Please cite this article as: Changizi F, Haddad A, Strength properties of soft clay treated with mixture of nano-SiO 2 and recycled polyester fiber, Abstract: This paper investigates the effect of recycled polyester fiber, produced from polyethylene (PET) bottles, in combination with nano-SiO2 as a new stabilizer to improve the mechanical properties of soils. We intend to study the effect of adding nano-SiO2 and recycled polyester fiber on soil engineering properties, especially the shear strength and unconfined compressive strength (UCS), using clayey soil with low liquid limit. Three different combinations of fiber-soil ratios ranging between 0.1% and 0.5% as well as three different combinations of nano-soil ratios ranging between 0.5% and 1% are used. The shear strength and UCS of treated specimens are obtained from direct shear test and unconfined compression test, respectively. Results of this study show that the addition of recycled polyester fiber and nano-SiO2 increases the strength of soil specimens. Both the shear strength and UCS are improved by increasing the contents of recycled polyester fiber and nano-SiO2 in the soil mixture. The increase in the nano-SiO2 content leads to a reduction in failure strain, but the increase in the content of recycled polyester fiber leads to an increase in failure strain. The increase in the contents of recycled polyester fiber and nano-SiO2 leads to an increase in elastic modulus of soils. Based on the test results, the addition of recycled polyester fiber improves the mechanical properties of soils stabilized with nano-SiO2 as well as the recycled polyester fiber has a positive effect on soil behaviors.
This paper reports on an investigation into the effect of using nano-silica particles to improve the mechanical properties of clayey soil with low and high liquid limits. The engineering properties studied included Atterberg limits, maximum dry unit weight, optimum moisture content, California bearing ratio, consolidation and unconfined compressive strength. Nano-silica to soil ratios of 0·5, 0·7 and 1·0% were used. Both the Atterberg limits and California bearing ratio values improved with increasing nano-silica content. Increasing ratios led to a reduction in the plasticity index and an increase in the shrinkage limit. The reduction in soil settlement was attributed to a viscous gel in the soil–additive interaction, which resulted in an increase in the pre-consolidation stress of the stabilised soil. The test results showed that the viscous gel caused an increase in initial pre-consolidation stress of 70 kN/m2 for a soft clay soil to 300 kN/m2 for a soil stabilised with 0·7% nano-silica. Undrained compressive strength also increased by up to 56%. An increase in nano-silica content led to a reduction in failure strain but an increase in the elastic modulus of soils. Based on the results, it can be concluded that the addition of nano-silica improves the mechanical properties of clay significantly.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.