PERSON] [51] and [PERSON] [25], CFRP-LVL samples presented higher values in bending properties compared to an unreinforced sample, which generally occurred in this investigation in MOE results. Furthermore, in the investigation of [PERSON] [28], BFRP-gulam beam samples also presented higher values in bending properties compared to an unreinforced sample, which occurred in edgewise samples of this investigation. Figure 4: Results of strength (MOR) and stiffness (MOE) bending properties and density of each sample in the flatwise position (error bars indicate standard deviations). The bending test results indicated that the samples glued with ER have a higher stiffness and strength compared to the samples glued with PVAc adhesive. This might be associated with the ten-times-higher MOE of ER than that of wood [52], but also the cure temperature needed for each adhesive, because while PVAc was hot pressed, it could have lost its mechanical properties by the water evaporation and its less solid content percentage. On the other hand, thermosetting polymers of ER make excellent structural adhesives because they undergo irreversible chemical change when cured [53], and thermoset adhesives generally are stronger than thermoplastic adhesives (PVAc) [49]. Anyways, good results of ER adhesive in the matrix are not consistent with the ecological perspective of this study. The highest bending test stiffness (MOE) results were obtained by the EW position samples, while the highest strength (MOR) results were obtained by the flatwise position samples. This result can be attributed to veneer classification and board assembly that prioritized more resistant veneers for the external layers of LVL [43]. Furthermore, all the samples tested mainly had tensile failure. However, in several cases, shear failure was observed, especially in the flatwise position tested samples. The reason lies in the fact that the flexural strength contribution of the FRP exceeds the shear strength of the veneer itself, causing this type of failure [25]. Thus, the flatwise position tested samples did not reach higher values than the edgewise position in MOE results. The bending test load-deflection curves of the flatwise and edgewise positions samples demonstrated that the FRP-LVL panels exhibited increased maximum load and maximum deflection when compared to the LVL panels (Figures 6 and 7); these results are consistent with the results of the authors [PERSON] and [PERSON] [54] who also obtained higher maximum load and deflection values for FRP-LVL compared to the control LVL. Figure 5: Results of strength (MOR) and stiffness (MOE) bending properties and density of each sample in the edgewise position (error bars indicate standard deviations). Figure 6: Load-deflection curves were obtained during the four-point bending test for the samples in the (**a**) flatwise position and in the (**b**) edgewise position. A characteristic curve for each sample was used as a representation of the behavior of each one.