On the use of Strain-Hardening Cementitious Composite covers to mitigate corrosion in reinforced concrete structures

Previous research has shown the effectiveness of Strain-Hardening Cementitious Composites (SHCC) in mitigating corrosion-induced damage in reinforced-concrete (RC) structural members due to the inherently limited crack widths of this material. The objective of this research is to investigate whether using SHCC only in the cover of a RC member is as effective in mitigating corrosion-induced damage as using SHCC in the entire member. Potentiostatic accelerated macro-cell corrosion experiments with wetting and drying cycles were used to simulate corrosion-induced damage in four different types of cylindrical specimens with steel reinforcement: type (a) made entirely with normal concrete, type (b) made entirely with SHCC, type (c) made with a conventional concrete core and an intact SHCC shell, and type (d) made with a conventional concrete core and a pre-damaged SHCC shell. Results show that the extent of corrosion damage, as measured by rebar mass loss over time, in types (b) and (c) is similar. Furthermore, in spite of the pre-existing damage, type (d) specimens offer corrosion protection similar to type (a) specimens. These results, combined with additional investigations on shrinkage and bond strengths between SHCC and concrete, demonstrate the feasibility of using precast SHCC shells for effective mitigation of corrosion in RC structures.