PSI - Issue 64

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 64 (2024) 6–13

SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Toward optimized carbon fiber cementitious sensors Niloofar Heirani ᵃ , Fae Azhari ᵃ * ᵃ University of Toronto, 5 King’s College Road, Toronto, ON, M5S 3G8, Canada Abstract With physical and mechanical properties comparable to those of concrete, piezoresistive cementitious composites are poised to enable seamless strain and defect monitoring in civil infrastructure. Many research projects have demonstrated the sensing properties of cementitious sensors. The sensitivity, repeatability, and stability of their response are heavily dependent on mix design and fiber dispersion. This paper presents a preliminary framework using microscopy and the Taguchi method for identifying best practices in fabricating cement paste sensors containing carbon fibers. Higher fiber content, the use of a centrifugal mixer, and supplementary cementitious materials significantly improved repeatability, while mixing order and speed had minimal impact. Further research should examine the effects of mixing duration, additional conductive fillers, and environmental factors on the sensitivity, repeatability, durability, and stability of the sensors under both compression and tension at different loading rates. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers Keywords: Cementitious sensors, Piezoresistivity, Carbon fibers, Fiber breakage and dispersion, Sensitivity, Repeatability 1. Introduction Structural monitoring can significantly extend the service life of concrete structures. The past two decades have seen significant research activity on the use of self-sensing cementitious composites for structural monitoring of concrete infrastructure (Abedi et al., 2021; Qin et al., 2024). Cementitious sensors are made by incorporating conductive fillers such as carbon fibers (CF), carbon nanotubes or nano fibers (CNT or CNF), carbon black (CB), and steel fibers (SF) into a cementitious matrix, which can be cement paste, mortar, or concrete (Abedi et al., 2021; © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers

* Corresponding author. Tel.: +1-416-978-2534; fax: +0-000-000-0000 . E-mail address: fae.azhari@utoronto.ca

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers 10.1016/j.prostr.2024.09.189