Uniaxial compressive behaviors of mortar cylinders reinforced with crimped NiTi SMA fibers

Abstract

This study investigated the axial compressive behaviors of cement mortar reinforced with crimped SMA fibers produced by cold drawing. The performance of the crimped fiber was investigated in term of tensile behavior, deformation recovery, recovery stress, and pullout behavior. After that, compressive tests of mortar reinforced with two types of SMA fibers, namely, dog-bone-shaped fibers and crimped fibers, were conducted to compare their compressive behaviors. The results showed that both types of SMA fibers increased the compressive strength of mortar, and a 1.0% volumetric ratio of SMA fibers is effective to increase the compressive strength of mortar, whereas a 0.5% volumetric ratio did not significantly increase the compressive strength. The recovery stress of the SMA fibers induced by the shape memory effect does not significantly increase the compressive strength of mortar. However, when crimped SMA fibers with a 1.0% volumetric ratio were heated and recovery stress was induced, they controlled volume expansion more effectively after cracking than crimped SMA fibers without recovery stress. The findings indicate that crimped SMA fiber with recovery stress can provide crack-bridging capacity. © 2022 ICE Publishing: All rights reserved.