## 5 Durability Tests (Wetting and Drying)
### Microscopic Investigation  
By using an SEM Hitachi S 3700, the morphology of the silt and soil and admixtures was examined. With reference to Figures 10 and 11a-e, it is evident from the micrograph that silty sand, lime, and stone dust underwent pozzolanic reactions, resulting in stone dust and lime particles accumulating over the silty sand soil and generating the various cementitious compounds.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Standard Durability of Soil +** & **Slake Durability of Soil +** \\  & **10\% CACW + 2\% C** & **10\% CACW + 2\% C** \\ \hline Mean & 8.333333 & 10 \\ Variance & 1.166667 & 0.9 \\ Observations & 6 & 6 \\ Pearson Correlation & 0.634335 & \\ Hypothesized Mean & 0 & \\ Difference & 5 & \\ dí & \(-\)4.66252 & \\ r (T \(<\) t) one-tail & 0.00276 & \\ t Critical one-tail & 2.015048 & \\ P (T \(<\) t) two-tail & 0.00552 & \\ t Critical two-tail & 2.570582 & \\ \hline \hline \end{tabular}
\end{table}
Table 3: \(t\)-test: Paired two sample for means for durability test results.  
Figure 9: Durability using Modified Slake test: (**a,b**) slake test machine, (**c**) specimen with standard brush (**d**) speciemns after testing [44; 45].  
The SEM micrograph of silty sand soil stabilized with the optimal dose of 10% CACW and 2% cement in Figure 11b shows a significant amount of the white fibrous cloth-like cementing gel, C-S-H, coating the sand and/or silt particles. This improved the UCS of the stabilized silty sand soil. The system contains discrete sand and/or silt grains. Both direct  
Figure 11: (**a–d**): SEM images illustrating the effect of CACW addition at 5, 10, 15 and 20%, respectively, (**e**) is EDX to illustrate the composition of soil and CACW, yellow arrows refered to minor cracks at 15% of CACW.  
Figure 10: Effect of CACW addition on voids and density.  
interactions between particles and connectors are visible. The stabilized soil matrix had weight proportions of 4.18, 5.53, 10.96, 4.42, 0.30, and 5.90% for C, Mg, Si, Ca, K, and Fe, according to EDX results.  
To keep soil stable, various fundamental stabilizing mechanisms are in operation. The direct cementitious effects of Portland cement strengthen sandy materials since they are less plastic and volumetrically unstable (as measured by their bearing capacity, unconfined compressive strength, etc.). In this case, the main reaction takes place when the C\({}_{3}\)S and C\({}_{2}\)S in cement combine with water to form calcium silicate hydrate. Cementation is considerably enhanced by the concentration of available alkali in solution [47]. By combining soil, cement, and water, cement stabilizes soils [12]. The size has been reduced. The resultant mixture is a novel building material that is heat, water, and frost resistant. Stabilized soils can be used for canal lining, building foundations, road paving, and other purposes.  
The two most important phases for stabilizing soil are the calcium silicate phases (C\({}_{3}\)S and C\({}_{2}\)S). These two phases aid in the formation of calcium silicate hydrate, or C-S-H, which acts as a binder in the soil matrix. By making calcium available for cation exchange, flocculation, and agglomeration when those phases are hydrated, calcium hydroxide stabilizes the clayey soil [17,48]. Everywhere soil is used to make pavements, it is first dumped in a loose state and then compacted using rolling or vibrating machinery until the required amount of compaction is obtained. A technique for controlling soil compaction on the site is provided by field moisture-density tests. The soil's field compaction is the sole purpose of the moisture-density test. The assumption is that a soil's stability increases along with its dry density.