Crack closure and flexural tensile capacity with SMA fibers randomly embedded on tensile side of mortar beams

Abstract

In this study, an experimental investigation was conducted to assess the flexural tensile strength and crack-closing performance of mortar beams containing short shape memory alloy (SMA) fibers, randomly distributed only on the tensile side. The SMA fibers were mainly composed of titanium (Ti), nickel (Ni), and niobium (Nb). In addition, the effect of tensile steel wires on the flexural strength and crack-closing performance was evaluated. A four-point bending test was performed to evaluate the post-cracking tensile strength. This study also suggested a proper model to calculate the ultimate flexural moment of the SMA fiber–embedded beams. Subsequently, a heating plate that could be installed at the bottom of the beam was used to induce the shape memory effect and measure the closed crack width. This study assessed the crack-closing performance induced by the SMA fibers at the bottom side of the beams and the resistance of the tensile wires in the beams.

Keywords

• shape memory alloy
• shape memory effect
• crack closure
• ultimate flexural strength
• residual flexural strength
• volume fraction
• fiber reinforced
• cement mortar beams