Microstructural investigation of fine-grained soil improvement by mixing of Nano-clay and lime

The construction of different paths on fine-grained soil beds is often inevitable and, it is necessary to select and design suitable methods of soil improvement. One of these methods is shallow soil mixing with different additives such as lime and Nano-clay. These particles can improve the physical and chemical properties of the soil as much as possible and make changes on a microscopic scale. In this paper, the stabilization of fine-grained soil beds and their strength properties due to the addition of Nano-clay and lime mixing are investigated. For this purpose, the series of unrestricted compressive strength tests, Atterberg limits, density, PH and microstructural tests including X-ray diffraction (XRD) and scanning electron microscope (SEM) have been performed on the mixture of soil with Nano-clay and lime with different adding percentages at 7, 14 and 28-day curing period. The obtained results indicate that the optimum soil properties were obtained by adding 3% lime and 3% Nano-clay during the 28-day curing period and according to the results of microstructural analysis, it was found that soil resistance increased due to the formation of calcium silicate hydrated gel with reducing the voids and increasing the contacts between soil particles.