The role of self-healing for corrosion mitigation of Ultra-High Performance Fiber Reinforced Concretes (UHPFRC) under cracked conditions.

Cracks in concrete provide pathways for chloride penetration and early initiation of reinforcement corrosion. Self-healing phenomena can prevent and delay this deterioration. This work evaluates the corrosion risk in presence of cracks and the attenuation due to self-healing. The methodology allows to demonstrate of scalability of self-healing response of normal strength concrete (NSC) and UHPFRC from lab-scale 8x8x25cm specimens to 4 m full-scale beams industrially produced. Cracks were generated by three and four-point bending test respectively and exposed to chloride environment. Corrosion of reinforcement was monitored, characterizing the chloride transport in the cracked region. Results confirm that cracks increased chloride penetration and accelerates the onset of corrosion in NSC while this phenomenon is not appreciated or is significantly delayed in UHPFRC due to the high self-healing capacity associated to this type of concrete. The presence of the fibers control crack width, and the cement content improve the rebar protection and crack sealing.