Experimental and numerical investigation on flexural self-strengthening response of iron-based shape memory alloy fiber-reinforced concrete

An experimental program investigated the performance of concrete prisms reinforced with randomly dispersed Fe–SMA fibers (baseline), steel fibers (derivative), and plain concrete (reference). The tests were conducted using a three-point bending setup in two phases. Phase I involved pre-damaging the specimens to 90% of their load-bearing capacity, followed by unloading. This was then succeeded by thermal treatment at either ambient temperature or 160 °C. Phase II consisted of reloading the specimens to failure. Image analysis was utilized to quantify changes in crack width between the two phases. For steel-fiber specimens tested at ambient temperature, the average peak load in Phase II decreased by 18.65% compared to Phase I. In contrast, specimens subjected to a 160 °C treatment showed a significant decrease of 43.03%, indicating temperature-induced degradation of the concrete. For Fe–SMA fiber specimens at ambient temperature, the decrease in flexural strength was 17.88%. Notably, specimens heated to 160 °C exhibited a 15.93% increase in flexural strength, likely due to the activation of recovery stresses from thermal exposure. Image analysis indicated that steel-fiber specimens heated to 160 °C experienced an average crack-width increase of 25.95% as a result of thermal expansion. In comparison, heated Fe–SMA specimens showed only a 10.88% increase in crack width, suggesting some level of restraint on crack widening, even though full crack closure was not achieved. A numerical model for concrete reinforced with randomly dispersed Fe–SMA fibers was developed, and it reproduced the experimental responses with acceptable accuracy. The research data available comprises two zip files associated with the published study (https://doi.org/10.1016/j.conbuildmat.2026.145125). The contents of each file are outlined below: Simulations.ZIP: This archive includes data relate to the conducted simulations. Tests.ZIP: This archive contains data related to the conducted tests. A. Tabrizikahou & J. BiałasikPost-damage flexural self-strengthening response of iron-based shape memory alloy fiber-reinforced concrete: Experimental and numerical investigationConstruction and Building Materials, Elsevier, 2026, 508, 145125. DOI: 10.1016/j.conbuildmat.2026.145125