Influence of Carbon Nanofibers on the Shear Strength and Comparing Cohesion of Direct Shear Test and AFM

Abstract

The stabilization and enhancement of the engineering properties of fine and coarse grained soil has heavily relied on reinforcement and admixture materials. This study discusses the effect of the additive of Carbon nanofibers (CNF) on the characteristics of soils in terms of shear strength. The content of CNF was changed within the range of 0.05 to 0.2% by total dry weight of the reinforced samples. In achieving the objective of minimizing the number of experimental runs and thus conserve material, time as well as overall cost, the Box–Behnken approach was chosen as the method for statistical prediction. The scanning electron microscopy (SEM) and Atomic force microscopy (AFM) has been utilized in studying features of CNF in stabilized soil samples and force at the origin of the cohesion (c) of soil. Test results reveal that the increases peak and residual shear strength of the reinforcement soil samples were increased with an increase in the CNF content. The pre-eminence of ionic correlation forces in the cohesion of soil was confirmed by the force (cohesion) measurements by (AFM). The statistical prediction’s relatively high correlation coefficients justified the results.