Effect of Shape Memory Alloy Fibers on Volumetric Strain and Moduli of Concrete in Cyclic Compression

This study investigated the impact of dog-boned and crimped shape memory alloy (SMA) fibers on the volumetric strain and moduli of concrete. The SMA fibers were produced via cold drawing and shaping through crimping or heating. Cyclic compression tests were conducted on plain and 1.0–1.5% fiber content concrete under heating and non-heating conditions. Results showed that adding SMA fibers decreases volumetric strain and increases ductility of concrete. However, heating led to an increase in volumetric strain due to recovery stress. The presence of SMA fibers also increased secant and tangent moduli, with dog-boned fibers proving more effective than crimped fibers. The recovery stress caused a factor of 2 and 1.6 increase in secant and tangent moduli, respectively, enhancing the stiffness of the SMA fiber-reinforced concrete. The study provides valuable insights into the potential use of SMA fibers in improving the ductility and stiffness of reinforced concrete structures.