## 3 Results and Discussion
### Destructive Tests
#### 3.3.3 Discussion of the Test Results  
From the results obtained in the destructive tests (Tables 6 and 7), it appears that the highest mechanical strengths correspond to groups V and V.NMS, which present aggregate contents of 25% and 24%, respectively, while the P and P.NMS groups have aggregate contents of 50% and 49%, respectively. The assessment of the developed mortars' destructive test results allowed to observe a decrease in the flexural and compression strengths when higher amounts of aggregates were added. Furthermore, in most of the \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Specimen Designation** & **Maximum Load (N)** & **Average Load (N)** & \(f_{ct,ft}\) (MPa)** & **SD** \\ \hline C.1 & 984.0 & & & \\ C.2 & 922.9 & 939.4 & 1.945 & 0.066 \\ C.3 & 911.3 & & & \\ \hline P.1 & 445.4 & & & \\ P.2 & 478.1 & 461.3 & 0.955 & 0.028 \\ P.3 & 460.4 & & & \\ \hline P.NMS.1 & 404.1 & & & \\ P.NMS.2 & 445.6 & 419.5 & 0.868 & 0.038 \\ P.NMS.3 & 408.9 & & & \\ \hline V.1 & 1065.4 & & & \\ V.2 & 1047.7 & 1057.5 & 2.189 & 0.015 \\ V.3 & 1059.3 & & & \\ \hline V.NMS.1 & 979.1 & & & \\ V.NMS.2 & 971.4 & 969.8 & 2.008 & 0.017 \\ V.NMS.3 & 959.0 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Flexural test results. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Specimen Designation** & **Maximum Load (N)** & **Average Load (N)** & \(f_{ct,c}\) (MPa)** & **SD** \\ \hline C.1.1 & 5259.0 & & & \\ C.1.2 & 5306.1 & 5275.2 & 3.297 & 0.013 \\ C.2.1 & 5260.5 & & & \\ \hline P.1.1 & 1628.0 & & & \\ P.1.1 & 1575.4 & 1636.6 & 1.023 & 0.034 \\ P.2.1 & 1706.4 & & & \\ \hline P.NMS.1.1 & 1833.9 & & & \\ P.NMS.1.2 & 1711.7 & 1775.9 & 1.110 & 0.050 \\ P.NMS.2.1 & 1782.1 & & & \\ \hline V.1.1 & 5040.3 & & & \\ V.1.2 & 4937.9 & 5007.5 & 3.139 & 0.031 \\ V.2.1 & 5044.3 & & & \\ \hline V.NMS.1.1 & 4387.8 & & & \\ V.NMS.1.2 & 4552.7 & 4427.5 & 2.767 & 0.091 \\ V.NMS.2.1 & 4341.9 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Compression test results. results obtained, the addition of nano and micro silica particles caused a decrease in flexural and compressive strength. In cement-based concrete, the mechanical strength can be enhanced by incorporating fly ash or silica fume. Fly ash contributes to long-term strength through pozzolanic reactions, while silica fume improves early strength and densification due to its high reactivity and fine particle size [45; 46; 47]. Similarly, for gypsum-based mortars, it was anticipated that the introduction of nano and micro silica particles would improve the microstructure by filling the pores in the matrix and promoting pozzolanic reactions during gypsum hydration. This process would theoretically result in increased density, better adhesion within the matrix, and consequently, enhanced mechanical strength. However, the experimental results indicated otherwise, showing a decrease in mechanical strength. This outcome may be attributed to the inadequate distribution of silica particles within the gypsum matrix, leading to the formation of agglomerates. These agglomerates create weak zones in the microstructure, reducing cohesion and ultimately compromising the mechanical strength. Furthermore, the high reactivity and specific surface area of the particles might alter the water-to-gypsum ratio, potentially interfering with the hydration process and promoting the formation of microcracks, which further degrades the material's mechanical properties. Experimental studies on mortars carried out by different authors [21; 22; 23] indicate that with an increase in the number of aggregates with low mechanical strength or an increase in the water/binder ratio increases, the lower their mechanical strength values will be. The reviewed literature agrees with the results obtained from flexural and compression tests. Table 8 summarises each mortar's strengths and the relationship between the developed mortar's and the commercial composition's strengths.