Soil Improvement of Clayey Sand Using Nanoparticle

The field of nanotechnology encompasses all technologies that operate on a nanoscale, typically ranging from 1 to 100 nanometers. Nano-particles are the most commonly used materials in this technology. Given the provided definition of nanotechnology, there is a growing interest in exploring its applications in the field of geotechnical engineering. Recently, numerous researchers have directed their efforts toward discovering these applications. This strong interest stems from the unique properties of these particles and their potential to enhance the mechanical and structural characteristics of soil. This article explores the impact of different percentages of calcium oxide and aluminum oxide nanoparticles on the compressive strength of clayey sandy soil with a constant clay content. To achieve this, clayey sandy soil comprising 80% sand and 20% clay, after being treated with varying percentages (0.05%, 0.1%, and 0.2% by dry soil weight) of nanoparticles, including aluminum oxide and calcium oxide, in three different curing times of 7, 14 and 28 days was tested for unconfined compressive strength. The results indicate that samples containing 0.05%, 0.1%, and 0.2% aluminum oxide nanoparticles after 28 days of curing experienced a 24.92%, 46.78%, and 43.28% increase in strength, respectively, compared to the control sample. Similarly, the increase in strength for samples with calcium oxide nanoparticles was 18.73%, 40.43%, and 36.72%, respectively. According to the findings, the curing time did not have a significant effect on strength improvement, and the optimum percentage for both types of nanoparticles was determined to be 0.1%. Further analysis of stress-strain curves revealed that samples with aluminum oxide nanoparticles exhibited a more brittle behavior compared to those with calcium oxide nanoparticles. Subsequently, for microstructural investigations, the samples were analyzed using Field Emission Scanning Electron Microscopy (FESEM). The microstructural examinations demonstrated better compactness among the treated samples, indicating improved microstructural characteristics in the nanoparticle-amended soils.