Novel Methods for Post-Fire Self-healing of Concrete

Abstract

Abstract Fire is a significant threat to civil infrastructures. It is well established that fire exposure deteriorates, whereas selected bacteria self-heal the concrete. Civil engineers crave to substitute concrete with alternatives having superior post-fire performance. The post-fire rehydration of concrete allows recovery of the pore structures to an extent without much change in the mechanical properties and durability. The present work reports the post-fire self-healing of the concrete using encapsulated or immobilized bacteria for the first time in literature. The significant challenges to achieving post-fire self-healing are ensuring the survival of bacteria during the fire and triggering activation afterward. Novel encapsulation and immobilization strategies are reported to protect bacteria incorporated in the concrete samples during the fire and later facilitate bacteria activation for strengthening. Along with the destractive testing, ultrasonic testing was performed to evaluate deterioration of concrete due to fire. Morphology of the samples was investigated using Scanning Electron Microscopy. Finally, a comparison of post-fire self-healing methods of concrete is discussed. The study establishes temperature limits for self-healing with the tested encapsulation methods.