EFFECT OF MULTIWALLED CARBON NANOTUBES ON MECHANICAL PROPERTIES OF GYPSUM-TREATED SOIL

Abstract

Being a modern-day technology, nanotechnology has a lot of uses in both engineering and non-engineering fields. While structural engineers have been using carbon-based nanomaterials to improve the compressive and flexural strengths of concrete, very little research is being done in the field of geotechnical engineering. The main objective of this research is to analyse the effects of multiwall carbon nanotubes in the improvement of cementitious properties of Gypsum in soil. Unconfined Compressive Strength (UCS) and Direct Shear Test (DST) were conducted on treated and untreated Low Plastic Clay (CL), and the results were compared. The interactions at the interface between nanotubes surface and soil particles were investigated by using Scanning Electron Microscopy (SEM). Carbon Nanotubes (CNTs) are non-cementitious materials, but when introduced into the soil along with Gypsum, they act as nanofillers and reduce the inter-particle spacing, resulting into a denser, stiffer and stronger soil skeleton matrix, and ultimately improving the mechanical properties of soils. Varying the amount of Multiwalled Carbon Nanotubes (MWCNTs) from 0.001 percent to 0.1 percent by mass of Gypsum resulted in the improvement of the UCS and shear strength parameters. The SEM analysis confirmed nanofiller and nano reinforcement effect of MWCNTs between the soil particles. The results concluded that the performance of Gypsum as a soil stabilizer was successfully improved by the addition of MWCNTs.