Influence of Damage on the Effectiveness of SHCC Covers for Reducing Corrosion Rates in Reinforced-Concrete Structural Elements

Chloride-induced corrosion of rebars and resulting spalling and sectional loss is one of the most commonly observed deterioration mechanisms in reinforced-concrete (RC) structures. Strain-hardening cementitious composites (SHCC) offer a more durable alternative to concrete; however, cost and processing considerations limit the extensive application of SHCC. A prior study by the same authors has shown the feasibility of using SHCC only in the cover of RC structures to achieve the same reduction in corrosion rates, compared to concrete, as that achieved with structures made entirely of SHCC. This study investigates the influence of pre-existing, non-corrosion-related damage on the effectiveness of SHCC cover shells in limiting the corrosion-induced deterioration of RC columns. Potentiostatic accelerated corrosion of lab-scale cylinder specimens (150 mm × 300 mm) is used to simulate the corrosion-induced damage in RC columns. Two different configurations of these cylinder specimens are used in this study: one set of specimens with pre-damaged SHCC shells and second set with intact SHCC shells. The results show that the pre-damaged and intact SHCC shells have the same corrosion rates after initial micro-cracking in the intact shell. In other words, the pre-damaged SHCC shells are as effective in reducing the corrosion rate (compared to conventional concrete) as the intact SHCC shells.