Effect of Multiwalled Carbon Nanotubes (MWCNTs) on Mechanical Properties of Gypsum-Treated Soil

Abstract

The introduction of nanomaterial into structural engineering has resulted in improved compressive and flexural strengths of concrete. Whereas, very little research has been carried out in exploring its benefits in the field of geotechnical engineering. In this study, the effects of Multiwalled Carbon Nanotubes (MWCNTs) on the properties of gypsum (cementitious agent) treated low plastic clays were investigated. Unconfined compressive strength (UCS) and direct shear tests were conducted on untreated and treated samples with varying gypsum contents (9–18% by weight) and MWCNTs, (0.001–0.1% by weight of gypsum). The durability study of optimum treated sample was conducted by curing them for 2–28 days in unsoaked and soaked conditions. Results revealed that UCS, cohesion, and angle of internal friction of the treated samples improved up to 414, 232, and 78%, respectively, compared to untreated samples. Moreover, scanning electron microscopy (SEM) analysis of the treated samples also carried out. SEM results revealed that MWCNTs act as nano-fillers and nano-reinforcements, reducing the inter-particle spacing, resulting in a denser, stiffer, and stronger soil skeleton matrix, and ultimately improving the mechanical properties of soil. Therefore, nanomaterials can be used as potential contenders in soil stabilization for enhancing the mechanical properties of the soils.