The effect of size and replacement content of nanosilica on strength development of cement treated residual soil

In this study, effects of size and replacement content of nanosilica on physical, chemical, and microstructural characteristics of cemented residual soil were investigated. Accordingly, UCS and electrical resistivity tests were conducted on cemented specimens with replacement contents of 0.2%–1% nanosilica of 15 and 80 nm at 7, 14 and 28 days. XRD, Zeta potential, CEC, FTIR, and SEM tests were performed to identify chemical and microstructural changes over time. The results showed that smaller size nanosilica had an accelerated influence on samples while nanosilica of larger size was more effective at ages after 14 days of curing

Properties of residual soil treated with silicon dioxide and cement

The present study addresses the effect of nano particles on engineering properties of residual soil from Malaysia. This study looks at the innovative work being done by nanotechnology and Nano-materials. Nanoparticles are particles whose dimensions can range between 1 to 100 nm. Due to their extremely small size in nano-scale (10 -9m) and ultra-high surface area, some nano particles show unique properties that can help to improve physical and mechanical properties of the materials. The residual soil is classified as a soil that is the in-situ weathered remnants of a pre-existing parent rock;the parent rock can be sedimentary, igneous or metamorphic, accordingly the term ‘residual soil’ covers a broad range of materials and possible engineering behaviour. The study was conducted to investigate the effect of nano particles (SiO2) with two different sizes 15 and 80 nm that mixed with water and after that add to residual soil treated by cement with different ratios. The investigation includes the evaluation of soil properties such as consistency, compaction, shear strength and hydraulic conductivity properties. Results of Atterberg limit tests showed that the plasticity index increased initially, but decreased at lesser percentage of additives. The addition of nano particles and Portland cement is found to increase the optimum water content but to decrease the maximum dry density weight of the mix soils. Their addition also resulted in significant improvement in unconfined compressive strength and modulus of elasticity after 7 and 28 days curing time. From the viewpoint of plasticity, compaction and strength characteristics, and economy, addition of 0.2 - 0.4% nano particles are recommended as useful amounts. The hydration products were determined by X-Ray diffraction (XRD),Scanning Electron Microscopy (SEM); moreover, the synthesized gels were exposed to different amounts of nano particles to determine their chemical stability and subsequently characterized by Fourier Transform IR Spectroscopy (FTIR). Their addition also resulted in significant improvement in unconfined compressive strength. The results showed that the addition of different amount of nano particles leads to C–S– H gel modification even in the very short term

Variación de las propiedades fisicoquímicas de los suelos del Depósito Lacustre de la ciudad de Tunja, zona Universidad Pedagógica y Tecnológica de Colombia

Spa: Desde hace varias décadas se ha venido trabajando en la búsqueda de diferentes materiales y métodos que reduzcan los cambios volumétricos abruptos en el suelo y que a su vez contribuyan al aumento de las propiedades de resistencia, teniendo en cuenta lo anterior se realiza en esta investigación el mejoramiento de un suelo fino con el adicionamiento de silicatos, condición que pretende optimizar las propiedades mecánicas del suelo del depósito lacustre que se compone principalmente de arcillas y suelos blandos, que los hacen susceptibles a grandes deformaciones ante la aplicación de cargas. Diferentes autores han propuesto el tratamiento de suelos con silicato de calcio, para mejorar las condiciones del terreno, además de la búsqueda de materiales de bajo costo que reduzcan el precio de las inyecciones químicas y de ecuaciones probabilísticas que permitan la aplicación de la sílice de cal en diferentes suelos. Por lo anterior, la presente investigación tiene como objetivo principal evaluar el mejoramiento de las propiedades fisicoquímicas de un suelo fino extraído del depósito lacustre de la ciudad de Tunja, mediante la aplicación de diferentes porcentajes de silicato de calcio a base de cascarilla de arroz, ejecutando pruebas de laboratorio antes y después del mejoramiento, igualmente se hicieron pruebas de Difracción de rayos x (DRX) para evaluar los cambios moleculares que presenta la muestra.PregradoIngeniero Civi