Steel reinforcement corrosion in strain hardening cementitious composites (SHCC): the role of multiple microcracks and surface impregnation

Fiber reinforcement in SHCCs causes the formation of many fine cracks under imposed strain. In this way, ductility is increased, but water and chloride may still quickly penetrate deep into microcracks by capillary action. As a consequence, corrosion of steel rebars can be initiated at early stage. In this contribution, multiple cracked steel reinforced SHCC specimens with and without hydrophobic surface impregnation were prepared. The corrosion of the rebars in multi-cracked SHCCs was monitored and it can be concluded that multiple cracked SHCCs with fine small cracks exhibit a higher corrosion resistance to steer reinforcement than fractured ordinary mortar. The corrosion of steel reinforcement initiates from the bottom interface between the rebar and matrix. Steel reinforcement corrosion can be reduced remarkably through hydrophobic surface impregnation, even in the cracked state. In this way, the working life of steel strengthened SHCC elements exposed to erosive environments could be substantially prolonged.