Investigations of direct shear characteristics of cementitious mortar reinforced with steel and nylon fibres

Abstract

In the present study, the shear characteristics of cementitious mortar reinforced with steel and nylon fibres were experimentally investigated through direct shear tests. The primary test parameters of the present study were fibre volume fractions of 0.15, 0.25, and 0.33% for nylon fibres; 0.5, 0.75, and 1.0% for steel fibre; and hybrid fibres comprised of different amounts of steel and nylon fibres. The test specimens were made with a singly rectangular notch at the centre to predefine the shear failure plane. Direct shear test was carried out following the guidelines specified in the Federation Internationale de la Precontrainte (FIP) standard. The results showed that the cementitious mortar reinforced with fibres exhibited more ductility than plain mortar matrix. It was determined that the use of higher amounts of steel and nylon fibres could significantly improve the peak shear stress. Finally, a shear stress-crack slip model was constructed to idealise shear stress-crack slip curves of cementitious mortar reinforced with steel and nylon fibres, and the prediction results were consistent with the experimental results.