# Vegetal-FRCM Failure under Partial Interaction Mechanism
## 4 Discussion
### FRCM Tensile Test  
Regarding the FRCM specimens, they showed a two-stage behavior, where the first stage is stiffer, and after the cracking and load transmission, it is reduced until failing through slippage. Hemp specimens have a more heterogenic behavior. Synthetic coating (polyester) provided higher strength values and failed through slippage or rupture of the mesh. On theother hand, natural coatings presented a complete slippage of the fibers from the mortar matrix. For cotton ones, the results were more homogeneous, maintaining the failure modes depending on the source of the resin. By observing Tables 9 and 10, the effect of the fiber reinforcement can be seen clearly during the first stage, where the specimen has not cracked yet. Even if it is considered that mainly the mortar was bearing the load, the slope was higher for hemp specimens when compared with the cotton cases. For the second stage, where multicracking and sliding happened, polyester and natural coating reduced the slope with the exception of PESHE. It can be related to the failure mode of each case. Polyester-coated hemp specimens were the only ones that failed by mesh rupture, which means that the load transmission between the materials was correct (Figure 8, II). Synthetic-coated specimens' failure consisted of the relative sliding of the mesh with the mortar, which resulted in cutting the mortar matrix (Figure 8, I), with the exception of PESHE. The anchoring system, a Clevis grip, where there was not any element that pressed the ends of the specimens while applying the load with low fiber-matrix compatibility, caused a relative displacement between the mesh and the matrix. The only case that had the expected failure was polyester-coated hemp FRCM. Finally, the naturally coated specimens also showed a different failure mode, as the mesh completely slid from the mortar matrix. After the multicracking stage, the longitudinal yarns were not broken, they debonded completely from the matrix, and the remaining strength consisted of the friction between the fibers and the matrix. Which clearly states the low compatibility between natural-coated fibers and the matrix for the concentrations used in this research. The surface of the fibers was smoother for synthetic coated fibers, probably due to the reticulation time. Liquids tend to form spherical shapes to reduce the superficial tensions [30]; therefore, the increase in the reticulation time allowed the natural resins to reshape homogeneously, reducing the roughness of the surface. Furthermore, considering the epoxy-coated specimens as a reference, in Figures 9 and 10, there is a variation in the load and the different slopes of each case. Polyester resin increased the tensile strength and stiffness of the specimens, while the Arabic gum increased the stiffness of the specimens but decreased their tensile strength. Finally, colophony increased the stiffness of the specimens and also increased the cotton specimen's strength but decreased the hemp ones. In general, all three coatings increased the stiffness when compared with epoxy coating as the epoxy coating is more flexible than the other ones. Epoxy resin was the coating that provided more stiffness during the first stage in all cases except for PESCO specimens, where the polyester resin exceeded the stiffness of epoxy. Even if during the yarns and meshes tensile test, there are vegetal coatings that provide higher stiffness, in FRCM specimens, its stiffness decreased. It can be due to the deterioration of the coatings during the curing period because of the alkalinity environment of the mortar matrix. For natural coatings, Arabic gum showed less compatibility with the matrix as the strength of the specimens decreased. It can be due to the fact that Arabic gum's solvent is distilled water, which maybe was more diluted during the curing period of the mortar. In the case of colophony, the effect is different depending on the type of fiber to coat. Probably due to the resistance of the fiber to the solvent (acetone), where cotton has more resistance.