# Expansive Soil Stabilization with Time, Cement, and Silica Fume
## 1 Introduction  
Plate-shaped clay particles can be assembled in many ways. The ability of some clay particles to attract and hold water molecules on their surfaces and absorb them is of great interest. It is well known that water molecules exhibit a phenomenon known as polarization, in which each molecule has a distinct charge on its opposite sides, one positive and the other negative [1]. These polar water molecules adhere to each of the plate-shaped particles, forming a film of charged fluid on them. The swell or heave noticed in the swelling soil when the water content of this soil is increased is caused by the clay particles repelling one another as a result of the \"double layer phenomenon\", which emerges when distinct nearby particles are taken into account. Greater clay-particle-specific surfaces and higher charge densities make clay soils better suited to take water into their structure. The liquid limit and plastic limit indices are used to determine how well a cohesive soil can keep water molecules inside its structure. Montmorillonite clays have the greatest tendency to swell when compared to other clay minerals, whereas kaolinite has relatively low swelling potential [2]. [PERSON] et al. [3] used a model test to study the swelling behavior of expansive soil at various elevations under fully saturated conditions of water injection from the top to the bottom. The results showed that there was a clear distinction in swelling between the expanding soil layers at various elevations during the saturation process and the electric charge effect, which comprises two variables, The primary causes of the swelling disparity between diverse expansive soil layers were (i) the transformation impact and(ii) the electrical environment. The expansive soil's ability to expand may be lessened in the first scenario due to the cation exchange that occurs between expansive soil and aggregation bivalent cations. Additionally, the water film that has formed around the aggregates prevents additional water molecules from adhering into the montmorillonite interface, which halts the expansion of the swelling soil. A swelling soil was treated by [PERSON] et al. [PERSON] et al. (2018), including a different range of additives, such as cement, steel fibers, gasoline and cement-based grout. Results were better when cement grout was injected or when the expansive soil was treated with 5% cement or steel fibers, although 4% gasoline oil is enough to show this material's best uses. The treatment does not affect the angle of internal friction, but the addition of these components caused a small variation in the adherence of the additive to the particles of the soil, which has a small impact on the cohesion between the particles. A soil treated with waste fly ash was studied by [PERSON] et al. [PERSON] et al. (2018). The findings of this study, demonstrated that adding different percentages of waste fly ash causes stabilized soil to expand, but that the expansion can be slowed down by waiting for around 30 min before combining the material with water and compacting it. [PERSON] (2018) used clayey soil mixed with 30, 50 and 70% of bentonite and stabilized the mixing soil with 3, 5 and 7% of nano-silica fume, and the findings showed that the Atterberg limits, specific gravity, maximum dry unit weight and optimum water content improved when increasing the nano-silica fume percentage. When built on expansive soils, roads and other structures that are considered as light structures are significantly impacted. After a few years, the capacity of these soils to heave causes damage to these structures due to the swelling pressure, which causes cracking and swelling, with rapid lifting of the subgrade beneath the road and foundations causing cracks in the floor, walls and road that result from water seeping into the soil [PERSON] et al. (2018).