Effect of Nanotalc on the Shear Strength of Disintegrated Carbonaceous Mudstone

This work was aimed to improve the shear strength of disintegrated carbonaceous mudstone (DCM) with nanotalc (NT). A series of direct shear tests were carried out on the NT-modified DCM specimens to determine their shear strengths at various NT concentrations. Subsequently, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to reveal the underlying mechanism which the results showed that shear strength was first increased and then decreased with increasing certain NT concentration. Moreover, the increase in NT concentration also resulted in rise in cohesion and reduction in angle of internal friction. The optimum NT concentration for shear strength improvement of DCM is 4%. This improvement of shear strength is achieved because NT can fill the pores in DCM and its products can bind with particles. This results in formation of large aggregates owing to the small size, strong adsorption capacity and cation-exchange capacity.