# An Experimental Study for Swelling Effect on Repairing of Cracks in Fine-Grained Clayey Soils
###### Abstract
The analysis indicated that the wet swelling of concrete significantly impacted the increase in tensile stress distribution in the concrete slab around the water surface. [PERSON] and [PERSON] [6] investigated the nano-montmorillonite impact on self-healing on clayey soil concerning the geotechnical characteristics of the fine-grained soil. According to their results, the geotechnical properties of clayey soils were modified by treatments. Data was collected from uniaxial tests and scanning of electron microscope images, which indicated that the maximum amount of self-healing occurred in the 5% nano-clay samples on the 60 th day after the initial crack. [PERSON] et al. [18] established the experimental task of applying expanded clay for self-healing concrete. The clay particles crystallized the cracks and sealed the crack fracture in the face of the water. [PERSON] et al. [10] mentioned that the piping from the existence of cracks in the dam core is one of the major reasons for the failure of earth dams. The article used different empirical approaches based on Bentonite clay (10%) to estimate the capability of Bentonite to heal the Vanyar dam borrow pit. [PERSON] and [PERSON] [19] used the swellable effect of the polydimethylsiloxane (PDMS) polymer and plate-like nano-montmorillonite (MMT) to investigate the healing efficiency in the Kaolinite-rich soil of Western South Dakota. The results indicated that the additives led to substantial changes in crack formation, propagation, and increased the healing efficiency. [PERSON] et al. [20] performed an experiment assessment to analyze the swellable clay for self-healing in Vanyar earth-fill dams. According to the results, the sample with 20% bentonite and 2% moisture content less than the optimum showed the most reduction in the outflow (38%) when compared with the natural soil sample. So, it can be concluded that a PI between 7% and 26% can cause non-dispersive clay and increase the self-healing ability. The research conducted various geotechnical tests on basic materials of the dam's core to evaluate the swelling effects on crack control. [PERSON] et al. [11] utilized the experimental procedure to investigate the clay's crack self-healing phenomenon in compacted clay layersusing the pinhole test. The authors provide the empirical relationship between Bentonite and moisture content in soils. Referring to the mentioned literatures, the main shortcomings of previous research considered in this article and used to modify the analysis can be classified as the lack of knowledge regarding bentonite or other clay materials usage limits, the divergence property of bentonite soils in threshold uses, and the deviation of PI with an increasing percentage of bentonite in the self-healing process. The study aims to reconstruct the dam's clay core conditions and the possibility of improving the invisible cracks in the core using a self-healing process. This event is with respect to the limits of swelling pressure, which itself is the main factor in the dam core's failures. As the objective of the study, it can be stated as the assessment of an alternative task to investigate the self-healing behavior of clayey materials that are useable in a dam's core to prevent core failure and the destruction of a dam. In addition, using self-healing clays reduces the environmental impacts, provides fast stabilizations, and reduces renovation costs. In this regard, the presented article focuses on the self-healing behavior assessment of fine-grained clayey soil (Kaolin and Bentonite) concerning the geotechnical properties of clayey soil, which is mainly used for crack closing in earth-fill dams' cores. The physiomechanical soil properties are investigated to obtain the geotechnical characteristics, which are concluded through various soil index experiments such as sieve analyses, hydrometers, Atterberg limits, proctors, and pinhole tests. Entire experiments were conducted in ASTM instructions with repetition tests that were done to reduce the calculations error.