## 3 Results and Discussion
### Physical Properties
#### 3.1.3 Total Water Absorption  
In the vast majority of buildings, water infiltration is inevitable in the construction materials, either through capillary action or immersion. The principal result from the total water absorption (TWA) test is that all the composites remained unaffected and stable after 4 days of immersion in water, as all of the blocks maintained their original shapes and handling capacities without suffering from any significant deterioration, which is an important benefit.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Cement Content**} & **Fibers** & **Density (Kg/m\({}^{3}\))** & **Ultrasonic Wave** \\  & **Content (\%)** & **Density (Kg/m\({}^{3}\))** & **Velocity (m/s)** \\ \hline \multirow{4}{*}{4\%} & 0.00 & \(1624\pm 20\) & \(1507\pm 24\) \\ \cline{2-4}  & 0.05 & \(1563\pm 15\) & \(1397\pm 16\) \\ \cline{2-4}  & 0.10 & \(1523\pm 18\) & \(1250\pm 24\) \\ \cline{2-4}  & 0.15 & \(1484\pm 15\) & \(1172\pm 20\) \\ \cline{2-4}  & 0.20 & \(1425\pm 10\) & \(1067\pm 16\) \\ \hline \multirow{4}{*}{8\%} & 0.00 & \(1728\pm 20\) & \(1590\pm 20\) \\ \cline{2-4}  & 0.05 & \(1663\pm 17\) & \(1490\pm 10\) \\ \cline{2-4}  & 0.10 & \(1620\pm 15\) & \(1400\pm 18\) \\ \cline{2-4}  & 0.15 & \(1579\pm 10\) & \(1320\pm 20\) \\ \cline{2-4}  & 0.20 & \(1516\pm 22\) & \(1239\pm 20\) \\ \hline \multirow{4}{*}{12\%} & 0.00 & \(1819\pm 19\) & \(1666\pm 16\) \\ \cline{2-4}  & 0.05 & \(1715\pm 12\) & \(1600\pm 24\) \\ \cline{2-4}  & 0.10 & \(1705\pm 20\) & \(1573\pm 24\) \\ \cline{2-4}  & 0.15 & \(1662\pm 14\) & \(1500\pm 14\) \\ \cline{2-4}  & 0.20 & \(1630\pm 19\) & \(1400\pm 24\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Results of density and ultrasonic wave velocity.  
The variation of the total water absorption (TWA) for one day of immersion as a function of cement content for different fiber substitution levels is shown in Figure 12. A decrease in TWA with an increase in cement content can be observed. For blocks without fibers, the value of TWA varied between 14.37% for 4% cement and 12% for blocks containing 12% cement. This corresponded to approximately 19%, which can be attributed to the capacity of cement to fill voids and reduce the porosity between soil particles and fibers, and then decrease the infiltration of water into the composite.  
The evolution of TWA as a function of immersion time is presented in Figure 13. Based on the obtained results, the specimens without fibers display less TWA than blocks reinforced with fibers. It is crucial to note that the majority of water was retained during the first two days, while over the following two days, the evolution of TWA was insignificant, considering that the increase in its value did not surpass 2% for all of the compositions. Moreover, it should be noted that the introduction of fibers increases the TWA, which means  
Figure 11: Ultrasonic pulse velocity as a function of fiber content.  
Figure 12: Effect of cement content and fiber replacement on the total water absorption after one day of immersion.  
that there is more infiltration of water into the specimens. This behavior could be explained by the capacity of fibers to absorb water, which is related to their hydrophilic constitution composed mainly of cellulose and hemicellulose and also their porous network structure.  
Figure 13: Total water absorption of composites as a function of immersion time for **(a)** 4% cement; **(b)** 8% cement; **(c)** 12% cement.