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Applications and life cycle assessment of shape memory polyethylene terephthalate in concrete for crack closure
Maddalena, R. Sweeney, John Winkles, J. Tuinea-Bobe, Cristina-Luminita Balzano, B. Thompson, Glen P. Arena, N. Jefferson, T.
Maddalena, R.
Sweeney, John
Winkles, J.
Tuinea-Bobe, Cristina-Luminita
Balzano, B.
Thompson, Glen P.
Arena, N.
Jefferson, T.
Publication Date
2022-02
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© 2022 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
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Yes
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Gold
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2022-02-21
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Abstract
Shape memory polymer (SMP) products have been developed for application as crack closure de-vices in concrete. They have been made from PET in the form of both fibres and hollow tubes. Here, manufacturing methods using die-drawing and mandrel-drawing to induce shape memory are reported. The fibre-based devices are incorporated into concrete and, upon triggering, exert shrinkage restraint forces that close cracks in the concrete. The evolution of shrinkage restraint force in the fibres as manufactured was measured as a function of temperature, showing stresses in excess of 35 MPa. Tendons consisting of fibre bundles are incorporated into concreate beams subjected to controlled cracking. When activated, the tendons reduce the crack widths by 80%. The same fibres are used to produce another class of device known as knotted fibres, which have knotted ends that act as anchor points when they incorporated directly into concrete. Upon acti-vation within the cracked concrete, these devices are shown to completely close cracks. The tubes are used to enclose and restrain prestressed Kevlar fibres. When the tubes are triggered, they shrink and release the prestress force in the Kevlar, which is transferred to the surrounding con-crete in the form of a compressive force, thereby closing cracks. The Kevlar fibres also provide substantial reinforcement after activation. The devices are shown to be able to partially and fully close cracks that have been opened to 0.3 mm and achieve post-activation flexural strengths com-parable to those of conventional reinforced and prestressed structural elements. Finally, a pre-liminary life cycle assessment study was used to assess the carbon footprint a nominal unit of concrete made with SMPs fibres compared to conventional concrete.
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Published version
Citation
Maddalena R, Sweeney J, Winkles J et al (2022) Applications and life cycle assessment of shape memory polyethylene terephthalate in concrete for crack closure. Polymers. 14(5): 933.
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Article