## 3 Results and Discussion
### Mechanical Characterization Tests  
Masonry mortars must act in the vast majority of their applications as strong bonding elements that share the stresses of the construction system of which they are part [76]. For \begin{table}
\begin{tabular}{c c c} \hline \hline
**Factors** & **Levels** & **Nomenclature** \\ \hline Dosage & 1:3/1:4 & A/B \\ Fiber type & No Fiber/Aggregate Fiber & NF/AF \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Factors and levels used for the analysis of variance (ANOVA). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Type** & **Cement (g)** & **Aggregate (g)** & **Water (g)** & **Fiber (g)** & **Additive (g)** & **Consistency (UNE-EN 1015-2: 2007 [68])** \\ \hline NA-1:3 & 450.0 & 1350 & 243 & - & - & 176 \\ NA-1:4 & 337.5 & 1350 & 196 & - & - & 174 \\ RA-1:3 & 450.0 & 1350 & 311 & - & 4.5 & 171 \\ RA-1:4 & 337.5 & 1350 & 250 & - & 3.4 & 169 \\ RA-1:3-AF & 450.0 & 1350 & 311 & 2.5 & 4.5 & 172 \\ RA-1:4-AF & 337.5 & 1350 & 250 & 2.5 & 3.4 & 168 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Dosages used for the elaboration of mortars. this reason, the flexural and compressive mechanical strengths shown in Figures 3 and 4 were evaluated. As can be seen in Figure 3, the flexural strength of mortars made with natural aggregate is higher than that obtained for mortars made with recycled aggregate, regardless of the cement/aggregate ratio by weight. However, the incorporation of aramid fibers in the mortar matrix has considerably improved the flexural strengths of recycled mortars, with the best results obtained for the RA-1:3-AF mix, since it has a higher cement content [77]. On the other hand, the results of the compression test also show how traditional mortars have higher strengths than recycled mortars, with higher strengths for the mixes with a cement/aggregate ratio of 1:3 by weight. In this case, it can be seen that the addition of fibers in mortars made with recycled concrete aggregate hardly produces an improvement in compressive strength [78]. In addition, in the case of compressive strength, the lower strengths obtained for mortars made with recycled aggregate may be linked to the higher porosity of this type of material, which has been analyzed in depth by other researchers [79]. The analysis of variance (ANOVA) performed to statistically evaluate the effect produced by the incorporation of aramid fibers in mortars made with recycled concrete aggregate is presented in Table 7.  
Figure 4: Results of the compressive strength test image of specimen RA-1:3-AF type tested. Figure 3: Flexural strength test results and image of specimen RA-1:3-AF type tested. As can be seen in Table 7, for the case of flexural strength the two factors included in the study can be considered statistically significant by having a \(p\)-value below the significance level (\(\alpha\) = 0.05). However, for the case of mechanical compressive strength, it can be seen how the cement/aggregate ratio can be considered statistically significant (\(p\)-value \(<\alpha\)), but the incorporation of fibers cannot be considered significant for this property. In Tables 8 and 9, the results obtained after performing the multiple range test for the mechanical properties are presented. In the multiple range test shown in Tables 8 and 9 for flexural strength, it can be observed that there are significant differences at all levels for each of the factors analyzed. It can be concluded that the mixes incorporating aramid fibers and 1:3 dosage present better performance in terms of this property. However, in the case of compressive strength, it can be seen from the analysis of Table 9 that the incorporation of fibers is not a significant factor in increasing this property. On the other hand, Figure 5 shows the images obtained by scanning electron microscopy for the mortar samples made with recycled concrete aggregate with and without aramid fibers.