Abstract
Shape-memory effect in nickel-titanium (nitinol) alloy was successfully utilized as a way of inducing additional prestressing in concrete. Strands made with NiTi (nickel/titanium) shape-memory alloy (SMA) wires were elongated beyond their plastic limit and subsequently were embedded in model concrete (mortar) beams. Upon electrical heating, a martensite-to-austenite phase transformation takes place and the material undergoes large shrinkage strains. This strain energy can be used to generate a significant prestressing force in concrete. Potentially, this provides a means of creating a “smart bridge,” where the amount of prestress can be increased or decreased as needed. Such a structure could actively accommodate additional loading, or remedy prestress losses over time. Properties of the SMA material and the micromechanics of its bond with concrete were investigated. Strands made with SMA wires were electrically actuated to induce deflection and failure in concrete (mortar) beams. Optical microscopy and the acoustic emission technique were used to understand the actuation mechanisms.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
