Speaker
Description
Iron-based shape memory alloys (Fe-SMAs) exhibit unique shape memory effect (SME) behavior upon thermal activation, making them advantageous for various structural applications such as prestressing. Introducing short Fe-SMA fibers into concrete structures allows for a uniform and localized distribution of prestressing forces within the concrete matrix. In this study, an experimental campaign was conducted to evaluate the efficiency of prestressing concrete using short Fe-SMA fibers. Concrete samples reinforced with Fe-SMA fibers, steel fibers, and plain concrete were tested under three-point bending after exposure to ambient temperature, 160°C, and 200°C. All fiber-reinforced samples contained a 2\% volume fraction of fibers with identical geometries featuring end-hooked shapes for enhanced pull-out resistance. The results indicated that at ambient temperature, samples with steel fibers exhibited higher strength (22.95 MPa) than those with Fe-SMA fibers (20.2 MPa) due to the absence of phase transformation in the Fe-SMA fibers, however, at elevated temperatures of 160°C and 200°C, samples with Fe-SMA fibers demonstrated higher strength (26.65 MPa and 24.39 MPa, respectively) compared to those with steel fibers (19.46 MPa and 16.67 MPa, respectively), highlighting the activation of the SME. Based on these findings, a numerical model was developed to simulate the behavior of concrete composites reinforced with Fe-SMA fibers. An algorithm was created to define the random distribution of fibers, and a novel modeling approach accounted for the end-hooked geometry by assigning different contact properties to the modeled straight fiber ends and middle sections. A mesh sensitivity analysis was performed to determine the optimal mesh size, and the model was validated by comparing numerical results with experimental data.
Acknowledgements:
This research was partially funded by the National Science Centre of Poland (Grant No. 2023/49/N/ST8/03063) and Poznań University of Technology (Grant No. 0412/SBAD/0091).
References:
Tabrizikahou, Alireza, et al. "From experimental testing to computational modelling: A review of shape memory alloy fiber-reinforced concrete composites." Composites Part B: Engineering (2024): 111530.
Tabrizikahou, Alireza, Mieczysław Kuczma, and Moslem Shahverdi. "Impact of fiber geometry, temperature, loading rate, and concrete mix on the pull-out resistance of iron-based shape memory alloy (Fe-SMA): Experimental investigation." Construction and Building Materials 456 (2024): 139298.
Tabrizikahou, Alireza, et al. "Prestressing of concrete using iron-based shape memory alloy (Fe-SMA) short fibers: Experimental and numerical analysis." Construction and Building Materials 467 (2025): 140309.
