The effect of self-healing process on the strength increase in clay (original) (raw)
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Soil being particulate system, encompasses a wide variety of particles, which has made it one of the most complicated natural materials to be modeled. Among soils, soft soil deposits pose challenging problems to geotechnical engineers for the assessment of reliable behaviour of these soils to be used either as a foundation medium or construction material. In this study, Nano-Material additives have been chosen to investigate their influence on strength behavior of clayey soil. Two soil samples are treated with Nano-material additives of Nanocopper (CuO) and Nano-Gypsum (CaSO4•2H2O) at varying percentages of 0.5%, 1.0%, 1.5% and 2.0% respectively. The test results revealed that the unconfined compressive strength of soil increased significantly with increasing Nano-Material additives. However, the optimum value of Nano-Material additives content was observed around 1.5%. Therefore, the main goal of this study was to stabilize soft soil deposits for its bulk utilization in various geotechnical applications for sustainable environment.
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In Egypt, the Kaolin soil is the most widespread dispersion. So, it has appeared to the necessary to investigate new techniques for improving the performance properties of these soils, especially for highway construction. This study aims to assess and compare the efficiency of nano-white cement in enhancing the mechanical properties of kaolin alone and kaolin mixed with nano-silica. The results of the compaction tests of the kaolin soil treated with different percentages of nano-white cement revealed a decrement in the maximum dry density, the plasticity index, and the workability. While they had elevated the optimum moisture content, plastic limit, Liquid limit, and unconfined compressive strength. The tested samples treated only with nano-silica reached their maximum strength properties with a concentration of 0.9% nano-silica then declined. The samples treated with the lowest percent of nano-silica and the different percentages of nano-white cement recorded higher readings in the unconfined compressive strength compared with the result of the sample treated with the highest percent of nano-white cement individually. Furthermore, the SEM images of treated samples represented the physical and chemical bonds between soil particles, nano-white cement, and nano-silica. In conclusion, the nano-white cement and nano-silica additive mixtures have a powerful improving effect on the mechanical properties of kaolin soil than the nano-white cement additive only. From the results, the nano-additive (nano-silica) in tested clay blended with nano-white cement had a significant positive effect on the behavior of clay soil. So, using additives and activators on a nanoscale has economic feedback with a positive ecological effect.
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Earth-dam failure starts with cracking in the clay core, and this cracking is not easy to detect and prevent. Therefore, swellable clay is a feasible solution, which helps to close the cracks automatically based on the self-healing process. The presented study utilizes experimental procedures to analyze the swelling behavior of fine-grained clayey soils to prevent structural failure regarding crack generations. In this regard, the clayey materials were modified using Kaolin and Bentonite mixed with various weight percentages (2.5, 5.0, 7.5, 10.0, and 12.5%) and extracted the geotechnical characteristics of the studied soils, which included 90 specimens and 85 tests, such as physical properties, consolidation, particle-size analysis, hydrometry, Atterberg limits, compaction, odometer, and pinhole. The experimental results revealed that the swelling of the Bentonite is more than Kaolin satisfied for self-healing features in clayey soils. Regarding the numerous swelling tests, Bentonit...
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With the rapid development of nanotechnology multi-disciplinary cross applications as well as the limitations of traditional materials, nanomaterials have been introduced to improve the soil. This paper investigates the potential advantages of nanotechnology for innovative solutions in the area of soil improvement. Studies on applied nanomaterials in geotechnical engineering show the way these nanoparticles are applied to improve soil engineering parameters. In the present study, we aimed to investigate the effect of adding Nano clay on the geotechnical properties of clay and silt soil and improve their engineering properties. For this purpose, a series of tests were conducted including granulation, uniaxial, direct shear, Atterberg limits, compaction and triaxial tests on clay and silty soils. The results show that the liquid and plastic limits of soil will increase with increasing nanoparticles in soil composition. Also, according to the results of compaction test, by increasing in Nano clay the unit weight of clay soil will increase and optimum moisture content will decrease. According to the results from direct shear tests, by increasing in nanoparticles, the adhesion of clay and silt soils also increase. However, the internal friction angle of both clay and silt soil is reduced.