## 3 Results and Discussion
The SEM images with 1000\(\times\) and 10,000\(\times\) magnification for clays with cement and calcium chloride indicated typical flakes and particle-to-particle contact. The Al-Qatif dry clay particles are shown as twisted flakes and voids shown in black are dominant. With the increase in the calcium chloride content, the crinkled particle nature of clay with cement becomes flatter, and the pore intensity decreased (Figure 13). Square marks are added to some images to highlight the twisted and flattened flake conditions. The mineralogy as detected by the XRD patterns shown in Figure 14 indicated the similarity of peaks for treated and untreated clay. The pozzolanic compounds formed due to cement were not reflected in Figure 14, but the peaks expected at a 2 \(\theta\) value of 35 may be affected by a neighboring high-intensity peak. Notably, the background intensity in Figure 14 increased at 2 \(\theta\) values ranging from 5 to 15, and reduced at 2 \(\theta\), ranging from 20 to 40 compared to Figure 14. The intensity corresponds to quantities, and the addition of the calcium chloride affects the mineral concentrations, leading to different peak intensities. The peaks corresponding to chlorite, illite, mica, and quartz were visible. The peaks corresponding to newly formed pozzolanic compounds were not detected. The mineralogy remained unchanged for all of the different mixtures. Figure 14 shows the typical charts indicating the detected peak intensities. Using calcium chloride and cement together can help in controlling the moisture and stabilizing the mix. The cement provides additional strength and stabilization. This combination of materials can be particularly effective in improving the stability and performance of soils in construction projects, such as light structure foundations, roadways, and other structures built on hazardous expansive soils. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Chemical** & **MgO** & **Al2O3** & **SiO2** & **KCI** & **CaSiO3** & **Fe52** & **Fe2O3** & **CaCO3** \\
**Compound** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline
0\% CaCl2 & 4.23 & 6.79 & 22.8 & 0.31 & 5.91 & 0.6 & 5.63 & - \\
4\% CaCl2 & 3.65 & 6.48 & 22.07 & 2.27 & 6.04 & 0.86 & 4.72 & 3.16 \\
6\% CaCl2 & 3.92 & 6.43 & 21.53 & 2.97 & 6.48 & 0.9 & 5.21 & - \\
8\% CaCl2 & 3.63 & 5.83 & 19.5 & 3.6 & 6.21 & 0.67 & 4.58 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Chemical composition of Al-Qatif clay with 2% cement and different % CaCl2. Figure 12: Stress versus axial strain at a curing period of 28 days. The practical implication of this study includes a new choice for the treatment method that is likely cheaper and more effective compared to a single additive approach. The future directions can be fine-tuned to obtain the optimum combination that is suitable for each region of different mineralogy. The optimum calcium chloride content for use in the stabilization of expansive soils is dependent on many factors, including the type of soil, mineralogy, and the desired level of stabilization. The treatment methods conducted to improve the quality of construction materials in general has been an active continuing research area in recent years [38; 39]. Recent studies also included the works of [PERSON] [40], covering the effect of fluid chemistry on the hydraulic properties of clays. It is worth mentioning that the initial addition of 1% cement led to minor improvements. The addition of 2% was selected based on previous studies. The more cement added, the more the improvement in strength and rigidity. Adding higher amounts of cement will cause the paste to be more rigid and stiff and it will not be easily compacted on site. Figure 13: _Cont._  
Figure 13: The SEM images of samples (**a**) for Al-Qatif clay pure, (**b**) with 2% cement, (**c**) for 2% cement +4% CaCl\({}_{2}\), (**d**) for 2% cement +6% CaCl\({}_{2}\), (**e**) for 2% cement +8% CaCl\({}_{2}\). The cost of cement is also high compared to other additives.