Properties of residual soil treated with silicon dioxide and cement

• Main Author: Bahmani, Sayed Hessam
• Format: Thesis
• Language: English
• Published: 2013
• Online Access: http://psasir.upm.edu.my/id/eprint/47860/1/FK%202013%2020R.pdf; http://psasir.upm.edu.my/id/eprint/47860/

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.