## 3 Results
### Tests on Behavior Regarding Water Exposure  
In this section, the behavior regarding the water exposure of the gypsum composites developed in this work is analyzed. To begin with, the results obtained for the total water absorption coefficient and open porosity of each formulation are shown in Table 7.  
As shown in Table 7, there is a decrease in total water absorption as the content of added hemp material increases. This is attributed to the replacement of the original gypsum material with this plant-based addition, resulting in the composite retaining less water in its matrix. Similar observations have been made in prior research [11; 58]. Additionally, it is observed that composites with hemp fiber addition exhibit a lower water absorption capacity compared to their counterparts with hemp powder. Similarly, the volume of pores accessible from the exterior is reduced, with the G0.65-30%F composite having the lowest open porosity. Figure 5: SEM analysis of the G0.65–30%P composite. (**a**) 20\(\times\) magnification; (**b**) 250\(\times\) magnification; (**c**) 500\(\times\) magnification; and (**d**) 2000\(\times\) magnification. In Figure 6, it can be observed that the mass of water absorbed per unit area over time is lower in the composites with hemp addition. Additionally, there is lower absorption in the composites with hemp fiber compared to those containing hemp powder, which is consistent with the results shown in Table 7. Thus, the material exhibiting a better performance after the capillarity test is the sample G0.65-30%F. Previous research has also confirmed the positive effect of replacing gypsum material with secondary raw materials to reduce capillary water absorption, as seen in gypsum composites made with rice husk waste [51] or cotton fiber [59]. Complementary to this, a thermographic analysis conducted after the capillarity test is presented in Figure 7a, with Figure 7b showing the maximum water height reached in the various produced composites. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Series** & **G0.65** & **G0.65-15\%P** & **G0.65-30\%P** & **G0.65-15\%F** & **G0.65-30\%F** \\ \hline Total Water Absorption [\%] & 42.5 \(\pm\) 1.2 & 39.3 \(\pm\) 0.9 & 37.2 \(\pm\) 1.2 & 37.8 \(\pm\) 0.8 & 36.7 \(\pm\) 1.0 \\ Open Porosity [\%] & 40.9 \(\pm\) 0.6 & 38.1 \(\pm\) 0.6 & 37.0 \(\pm\) 0.7 & 37.1 \(\pm\) 1.1 & 34.8 \(\pm\) 0.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Total water absorption coefficient and open porosity of the gypsum composites developed. Figure 6: Capillarity test: mass variation per unit area over time. Figure 7: Capillarity test: (**a**) Thermographic image of the composites; and (**b**) the maximum height reached by water. Thus, in Figure 7, it can be observed that the height reached by water inside the gypsum composites with partial hemp substitution is lower than in the reference material (G0.65). With a higher percentage of substitution, there is a lower final height reached by water after the test. These differences are quantified numerically in Figure 7, showing a decrease of up to 36.8% for the G0.65-30%F compound compared to traditional gypsum material. This positive effect resulting from the incorporation of hemp into the matrix of gypsum composites as partial substitution for the original raw material constitutes a step forward in mitigating potential pathologies caused by capillary water penetration into the matrix of the manufactured compounds. Notwithstanding, this phenomenon has been observed previously in other studies, where the use of low-density secondary raw materials decreases the capillary water absorption capacity [60]. Finally, it is important to note that this study utilized manually processed and crushed hemp material. In general, natural fibers are very heterogeneous, hydrophilic, and exhibit reduced long-term durability, leading to a decrease in the bond strength between the hemp composite and the binder matrix.