Preparation and experimental study of corrosion-induced shape-memory fibers for crack repair

Repairing concrete cracks is crucial for enhancing the safety and durability of concrete structures. However, current repair technologies face limitations in corrosive environments such as marine settings. This study presents a novel corrosion-induced shape-memory fiber (CSF) based on the concept of corrosion-induced intelligent fiber (CIF). The CSF1 was made by coating elongated spandex-covered yarn with polyvinyl alcohol, and the CSF2 was prepared by winding stretched nylon fiber with iron wire. Experimental results demonstrate that CSF1 specimens can rapidly heal a 10 mm wide crack within two seconds when exposed to water, while CSF2 specimens exhibit obvious shape recovery when exposed to seawater. Moreover, under midspan loads, pre-cracked CSF2-acrylic plate specimens achieve effective crack closure in seawater. These findings confirm the successful transfer of prestress from CSFs to the matrix, thereby validating the feasibility of CIF-based crack repair theory. This research provides experimental evidence for designing and optimizing self-repairing composite materials tailored for various corrosive environments and engineering applications.